考虑渗吸效应的致密油藏体积改造可行性分析  

Application of Imbibition Mechanism in Massive Fracturing of Tight Oil Reservoir

作　　者：李帅[1,2] 丁云宏[2] 顾岱鸿[3] 刘广峰[3] 才博[2] 

机构地区：[1]中国石油勘探开发研究院,北京100083 [2]中国石油勘探开发研究院廊坊分院,河北廊坊065007 [3]中国石油大学(北京)石油工程教育部重点实验室,北京102249

出　　处：《地质科技情报》2017年第6期245-250,共6页Geological Science and Technology Information

基　　金：国家科技重大专项"大型油气田及煤层气开发"(2016ZX05023)

摘　　要：为探究致密储集层在毛管力、重力作用下的渗吸机理,考虑致密储集层特征(相渗、毛管力等),推导出了一维两相逆向渗吸模型,利用Mattax和Kyte方法对时间无因次处理后,采用差分方法进行求解,给出了3种边界条件下方程的解,并对常规砂岩和致密岩心渗吸结果进行了对比。结果表明:(1)体积改造后形成复杂缝网,储集层渗吸作用可分为重力辅助渗吸、重力抑制渗吸和零重力渗吸;(2)尽管致密储集层孔喉半径小,毛管压力高,渗吸动力强,但由于其孔渗条件差,流体流动受限,综合来说其饱和度前缘慢于常规高渗储集层;(3)毛管力在常规砂岩和致密储集层的渗吸中均起主导作用,重力在高渗砂岩渗吸中表现明显,而在致密储集层渗吸中表现不明显;(4)对于致密储集层,通过水平井分段多簇、细分切割,甚至"体积改造"的压裂模式,增加润湿相与裂缝壁面的接触面积和接触体积,则可充分发挥渗吸作用,置换出更多的油气,提高原油产量。新疆油田玛18区块现场试验表明,致密储集层发挥渗吸作用可提高原油产量2~4t/d。Spontaneous imbibition is an important mechanism for fractured reservoir to enhance oil recover- y. To investigate the imbibition of tight reservoirs, on the consideration of tight reservoir characteristics, this paper has developed a one dimension and two phases counter-current imbibition model, After dimen- sionless distance and time, spatial discretization and time integration, solutions are given, and then con- trast of conventional sandstone and tight formation is made. The results indicate that： ①imbibition can be divided into gravity assisting, gravity opposing and zero gravity in terms of different gravity conditions. ② Saturation front of tight formation moves slower than sandstone ever of its high capillary pressure. ③Cap- illary pressure plays the dominant role in imbibition. Influence of gravity is much greater in conventional sandstone than in tight reservoirs. ④Horizontal well multi-stage fracturing or volume fracturing can in- crease the fracture area and volume, and increase the contact area with wetting phase, which may result in a greater recovery of oil. Field practice in Mahu has proved that oil extraction can increase 3.5 t/d.

关 键 词：致密油藏 体积改造 渗吸效应 毛管力 重力 

分 类 号：P588.12[天文地球—岩石学]