裂缝在吉林两井低渗透砂岩油田开发中的作用

在研究吉林两井低渗透砂岩油田裂缝分布特征与发育规律的基础上 ,探讨了裂缝对该区油气富集规律、可动流体饱和度分布、渗流作用、开发井网部署、注水效果和压裂缝展布等方面的影响 .结果表明 :该区主要发育 4组高角度构造裂缝 ,由于各组裂缝密度及现应力场影响下的开度不同 ,引起裂缝渗透率各向异性 .随着裂缝密度增大 ,油气的富集程度和可动流体饱和度增高 .在注水开发中 ,由于裂缝的高渗透性、渗透率非均质性和压力敏感性特征 ,影响油田开发方案的部署 .天然裂缝控制了整个渗流系统 ,人工压裂缝主要起改善东西向渗流通道的作用 .各组天然裂缝及其渗透性的综合评价 ,是该低渗透砂岩油田合理开发的主要地质依据

Effect of Fractures on the Development of Liangjing Low-permeability Sandstone Oilfield

Based on the research in the distribution and the development laws of the fractures in Liangjing low-permeability sandstone oilfield in Jilin province, the influences of the fractures on oil enrichment, moveable fluid saturation, seepage, pattern arrangement, water injection efficiency and artificial fracturing fracture distribution are studied. There are four sets of tectonic fractures with high dip angles in the oilfield. The fractures have different permeability because of different density of each set of fractures and different present stress field in the area. The degree of oil enrichment and moveable fluid saturation linearly increase with the increase of fracture density. High seepage, permeability anisotropy and pressure sensitivity of the fractures are the main factors of influencing the development program of Liangjing low-permeability oilfield. The natural fractures control all seepage system, and fracturing cracks improve EW seepage channel. Therefore, the evaluation of the seepage of each set of fractures is the main geological basis of the reasonable development of the low-permeability sandstone oilfield.