Mechanisms of water block removal by surfactant micellar solutions in low permeability reservoirs  

作　　者：LI Junjian LIU Ben GUO Cheng SU Hang YU Fuwei MA Mengqi WANG Lida JIANG Hanqiao 

机构地区：[1]State Key Laboratory of Petroleum Resources and Prospecting,China University of Petroleum,Beijing 102249,China [2]Research Institute of Petroleum Exploration&Development,PetroChina,Beijing 100083,China

出　　处：《Petroleum Exploration and Development》2022年第2期394-405,共12页石油勘探与开发（英文版）

基　　金：Supported by the China National Science and Technology Major Project (2017ZX05009-005-003);Research Fund of China University of Petroleum (Beijing)(2462019QNXZ04)。

摘　　要：The existing researches on surfactant micellar solutions mainly focus on the formulation optimization and core flooding test, and the types and mechanisms of cleanup additives suitable for low permeability reservoir remain unclear. The flowback efficiencies of different types of surfactant micellar solutions were evaluated by core experiments, a multi-level pore-throat system micromodel characterizing pore-throat structures of low permeability reservoir was made, and flooding and flowback experiments of brine and surfactant micellar solutions of different salinities were conducted with the micromodel to show the oil flowback process in micron pores under the effect of surfactant micellar solution visually and reveal the mechanisms of enhancing displacement and flowback efficiency of surfactant micellar solution. During the displacement and flowback of brine and low salinity surfactant micellar solution, many small droplets were produced, when the small droplets passed through pore-throats, huge percolation resistance was created due to Jamin’s effect, leading to the rise of displacement and flowback pressure differences and the drop of flowback efficiency. The surfactant micellar solutions with critical salinity and optimal salinity that were miscible with crude oil to form Winsor Ⅲ micro-emulsion didnot produce mass small droplets, so they could effectively reduce percolation resistance and enhance oil displacement and flowback efficiency.

关 键 词：low permeability reservoir cleanup additive cleanup mechanism SURFACTANT microfluidic visualization experiment crude flowback 

分 类 号：TE357[石油与天然气工程—油气田开发工程]