Logging Evaluation Of Source-reservoir Configuration Relationship Of Tight Oil From The 8th Member Of Yanchang Formation From Shuimogou In Fuxian Area,Ordos Basin

With the increasing demand for oil and gas in the world and the improvement of horizontal drilling technology,the economically exploitable value of tight oil is getting higher and higher.In the Ordos Basin,a large number of tight oil field have been discovered in the past ten years,such as the Shuimogou oil field in Fuxian exploration area,which has considerable reserves.However,the understanding of tight oil in Chang 8 Member of Shuimogou demonstration zone is low,and the physical properties of the reservoir are poor and the heterogeneity is strong.Therefore,it is difficult to evaluate the tight oil reservoirs,and the relationship between source and reservoir is difficult to clarify and as a result,the exploration and development work comes into difficulties.Above all,the establishment of an effective logging interpretation model to evaluate the tight reservoirs in the 8th Member of the research area and the characteristics of source rocks to analyze the source-storage configuration relationship is of great significance for the subsequent exploration and development of the research area.Based on the core characteristics,analytical data and production dynamics in the area,the well logging technique was applied to evaluate the research area to analyze the source-storage configuration relationship.The specific understandings are as follows:?1?It is considered that the source rocks in the research area in Yanchang Formation are mainly oil shale and mudstone at the bottom of Chang 7 and the top of Chang 9,and their organic abundance is high-quality source rocks.The types are mainly type I and type II₁,belonging to the mature-high maturity stage and believed to be high-quality source rocks.This lays an important material foundation for the formation of tight oils in this area.?2?The lithology of the Chang 8 reservoirs are dominated by feldspar sandstone.The reservoirs have various pore types,with intergranular dissolved pores and intergranular pores.The reservoir porosity is 8.73%on average,and the permeability is mainly in the range of0.15×10^-3?m²⁰.5×10^-3?m²,which is thought to be tight reservoirs.?3?Through the core and corresponding logging curve characteristics,the overlapping diagram is the main technical means and the reservoir lithology logging identification method is established.The source rock is effectively identified by the acoustic time difference-resistivity overlapping diagram and multi-logging curves combination characteristics,and the?LogR method is used to characterize the organic matter abundance.?4?The multi-parameter multiple regression was used to establish the reservoir physical property interpretation model,and the Archie empirical formula was applied to explain the oil saturation of the reservoir.?5?The reservoirs in research area were divided into three types,and combine the evaluation results of source rocks,it is suggested that the source-storage relationship of tight oil in the area are mainly four types:“high-quality source rocks and high-quality reservoir”often form high-yield oil layers;“high-quality source rocks and medium-poor reservoir”forms poor oil layers;“poor source rocks and high-quality reservoir”forms more water layers or oil-bearing water layers;“poor source rocks and medium-poor reservoir”often forms water layers or dry layers.The above understanding provides effective support for the exploration and development of Chang8 in Shuimogou oil field.