967 resultados para Permeability.
Resumo:
Micro-cracks appeared between the boundaries of different minerals of rocks during heating process, because of different thermal expansion coefficients of minerals, this phenomenon is referred as thermal cracking of rocks. The transport property of rocks was changed greatly due to the thermal cracking induced micro-cracks network, for example, the permeability of carbonate increases about 10 times when the temperature arise from room temperature to 110~120℃. Thermal cracking of rocks is a new research field of rock physics, which related closely to rock mechanics, mineralogy as well as experimental technology. The thermal cracking experiments of various rocks were performed, the rock macroscopic properties such as porosity, permeability, velocities of elastic waves in rocks were obtained as a function of temperature of heating process, and the microscopic structures of rocks were observed by using Scanning Electro-Microscope (SEM). The mechanism and the theoretical model of thermal cracking of rocks are given at present paper. Finally, the potential implication of rock thermal cracking to petroleum industry is discussed.
Resumo:
Productivity prediction is a serious factor to oil reservoir management and working out economic plans so that it is paid great attention to all the time. Gudao Oil Field, which has been yielding more than 100 million tons of crude oil accumulatively since it was put into developing in 1970's as a complete set of oil field, now entering double extra high water-bearing period after productivity construction, stable production and depletion stage. It's main layer series of development is thought to be type of channel sand reservoir in east China. Form channel sand reservoir in upper Guantao Group of Shengli Oil Field, there are several large oil fields such as Gudao, Gudong and Chengdao etc. with almost one-third reserves of whole Shengli Oil Field. It is considered the common characteristics in this area would be that the layer is less developed, the sand distribution is sporadic, the connectivity is weak, the heterogeneity is strong in plane, the oil layer is unconsolidated with big porosity, high permeability and serious sanding, and the oil is heavy. Because of the restricted factors to productivity of this kind of reservoir, it is very significant to study the productivity prediction this kind of reservoir. By selecting the upstream fluvial reservoir in Guantao Group of Neogene system as researching object, the author studied the forecasting technology with heterogeneous reservoir. Firstly, the author constructed the 3D subtle geological model quantificationally through researching exploitation geology in the way of combination of dynamic and static methods. Secondly, by the aid of dynamic material obtained while producing, the author analyzed the oil distribution law and influencing factors, then finished dynamic oil reservoir description on the basis of static oil reservoir description. Thirdly, via comparing and analyzing all the forecasting methods of productivity existed, the author developed a set of method to forecast productivity of single well and oil field which fit to channel sand reservoir. At last, under the support of ORACLE database, with the advanced computer technology, the author programmed the software called 'Channel Sand Reservoir Prediction System'. Up to now, this system has been putting into use in Gudao Oil Field and very successful.
Resumo:
Lukeqin arc belt is a compound structure generated by multi-movements and composed of 6 sub-structural zones, which are connected by Huoyanshan Mountain. General characteristics of the arc belt are multi-patterns of structure, multi-phases for petroleum, multi-types of trap and multi-layers for reservoirs. As a part of the eastern Lukeqin arc belt located on the south of Taibei depression, Lukeqin structural zone behaves as a complex faulted-fold zone, in which the formation and distribution of hydrocarbons are controlled by structures. As the dominant source of dynamics for the second migration of hydrocarbon, structure stress field is closely related with the potentials of hydrodynamics. Results derived from the simulations of stress field by finite element method indicate that the northwest tending faults prefer seal to the northeast tending ones. The reason is that the northwest tending faults were squeezed more strongly than the northeast tending ones. Therefor, the northeast tending faults become always the paths for oil to migrate southeastward. Lukeqin structural zone is the main site for oil to concentration because it is surrounded by high stress. Situated on the front of the foreland basin of Turpan-Hami, Lukeqing arc belt is a dam to hold back the southward migrating oil from Shengbei depression. The axis line of Shenquan-Shengnan-Yanmuxi, Lukeqin and Yubei controls the migrating paths and concentrating process of oil and gas. Results derived from stress simulation and structure analyses indicate consistently that both Yubei and Lukeqin structural zones are the favorite areas for oil to migrate. The generally southward paths for oil to migrate out of Taibei depression can be two ways. One of them is from Taibei depression to Yubei structural zone and the other is from Taibei depression to Lukeqin structural zone. By the both ways, oil migrated upward along the faults and southeastward along the structural axis to concentrate in either Permian or Triassic system. The newly ascertained path for oil migration, which is accurately southeastward instead of coarsely southward, indicates the directions for further explorations on the compound Lukeqin block zone. Five kinds of seal models of fault are all found in Lukeqin block zone by studying the seal features of faults occurred in the zone. Having studied the fault seal and their controlling factors by fuzzy set method, the paper deems that the northwest tended faults are better than the northeast tended ones for oil to concentrate. The most important factors to decide the seal extent of faults in this zone are the characteristics of main stress and fluids instead of capillary pressure differences between the two sides of fault and smear mud factors. There exist seal differences not only between the faults of different time but also between the sections within a fault due to the variation of depths, strata and positions. The general distribution rules of reservoirs were dominated by the seal characteristics of a fault during the time reservoirs formed. While the current features of fault seal decide the conservation of reservoirs and heights of oil accumulations. Seal or not of a fault is not absolute because the essential for fault to seal is the distribution of permeability of fault zone. Therefor, the multi cyclical activities of faults create the space-time variation of seal features of the fault. Totally, the seal extent of the faults within the area is not as perfect as to accumulate ordinary crude. Crude oil can only be sealed when it becomes viscous. Process for crude oil to become viscous and viscous happened strongly because of the fault-fold movements. Shallowly burying and even revealing of the objective layers of the reservoirs made the crude oil to be thickened by water washing biologically degradation and oxidation degradation. The northwestward deepening during or after the reservoir formation of the structural zone provided the power for oil to migrate one or more times. The main reason for oil accumulation is the formation of Lukeqin block zone during Xishanyao stage, middle Jurassic Period, Early Yanshanian Movement. While the main reason for reservoir conservation is the placidity of Triassic blocks after the formation of reservoirs. Contrasting to former opinions, it is concluded that the reservoirs in Lukeqin zone, including viscous reservoirs, were formed by one time but not more times. So the author proposes the opinion that the reservoirs of viscous oil were formed by viscous oil migration under the conditions of aptitude sets of fault seals controlled by fluid and other factors. To grope the distribution rules outside Taibei depression and discuss the formation mechanism of Anjurassic reservoirs, it is necessary to study the dominate factors for the formation of reservoirs in Lukeqin structural zone such as structural stress, fault seals and thickening mechanism of crude oil. Also, the necessary studies are the key to break through the Taibei depression and Anjurassic systems. Therefor, they are significant for the future exploration and reserve increasing of hydrocarbon within the Turpan-Hami basin. The paper studied the distribution rules of block reservoirs and forecasted the favorable zones for further exploration in Turpan-Hami basin. Conclusions can be useful for not only the exploration in the area but also the theory consult in the adjacent areas.
