Abstract:

Through the analysis of casting thin sections, 3D geological modeling, special logging series and micro seismic monitoring, reservoir stress characteristics of Jing’an area were studied. The results show that: 1) the distribution of the direction of micro pore and throat would cause the stress anisotropy; 2) differences in each layer of Chang 4+5₂ sandstone are big, the lateral superposition characteristics of multi-periods channels have the major influence on stress distribution; 3) the stress difference in the study area is generally not large with the value of 3?6 MPa, with the development of water flooding development, the variation of the two main stress varies in the reservoir, resulting in the multi-directional development of fractures in the process of repeated fracturing. The results can provide a scientific basis for improving oil recovery in the middle and late development of low permeability reservoirs.

Key words: Ordos Basin, stress, hydraulic fracture, oil recovery

摘要：

通过铸体薄片观察、三维地质建模、特殊测井系列和微地震监测分析, 研究靖安地区延长组储层的应力特征。结果显示: 1) 研究区储层微观孔喉的方向性展布在一定程度上导致应力各向异性; 2) 长4+5₂砂岩组各小层砂岩分布存在较大差异, 多期河道侧向叠加特点显著, 对应力分布产生较重要的影响; 3) 研究区应力差总体上不大, 在3~6 MPa之间, 随着注水开发的进行, 两水平主应力的变化幅度在油藏中存在分布不均的现象, 造成重复压裂过程中裂缝的多向性发展。研究结果可为低渗储层开发中后期提高油田采收率提供科学依据。

关键词: 鄂尔多斯盆地, 应力, 水力压裂缝, 原油采收率