吉木萨尔凹陷页岩油水平井地质工程一体化三维压裂设计探索

准噶尔盆地吉木萨尔凹陷芦草沟组页岩油储层埋藏深度大、物性差、非均质性强,常规二维压裂设计难以实现对该类储层的精细、高效动用。为充分挖潜页岩油资源,基于Petrel平台,采用序贯高斯模拟方法构建页岩油区块部分区域三维地质模型,刻画了页岩油砂泥频繁互层、岩性复杂多样的地质特征;采用DFN离散裂缝网络建模方法描述了页岩油区块部分区域天然裂缝发育情况;通过地质力学模拟器VISAGE耦合了天然裂缝模型的地应力场计算;结合地质认识,模拟分析了差异化布缝、应力阴影与天然裂缝对水力裂缝延伸及生产效果的影响。结果表明,差异化布缝对近井地带富油气区的改造更为充分,初期生产效果更好;应力阴影不利于最大主应力方向裂缝延伸,裂缝转向导致井周储层改造充分,对生产效果的综合影响较弱;天然裂缝有利于造缝网复杂化、沟通远井油气富集区,提产效果显著。

Exploration of geological engineering integrated 3D fracturing design for horizontal wells in Jimsar shale oil reservoirs

The shale oil reservoir of Lucaogou formation in Jimusaer sag,Junggar basin is characterized by large burial depth,poor physical properties and strong heterogeneity,so it is difficult to realize the fine and efficient production of this kind of reservoir by conventional 2D fracturing design.In order to fully tap shale oil resources,based on Petrel technology,the sequential Gaussian simulation method is used to construct a 3D geological model of shale oil block,which depicts the geological characteristics of frequent inter-bedding of shale oil sand and mud and complex lithology.Based on the statistical analysis of the logging data of 8 wells in the block,DFN discrete fracture network modeling method is used to describe the development of natural fractures in some areas of shale oil block.The in-situ stress field calculation of natural fracture model is coupled by visage geo-mechanical simulator.Combined with geological knowledge,the influence of differential fracture arrangement,stress shadow and natural fracture on hydraulic fracture extension and production effect is simulated and analyzed.The results show that the differential arrangement of fractures is more sufficient for the transformation of oil-gas rich areas near the well,and the initial production effect is better.The stress shadow is not conducive to the fracture extension in the direction of maximum principal stress,and the fracture diversion leads to full reservoir reconstruction around the well,and the comprehensive influence on production effect is weak.Natural fractures are beneficial to the complexity of fracture network and the communication of oil and gas rich areas in remote wells,and the effect of increasing yield is good.