盐间页岩油CO_(2)-纯水吞吐开发机理实验及开采特征  

Experimental Study on Development Mechanism and Production Characteristics of CO_(2)-Pure Water Stimulation of Inter-Salt Shale Oil

作　　者：张冲[1] 萧汉敏[2] 肖朴夫 崔茂蕾[3,4] 赵清民 赵瑞明[5] Zhang Chong;Xiao Hanmin;Xiao Pufu;Cui Maolei;Zhao Qingmin;Zhao Ruiming(Northeast Oil&Gas Branch of SINOPEC,Changchun,Jilin 130072,China;Research Institute of Petroleum Exploration&Development,Beijing 100083,China;Centre of SINOPEC Petroleum Exploration and Production Research Institute,Beijing 100083,China;State Key Laboratory of Shale Oil and Gas Enrichment Mechanisms and Effective Development,Beijing 100083,China;SINOPEC Northwest Oil Field Company,Urumqi,Xinjiang 830011,China)

机构地区：[1]中国石化东北油气分公司,吉林长春130072 [2]中国石油勘探开发研究院,北京100083 [3]中国石化石油勘探开发研究院,北京100083 [4]页岩油气富集机理与有效开发国家重点实验室,北京100083 [5]中国石化西北油田分公司,新疆乌鲁木齐830011

出　　处：《特种油气藏》2022年第1期121-127,共7页Special Oil & Gas Reservoirs

基　　金：国家科技重大专项“陆相页岩油流动机理及开采关键技术研究”(2017ZX05049003)。

摘　　要：潜江凹陷页岩油储层储量丰富,其孔隙中富含多种可溶性矿物,采用CO_(2)-纯水吞吐进行开发,不仅能利用CO_(2)的超临界特性驱油,而且有利于提高CO_(2)在目的储层中的埋存,有效减少CO_(2)排放。但CO_(2)-纯水体系能否进入页岩微纳米孔隙,并有效动用孔隙中的原油是该方法能否实施的关键。通过设计CO_(2)、CO_(2)-纯水和CO_(2)-地层水的吞吐实验,基于核磁共振方法,明确了注CO_(2)、注CO_(2)-纯水和注CO_(2)-地层水组合的吞吐特征,总结了不同孔隙的原油动用规律和作用机理。实验结果表明:注CO_(2)-纯水体系比纯CO_(2)吞吐效率高8.62个百分点,比CO_(2)-地层水组合高12.66个百分点,CO_(2)-纯水组合形成的酸性流体会溶蚀孔隙表面的可溶性矿物,改善孔隙连通性,提高储层渗流能力,并且能有效提高小于0.01μm、0.01~0.10μm孔隙中的原油动用程度。多周期吞吐后,产出液中的离子物质的量浓度明显下降,表明后续注入纯水并未扩大波及体积,只是提高原油动用效率。该研究证实注CO_(2)-纯水体系可以有效提高页岩油藏采收率,为陆相页岩油有效开发提供新思路。The shale oil reservoirs in Qianjiang Sag are of abundant reserves,and their pores are rich in a variety of soluble minerals.In the development with CO_(2)-pure water stimulation,the supercritical characteristics of CO_(2)can be utilized for oil displacement and the CO_(2)sequestration in the target reservoirs also can be improved,which effectively reduce CO_(2)emissions.However,the key to implementation of this method lies in whether the CO_(2)-pure water system can enter the shale micro-nano pores and effectively drive the crude oil in the pores.Experiments of stimulation with CO_(2),CO_(2)-pure water and CO_(2)-formation water were designed,the stimulation characteristics of CO_(2)injection,CO_(2)-pure water injection and CO_(2)-formation water injection were clarified based on NMR method,and the law and mechanism of crude oil production in different pores were summarized.The experimental results showed that the stimulation efficiency of CO_(2)-pure water injection was 8.62 percentage points higher than that of CO_(2)injection,and 12.66 percentage points higher than that of CO_(2)-formation water injection,and the acidic fluid formed by the combination of CO_(2)-pure water could dissolve the soluble minerals on the pore surface,improve the pore connectivity and enhance the reservoir permeability,and effectively increase the production of crude oil in pores smaller than 0.01μm and 0.01 to 0.10μm.After multiple cycles of stimulation,the volumetric solubility of ionic substances in the produced liquid was decreased significantly,indicating that the subsequent injection of pure water failed to expand the swept volume,but only improved the production of crude oil.This study proves that the CO_(2)-pure water injection can effectively improve the recovery rate of shale reservoirs,and provides a new idea for the effective development of onshore shale oil.

关 键 词：页岩油 CO_(2)-纯水吞吐开发机理 核磁共振 微纳米孔隙 开采特征 

分 类 号：TE357.45[石油与天然气工程—油气田开发工程]