CO_(2)混相驱胶质、沥青质析出规律——以东河6油藏为例  

Gum and asphaltene precipitation pattern in CO_(2)miscible flooding:A case study of Donghe 6 reservoir

作　　者：张利明[1] 李汝勇[1] 袁泽波[1] 侯大力[2,3] 王小强[1] 曾昌民[1] ZHANG Liming;LI Ruyong;YUAN Zebo;HOU Dali;WANG Xiaoqiang;ZENG Changmin(PetroChina Tarim Oilfield Company,Korla,Xinjiang,841000,China;The State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Chengdu University of Technology,Chengdu,Sichuan,610059,China;College of Energy,Chengdu University of Technology,Chengdu,Sichuan,610059,China)

机构地区：[1]中国石油塔里木油田公司,新疆库尔勒841000 [2]成都理工大学油气藏地质及开发工程国家重点实验室,四川成都610059 [3]成都理工大学能源学院,四川成都610059

出　　处：《天然气与石油》2024年第1期63-67,共5页Natural Gas and Oil

基　　金：四川省科技计划项目“储层条件超临界CO_(2)压裂液页岩气页岩多相相互作用复杂机理研究”(2021YJ0352)。

摘　　要：掌握油田原油在注CO_(2)过程中是否混相及油层沥青质的沉淀规律具有重要意义。设计了一套高温、高压混相及沉淀实验装置,并开展CO_(2)混相驱胶质、沥青质析出规律的实验研究,模拟东河6油藏注气开采过程,判断注入气体与地层流体是否达到混相,表征油层内胶质、沥青质的析出规律。实验结果表明:东河6油藏注CO_(2)驱提采机理为一次混相;沥青质相对沉淀量随CO_(2)注入比例的增加而迅速增加后又缓慢减少,胶质相对沉淀量随注入比例的增加先降低后增加;注CO_(2)后降压衰竭开采优先采出饱和烃,油层原油沥青质含量迅速增加。东河6油藏注CO_(2)驱保持最低混相压力45.4 MPa以上开采,可提高驱替效率,减少开采过程中胶质、沥青质的析出,提高原油采收率。研究结果可为注CO_(2)油藏提供一种混相压力及沥青质沉淀测定的方法,支撑注CO_(2)油藏开发方案的制定。During the CO_(2)injection process,it's essential to understand whether miscibility significantly impacts oil displacement efficiency and how asphaltene precipitation behaves in oil layers under CO_(2)injection.This paper outlines the design of a high-temperature and high-pressure mixing and precipitation experimental apparatus and details experimental studies on the precipitation pattern of asphaltenes and resins during CO_(2)miscible flooding.The research simulates the injection and production processes of the Donghe 6 reservoir,assessing the miscibility of the injected gas with the formation fluid and monitoring the precipitation pattern in asphaltene and resin content within the reservoir.The experimental results indicate that the CO_(2)flooding mechanism in the Donghe 6 reservoir is primarily of the contact miscible type.The relative precipitation of asphaltenes initially surges and then tapers off with increasing amounts of injected CO_(2),whereas the precipitation of resins first diminishes and then rises.After the CO_(2)injection,employing depressurization and depletion techniques preferentially extracts saturated hydrocarbons,resulting in a marked increase in asphaltene concentration in the reservoir's crude oil.To enhance displacement efficiency and mitigate resin and asphaltene precipitation during extraction,maintaining a minimum miscibility pressure of 45.4 MPa or higher for CO_(2)flooding in the Donghe 6 reservoir is recommended,which also contributes to an elevated crude oil recovery rate.The research results provide a method for measuring miscibility pressure and asphaltene precipitation in reservoirs undergoing CO_(2)injection,thereby supporting the development strategies for such reservoirs.

关 键 词：油层流体混相 CO_(2)混相驱 胶质沉淀 沥青质沉淀 东河6油藏 原油采收率 

分 类 号：TE357.45[石油与天然气工程—油气田开发工程]