Resumo:
During the exploration of fractured reservoirs, worldwide difficult problems will be encountered: how to locate the fractured zones, how to quantitatively determine the azimuth, density, and distribution of the fractures, and how to compute the permeability and porosity of the fractures. In an endeavor to solve these problems, the fractured shale reservoir in SiKou area of ShengLi oil field was chosen as a study area. A study of seismic predictive theory and methods for solving problems encountered in fractured reservoir exploration are examined herein. Building on widely used current fractured reservoir exploration techniques, new seismic theories and methods focusing on wave propagation principles in anisotropic medium are proposed. Additionally, integrated new seismic data acquisition and processing methods are proposed. Based on research and application of RVA and WA methods from earlier research, a new method of acoustic impedance varying with azimuth (IPVA) creatively is put forth. Lastly combining drilling data, well log data, and geologic data, an integrated seismic predictive method for cracked reservoir bed was formed. A summary of the six parts of research work of this paper is outlined below. In part one, conventional geologic and geophysical prediction methods etc. for cracked reservoir exploration are examined, and the weaknesses of these approaches discussed. In part two, seismic wave propagation principles in cracked reservoirs are studied. The wave equation of seismic velocity and attenuation factor in three kinds of fracture mediums is induced, and the azimuth anisotropy of velocity and attenuation in fracture mediums is determined. In part three, building on the research and application of AVA and WA methods by a former researcher, a new method of acoustic impedance creatively varying with azimuth (IPVA) is introduced. A practical software package utilizing this technique is also introduced. In part four, Base on previously discussed theory, first a large full azimuth 3d seismic data (70km~2) was designed and acquired. Next, the volume was processed with conventional processing sequence. Then AVA, WA, and IPVA processing was applied, and finally the azimuth and density of the fractures were quantitatively determined by an integrated method. Predictions were supported by well data that indicate the approach is highly reliable. in part five, geological conditions contributing to cracked reservoir bed formation are analyzed in the LuoJia area resulting in the discovery that the main fractured zones are related to fault distribution in the basin, that also control the accumulation of the oil and gas, the generation mechanisms and types of fractured shale reservoirs are studied. Lastly, by using full 3D seismic attributes, azimuth and density of cracked reservoir zones are successfully quantitative predicted. Using an integrated approach that incorporates seismic, geologic and well log data, the best two fractured oil prospects in LouJia area are proposed. These results herein represent a break through in seismic technology, integrated seismic predictive theory, and production technology for fractured reservoirs. The approach fills a void that can be applied both inside China, and internationally. Importantly, this technique opens a new exploration play in the ShengLi oil field that while difficult has substantial potential. Properly applied, this approach could play an important role toward stabilizing the oil field' production. In addition, this technique could be extended fracture exploration in other oil fields producing substantial economic reward.
Resumo:
Based on the study of fluvial sandstone reservoir in upper of Guantao group in Gudao and Gudong oilfields, this paper first introduces A.D.Miall's(1996a) architectural-element analysis method that was summarized from ground outcrop scale into the reservoir formation research of the study area, more subtly divides sedimentary microfacies and establishes sedimentary model of research area.on this base, this paper summarizes the laws of residual oil distribution of fluvial formation and the control effect of sedimentary microfacies to residual oil distribution, and reveals residual oil formation mechanism. These results have been applied to residual oil production, and the economic effect is good. This paper will be useful for residual oil research and production and enhancement of oil recovery in similar reservoir. The major conclusions of this paper are as follows. 1. Using the architectural-element analysis method to the core data, a interfacial division scheme of the first to the dixth scale is established for the studied fluvial formation. 2.Seven architectural-elements are divided in upper of Guantao group of study area. The sandstone group 5~1+2 of Neogene upper Gutao group belongs to high sinuous fine grain meandering river, and the sandstone group 6 is sandy braided river. 3. Inter layer, the residual oil saturation of "non-main layer" is higher than "main layer", but the residual recoverable reserve of former is larger. Therefore, "main layer" is the main body of residual oil distribution. The upper and middle part of inner layer has lower permeability and strong seeping resistance. Addition to gravity effect in process of driving, its driving efficiency is low; residual oil saturation is high. Because of controlling of inside non-permeable interlayer or sedimentary construction, the residual oil saturation of non-driving or lower driving efficiency position also is high. On plane, the position of high residual oil saturation mostly is at element LV, CS, CH (FF), FF etc, Which has lower porosity and permeability, as well as lens sand-body and sand-body edge that is not controlled by well-net, non-perfect area of injection and production, lower press difference resort area of inter-well diffiuent-line and shelter from fault, local high position of small structure. 4.Microscopic residual oil mainly includes the non-moved oil in the structure of fine pore network, oil in fine pore and path, oil segment in pore and path vertical to flow direction, oil spot or oil film in big pore, residual oil in non-connective pore. 5.The most essential and internal controlling factor of fluvial formation residual oil distribution is sedimentary microfacies. Status of injection and production is the exterior controlling factor of residual oil distribution. 6. The controlling effect of formation sedimentary microfacies to residual oil distribution indicates inter-layer vertical sedimentary facies change in scale of injection and production layer-series, planar sedimentary face change and inner-layer vertical sedimentary rhythm and interbed in single layer to residual oil distribution. 7. It is difficult to clear up the inter-layer difference in scale of injection and production layer-series. The using status of minor layer is not good and its residual oil saturation is high relatively. It is obvious that inter-layer vertical sedimentary facies changes control inter-layer residual oil distribution at the same or similar conditions of injection and production. For fluvial formation, this vertical sedimentary facies change mainly is positive
gyration. Namely, from down to top, channel sediment (element CHL, LA) changes into over-bank sediment (element LV, CR, CS).
