黄骅坳陷港西开发区河流相储层构型与剩余油分布模式研究

In the production tail of oilfield, water-cut is very high in thick channel sand oil reservoir, but recovery efficiency is relative low, and recoverable remaining oil reserves is more abundant, so these reserves is potential target of additional development. The remaining oil generally distributed with accumulation in certain areas, controlled by the reservoir architecture that mainly is the lateral accretion shale beddings in the point bar, so the study of reservoir architecture and the remaining oil distribution patterns controlled by architecture are very significant. In this paper, taking the Minghuazhen formation of Gangxi oilfield as a case, using the method of hierarchy analysis, pattern fitting and multidimensional interaction, the architecture of the meandering river reservoir is precisely anatomized, and the remaining oil distribution patterns controlled by the different hierarchy architecture are summarized, which will help to guide the additional development of oil fields. Not only is the study significant to the remaining oil forecasting, but also it is important for the theory development of reservoir geology. With the knowledge of sequence correlation and fluvial correlation model, taking many factors into account, such as combination of well and seismic data, hierarchical controlling, sedimentary facies restraint, performance verification and 3-D closure, an accurate sequence frame of the study area was established. On the basis of high-resolution stratigraphic correlation, single layer and oil sand body are correlated within this frame, and four architecture hierarchies, composite channel, single channels, point bars and lateral accretion sandbody are identified, The result indicates that Minghuazhen Formation of Gangxi oilfield are dominated by meandering river deposition, including two types of channel sandbodies, narrow band and wide band channel sandbody, and each of them has different characteristics of facies variation laterally. Based on the identification of composite channel, according to the spatial combination patterns and identified signs of single channel, combined with channel sandbody distribution and tracer material data, single channel sandbodies are identified. According to empirical formula, point-bar scales of the study area are predicted, and three identification signs are summarized, that is, positive rhythm in depositional sequence, the maximum thick sand and near close to the abandoned channel, and point bars are identified. On the basis of point bar recognition, quantitative architecture models inner point bar are ascertained, taking the lateral accretion sand body and lateral accretion shale beddings in single well as foundation, and quantitative architecture models inner point bar as guidance, and result of tracer material data as controlling, the the lateral accretion sand body and lateral accretion shale beddings are forecasted interwell, so inner architecture of point bar is anatomied. 3-D structural model, 3-D facies model and 3-D petrophysical properties models are set up, spatial distribution characteristics of sedimentary facies and petrophysical properties is reappeared. On the basis of reservoir architecture analysis and performance production data, remaining oil distribution patterns controlled by different hierarchy architecture units, stacked channel, single channel and inner architecture of point bar, are summarized, which will help to guide the additional development of oil fields.