摘要
针对CO_(2)驱替过程中碳酸盐岩孔渗-力学协同演化机制不明确的问题,通过碳酸水驱替实验和单轴应力测试,建立溶蚀-堵塞双因素作用下的储层物性动态预测模型,系统研究不同驱替倍数(PV)下岩心的孔渗变化及力学参数(抗压强度、弹性模量、泊松比)的响应规律,揭示碳酸溶蚀-堵塞效应对储层改造的影响机制。以鄂尔多斯盆地长6段碳酸盐岩为对象,基于驱替实验数据构建孔隙度-渗透率双参数演化方程,采用Pearson相关系数量化驱替倍数与抗压强度、弹性模量、泊松比的关联性,结合核磁共振T_(2)谱分析驱替前后岩心孔隙分布特征,阐明驱替前后碳酸盐岩孔隙结构变化规律。结果表明:①孔隙度与渗透率随驱替倍数呈先增后降趋势,变化幅度分别为-2.53%~2.87%和-12.31%~5.71%,溶蚀作用初期增大孔隙但后续沉淀堵塞导致渗流能力下降;②抗压强度与驱替倍数强相关(增幅显著),弹性模量中等相关(缓增1.2%~4.8%),泊松比无显著规律;③孔隙度与抗压强度、弹性模量呈负相关(R^(2)>0.65),渗透率仅与抗压强度负相关;溶蚀作用通过扩大孔隙连通性降低岩石强度,而矿物沉淀则增强结构稳定性。该研究为低渗碳酸盐岩储层CO_(2)封存安全评估提供了孔隙-力学协同演化判据,指导注采参数优化以平衡封存容量与盖层完整性。
Aiming at the problem of the unclear co-evolution mechanism of pore infiltration and mechanics in carbonate rocks during the CO_(2) displacement process,through carbonated water displacement experiments and uniaxial stress tests,a dynamic prediction model of reservoir physical properties under the dual factors of dissolution and blockage was established.A systematic study was conducted on the porosity and permeability changes of cores under different displacement ratios and the response laws of mechanical parameters(compressive strength,elastic modulus,Poisson's ratio),revealing the influence mechanism of the carbonic acid dissolution-blocking effect on reservoir modification.Taking the long 6-section carbonate rocks in the Ordos Basin as the object,a porosity-permeability two-parameter evolution equation was constructed based on the displacement experimental data.The Pearson correlation coefficient was used to quantify the correlation between the displacement multiple and the mechanical parameters(compressive strength,elastic modulus,Poisson's ratio).The pore distribution characteristics of the core before and after displacement were analyzed by combining the nuclear magnetic resonance T_(2) spectrum to clarify the change law of the pore structure of carbonate rocks before and after displacement.The results show that:①Porosity and permeability show a trend of increasing first and then decreasing with displacement PV,with the variation ranges being-2.53%to 2.87%and-12.31%to 5.71%respectively.The porosity increases in the early stage of dissolution,but the subsequent sedimentation and blockage lead to a decrease in seepage capacity.②The compressive strength is strongly correlated with displacement ratio(increased significantly),the elastic modulus is moderately correlated(increased slowly by 1.2%~4.8%),and the Poisson's ratio has no significant rule.③Porosity is negatively correlated with compressive strength and elastic modulus(R2>0.65),while permeability is only negatively correlated with compressive strength.Dissolution reduces the strength of rocks by expanding pore connectivity,while mineral precipitation enhances structural stability.This study provides a pore-mechanical co-evolution criterion for the safety assessment of CO_(2) storage in low-permeability carbonate reservoirs,guiding the optimization of injection and production parameters to balance storage capacity and cap integrity.
作者
康智法
石洋
王汝旭
陈景杨
KANG Zhifa;SHI Yang;WANG Ruxu;CHEN Jingyang(School of Petroleum Engineering,Xi'an Shiyou University,Xi'an,Shaanxi 710065,China;Xi'an Shiyou University/Engineering Research Center of the Ministry of Education for the Development and Management of Low-Permeability and Ultra-Low-Permeability Oilfields in Western China,Xi'an,Shaanxi 710065,China)
出处
《石油工业技术监督》
2025年第10期1-8,共8页
Technology Supervision in Petroleum Industry
关键词
碳酸盐岩
溶蚀
孔隙度
渗透率
力学参数
carbonate rocks
dissolution
porosity
penetration rate
mechanical parameters
