南海礁灰岩稠油油藏注富气混相驱实验研究  

Research on miscible flooding with rich gas in reef limestone heavy oil reservoir in the South China Sea

作　　者：王亚会 闫正和 涂乙 汤小龙 张晓林 徐伟 汪毅 WANG Yahui;YAN Zhenghe;TU Yi;TANG Xiaolong;ZHANG Xiaolin;XU Wei;WANG Yi(CNOOC China Limited,Shenzhen Branch,Shenzhen,Guangdong 518054,China)

机构地区：[1]中海石油(中国)有限公司深圳分公司,广东深圳518054

出　　处：《中国海上油气》2020年第5期100-106,共7页China Offshore Oil and Gas

基　　金：中海石油(中国)有限公司科技项目课题“南海东部生物礁灰岩油田提高采收率研究(编号:YXQI-2015-SZ-01)”部分研究成果。

摘　　要：南海东部礁灰岩L油田原油黏度高、裂缝发育复杂、非均质性强、采出程度低,为提高采收率,选取附近高气油比油田H油田的伴生富气开展了混相驱室内实验研究。首先为明确注入气的驱油机理,对配置的实验用注入富气与原油进行了PVT相态物性测试;然后开展了地层温度不同压力下注入1.2 PV的细管驱替实验、原始地层压力下高倍数注入体积(最大4.0 PV)的扩展细管驱替实验。结果表明:注入气具有较好的增容、降黏效果,随着注入量的增加,地层原油的膨胀系数增大了1.25倍,原油黏度由50 mPa·s降低至6.7 mPa·s;在原始地层压力12 MPa下,注入体积大于3.0 PV时可以实现多次接触后缘凝析气驱混相;因此原始地层压力下,H油田具备注伴生富气混相驱的条件。本文研究成果可以为下步长岩心物模、混相数模和矿场实施提供依据。The reef limestone L oilfield in the eastern South China Sea is characterized by high crude oil viscosity,complex fracture development,high anisotropy and low recovery percent.In order to enhance oil recovery,associated gas from nearby H oilfield with high gas-oil ratio was selected to conduct laboratory study on miscible flooding.First,the PVT phase state and physical properties of the prepared rich gas to be injected and crude oil were tested so as to make clear the oil-displacement mechanism of the injected gas.Then slim-tube test was conducted by injecting 1.2 PV under different pressures at formation temperature,and extended slim-tube test was conducted by injecting high volume(up to 4 PV)under initial reservoir pressure.The results show that the injected associated gas works well in terms of compatibilization and viscosity reduction.With increase of the injected volume,the expansion coefficient of reservoir oil increased by 1.25 times and the oil viscosity decreased from 50 mPa·s to 6.7 mPa·s.Condensate gas miscible flooding can be observed in the displacement trailing edge after multiple contact of the crude oil with the injected gas when the injected volume is more than 3.0 PV under initial reservoir pressure of 12 MPa.Therefore,H oilfield has the condition of achieving miscible flooding with associated rich gas under initial reservoir pressure.The research results can provide a basis for physical model of long core,mathematical model of miscible phase and field application in the next step.

关 键 词：礁灰岩 稠油油藏 富气驱 混相机理 

分 类 号：TE344[石油与天然气工程—油气田开发工程]