8. In water-injection developing process of transverse connecting fluvial sandstone oil formation, injection water always comes into channel nearby, and breaks through along
channel and orientation of high pressure gradient, does not expand into side of channel until pressure gradient of channel orientation changes into low. It brings about that water-driving status of over-bank sedimentary element formation (LV, CR, CS) is not good, residual oil saturation is high. In non-connective abandoned channel element (CH
Resumo:
This paper builds the model of oil accumulation and achieves the prediction of exploration goal. It uses multiple subject means, the ways of synthetic research and the viewpoint of analyzing genesis, with the academic guidance of sedimentology, structural geology, petroleum geology and geochemistry, the basis of strata sequence frame and structural frame, the frame of "four history" - the burying history, the structural history, the filling history and the evolving history of oil, the masterstroke of hydrocarbon's generation, migration and accumulation, the aim of revealing the genetic relation between mature source rock and oil reservoir in space and time. Some achievements and viewpoints in this study are following. 1. It is proposed that the structural evolution in this area had many periods, and the structural movement of the Xiazijie group telophase formed the structural pattern for the first time. 2. The character of strata sequence in this area is divided by the character of episodic cycle firstly. The study of dividing the facies of single well and the facies of well tie is based on the data of single well. The character of sedimentary facies is con-structed initially. 3. It is believed that Jiamuhe group is the main source rock, which can supply considerable oil and gas resources for the first time. Some criterions of source rock such as the type ,the abundance in Jiamuhe group are analysed. Using the thermal history of source rock, we drawn a conclusion that the original type of source rock in Jiamuhe group is II_1-III, and the abundance achived the level of good source rock, and this set of source rock had contributed to this area. 4. The reservoir strata in this area are assessed and analysed with the reservoir evaluation. There are multi-type reservoirs, such as volcanic lava facies, sedimentary clast facies, continental belch facies. The physical property in reservoir strata is characterized by low porosity and low permeability. The study of diagenetic stage show that the diageneses in Jiamuhe group is A-Bsubage, and the reservoir room is mainly secondary corroded hollow and cleft. 5. The synthetic research on oil system in Jiamuhe group is made for the first time. The type of petroleum system is divided , and we consider that the petroleum system of Jiamuhe group is at the reliable rank. There are two critical time in oil accumulation through studying the critical time of oil accumulation : the early generation of hydrocarbon is oil, and the later is gas. 6. The mechanism of accumulation is analysed. We consider that the accu-mulation of oil in this area has many periods, and the early generated hydrocarbon is expeled by the later , and formed the character of zonal distribution in planar. 7. A bran-new model of oil and gas is proposed. Beneficial enrichment area of oil and gas is analyzed, which can be divided into three sections: Section I can be divided into two sections: I_1 and I_2. The lower subgroup of Jiamuhe is covered by the triassic layer of I_1 section. Fault zone and near the foot wall of fault are charactered with thick phase belt. Then the cover capability in this area is relatively poor, oil can migrate into triassic layer by vertical or lateral migration , and forms I_1 Kelamayi triassic oil pool consequently. The lower subgroup of Jiamuhe is covered by the triassic layer of I_2 section ,which is charactered with thin phase belt. Then the cover capability in this area is relatively good, and forms I_1 Kelamayi triassic oil pool consequently. Section II can be divided into two sections: II_1-I_(I~2). The cover of Jiamuhe group in section II_1 is the low resistivity segment in Wuerhe group, which has thin lithology and poor porosity and permeability. Oil and gas in Jiamuhe group can be covered to form beneficial accumulation area. There are some wells in this area, such as Ke 007 well, 561 well. The thick phase belt layer of Wuerhe high resistivity segment in section II_2 has unconformable relation with Jiamuhe group. The cover ability of the high resistivity segment is poor, petroleum in Jiamuhe can migrate into Wuerhe layer vertically. This area is the beneficial area for accumulating petroleum in Wuerhe layer. there are some wells in this area, such as Ke 75 well, Ke 76 well, Ke 77 well, Ke 78 well, Ke 79 well. Section III can also be divided into two sections: III_1 and III_2. Wuerhe group in section III_1 has unconformable relation with Jiamuhe group. There is thick lithology and poor cover in Wuerhe group, but the strata sequence evolution character of upper subgroup in Jiamuhe group has determined that it has lateral and vertical cover ability. thus, this area is petroleum abundant belt of jiamuhe group, which has the trap. Section III_2 is an area controled by wedgeout of Fengcheng group, Fengcheng group in this area has quite thick lithology so that It has beneficial resevoir phase belt. It can accumulate oil in itself or accept some oil in Jiamuhe group. Jiamuhe group has some oil accumulation condition in this area. Thus, section III_2 is jiamuhe-Fengcheng multiple petroleum accumulation belt, such as Ke 80 well. 8. The goal of exploration is suggested: Depositional trap or combination trap is the important aspect in later exploration. Both types of traps are the goal of the next drilling: Fault block trap in the east of 576 well and the NO. 2 fault block trap in the north of Ke 102 well It is suggested that we should study the law of oil and gas in Jiamuhe group and enhance the study of combination in forming reservoir and trap scale. We do some lithology forecast and reservoir diatropic forecast in order to know the area of oil and gas.
