Shale oil recovery by CO_(2)injection in Jiyang Depression,Bohai Bay Basin,East China  

作　　者：LI Yang ZHU Yangwen LI Zongyang JIANG Tingxue XUE Zhaojie SHEN Ziqi XIAO Pufu YU Hongmin CHENG Ziyan ZHAO Qingmin ZHANG Qingfu 

机构地区：[1]China Petroleum&Chemical Corporation,Beijing 100728,China [2]Sinopec Petroleum Exploration and Production Research Institute,Beijing 102206,China [3]Exploration and Development Research Institute,Sinopec Shengli Oilfield Company,Dongying 257015,China [4]Sinopec Research Institute of Petroleum Engineering Co.,Ltd.,Beijing 102206,China

出　　处：《Petroleum Exploration and Development》2024年第4期981-992,共12页石油勘探与开发（英文版）

基　　金：Supported by Basic and Forward-Looking Project of the Science and Technology Department of SINOPEC(P22213-4)。

摘　　要：Laboratory experiments,numerical simulations and fracturing technology were combined to address the problems in shale oil recovery by CO_(2)injection.The laboratory experiments were conducted to investigate the displacement mechanisms of shale oil extraction by CO_(2)injection,and the influences of CO_(2)pre-pad on shale mechanical properties.Numerical simulations were performed about influences of CO_(2)pre-pad fracturing and puff-n-huff for energy replenishment on the recovery efficiency.The findings obtained were applied to the field tests of CO_(2)pre-pad fracturing and single well puff-n-huff.The results show that the efficiency of CO_(2)puff-n-huff is affected by micro-and nano-scale effect,kerogen,adsorbed oil and so on,and a longer soaking time in a reasonable range leads to a higher exploitation degree of shale oil.In the"injection+soaking"stage,the exploitation degree of heavy hydrocarbons is enhanced by CO_(2)through its effects of solubility-diffusion and mass-transfer.In the"huff"stage,crude oil in large pores is displaced by CO_(2)to surrounding larger pores or bedding fractures and finally flows to the production well.The injection of CO_(2)pre-pad is conducive to keeping the rock brittle and reducing the fracture breakdown pressure,and the CO_(2)is liable to filter along the bedding surface,thereby creating a more complex fracture.Increasing the volume of CO_(2)pre-pad can improve the energizing effect,and enhance the replenishment of formation energy.Moreover,the oil recovery is more enhanced by CO_(2)huff-n-puff with the lower shale matrix permeability,the lower formation pressure,and the larger heavy hydrocarbon content.The field tests demonstrate a good performance with the pressure maintained well after CO_(2)pre-pad fracturing,the formation energy replenished effectively after CO_(2)huff-n-puff in a single well,and the well productivity improved.

关 键 词：shale oil carbon dioxide pre-pad fracturing huff-n-puff for energy replenishment laboratory experiment field test recovery efficiency enhanced oil recovery 

分 类 号：TE53[石油与天然气工程—油气田开发工程]