裂缝对致密砂岩储层应力敏感性及渗流特征影响研究  

The Effect of Fractures on Stress Sensitivity and Seepage Characteristics in Tight Sandstone Reservoirs

作　　者：付兰清[1] 

机构地区：[1]中石油大庆油田有限责任公司勘探开发研究院,黑龙江大庆163712

出　　处：《长江大学学报（自科版）（中旬）》2016年第7期14-18,3-4,共5页Journal of Yangtze University(Nature Science Edition)

摘　　要：裂缝的存在对致密砂岩油藏渗流特征和开发效果有较大影响。选取松辽盆地北部致密砂岩岩样,采用恒定驱替压差、恒定净围压2种试验方法评价了人工裂缝对致密砂岩岩心应力敏感性影响,通过建立考虑启动压力梯度的油水相对渗透率计算模型,利用非稳态恒压法测定得到了致密砂岩储层岩心造缝前后的油水相对渗透率曲线,分析评价了裂缝对致密砂岩油藏渗流特征的影响规律。结果表明,带裂缝致密砂岩岩心具有强应力敏感性,增大孔隙内压可以促进裂缝开启,降低应力敏感性损害程度;裂缝的存在,使致密储层岩心油水相对渗透率曲线的共渗区范围增大,驱油效率增加,残余油饱和度下水相相对渗透率显著增大,改善了致密砂岩储层的整体开发效果。The existence of fractures would greatly influence the seepage characteristics and development effect of tight sandstone reservoirs.The effect of artificial fracturing on stress sensitivity of tight sandstone cores from the northern Songliao Basin was evaluated by using the constant displacement pressure and constant net confining pressure.By establishing a calculation model for oil-waterrelative permeability considering starting pressure gradient,the oil-water relative permeability curves both before and after the fracture creation was derived by using unsteady constant pressure method,and the law of fractures influencing the seepage characteristics in tight sandstone reservoirs was evaluated.Results demonstrate that the artificially fractured tight sandstone core samples are strong stress sensitivity,the increase of pore pressure can promote fracture opening and reduce the damage level of stress sensitivity.For the existence of fractures,the common flow interval of oil-water relative permeability curves of artificial fracture samples increases,and oil displacement efficiency also increases,the relative water permeability is significantly raised under the condition of residual oil saturation,the overall development effect of tight sandstone reservoirs is improved.

关 键 词：致密砂岩 人工裂缝 应力敏感 相对渗透率 驱油效率 

分 类 号：TE312[石油与天然气工程—油气田开发工程]