西233区长7致密储层三维脆性分布特征

Study on 3D brittleness distribution characteristics of Chang 7 tight reservoir in XI 233 area

明确致密储层的三维脆性分布特征,有助于压裂层段优选和压裂施工设计。文中以鄂尔多斯盆地西233区长7致密储层为研究对象,利用岩心矿物组分、岩石力学化验分析和地球物理测井资料,在岩心刻度测井的思想指导下,对研究区目的层的矿物组分、弹性模量、泊松比进行了处理解释,构建了基于矿物成分-力学参数的脆性指数计算模型;基于脆性指数,采用三维地质建模的思想,构建了脆性指数三维分布模型,进而刻画了脆性三维分布特征。研究结果表明:西233区长7致密储层脆性分布连片性较差,整体上脆性受储层岩性和非均质性影响较大;脆性发育区向西南方向延伸,并演化为西北、西南和东南方向3条次级脆性发育带,南部脆性连续性较差,整体上呈现出较强的脆性非均质性。

To find out the 3D brittleness distribution characteristics of tight oil reservoir is helpful to the optimization of fracturing interval and the design of fracturing operation.Taking the Chang 7 tight reservoir in the XI 233 area of Ordos Basin as the research object,using the mineral composition of core,rock mechanics laboratory analysis and geophysics logging data,the mineral composition,elastic modulus and Poisson ratio of the target layer were processed and interpreted under the guidance of the idea of core calibration logging,and calculation model of brittleness index based on mineral composition-mechanical parameters was established.Based on the Brittleness Index,a 3D distribution model of brittleness index was established by using the idea of 3D geological modeling,and then the characteristics of 3D distribution of brittleness were described.The results show that brittleness distribution of Chang 7 tight reservoir in the XI 233 area has poor continuity,and the brittleness is greatly affected by reservoir lithology and heterogeneity.The brittle zone extends to the southwest and evolves into three sub-brittle zones in the northwest,southwest and southeast.In the south,the brittleness continuity is poor and the brittleness heterogeneity is strong as a whole.