二氧化碳收集利用与处置技术分析

化石燃料的燃烧是百余年来大气中二氧化碳（CO2）浓度增加的主要原因。CO2的收集和处置则是抑制这一趋势的有效途径。本文通过对现有收集利用和处置技术的分析，认为火电厂是收集CO2的重点考虑对象；CO2用于三次采油及天然气回收在技术上和经济上比较可行；蓄水层储气前景广阔值得研究；深海处置有待进一步探索；CO2用于置换开采天然气水合物也是很有前景的方案。

碎屑岩储层低电阻率油层识别方法与应用——以济阳坳陷为例

So far, there is no methods of logging interpretation effective enough to identify a low resistivity payzone since its resistivity value almost equals to that of an aquifer although many low-resistivity payzones have been found in lots of petroliferous basins worldwide. After a thorough study on those technical difficulties of the logging interpretation for the low-resistivity payzones, some corresponding resolutions have been put forward in this paper. In order to reveal its microscopic mechanism, researches on the discovered low-resistivity payzones have been carried on with analyses of core and lab test data, thus main influencing factors of the low-resistivity reservoirs have been pointed out including conductivity minerals, clay minerals, fluids, porosity and pore structure. In order to make clear the degree of influence of those reservoir factors on resistivity logging(log), lab studies and numeral simulations have been done with the typical core and formation water samples, therefore, their influence degrees have ascertained quantitatively or semi-quantitatively. The distribution law and possible distribution areas of the low-resistivity payzones in Jiyang Depression have been figured out firstly after the macroscopic geology origins (sedimentation, dynamic accumulation process, diagenesis etc.) in the area have been studied. In order to resolve the problem of difficult logging-interpretation, methods of interpretation and identification have been brought forward creatively according to the low-resistivity payzone type ascribed to macroscopic geology laws and to the combined features of logging traces, after a systemic summary of different responses of logging caused by different microscopic mechanism. Those methods have been applied in Dongying and Huimin Sag of Shengli Exploration Area, precision of identification of the low-resistivity payzones improved effectively and good economic attraction prove their great prospect.