Resumo:
The practice of coalbed methane development from home and abroad demonstrated Hydrogeological factor is one of the important geological factors influencing the coalbed methane productivity. The grasp of groundwater behavior feature is the prerequisite to success development of coalbed methane. Through researching the mechanism by which hydrodynamics factors control the storage and transportation of coalfen methane, the ground- water behavior reflecting the feature of coalbed, and mathematics model describing the production process of coalbed methane, this paper devoted to finding the law of groundwater behavior during the course of storage and production and gave hydrogeology theoretical support to the development of coalbed methane. This paper firstly studied hydrodynamic factors influencing the productivity of coalbed methane, based on the analysis of the relative feature of coalbed methane and that of it's reservoir. The productivity of coalbed methane is controlled by reservoir pressure、permeability and recharge conditions. Reservoir pressure, the key factor controlling gas content of coalbed, is ruled by the history of hydrodynamic and current hydrogeological conditions. It indirectly controls the poductivity through influencing the permeability. The permeability of coalbed is the direct factor controlling the productivity. The recharge conditions controls the productivity through influencing initial reservoir pressure and the descend of reservoir pressure during development of coalbed methane. The field of hydrodynamic and the field of hydrochemistry can be used to identified the flow model of groundwater and the coalbed feature can be deducted by the hydraulic gradient、pressure compartment and hydrochemistry. The production of coalbed methane is a complex physical process which including the mutual action between water、solid and gas. This paper studied the mechanism of water-solid action and that of water-gas action, conducted the controlling equation describing the complex process and gave the corresponding mathematics model with its solution by finite-Element method. Finally, this paper analysised the prospective of coalbed methane development of the south section of Hongguo area in Yizikong basin and put emphasis on the analysis of productivity of liangshan and jingzhuping blocks.
Resumo:
Natural gas pays more important role in the society as clean fuel. Natural gas exploration has been enhanced in recent years in many countries. It also has prospective future in our country through "85" and "95" national research. Many big size gas fields have been discovered in different formations in different basins such as lower and upper Paleozoic in Erdos basin, Tertiary system in Kuche depression in Tarim basin, Triassic system in east of Sichuan basin. Because gas bearing basins had been experienced multiple tectogenesis. The characteristics of natural gases usually in one gas field are that they have multiple source rocks and are multiple maturities and formed in different ages. There has most difficult to research on the gas-rock correlation and mechanism of gas formation. Develop advanced techniques and methods and apply them to solve above problems is necessary. The research is focused on the critical techniques of geochemistry and physical simulation of gas-rock correlation and gas formation. The lists in the following are conclusions through research and lots of experiments. I 8 advanced techniques have been developed or improved about gas-rock correlation and gas migration, accumulation and formation. A series of geochemistry techniques has been developed about analyzing inclusion enclave. They are analyzing gas and liquid composition and biomarker and on-line individual carbon isotope composition in inclusion enclave. These techniques combing the inclusion homogeneous temperature can be applied to study on gas-rock correlation directly and gas migration, filling and formation ages. Technique of on-line determination individual gas carbon isotope composition in kerogen and bitumen thermal pyrolysis is developed. It is applied to determine the source of natural is kerogen thermal degradation or oil pyrolysis. Method of on-line determination individual gas carbon isotope composition in rock thermal simulation has being improved. Based on the "95"former research, on-line determination individual gas carbon isotope composition in different type of maceral and rocks thermal pyrolys is has been determined. The conclusion is that carbon isotope composition of benzene and toluene in homogenous texture kerogen thermal degradation is almost same at different maturity. By comparison, that in mixture type kerogen thermal pyrolysis jumps from step to step with the changes of maturity. This conclusion is a good proof of gas-rock dynamic correlation. 3. Biomarker of rock can be determined directly through research. It solves the problems such as long period preparing sample, light composition losing and sample contamination etc. It can be applied to research the character of source rock and mechanism of source rock expulsion and the path of hydrocarbon migration etc. 4. The process of hydrocarbon dynamic generation in source rock can be seen at every stage applying locating observation and thermal simulation of ESEM. The mechanism of hydrocarbon generation and expulsion in source rock is discussed according to the experiments. This technique is advanced in the world. 5. A sample injection system whose character is higher vacuum, lower leaks and lower blank has been built up to analyze inert gas. He,Ar,Kr and Xe can be determined continuously on one instrument and one injection. This is advanced in domestic. 7. Quality and quantity analysis of benzene ring compounds and phenolic compounds and determination of organic acid and aqueous gas analysis are applied to research the relationship between compounds in formation water and gas formation. This is another new idea to study the gas-rock correlation and gas formation. 8. Inclusion analysis data can be used to calculate the Paleo-fluid density, Paleo-geothermal gradient and Paleo-geopressure gradient and then to calculate the Paleo-fluid potential. It's also a new method to research the direction of hydrocarbon migration and accumulation. 9. Equipment of natural gas formation simulation is produced during the research to probe how the physical properties of rock affect the gas migration and accumulation and what efficiency of gas migrate and factors of gas formation and the models of different type of migration are. II study is focused on that if the source rocks of lower Paleozoic generated hydrocarbon and what the source rocks of weathered formation gas pool and the mechanism of gas formation are though many advanced techniques application. There are four conclusions. 1.The maturity of Majiagou formation source rocks is higher in south than that in north. There also have parts of the higher maturity in middle and east. Anomalous thermal pays important role in big size field formation in middle of basin. 2. The amount of gas generation in high-over maturity source rocks in lower Paleozoic is lager than that of most absorption of source rocks. Lower Paleozoic source rocks are effective source rocks. Universal bitumen exists in Ordovician source rocks to prove that Ordovician source rocks had generated hydrocarbon. Bitumen has some attribution to the middle gas pool formation. 3. Comprehensive gas-rock correlation says that natural gases of north, west, south of middle gas field of basin mainly come from lower Paleozoic source rocks. The attribution ratio of lower Paleozoic source rocks is 60%-70%. Natural gases of other areas mainly come from upper Paleozoic. The attribution ratio of upper Paleozoic source rocks is 70%. 