Compressibility evaluation and application of E32 shale oil in Yingxiongling Area,Qaidam Basin
The evaluation of shale reservoir compressibility is almost equivalent to a single brittleness coefficient.Therefore,the impacts of brittleness,horizontal principal stress difference,and fracture density on shale compressibility were evaluated respectively to clarify shale oil's engineering sweet spot quality in Yingxiongling area,Qaidam Basin.The results indicate that:1)The comprehensive matrix brittleness index proposed in this article includes characteristics of mineral content and bedding development,et al,and is more suitable for the brittleness evaluation of Ganchaigou shale oil reservoir in Yingxiongling Area;2)The development of microfractures and bedding fractures is also one of the critical factors affecting compressibility.The stronger the ability of the reservoir to form complex fracture networks,and the better its compressibility when there are a large number of microfractures in the reservoir;3)This article proposes a comprehensive compressibility evaluation method based on the matrix brittleness evaluation,microfracture development,and in-situ stress.The greater the brittleness of the matrix,the higher the fracture density,and the smaller the coefficient of the horizontal stress difference in the reservoir,the easier it is to form complex fracture networks;4)The comprehensive compressibility index evaluation method established in this article was applied to well CP1 in Yingxiongling Area,with a comprehensive compressibility index of 0.52～0.69,and overall,it is mainly composed of Class I reservoirs.The distribution of microseismic monitoring event points in the well is scattered and uniform,the average fracture complexity index is 0.303,and the fracture network is relatively complex,consistent with the compressibility evaluation results,indicating that the established comprehensive compressibility evaluation method is reliable.
Yingxionglingshale oilcompressibilitybrittlenessfracture density
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