二氧化碳在孔隙咸水层中多相流动数值模拟研究

There has been a growing concern about the use of fossil fuels and its adverse effects on the atmospheric greenhouse and ecological environment. A reduction in the release rate of CO2 into the atmosphere poses a major challenge to the land ecology of China. The most promising way of achieving CO2 reduction is to dispose of CO2 in deep saline aquifers. Deep aquifers have a large potential for CO2 sequestration in geological medium in terms of volume and duration. Through the numerical simulation of multiphase flow in a porous media, the transformation and motion of CO2 in saline aquifers has been implemented under various temperature and hydrostatic pressure conditions, which plays an important role to the assessment of the reliability and safety of CO2 geological storage. As expected, the calculated results can provide meaningful and scientific information for management purposes. The key problem to the numerical simulation of multiphase flow in a porous media is to accurately capture the mass interface and to deal with the geological heterogeneity. In this study, the updated CE/SE (Space and time conservation element and solution element) method has been proposed, and the Hybrid Particle Level Set method (HPLS) has extended for multiphase flows in porous medium, which can accurately trace the transformation of the mass interface. The benchmark problems have been applied to evaluate and validate the proposed method. In this study, the reliability of CO2 storage in saline aquifers in Daqingzi oil field in Sunlong basin has been discussed. The simulation code developed in this study takes into account the state for CO2 covering the triple point temperature and pressure to the supercritical region. The geological heterogeneity has been implemented, using the well known geostatistical model (GSLIB) on the base of the hard data. The 2D and 3D model have been set up to simulate the CO2 multiphase flow in the porous saline aquifer, applying the CE/SE method and the HPLS method .The main contents and results are summarized as followings. (1) The 2D CE/SE method with first and second –order accuracy has been extended to simulate the multiphase flow in porous medium, which takes into account the contribution of source and sink in the momentum equation. The 3D CE/SE method with the first accuracy has been deduced. The accuracy and efficiency of the proposed CE/SE method have been investigated, using the benchmark problems. (2) The hybrid particle level set method has been made appropriate and extended for capturing the mass interface of multiphase flows in porous media, and the numerical method for level set function calculated has been formulated. (3) The closed equations for multiphase flow in porous medium has been developed, adept to both the Darcy flow and non-Darcy flow, getting over the limitation of Reynolds number to the calculation. It is found that Darcy number has a decisive influence on pressure as well as velocity given the Darcy number. (4) The new Euler scheme for numerical simulations of multiphase flows in porous medium has been proposed, which is efficient and can accurately capture the mass interface. The artificial compressibility method has been used to couple the velocities and pressure. It is found that the Darcy number has determinant effects on the numerical convergence and stability. In terms of the different Darcy numbers, the coefficient of artificial compressibility and the time step have been obtained. (5) The time scale of the critical instability for critical CO2 in the saline aquifer has been found, which is comparable with that of completely CO2 dissolved saline aquifer. (6) The concept model for CO2 multiphase flows in the saline aquifer has been configured, based on the temperature, pressure, porosity as well as permeability of the field site .Numerical simulation of CO2 hydrodynamic trapping in saline aquifers has been performed, applying the proposed CE/SE method. The state for CO2 has been employed to take into account realistic reservoir conditions for CO2 geological sequestration. The geological heterogeneity has been sufficiently treated , using the geostatistical model. (7) It is found that the Rayleigh-Taylor instability phenomenon, which is associated with the penetration of saline fluid into CO2 fluid in the direction of gravity, has been observed in CO2 multiphase flows in the saline aquifer. Development of a mushroom-type spike is a strong indication of the formation of Kelvin-Helmholtz instability due to the developed short wavelength perturbations present along the interface and parallel to the bulk flow. Additional key findings: the geological heterogeneity can distort the flow convection. The ascending of CO2 can induce the persistent flow cycling effects. The results show that boundary conditions of the field site have determinant effects on the transformation and motion of CO2 in saline aquifers. It is confirmed that the proposed method and numerical model has the reliability to simulate the process of the hydrodynamic trapping, which is the controlling mechanism for the initial period of CO2 storage at time scale of 100 years.

关中盆地东部浅层地下水水化学与CFC年龄研究

Hydrochemistry, isotope and CFCs were used to determine groundwater transport in the eastern part of the Guanzhong Basin. In this paper, we systematically collected water samples and measured major ions, 2H-18O and CFCs in surface water and shallow groundwater. Groundwater in this region can be divided into three categories based on total dissolved solids (TDS): fresh water with TDS < 1g/L, brackish water with TDS between 1～3g/L, and saline water with TDS > 3g/L. Saline water is mainly located in the north of the Wei River, and saline groundwater is not in the south. Tributaries in the south of the Wei River and underlain groundwater had similar 2H-18O values, indicating a close hydraulic connection between them. Tributaries in the north of the Wei River characterized certain extent of evaporation, and 2H-18O values deviated to a differing extent between surface water and groundwater, indicating that surface water in the north bank of the Wei River has little hydraulic connection with underlain groundwater. The CFCs age of groundwater from the piedmont recharge area was young, and became older toward the Wei River valley. Vertically, the CFCs age of groundwater increased with well depth. The shallow groundwater is mainly composed of young water with ages < 60 years and old water with ages > 60 years. Young water is in a larger proportion. The NO3-N concentration positively correlates with the CFC-12 concentration in the groundwater, which indicates that young water is subjected to be contaminated. Keyword: Guanzhong Basin , shallow groundwater, isotope, CFC

地质体科学计算可视化研究及其应用

Describing visually space-time properties of geological phenomena consists of one of the most important parts in geology research. Such visual images are of usually helpful for analyzing geological phenomena and for discovering the regulations behind geological phenomena. This report studies mainly three application problems of scientific visualization in geology: (Dvisualizing geological body A new geometric modeling technique with trimmed surface patches has been eveloped to visualize geological body. Constructional surfaces are represented as trimmed surfaces and a constructional solid is represented by the upper and lower surface composed of trimmed surface patches from constructional surfaces. The technique can completely and definitely represent the structure of geological body. It has been applied in visualization for the coal deposit in Huolinhe, the aquifer thermal energy storage in Tianjin and the structure of meteorite impact in Cangshan et al. (2)visualizing geological space field Efficient visualization methods have been discussed. Marching-Cube algorithm used has been improved and is used to extract iso~surface from 3D data set, iso-line from 2D data set and iso-point from ID data set. The improved method has been used to visualize distribution and evolution of the abnormal pressures in Zhungaer Basin. (3)visualizing porous space a novel way was proposed to define distance from any point to a convex set. Thus a convex set skeleton-based implicit surface modeling technique is developed and used to construct a simplified porous space model. A Buoyancy Percolation numerical simulation platform has been developed to simulate the process of migration of oil in the porous media saturated with water.

