煤层气-水-固三相流动模型与数值模拟研究  

Tri-phase flow model of coalbed methane-water-solid and numerical simulation study

作　　者：张健 朱苏阳[2] 彭小龙[2] 邓鹏 ZHANG Jian;ZHU Suyang;PENG Xiaolong;DENG Peng(CNOOC Research Institute Ltd., Beijing 100028, China;State Key Laboratory of Oil and Gas Geology and Exploitation, Southwest Petroleum University, Chengdu, Sichuan 610500, China)

机构地区：[1]中海油研究总院有限责任公司,北京100028 [2]西南石油大学油气藏地质与开发工程国家重点实验室,四川成都610500

出　　处：《中国海上油气》2022年第1期117-127,共11页China Offshore Oil and Gas

基　　金：“十三五”国家科技重大专项“临兴-神府地区煤系地层煤层气、致密气、页岩气合采示范工程(编号:2016ZX05066)”部分研究成果。

摘　　要：中-高阶煤岩脆性较强,钻完井、增产及生产过程中易产生煤粉。排水采气过程中,煤粉的运移会堵塞地层并造成埋泵、卡泵事故,导致气井产量大幅度下降。为了探索煤粉在储层中的流动机理,本文分析了煤层气生产过程中煤粉的运移过程,将存在状态分为静煤粉与动煤粉,将运移中的物理过程简化为剥蚀产生、流化启动、悬浮运移、沉降堵塞与聚团生长等5个过程,并基于微乳相模型,建立了考虑煤粉运移的气-液-固三相流动数学模型,通过数值模拟方法,分析了控压排采、适度出粉以及快速排采等3种排水策略对生产动态的影响,并结合矿场实例,分析了煤粉运移中各物理过程对煤层气排采的影响。研究结果表明,对于产出煤粉的气井,采用控压连续排采策略最为稳妥;关井可对煤层渗透率带来不可逆的伤害,应尽量缩短修井与关井的时间和次数。本文研究成果可为煤粉运移定量化排采策略研究提供参考。Middle-high rank coal is relatively brittle,and coal fines are easily generated during drilling/completion,stimulation and production.In the process of drainage and gas production,the migration of coal fines tends to block the formation and cause accidents of buried pumps and stuck pumps,resulting in a significant decline in gas well productivity.In order to explore the flow mechanism of coal fines in the reservoir,this paper analyzes the migration process of coal fines in the process of coalbed methane(CBM)production,divides the existing states of coal fines into the static and dynamic ones,and simplifies the physical processes in the migration as the five processes of denudation generation,fluidization initiation,suspension migration,settlement blockage and agglomeration growth,and establishes a gas-liquid-solid tri-phase flow mathematical model considering coal fines migration on the basis of microemulsion phase model.By means of numerical simulation method,the influence of three drainage strategies(i.e.,pressure managed drainage,moderate powder extraction and rapid drainage)on production performance is analyzed,and the influence of various physical processes on CBM drainage and production during coal fines migration has been analyzed in combination with the field examples.The research results show that for gas well producing coal fines,it is the most reliable way to produce it with pressure managed continuous drainage.Meanwhile,the well shut-in can bring irresistible damage to coal permeability,and the duration and times of well intervention and shut-in should be shortened.The results in this paper can provide a reference for coal fines migration quantitative drainage strategy.

关 键 词：煤层气 煤粉运移 数学模型 排采制度 数值模拟 

分 类 号：TE311[石油与天然气工程—油气田开发工程]