二叠盆地Wolfcamp页岩油层测井评价研究

Petrophysical Evaluation Method of Wolfcamp Shale Reservoir in Permian Basin

以二叠盆地米德兰次盆Wolfcamp页岩为例,总结页岩油层测井评价流程、方法和应用,建立适合Wolfcamp页岩的测井评价模型。以测井资料和岩心分析资料为基础,分析页岩油层的矿物组成、物性特征,将页岩中有机质视为特殊矿物,应用ELANPlus模块评价页岩储层的矿物含量和孔隙度,建立矿物组分渗透率模型。以岩心分析含水饱和度刻度,确定Indonesia公式评价Wolfcamp页岩储层含水饱和度的计算参数。结合Wolfcamp页岩储层发育灰质夹层的特点,应用Passey法评价富含石英、黏土页岩和体积密度法评价富含方解石页岩总有机碳含量。以纵波时差和横波时差测井评价页岩储层弹性模量、泊松比、岩石脆性指数等力学参数,为水平井初步确定有利压裂段提供依据。利用成像测井资料、偶极声波测井资料确定最大水平主应力方向,结合常规测井资料评价最大、最小水平主应力大小、垂向应力及其与水平主应力的大小关系,确定水平井安全钻井方向。

Summarized are petrophysical evaluation flow,method,application and available models of Wolfcamp shale reservoir,taking the Permian Basin Midland Sub-basin for example.Analyzed are mineral composition and physical characteristics.Studied is a method to evaluate mineral composition and porosity using ELANPlus module by treating organic as a kind of special mineral.Studied are water saturation evaluation with Indonesia equation calibrated by saturation from core analysis,as well as TOC evaluation with Passey method for quartz and clay-rich intervals and density method for calcite-rich intervals.Calculated are mechanical parameters,such as Young Modulus,Poisson's Ratio and brittleness index using compressional slowness and shear slowness logs,which helps to identify fracturing interval preliminarily.Analyzed is maximum horizontal principal stress direction from image logs and dipole shear wave logs,and evaluated are of vertical stress, maximum horizontal principal stress, minimum horizontal principal stress,and relationship among them from conventional logs,which helps to define safe drilling direction of horizontal wells.