海上低渗高含水气藏基于可动水的产能评价方法  

A productivity evaluation method based on movable water for offshore low permeability and high water content gas reservoirs

作　　者：王琴 王攀荣 张骞 唐慧敏 杨柳 WANG Qin;WANG Panrong;ZHANG Qian;TANG Huimin;YANG Liu(Hainan Branch,CNOOC Limited(China),Haikou 570312,Hainan;Zhanjiang Branch,CNOOC Limited(China),Zhanjiang 524057,Guangdong)

机构地区：[1]中海石油(中国)有限公司海南分公司,海南海口570312 [2]中海石油(中国)有限公司湛江分公司,广东湛江524057

出　　处：《长江大学学报（自然科学版）》2024年第4期95-103,共9页Journal of Yangtze University(Natural Science Edition)

基　　金：国家自然科学基金项目“海上高温高压低渗透储层渗流流固耦合机理及表征方法研究”(U22B2073)。

摘　　要：南海西部乐东区低渗气藏原生含水饱和度高,探井测试水气比高、层间差异大、孔隙水的赋存状态和可动条件不清,产水气井产能认识不准确。通过气水驱替与核磁共振实验,明确了靶区不同物性岩心可动水赋存特征和变化规律,建立可动水饱和度预测模型,提出了基于可动水产出的产能评价方法。研究表明,低渗气藏储层孔喉半径小,可动水主要赋存在较大的微米级及亚微米级孔喉内;可动水饱和度与驱替压力梯度呈指数正相关关系,Ⅰ类岩心可动水饱和度的的主控因素是渗透率,Ⅱ类岩心主控因素是渗透率和驱替压差;可动水孔隙度与岩心孔隙度呈线性正相关关系,与岩心渗透率呈对数式正相关关系,极限驱替压差下Ⅰ类岩心可动水孔隙度在8%左右,Ⅱ类岩心则明显偏低,为4.2%~6.2%,且受渗透率影响较大。基于可动水产出的产能评价方法在乐东区探井应用效果好,可合理指导乐东区开发井产能研究。High primary water saturation of low permeability gas reservoirs in the Ledong area of the western South China Sea,exploration wells testing have a high water gas ratio and significant interlayer differences,the occurrence status and movable conditions of pore water are unclear,and the production capacity of water producing gas wells is not accurately understood.Through gas-water displacement and nuclear magnetic resonance experiments,the occurrence characteristics and variation patterns of movable water in cores with different permeability have been clarified,and a movable water saturation prediction model has been established.A productivity evaluation method based on movable water production has been proposed.The study shows that the pore throat radius of low permeability gas reservoirs is small,and movable water mainly exists in larger micron and submicron pore throat.There is an exponential positive correlation between movable water saturation and displacement pressure gradient,the main controlling factors for movable water saturation in typeⅠcore is permeability,while the main controlling factor for typeⅡcore are permeability and displacement pressure difference.The porosity of movable water is linearly positively correlated with the porosity of the core,and logarithmically positively correlated with the permeability of the core,the porosity of movable water in type I core under the extreme displacement pressure difference is about 8%,while that in typeⅡcore is significantly lower,ranging from 4.2%to 6.2%,and is greatly affected by the permeability.The production capacity evaluation method based on movable aquatic products has been applied effectively in exploration wells in Ledong area,which can reasonably guide the production capacity research of development wells in Ledong area.

关 键 词：低渗气藏 高含水饱和度 可动水 驱替压差 气水两相稳态产能 

分 类 号：TE311[石油与天然气工程—油气田开发工程]