微裂缝岩心启动压力梯度实验研究  

Experimental Study on Threshold Pressure Gradient of Micro-fracture Cores

作　　者：郑文宽 刘月田[1] 丁祖鹏 刘泽华[1] 张艺馨 

机构地区：[1]中国石油大学石油工程教育部重点实验室,北京102249 [2]中海油研究总院,北京100027 [3]密苏里科技大学,美国密苏里州63101

出　　处：《西安石油大学学报（自然科学版）》2017年第4期50-54,共5页Journal of Xi’an Shiyou University（Natural Science Edition）

基　　金：国家自然科学基金项目"各向异性裂缝页岩气藏渗流机理与理论研究"(编号:51374222);国家重大专项"中东典型碳酸盐岩油藏开发规律及技术政策研究"(编号:2016ZX05032005-002);国家重大专项"基于各向异性的特低渗透油藏井网优化与注采调控技术研究"(编号:2016ZX05013002-001);国家重点基础研究发展计划"陆相致密油高效开发基础研究"课题五之专题一"致密油藏产能预测方法"(编号:2015CB250905)

摘　　要：为了研究微裂缝对低渗、特低渗储层非线性渗流规律的影响,使用渗透率接近的天然裂缝岩心、人造裂缝岩心、无裂缝岩心进行了室内渗流实验。研究结果表明:岩心渗透率接近时,微裂缝的存在会大幅降低岩心的真实启动压力梯度,降低不可动流体比例,但是对拟启动压力梯度数值影响较小,同时微裂缝减小了流体流动过程中贾敏效应的影响,使得通过实验数据拟合的启动压力梯度幂函数幂指数更接近-1,此指数大小受孔喉非均质性控制,影响启动压力梯度预测准确性。The seepage experiments of natural fractured cores, artificial fractured cores and non-fractured cores were carried out in order to study the nonlinear seepage characteristics of low and extra-low permeability reservoir in which microfractures are developed. The re- sults show that when the permeability of the cores is similar, the existence of microfractures will significantly reduce the threshold pres- sure gradient of cores, and therefore reduce the proportion of immobile fluid, but has little effect on pseudo threshold pressure gradient; at the same time, microfractures reduce the Jiamin effect in fluid flow, which makes the power exponent of the threshold pressure gradi- ent power function fitted by experimental data is more close to -1. The power exponent is controlled by the heterogeneity of pore throat structure, and it will influence the accuracy of threshold pressure gradient prediction.

关 键 词：微裂缝 启动压力梯度 幂函数 贾敏效应 

分 类 号：TE312[石油与天然气工程—油气田开发工程]