渭北长裂缝性致密储层渗流特征及产能研究

A Study on Seepage Characteristics and Productivity of Fractured Tight Reservoir Chang 3 in Weibei

吴锦伟 李勇仁 曹军 吕栋梁

WUJinwei LIYongren CAOJun LüDongliang

中国石化华北油气分公司勘探开发研究院, 河南 郑州 450006 西南石油大学石油与天然气工程学院, 四川 成都 610500 苏州纽迈分析仪器股份有限公司, 江苏 苏州 215004

Exploration and Development Research Institution, Northeast China Oil and Gas Company, SINOPEC, Zhengzhou, Henan 450006, China Petroleum Engineering School, Southwest Petroleum University, Chengdu, Sichuan 610500, China Suzhou Niumag Analytical Instrument Corporation, Suzhou, Jiangsu 215004, China

为了研究基质与天然裂缝系统的渗流特征及其对产能的影响，以渭北油田长典型裂缝性致密储层为研究对象，通过核磁共振和室内测试综合实验，测定了储层渗流启动压力梯度的大小，基质和裂缝岩芯孔隙结构随围压的变化规律，基质和裂缝岩芯孔隙度随有效应力的变化规律及应力敏感系数，建立并验证了考虑启动压力梯度、基质与裂缝应力敏感差异的多级压裂水平井产能模型，分析了启动压力梯度、基质和裂缝应力敏感性对产能的影响规律。结果表明，拟启动压力梯度随着岩芯流度的降低而不断增加；裂缝岩芯的孔隙度应力敏感及渗透率敏感性均强于基质岩芯；基质应力敏感性对产能的影响更显著。因此，渭北长裂缝性致密储层的有效开发，应该考虑降低基质应力敏感性和启动压力梯度的影响。

In order to study the seepage characteristics of matrix and natural fracture system and its effect on productivity, We taking the typical fractured tight reservoir of Chang 3 in Wubei Oilfield as the research object, and through the nuclear magnetic resonance and the laboratory test synthesis experiment, the variation of reservoir seepage pressure gradient, the variation of matrix and fracture core pore structure with confining pressure and the variation of matrix and fracture core porosity with effective stress and stress sensitivity coefficient are determined. A multi-stage fracture horizontal well productivity model considering the initiation pressure gradient, matrix and fracture stress sensitivity differences is established and validated. The effects of starting pressure gradient, matrix and crack stress sensitivity on productivity are analyzed. The results show that the quasi-starting pressure gradient increases with the decrease of core fluidity; the porosity stress sensitivity and permeability sensitivity of fracture core are stronger than that of matrix core; the stress sensitivity of matrix has a more significant effect on productivity. Therefore, the effect of decreasing stress sensitivity and starting pressure gradient should be considered in the effective development of Chang-3 fractured tight reservoir in Weibei Oilfield.

10.11885/j.issn.16745086.2019.10.28.02