潜山裂缝性油藏见水规律及裂缝分布规律分析方法

摘要

潜山裂缝性油藏的裂缝分布随机性强,非均质性差别大,导致开发过程中油井水淹规律复杂,但目前还没有识别地下储层裂缝分布的有效方法.为此,以渤海JZS潜山油藏为例,利用其丰富的动态资料,分析了不同油井的见水特征,总结得出了该潜山裂缝性油藏"台阶形"见水特征及由局部裂缝见水逐渐发展为整体见水的含水率上升规律;基于该潜山裂缝性油藏的见水规律,选取剖面压力均等模型作为裂缝性油藏见水预测模型,通过拟合实际油井的见水特征反算了地下裂缝的分布情况,分析得出潜山裂缝性油藏具有较强的非均质性以及其裂缝具有对数正态分布的特征.研究认为,将裂缝对数正态分布这一特征作为约束条件应用到潜山裂缝性油藏的地质建模中,可在很大程度上提高该类油藏含水率拟合结果的准确性,这对类似裂缝性油藏的数值模拟和有效开发具有借鉴意义.%T he fracture distribution in a buried-hill reservoir characterized by strong randomness and high degress of heterogeneity,resulted in complex water flooding regularity in the development of oil wells.There was no effective method to identify the distribution of underground reservoir fractures in the last few years.In order to solve the problem,the Bohai JZS buried-hill reservoir was taken as an example to analyze the features of water production in different oil wells by using abundant dynamic data,together with obtained water cut rising regularity,i.e.water produced in footstep style gradually from local frac-tures to all fractures.Based on the water production regularity in the buried-hill reservoir,a homogeneous pressure profile model was selected to predict the water production in fracture reservoir,and calculated in-versely to the distribution of underground cracks by fitting the water production characteristics of actual oil wells.After that,the investigations arrived at a conclusion,considering the buried-hill reservoirs having strong anisotropy,with the characteristics of log-normal distribution of fractures.Research results showed that the log-normal distribution of fractures could be taken as a constraint in the geologic modeling of bur-ied-hill fracture reservoirs and could be used to improve the accuracy of history matching the water cut in these reservoirs,providing valuable references for numerical simulation and high-efficiency development of similar fracture reservoirs.