4. Paleozoic gases migration phase of Erdos basin are also interesting. The relative abundance of gasoline aromatic is quite low especially toluene that of which is divided by that of methyl-cyclohexane is less than 0.2 in upper Paleozoic gas pool. The migration phase of upper Paleozoic gas may be aqueous phase. By comparison, the relative abundance of gasoline aromatic is higher in lower Paleozoic gas. The distribution character of gasoline gas is similar with that in source rock thermal simulation. The migration phase of it may be free phase. IH Comprehensive gas-rock correlation is also processed in Kuche depression Tarim basin. The mechanism of gas formation is probed and the gas formation model has been built up. Four conclusions list below. 1. Gases in Kuche depression come from Triassic-Jurassic coal-measure source rocks. They are high-over maturity. Comparatively, the highest maturity area is Kelasu, next is Dabei area, Yinan area. 2. Kerogen thermal degradation is main reason of the dry gas in Kuche depression. Small part of dry gas comes from oil pyrolysis. VI 3.The K12 natural gas lays out some of hydro-gas character. Oil dissolved in the gas. Hydro-gas is also a factor making the gas drier and carbon isotope composition heavier. 4. The mechanism and genesis of KL2 gas pool list as below. Overpressure has being existed in Triassic-Jurassic source rocks since Keche period. Natural gases were expulsed by episode style from overpressure source rocks. Hetero-face was main migration style of gas, oil and water at that time. The fluids transferred the pressure of source rocks when they migrated and then separated when they got in reservoir. After that, natural gas migrated up and accumulated and formed with the techno-genesis. Tectonic extrusion made the natural gas overpressure continuously. When the pressure was up to the critical pressure, the C6-C7 composition in natural gas changed. The results were that relative abundance of alkane and aromatic decreased while cycloalkane and isoparaffin increased. There was lots of natural gas filling during every tectonic. The main factors of overpressure of natural gas were tectonic extrusion and fluid transferring pressure of source rocks. Well preservation was also important in the KL2 gas pool formation. The reserves of gas can satisfy the need of pipeline where is from west to east. IV A good idea of natural gas migration and accumulation modeling whose apparent character is real core and formation condition is suggested to model the physical process of gas formation. Following is the modeling results. 1. Modeling results prove that the gas accumulation rule under cap layer and gas fraction on migration path. 2. Natural gas migration as free phase is difficult in dense rock. 3. Natural gases accumulated easily in good physical properties reservoirs where are under the plugging layer. Under the condition of that permeability of rock is more than 1 * 10~(-3)μm~(-1), the more better the physical properties and the more bigger pore of rock, the more easier the gas accumulation in there. On the contrary, natural gas canonly migrate further to accumulate in good physical properties of rock. 4. Natural gas migrate up is different from that down. Under the same situation, the amount of gas migration up is lager than that of gas migration down and the distance of migration up is 3 times as that of migration down. 5. After gas leaks from dense confining layer, the ability of its dynamic plug-back decreased apparently. Gas lost from these arils easily. These confining layer can confine again only after geology condition changes. 6. Water-wetted and capillary-blocking rocks can't block water but gases generally. The result is that water can migrate continuously through blocking rocks but the gases stay under the blocking rocks then form in there. The experiments have proved the formation model of deep basin gas.
Resumo:
The dynamic prediction of complex reservoir development is one of the important research contents of dynamic analysis of oil and gas development. With the increase development of time, the permeabilities and porosities of reservoirs and the permeability of block reservoir at its boundaries are dynamically changing. How to track the dynamic change of permeability and porosity and make certain the permeability of block reservoir at its boundary is an important practical problem. To study developing dynamic prediction of complex reservoir, the key problem of research of dynamic prediction of complex reservoir development is realizing inversion of permeability and porosity. To realize the inversion, first of all, the fast forward and inverse method of 3-dimension reservoir simulation must be studied. Although the inversion has been widely applied to exploration and logging, it has not been applied to3-dimension reservoir simulation. Therefore, the study of fast forward and inverse method of 3-dimension reservoir simulation is a cutting-edge problem, takes on important realistic signification and application value. In this dissertation, 2-dimension and 3-dimension fluid equations in porous media are discretized by finite difference, obtaining finite difference equations to meet the inner boundary conditions by Peaceman's equations, giving successive over relaxation iteration of 3-dimension fluid equations in porous media and the dimensional analysis. Several equation-solving methods are compared in common use, analyzing its convergence and convergence rate. The alternating direction implicit procedure of 2-dimension has been turned into successive over relaxation iteration of alternating direction implicit procedure of 3-dimension fluid equations in porous media, which possesses the virtues of fast computing speed, needing small memory of computer, good adaptability for heterogeneous media and fast convergence rate. The geological model of channel-sandy reservoir has been generated with the help of stochastic simulation technique, whose cross sections of channel-sandy reservoir are parabolic shapes. This method makes the hard data commendably meet, very suit for geological modeling of containing complex boundary surface reservoir. To verify reliability of the method, theoretical solution and numerical solution are compared by simplifying model of 3-dimension fluid equations in porous media, whose results show that the only difference of the two pressure curves is that the numerical solution is lower than theoretical at the wellbore in the same space. It proves that using finite difference to solve fluid equations in porous media is reliable. As numerical examples of 3-dimension heterogeneous reservoir of the single-well and multi-well, the pressure distributions have been computed respectively, which show the pressure distributions there are clearly difference as difference of the permeabilities is greater than one order of magnitude, otherwise there are no clearly difference. As application, the pressure distribution of the channel-sandy reservoir have been computed, which indicates that the space distribution of pressure strongly relies on the direction of permeability, and is sensitive for space distributions of permeability. In this dissertation, the Peaceman's equations have been modified into solving vertical well problem and horizontal well problem simultaneously. In porous media, a 3D layer reservoir in which contain vertical wells and horizontal wells has been calculated with iteration. For channel-sandy reservoir in which there are also vertical wells and horizontal wells, a 3D transient heterogeneous fluid equation has been discretized. As an example, the space distribution of pressure has been calculated with iteration. The results of examples are accord with the fact, which shows the modification of Peaceman's equation is