摘要
根据滨里海盆地肯基亚克盐下异常高压碳酸盐岩油藏储集层特征,制备人造岩心,研究基质岩心、不充填裂缝性岩心、半充填裂缝性岩心以及全充填裂缝性岩心的应力敏感特征。实验采取气测法,实验中首先逐级增加人造岩心样品围压,然后逐级降压,稳定后测定每个压力点的孔隙度和渗透率,以分析岩心的应力敏感性。结果表明,4种岩心应力敏感性由强到弱依次为:不充填裂缝性岩心、半充填裂缝性岩心、全充填裂缝性岩心、基质岩心。随着岩心裂缝充填程度降低,岩心渗透率的应力敏感性增强,渗透率恢复程度降低;随着压力的恢复,基质岩心和全充填裂缝性岩心孔隙度和渗透率恢复程度较高,岩心表现为弹塑性特征,而半充填和不充填裂缝性岩心孔隙度和渗透率恢复程度较低,表现为塑性特征;随围压的增加,孔隙度、渗透率变化呈现较好的指数变化规律。
According to the characteristics of overpressure carbonate reservoirs of Kenkiyak pre-salt oil field in the littoral Caspian Basin, cores were made artificially and the stress sensibility of matrix cores and cores with non-packed, semi-packed and fully packed fractures were analyzed. The method of gas measurement was used in the experiment. The confining pressure of the sample cores was first increased and then decreased. When the confining pressure became stable, porosity and permeability data from each pressure point were obtained to analyze stress sensibility of cores. The results showed that the stress sensibility of these four types of cores with a descending order is cores with non-packed fractures, cores with semi-packed fractures, cores with packed fractures, and matrix cores. With the decrease in packing degree of core fractures, the stress sensitivity of core permeability increased and the recovery degree of permeability decreased; the recovery degree of porosity and permeability of the matrix cores and cores with fully packed fractures was high with the recovery of pressure and these two types of cores showed elastic-plastic features. By contrast, the recovery degree of porosity and permeability of cores with partly packed and unpacked fractures was lower and these two types of cores showed plastic features. With the increase of confining pressure, the variation of porosity and permeability showed relatively regular exponential variations.
出处
《石油勘探与开发》
SCIE
EI
CAS
CSCD
北大核心
2013年第2期194-200,共7页
Petroleum Exploration and Development
基金
中国石油天然气集团公司科学研究与技术开发项目(2008B-4405)
关键词
碳酸盐岩
异常高压
应力敏感
裂缝充填
渗透率变化
carbonates
abnormally high pressure
stress sensitivity
fracture packing
permeability variation