单（多）井抽灌对浅部地温场的影响研究

The technique of energy extraction using groundwater source heat pumps, as a sustainable way of low-grade thermal energy utilization, has widely been used since mid-1990's. Based on the basic theories of groundwater flow and heat transfer and by employing two analytic models, the relationship of the thermal breakthrough time for a production well with the effect factors involved is analyzed and the impact of heat transfer by means of conduction and convection, under different groundwater velocity conditions, on geo-temperature field is discussed.A mathematical model, coupling the equations for groundwater flow with those for heat transfer, was developed. The impact of energy mining using a single well system of supplying and returning water on geo-temperature field under different hydrogeological conditions, well structures, withdraw-and-reinjection rates, and natural groundwater flow velocities was quantitatively simulated using the finite difference simulator HST3D. Theoretical analyses of the simulated results were also made. The simulated results of the single well system indicate that neither the permeability nor the porosity of a homogeneous aquifer has significant effect on the temperature of the production segment provided that the production and injection capability of each well in the aquifers involved can meet the designed value. If there exists a lower permeable interlayer, compared with the main aquifer, between the production and injection segments, the temperature changes of the production segment will decrease. The thicker the interlayer and the lower the interlayer permeability, the longer the thermal breakthrough time of the production segment and the smaller the temperature changes of the production segment. According to the above modeling, it can also be found that with the increase of the aquifer thickness, the distance between the production and injection screens, and/or the regional groundwater flow velocity, and/or the decrease of the production-and-reinjection rate, the temperature changes of the production segment decline. For an aquifer of a constant thickness, continuously increase the screen lengths of production and injection segments may lead to the decrease of the distance between the production and injection screens, and the temperature changes of the production segment will increase, consequently.According to the simulation results of the single well system, the parameters, that can cause significant influence on heat transfer as well as geo-temperature field, were chosen for doublet system simulation. It is indicated that the temperature changes of the pumping well will decrease as the aquifer thickness, the distance between the well pair and/or the screen lengths of the doublet increase. In the case of a low permeable interlayer embedding in the main aquifer, if the screens of the pumping and the injection wells are installed respectively below and above the interlayer, the temperature changes of the pumping well will be smaller than that without the interlay. The lower the permeability of the interlayer, the smaller the temperature changes. The simulation results also indicate that the lower the pumping-and-reinjection rate, the greater the temperature changes of the pumping well. It can also be found that if the producer and the injector are chosen reasonably, the temperature changes of the pumping well will decline as the regional groundwater flow velocity increases. Compared with the case that the groundwater flow direction is perpendicular to the well pair, if the regional flow is directed from the pumping well to the injection well, the temperature changes of the pumping well is relatively smaller.Based on the above simulation study, a case history was conducted using the data from an operating system in Beijing. By means of the conceptual model and the mathematical model, a 3-D simulation model was developed and the hydrogeological parameters and the thermal properties were calibrated. The calibrated model was used to predict the evolution of the geo-temperature field for the next five years. The simulation results indicate that the calibrated model can represent the hydrogeological conditions and the nature of the aquifers. It can also be found that the temperature fronts in high permeable aquifers move very fast and the radiuses of temperature influence are large. Comparatively, the temperature changes in clay layers are smaller and there is an obvious lag of the temperature changes. According to the current energy mining load, the temperature of the pumping wells will increase by 0.7°C at the end of the next five years. The above case study may provide reliable base for the scientific management of the operating system studied.