correct. The problem has been solved in the space where there are vertical and horizontal wells. In the dissertation, the nonuniform grid permeability integration equation upscaling method, the nonuniform grid 2D flow rate upscaling method and the nonuniform grid 3D flow rate upscaling method have been studied respectively. In those methods, they enhance computing speed greatly, but the computing speed of 3D flow rate upscaling method is faster than that of 2D flow rate upscaling method, and the precision of 3D flow rate upscaling method is better than that of 2D flow rate upscaling method. The results also show that the solutions of upscaling method are very approximating to that of fine grid blocks. In this paper, 4 methods of fast adaptive nonuniform grid upscaling method of 3D fluid equations in porous media have been put forward, and applied to calculate 3D heterogeneous reservoir and channel-sandy reservoir, whose computing results show that the solutions of nonuniform adaptive upscaling method of 3D heterogeneous fluid equations in porous media are very approximating to that of fine grid blocks in the regions the permeability or porosity being abnormity and very approximating to that of coarsen grid blocks in the other region, however, the computing speed of adaptive upscaling method is 100 times faster than that of fine grid block method. The formula of sensitivity coefficients are derived from initial boundary value problems of fluid equations in porous media by Green's reciprocity principle. The sensitivity coefficients of wellbore pressure to permeability parameters are given by Peaceman's equation and calculated by means of numerical calculation method of 3D transient anisotropic fluid equation in porous media and verified by direct method. The computing results are in excellent agreement with those obtained by the direct method, which shows feasibility of the method. In the dissertation, the calculating examples are also given for 3D reservoir, channel-sandy reservoir and 3D multi-well reservoir, whose numerical results indicate: around the well hole, the value of the sensitivity coefficients of permeability is very large, the value of the sensitivity coefficients of porosity is very large too, but the sensitivity coefficients of porosity is much less than the sensitivity coefficients of permeability, so that the effect of the sensitivity coefficients of permeability for inversion of reservoir parameters is much greater than that of the sensitivity coefficients of porosity. Because computing the sensitivity coefficients needs to call twice the program of reservoir simulation in one iteration, realizing inversion of reservoir parameters must be sustained by the fast forward method. Using the sensitivity coefficients of permeability and porosity, conditioned on observed valley erosion thickness in wells (hard data), the inversion of the permeabilities and porosities in the homogeneous reservoir, homogeneous reservoir only along the certain direction and block reservoir are implemented by Gauss-Newton method or conjugate gradient method respectively. The results of our examples are very approximating to the real data of permeability and porosity, but the convergence rate of conjugate gradient method is much faster than that of Gauss-Newton method.
Resumo:
This article is an important part of "95" technological subject of SINOPEC. It has a large number of difficulties and workloads, and has significant theoretical meanings and practical value. The study area is composed of sandstone & conglomerate reservoir of alluvial fan & fan delta, which belong to Sha3 lower member and Sha4 upper member of lower tertiary of Yong'an Town Oilfield in Dongying Depression. The target stataum develops in the hanging wall of the synsedimentary fault in the scarp zone of Dongying Depression. The frequently intense movements result in the variation of sandstone and conglomerate reservoir and the evolution of the time and space of Sha3 lower member and Sha4 upper member in Yong'an Town Oilfield. As a result, it is difficult for the individual reservoir correlation at the root of fan, which bring about a tackle problem for the exploitation of oilfield. In this background, the research of fluid units will be more difficult. In this article, the new concepts, the new methods, and the new techniques of sedimentology, petroleum geology, reservoir geology, physics of crystal surface, dynamic & static state reservoir description and well logging geology are synthetically applied, and the computer technology are made full uses of, and the identifying, dividing and appraising of the two-formation-type sandstone & conglomerate reservoir fluid units of Sha3 lower member and Sha4 upper member systemically analyzed in Yong'an Town Oilfield, Dongying Depression. For the first time, the single-well model, the section model, the plane model, the nuclear magnetism log model, the microcosmic network model, the 4-D geology model and the simulation model of the two-formation-type reservoir fluid units of the of sandstone & conglomerate reservoir of Sha3 lower member and Sha4 upper member are established, and the formative mechanism and distributing & enrichment laws of oil-gas of the two type of sandstone and conglomerate reservoir fluid units are revealed. This article established the optimizing, identifying, classifying and appraising standard of the two-formation-type reservoir fluid units of the of sandstone and conglomerate reservoir of Sha3 lower member and Sha4 upper member, which settles the substantial foundations for static state model of the fluid units, reveals the macroscopic & microcosmic various laws of geometrical static state of the fluid units, and instructs the oil exploitation. This article established static state model of the two-formation-type sandstone and conglomerate reservoir fluid units by using the multi-subject theories, information and techniques, and reveals the geometrical configuration, special distribution and the oil-gas enrichment laws of the sandstone and conglomerate reservoir fluid units. For the first time, we established the nuclear magnetism log model of the two-formation-type sandstone and conglomerate reservoir of Sha3 lower member and Sha4 upper member, which reveals not only the character and distributing laws of the porosity and permeability, bat also the formation and distribution of the movable fluid. It established six type of microcosmic net model of the two-formation-type sandstone and conglomerate reservoir of Sha3 lower member and Sha4 upper member in the working area by using the advanced theories, such as rock thin section, SEM, image analysis, intrusive mercury, mold, rock C.T. measure & test image etc., which reveals the microcosmic characteristic of porosity & throat, filterate mode and microcosmic oil-gas enrichment laws of the sandstone and conglomerate reservoir. For the first time, it sets up the 4-D model and mathematic model of the sandstone and conglomerate reservoir, which reveals the distributing and evolving laws of macroscopic & microcosmic parameters of the two-formation-type sandstone and conglomerate reservoir and oil-gas in 4-D space. At the same time, it also forecasts the oil-gas distribution and instructs the oilfield exploitation. It established reservoir simulation model, which reveals the filterate character and distributing laws of oil-gas in different porosity & throat net models. This article established the assistant theories and techniques for researching, describing, indicating and forecasting the sandstone and conglomerate reservoir fluid units, and develops the theories and techniques of the land faces faulted basin exploitation geology. In instructing oilfield exploitation, it had won the notable economic & social benefits.
