非常规油气储集层粗糙压裂裂缝内支撑剂运移机理  

Proppant transport in rough fractures of unconventional oil and gas reservoirs

作　　者：尹邦堂 张超[4] 王志远 孙宝江[1,2,3] 高永海[1,2,3] 王晓鹏[4] 毕闯 张启龙[4] 王金堂 石军太[5] YIN Bangtang;ZHANG Chao;WANG Zhiyuan;SUN Baojiang;GAO Yonghai;WANG Xiaopeng;BI Chuang;ZHANG Qilong;WANG Jintang;SHI Juntai(Key Laboratory of Unconventional Oil&Gas Development,Ministry of Education,Qingdao 266580,China;School of Petroleum Engineering,China University of Petroleum(East China),Qingdao 266580,China;National Engineering Research Center of Oil&Gas Drilling and Completion Technology,Beijing 102206,China;Tianjin Branch of CNOOC(China)Co.,Ltd,Tianjin 300452,China;School of Petroleum Engineering,China University of Petroleum(Beijing),Beijing 102249,China)

机构地区：[1]非常规油气开发教育部重点实验室,山东青岛266580 [2]中国石油大学(华东)石油工程学院,山东青岛266580 [3]油气钻完井技术国家工程研究中心,北京102206 [4]中海石油(中国)有限公司天津分公司,天津300452 [5]中国石油大学(北京)石油工程学院,北京102249

出　　处：《石油勘探与开发》2023年第3期624-632,共9页Petroleum Exploration and Development

基　　金：国家自然科学基金项目(52274020,U21B2069,52288101);山东省自然科学基金面上项目(ZR2020ME095);国家重点研发计划项目(2021YFC2800803)。

摘　　要：基于分形插值理论建立了具有粗糙壁面裂缝的生成方法,同时考虑颗粒-颗粒、颗粒-壁面、颗粒-流体的相互作用,建立了基于计算流体力学(CFD)-离散单元法(DEM)耦合的支撑剂-压裂液两相流动模型。经实验数据的检验,证实该模型可以较好地匹配粗糙裂缝内支撑剂的运移情况及堆积过程。经多个方案的数值模拟研究表明:与光滑平板裂缝相比,支撑剂在粗糙裂缝内输送,壁面粗糙凸起会显著影响支撑剂的运移与沉降,裂缝模型的粗糙程度越高,裂缝入口附近的支撑剂颗粒沉降速度越快,其水平运移距离越短,越倾向于在裂缝入口附近堆积,并在较短时间内形成缝内砂堵。裂缝壁面粗糙度在一定程度上可控制流体的运移路径,改变支撑剂填充裂缝的方式,一方面粗糙壁面凸起抬升了支撑剂运移轨迹,使支撑剂流出裂缝,导致覆盖率减小;另一方面携砂液易在粗糙壁面凸起接触点附近发生转向流动,可在一定程度上扩大支撑剂覆盖范围。A method to generate fractures with rough surfaces was proposed according to the fractal interpolation theory.Considering the particle-particle,particle-wall and particle-fluid interactions,a proppant-fracturing fluid two-phase flow model based on computational fluid dynamics(CFD)-discrete element method(DEM)coupling was established.The simulation results were verified with relevant experimental data.It is proved that the model can match the transport and accumulation of proppant in rough fractures well.Several cases of numerical simulations were carried out.Compared with smooth flat fractures,when proppant was transported in rough fractures,protrusion on the rough fracture wall would significantly affect the transport and settlement of proppant.The higher the roughness of fracture,the faster the settlement of proppant particles near the fracture inlet,the shorter the horizontal transport distance,and the more likely to accumulate near the fracture inlet to form a sand plugging in a short time.Fracture wall roughness could control the migration path of fracturing fluid to a certain degree and changed the way of proppant filling the fracture.On the one hand,the rough wall bulge raised the proppant transport path and the proppant flowed out of the fracture,resulting in reduced sweep area.On the other hand,the sand-carrying fluid was prone to change flow direction near the contact point of protrusion,thus expanding the proppant sweep area.

关 键 词：非常规油气储集层 压裂改造 粗糙裂缝 分形插值 CFD-DEM耦合 支撑剂运移 

分 类 号：TE319[石油与天然气工程—油气田开发工程]