遵义市岩溶水地下水流和污染物运移数值模拟研究

地下水数值模拟技术已成为评估人类活动对地下水质和量的影响、评价地下水资源、预测地下水污染发展趋势等的最主要的方法和手段。喀斯特含水层由于含水介质和地下水流场的非均质性和各向异性，对其进行地下水流的数值模拟一直是水文地质学界的难题。 遵义市地处我国西南喀斯特发育区，为贵州省第二大工业城市，属重度缺水地区，地下水资源的开发利用极大缓解了区内的缺水危机。但长期以来，由于对地下水资源的开发利用缺乏合理的统筹规划和强有力的管理，引发了一些环境地质问题，如地下水降落漏斗、岩溶塌陷、地下水质恶化等。因此选择遵义市进行地下水流和污染物运移数值模拟研究具有理论和实际意义。 通过ArcGIS平台建立了研究区的水文地质信息数据库，对研究区地下水的水位动态以及水化学特征做了简单分析。概要总结和阐述了高桥－河溪坝块段的自然地理、地质概况和水文地质条件，建立了水文地质概念模型；在水文地质概念模型的基础上，利用Groundwater Vistas软件建立了枯水期和丰水期的二维非均质各向异性稳定流模型，三维有限差分地下水流模拟程序MODFLOW用于模拟地下水水流，三维溶质运移模块MT3DMS用于模拟污染物在对流弥散情况下的迁移。根据分析和模拟结果可以得出如下几点结论： 1、基岩裂隙水水位峰值滞后大气降水峰值2～3个月，属渐峰型动态；岩溶水水位、地下河出口和泉流量变化步调与降水强度一致，对降水响应敏感。 2、对NH4+、NO3-、NO2-、SO42-、Mn五种组分含量进行了时空分析，结果表明地下水污染物的含量可能受人为活动输入物质的不均匀性和降雨等各方面因素控制，各组分每年的污染面积不一致，没有明显的规律性；受污染的一般是岩溶水，尤其是在石灰岩溶洞、地下河强烈发育而三废排放量大的居民集中地区面积较大。 3、为了有效地进行地下水资源管理，论文对高桥－河溪坝岩溶含水系统进行了一定的概化，将岩溶含水介质近似作为等价多孔介质（Equivalent Porous Media, EPM）模型来进行研究，采用MODFLOW的六个子程序模拟含水层系统的源汇项：降水子程序包RCH模拟降水入渗量、井流子程序包WEL模拟抽水量、通用水头子程序包GHB模拟侧向补给/排泄量、排水沟渠子程序包DRN模拟地下河出口流量、河流子程序包RIV模拟河流与地下水的交换量和已知水头边界子程序包CHD。从水位观测点和地下水位等势面两者结合来校正模型，结果表明能够达到相应国家标准规定的要求。因此EPM模型是可以适用于我国西南喀斯特地区的地下水流模拟的。 4、通过稳定流模型识别了枯水期和丰水期的渗透系数。在高桥和茅草铺附近渗透系数较高，枯水期介于100～400 m/d，而丰水期在高桥最高可达到3220m/d；其余单元渗透系数低于100 m/d，大多数小于10m/d。总体来说，由于丰水期含水层的饱水度大，渗透系数要高于枯水期。 5、通过地下水均衡计算，确定了各补给项和排泄项的水量。枯水期最重要的补给来源是研究区东北角的侧向补给量，占总补给量的70％，人工开采是最大的排泄项；丰水期最重要的补给源是西部的已知水头边界，占总补给量的49％，东北角的侧向补给量是第二补给源，占39％，地下河出口是最主要的排泄方式，达到排泄总量的74％。 6、对水文地质参数和源汇项敏感度分析的结果表明，不管是枯水期还是丰水期，对研究区水位影响最大的是渗透系数，外部源汇项中则是抽水量对地下水流形态的影响最大。 7、研究区岩溶地下水流速很大，污染物的运移是一个对流占绝对优势的问题，弥散的作用则相对很小。通过在茅草铺地区假设污染源，用MT3DMS程序模拟了地下水污染物在时间和空间上的迁移特征。结果发现：污染羽的形状和扩散方位主要受地下水流场的控制，而污染物的浓度与水量多少相关。