Resumo:
The discovery of the highly productive Renqiu buried hill reservoir in Bohai Bay Basin in 1975 started the high tide of finding buried hill reservoirs in China and their research. As the advance of E&P technologies, the study of buried hill reservoir in China had a qualitative leap. The reservoir description and some other aspects of development have reached or approached to the international leading level. However, some core techniques for reservoir study such as structure & faulting system study, formation prediction and connection study and heterogeneous model's construction could not completely carry out the quantitative or accurate reservoir description, e. g. the areal distribution of porosity, permeability and oil saturation. Especially, the modeling for reservoir simulation is still wandering in the stage of simplicity. The inaccurate understanding of geology could not derive 3D heterogeneous geological model that can reveal the actual underground situation thus could not design practical and feasible oilfield development plan. Therefore, the problems of low oil recovery rate, low recovery factor and poor development effectiveness have not been solved. The poor connection of the reservoir determined that waterflooding could not get good development effect and the production had to depend on the reservoir elastic energy, and this will bring big difficulty for development modification and improvement of oil recovery. This study formed a series of techniques for heterogeneous model research that can be used to construct heterogeneous model consistent with the reservoir geology. Thus the development effectiveness, success ratio of drilling and percent of producing reserves can be enhanced. This study can make the development of buried hill reservoir be of high recovery rate and high effect. The achievements of this study are as follows: 1. Evaluated the resources, summarized the geological characteristics and carried out the reservoir classification of the buried hill reservoirs in Shengli petroliferous area; 2. Established the markers for stratigraphical correlation and formed the correlation method for complex buried hill reservoirs; 3. Analyzed the structural features of the buried hill reservoirs, finished the structure interpretation and study of faulting system using synthetic seismograms, horizontal slices and coherent analysis, and clarified structural development history of the buried hill reservoirs in Shengli petroliferous area; 4. Determined the 3 classes and 7 types of pore space and the main pore space type, the logging response characteristics and the FMI logging identified difference between artificial and natural fractures by the comprehensive usage of core analysis, other lab analyses, conventional logging, FMI logging and CMR logging; 5. Determined the factors controlled the growth of the fractures, vugs and cavities, proposed the main formation prediction method for buried hill reservoir and analyzed their technical principium and applicability, and formed the seismic method and process for buried hill reservoir description; 6. Established the reserve calculation method for buried hill reservoirs, i. e. the reserves of fractures and matrix are calculated separately; the recoverable reserves are calculated by decline method and are classified by the SPE criteria; 7. Studied restraining barriers and the sealing of the faults thus clarified the oil-bearing formations of the buried hill reservoirs, and verified the multiple reservoir forming theory; 8. Formed reasonable procedure of buried hill reservoir study; 9. Formed the 3 D modeling technology for buried hill reservoirs; 10. Studied a number of buried hill blocks on the aspects of reservoir description, reservoir engineering and development plan optimization based on the above research and the profit and social effect are remarkable.
Resumo:
Gas condensate reservoir research involves not only structure sediment reservoir liquid properties characterization but also the change of the temperature field, the change of the pressure field, the change of liquid phase and the reservoir sensitivity. To develop the gas condensate reservoir effectively .we must depict the static properties of the oil and gas system ,build exact and comprehensive parameter field, predict the rule of dynamic change and do the necessary reservoir characterization development plan dynamic prediction direct production. The MoBei Oil and Gas Field is the first gas condensate reservoirs which is found by the Xinjiang Oil Field Company in ZhunGaEr basin belly.it has deserved some knowledge after prospect evaluation, the MoBei Oil and Gas Field start development ,it is one of the important development blocks of Xinjiang Oil Field Company productivity constuction. During its development , it gradually appears some problems, such as complex oil and gas phase, great change of reservoir stretch .uncertain reservoir type and scale, controling its development strategy and plan difficultly. To deserve the high efficient development and long-term stable production of the gas condensate reservoir, it is necessary to characterize it systematically and form a suit of scientific development strategy. This thesis take the MoBei zone SanGongHe sand group reservoir as research object, applied advanced log techniques ,such as the nulear magnetism log ,MDT testing .etc. After comprehensive research of loging geology information, set up a suit of methods to identify oil gas water layer .these methods can identify the gas-oil level and the oil-water level. On the basis of reasonable development object system, according fine structure interpretation and structure modeling. build any oil water column height of the reservoir accurately. Through carefully analysis of the basic theory and method of reservoir seism prediction. optimize a reservoir inversion method .technique. software fitting the research region aiming strata, set up the GR field, porosity field, Rt field, impedence field .permeability field and initial oil saturation field, generating the base of quantity reservoir characterization. Discussing the characteristic of reservoir fluid and the movement and reallocating of muti-phase fluid in reservoir. And according the material of 100 soviet gas condensate reservoir ,build the recognition method and mode of gas condensate reservoir. Building the 3D geology model ,carry on the static and production evaluation, propose the development strategy and improve plan , provide the base of increasing reserves and advancing production and enriching the prospect development theory of the gas condensate reservoi
Resumo:
