摘要
通过开展人造致密岩心应力敏感滞后性室内实验,分析了致密储集层加压-卸压过程应力敏感性。基于实验结果,考虑岩心颗粒不同排列方式和变形方式,以颗粒堆积模型为基础,根据Hertz接触变形原理建立了致密储集层应力敏感滞后性定量表征模型,对致密储集层应力敏感滞后性造成的渗透率损失进行了量化分析,并通过对比模型计算结果与室内实验结果对新建模型进行了验证。研究表明,加压阶段前期,在岩石结构变形和本体变形共同作用下,岩心渗透率随着有效应力的增加快速下降,当有效应力超过一定值后,岩石结构变形趋于稳定,仅发生本体变形,岩心渗透率变化趋于平缓;卸压阶段,岩石本体变形随有效应力的降低得以逐渐复原,而结构变形不能复原,岩心渗透率无法完全恢复,应力敏感滞后现象明显。
Laboratory experiments were conducted on laboratory-made tight cores to investigate the stress-dependent permeability hysteresis of tight reservoirs during pressure loading and unloading process.Based on experiment results,and Hertz contact deformation principle,considering arrangement and deformation of rock particles,a quantitative stress dependent permeability hysteresis theoretical model for tight reservoirs was established to provide quantitative analysis for permeability loss.The model was validated by comparing model calculated results and experimental results.The research results show that during the early pressure-loading period,structural deformation and primary deformation worked together,rock permeability reduced dramatically with increasing effective stress.When the effective stress reached a certain value,the structural deformation became stable while the primary deformation continued;the permeability variation tended to be smooth and steady.In the pressure unloading process,the primary deformation recovered with the decreasing effective stress,while the structural deformation could not.The permeability thus could not fully recover,and the stress-dependent hysteresis was obvious.
作者
曹耐
雷刚
CAO Nai;LEI Gang(China University of Petroleum (Beijing),Beijing 102249,China;King Fahd University of Petroleum and Minerals,Dhahran 31261,Kingdom of Saudi Arabia)
出处
《石油勘探与开发》
SCIE
EI
CAS
CSCD
北大核心
2019年第1期132-138,共7页
Petroleum Exploration and Development
基金
国家科技重大专项(2016ZX05037-003
2017ZX05049-003)
关键词
致密储集层
应力敏感滞后
渗透率应力敏感
室内实验
理论模型
tight reservoir
stress sensitivity hysteresis
permeability stress sensitivity
laboratory experiment
theoretical model
