大庆油田台肇地区低渗透储层裂缝及其开发对策研究

介绍了大庆油田外围典型的低渗透储层——台肇地区葡萄花油层中东西向、南北向、北西向和北东向4组高角度构造裂缝，其发育程度依次由强变弱。受现今地应力影响，近东西向裂缝连通性好，地下张开度和渗透率大，是该区主渗流方向；其次是北西向、北东向裂缝，近南北向裂缝渗透性较差，裂缝发育程度受岩性、层厚、断层、构造应力等因素影响。根据地质条件和油藏数值模拟，认为该区适应于用矩形井网和菱形井网开发，效果比反九点和五点井网好。低渗储层由于裂缝发育，降低了地层破裂压力，注入压力容易超过地层破裂压力，使注入水沿裂缝快速流动，引起水

The Study of Fractures and Their Development Countermeasures on Taizhao Low-permeability Reservoir in Daqing Oilfield

The Putaohua reservoir in Taizhao area is the typical low-permeability reservoir which developed EW, SN, NW and NE tectonic fractures with high angles in the periphery of Daqing Oilfield. The development degree of above four group fractures in succession die down. By effect of modern stress field of approximately EW direction, the connectedness, opening and permeability of EW fractures are the best, then are NW and NE fractures, and that of SN fractures are the worst. The development degree of fractures are controlled by lithology, thickness, fault and tectonic stress. The effects of fractures on development include pattern arrangement, injecting water and fracturing. According to geological condition and numerical simulation of oil pool, the development effects of similar low-permeability reservoirs by rectangle and lozenge well pattern are better than by inverted 9-spot well pattern and 5-spot well pattern. Due to development of fractures in low-permeability, the stratum cracking pressure reduces, which is liable to be exceeded by the injecting pressure. This will make injecting water to flow fleetly along fractures, and cause water flooding, influenceing development effect. Therefore, it is very important to control injecting pressure in the development of low-permesability reservoirs. The artificial fractures are controlled by the modern stress field and natural fractures in fractured low-permeability reservoir. According to fractures and their seepage characteristics, three sets of adjustment schemes can be adopted on the basis of existing inverted 9-spot well pattern. At the same time, good effects can be obtained by early mild injecting water, controlling injecting pressure, linearity injecting mode, dynamic preparing water, pulse cycle injecting, perfecting pour and pick system, well pattern adjustment, choosing fracturing well and controlling fracturing scale, etc.[