论文详情
电成像测井技术与偶极横波远探测技术可以有效识别井周裂缝。对于裂缝性油气藏, 由于裂缝作为油气主要的储集空间与渗流通道, 因此对识别的井周裂缝进行流体疏导性能评价对于油田实际生产具有重要意义。利用岩石力学中的三维应力莫尔圆对地应力作用下从井壁延伸至储层的裂缝进行应力状态分析, 并结合莫尔-库仑破裂准则进行裂缝临界应力状态判别, 进而评价整体的流体疏导性能。数值模拟结果表明, 除地应力大小外, 不同断层类型的地应力状态和孔隙压力大小也决定着裂缝的临界应力状态。根据裂缝面应力状态求取裂缝的摩擦系数并进行校正可以定量反映裂缝的流体疏导性能, 将裂缝发育层段内校正后的裂缝摩擦系数加权于裂缝密度, 可实现目标井段流体疏导性能定量评价并为产能评价提供可靠依据。在渤中19-6裂缝性潜山凝析气田的应用实例表明, 该方法可以有效地分析井周裂缝的流体疏导性能, 实现不同裂缝对于产能贡献的定量评价, 评价结果与地层实际测试产能结果有较好的相关性, 为现场试油与开采方案的制定提供有效指导。
Fluid conductivity in near-borehole fractures, which could be effectively identified using electric imaging and dipole shear-wave reflection imaging, is important to hydrocarbon production because fractures function as major reservoir space and flowing channels in fractured reservoirs.We use the 3D Mohr circle in rock mechanics to examine the stress conditions of fractures extending from the borehole wall to reservoirs owing to the effect of terrestrial stress and diagnose the critical stress state of fractures based on the Mohr-Coulomb yielding criteria to evaluate fluid conductivity.Numerical simulations show that stress conditions of different fault types and pore pressure, in addition to terrestrial stress, dominate the critical stress state of fractures.Corrected frictional coefficient of fractures derived from the stress conditions of fracture faces may quantitatively indicate fluid conductivity in fractures, and fracture density weighted by corrected frictional coefficient may function as a quantitative indicator of fluid conductivity in the target well section for deliverability evaluation.The application to Bozhong19-6 fractured buried-hill condensate field shows successful quantitative evaluation of fluid conductivity in near-borehole fractures and fracture contribution to deliverability.The results of evaluation consistent with production tests provide support to oil testing and production planning.