高温高压低渗气藏可动水饱和度及水气比定量评价方法  

Quantitative evaluation method of movable water saturation(MWS)and water gas ratio(WGR)in high temperature high pressure(HTHP)and low permeability gas reservoirs

作　　者：王雯娟 鲁瑞彬 雷霄 张乔良 胡琳 WANG Wenjuan;LU Ruibin;LEI Xiao;ZHANG Qiaoliang;HU Lin(CNOOC China Limited,Hainan Branch,Haikou,Hainan 570311,China)

机构地区：[1]中海石油(中国)有限公司海南分公司,海南海口570311

出　　处：《中国海上油气》2022年第3期91-97,共7页China Offshore Oil and Gas

基　　金：中海石油(中国)有限公司重大科技项目“南海西部高温高压气藏勘探开发技术及勘探新领域研究(编号:CNOOC-KJ 135 ZDXM38 ZJ 02 ZJ)”部分研究成果。

摘　　要：南海西部高温高压低渗气藏探井测试及生产井生产过程中见水现象普遍,该类气藏初始含水饱和度高,可动水是该类气藏气井产水的主要来源之一。通过室内驱替、离心和核磁共振实验,研究了可动水变化规律,研究表明随着地层压力的不断降低及生产压差的不断增大,部分束缚水转化为可动水被采出;依据实验结果,建立了不同压力梯度下可动水饱和度计算模型,实现了该类气藏可动水饱和度的定量计算。结合气水相渗曲线及渗流理论,建立了生产水气比和可动水饱和度关系,实现了可动水饱和度到生产水气比的精细计算。综合可动水饱和度计算模型及生产水气比计算关系,得到南海西部高温高压低渗气藏可动水饱和度小于25%,计算水气比约在2.3 m^(3)/10^(4) m^(3)以下,与生产实践认识较为一致。本文研究成果为气藏开发过程中产能、废弃压力、采收率等研究奠定了理论基础,在南海西部高温高压低渗气藏应用效果较好。Water breakthrough is common in well test of exploration wells and in production of producing wells in high temperature high pressure(HTHP)and low permeability gas reservoirs in the west area of South China Sea.The initial water saturation is high,and the movable water is one of the main sources of water production of gas wells in this kind of gas reservoir.The change law of movable water is studied under indoor core flooding experiment,centrifuged laboratory experiment and nuclear magnetic resonance(NMR)experiment.The experiment results show that some immobile water are transformed into movable water and produced from the well with continuous formation pressure decrease and continuous production pressure drop increase;According to the experimental results,the MWS model of different pressure gradients is built,which realizes the quantitative calculation of MWS in HTHP and low permeability gas reservoirs.Based on the gas-water relative permeability curve and seepage theory,the relationship between WGR and MWS is established,and the accurate calculation from MWS to WGR is realized.According to the calculation of MWS model and WGR equation,the MWS in HTHP and low permeability gas reservoir in the west area of South China Sea is less than25%,and the WGR is less than2.3 m^(3)/10^(4) m^(3),which is almost agreement with the understanding obtained from production practice.The results concluded in this paper provide a theoretical foundation for the study of productivity,abandonment pressure and recovery factor in gas reservoir development,and is verified in HTHP and low permeability gas reservoirs in the west area of South China Sea with good application effect.

关 键 词：高温高压 低渗气藏 可动水 核磁共振实验 水气比 

分 类 号：TE311[石油与天然气工程—油气田开发工程]