This paper is belonging to Chinese Petrochemical Corporation's science and technology project. Although it is difficult, it has important theoretical and practical value. The study was aimed to reveal inhomogeneity of two kinds of reservoirs of fan-shaped delta and braided river by using new theories, new methods and new technology about 3-D model building and reservoir knowledge repository throughout the world, and to build reservoir knowledge repository and 3-D geological model which would predict the type of sand body forming reason and distribution rule in order to improve exploration result in Qiuling oil fields. Multi-discipline theories such as petroleum structure geology, reservoir geology, petroleum geology, sequence geology, logging geology, geomathematics and so on are used as guide. The information of geology, seism, logging and production test is combined. Outcrop area and overlap area are combined. By making full use of computer, stable structure, reservoir geometric shape, spatial distribution and inhomogeneity of bed of interest are investigated, described and characterized. Petroleum pool 3-D static geological model of reservoir knowledge repository was built. Sand body distribution was predicted. It has guided oil development, lowed the investment and improved development benefits. Several results are achieved as follows: (1) Strata framework of Sanjianfang group in Qiuling oil field has been established. (2) Geometric shape, spatial distribution and evolve rule of two different forming reason's reservoir of fan-shaped delta and braided river of Sanjianfang group in Qiuling oil field are discussed. (3) The two kinds of reservoirs have lower pore and permeability and very strong inhomogeneity. (4) Reservoir knowledge repository of two different forming reasons has been built of Sanjianfang group, which includes 5 geological knowledge sublibrary. (5) 3-D geological model of two kinds of forming reason's reservoirs has been built. (6) That same sequence instruction a simulation and probability field were used to predict sand body of Sanjianfang group was put forward. Coincidence rate is high after production test. It shows this method has great popularity value. (7) A set of theories, methods and technologies of knowledge repository of two kinds of reservoir of braided river and fan-shaped delta and 3-D geological model building were finished. (8) A set of theories, methods and technologies of investigating, describing, characterizing and predicting two kinds of oil pool were developed. It gets noticeable economic benefit after exploration. Theory and method about extrusion basin are developed.
Resumo:
Seepage control in karstic rock masses is one of the most important problems in domestic hydroelectric engineering and mining engineering as well as traffic engineering. At present permeability assessment and leakage analysis of multi-layer karstic rock masses are mainly qualitative, while seldom quantitative. Quantitative analyses of the permeability coefficient and seepage amount are conducted in this report, which will provide a theoretical basis for the study of seepage law and seepage control treatment of karstic rocks. Based on the field measurements in the horizontal grouting galleries of seepage control curtains on the left bank of the Shuibuya Hydropower Project on the Qingjiang river, a hydraulic model is established in this report, and the computation results will provide a scientific basis for optimization of grouting curtain engineering. Following issues are addressed in the report. (1) Based on the in-situ measurements of fissures and karstic cavities in grouting galleries, the characteristics of karstic rock mass is analyzed, and a stochastic structural model of karstic rock masses is set up, which will provide the basis for calculation of the permeability and leakage amount of karstic rock mass. (2) According to the distribution of the measured joints in the grouting galleries and the stochastic results obtained from the stochastic structural model of karstic rock mass between grouting galleries, a formula for computation of permeability tensor of fracturing system is set up, and a computation program is made with Visual Basic language. The computation results will be helpful for zoning of fissured rock masses and calculation of seepage amount as well as optimization of seepage control curtains. (3) Fractal theory is used to describe quantitatively the roughness of conduit walls of karstic systems and the sinuosity of karstic conduits. It is proposed that the roughness coefficient of kastic caves can be expressed by both fractal dimension Ds and Dr that represent respectively the extension sinuosity of karstic caves and the roughness of the conduit walls. The existing formula for calculating the seepage amount of karstic conduits is revised and programmed. The seepage amount of rock masses in the measured grouting galleries is estimated under the condition that no seepage control measures are taken before reservoir impoundment, and the results will be helpful for design and construction optimization of seepage curtains of the Shuibuya hydropower project. This report is one part of the subject "Karstic hydrogeology and the structural model and seepage hydraulics of karstic rock masses", a sub-program of "Study on seepage hydraulics of multi-layer karstic rock masses and its application in seepage control curtain engineering", which is financially supported by the Hubei Provincial key science and technology programme.
Resumo:
Guided by geological theories, the author analyzed factual informations and applied advanced technologies including logging reinterpretation, predicting of fractal-based fracture network system and stochastic modeling to the low permeable sandstone reservoirs in Shengli oilfield. A new technology suitable for precious geological research and 3D heterogeneity modeling was formed through studies of strata precious correlation, relation between tectonic evolution and fractural distribution, the control and modification of reservoirs diagenesis, logging interpretation mathematical model, reservoir heterogeneity, and so on. The main research achievements are as follows: (1) Proposed four categories of low permeable reservoirs, which were preferable, general, unusual and super low permeable reservoir, respectively; (2) Discussed ten geological features of the low permeable reservoirs in Shengli area; (3) Classified turbidite fan of Es_3 member of the Area 3 in Bonan oilfield into nine types of lithological facies, and established the facies sequences and patterns; (4) Recognized that the main diagenesis were compaction, cementation and dissolution, among which the percent compaction was up to 50%~90%; (5) Divided the pore space in ES_3 member reservoir into secondary pores with dissolved carbonate cement and residual intergranular pores strongly compacted and cemented; (6) Established logging interpretation mathematical model guided by facies- control modeling theory; (7) Predicted the fracture distribution in barriers using fractal method; (8) Constructed reservoir structural model by deterministic method and the 3D model of reservoir parameters by stochastic method; (9) Applied permeability magnitudes and directions to describe the fractures' effect on fluid flow, and presented four different fractural configurations and their influence on permeability; (10) Developed 3D modeling technology for the low permeable sandstone reservoirs. The research provided reliable geological foundation for the establishment and modification of development plans in low permeable sandstone reservoirs, improved the development effect and produced more reserves, which provided technical support for the stable and sustained development of Shengli Oilfield.