摘要
外来水补给导致煤层气井产水量高,影响了煤层内压力传播的有效性,最终影响产气量。为了查明不同补给水类型对煤层气井产水量的影响及产水/产气特征,以寿阳区块25口煤层气井勘探开发资料为基础,阐述了补给水类型划分参数获取的一般方法,提出了“阶梯法”的补给水类型划分方法,划分了补给水类型。分析了不同补给水类型对煤层气井产水量的控制作用和产水/产气曲线特征,并提出相应的开发对策。结果表明:煤层气井补给水类型可以划分为地表水补给、围岩水补给、无补给等三类,其中围岩水补给分为断层沟通型、突破隔层型、侧向补给型。寿阳的中、高产水块段主要分布在北部、西南部和南部;北部煤层埋藏浅,地表水是煤层气井外来水的主要补给源;西南部,围岩水补给-断层沟通型是煤层气井高产水的主控因素;中部、南部,围岩水补给-突破隔层型和侧向补给是煤层气井高产水的主控因素。最后,以柿庄南区块为例,验证了本文划分方法的可靠性,并提出不同补给水类型下的开发对策:地表水补给区,一般含气量较低,煤层气井一般表现为产气量小产水量大,需慎重布井;侧向补给区,产水量大,布井时避开径流区;断层沟通型补给区,产水量大、产气不稳定,建议不布井;突破隔层型补给区,压裂参数优化、井网协同排水降压是实现较高产气量的关键;无补给区,排水降压容易,优化压裂和排采工艺是煤层气高产的重要保障。多种补给水类型叠加区,开发难度大,布井需谨慎。
External water recharge of coalbed methane(CBM)wells leads to high water yield,thus affecting effective pressure propagation within coal seams and ultimately impacting gas production.This study aims to ascertain the influence of different types of recharge water on the water yield of CBM wells,as well as the characteristics of water yield and gas production of these wells under different recharge water types.Based on the exploration and development data of 25 CBM wells in the Shouyang block,this study presented general methods for obtaining the parameters for recharge water type classification and proposed the stepped method for the type classification.As a result,this study determined the recharge water types,analyzed their controlling effects on the water yield of CBM wells,as well as the characteristics of water yield and gas production curves,and proposed countermeasures against different types of recharge water.The results are as follows:(1)The recharge water of CBM wells can be divided into three types,namely surface water,surrounding rock water,and no recharge.Among them,the surrounding rock water recharge can be further divided into the fault connection type,the interlayer breakthrough type,and the lateral recharge type.(2)The moderate and high wa-ter yields in the Shouyang block are distributed primarily in the northern,southwestern,and southern parts of this block.The coal seams in the northern part are shallowly buried,and the surface water is the main recharge source of CBM wells.In the southwestern part,the surrounding rock water recharge of the fault connection type is the main factor con-trolling the high water yield of CBM wells.In the middle and southern parts of the Shouyang block,the surrounding rock water recharge of the remaining two types is the main factor controlling the high-yield water of CBM wells.Finally,this study verified the reliability of the classification method by applying this method to the southern Shizhuang block and proposed the development countermeasures against different recharge water types:(1)Areas with surface water re-charge are generally characterized by low gas content,and CBM wells in these areas generally exhibit low gas produc-tion and high water yield.Therefore,it is necessary to arrange CBM wells prudently in these areas;(2)Areas with later-al recharge show high water yield,and thus CBM wells should be kept away from runoff in these areas;(3)Areas with surrounding rock water recharge of the fault connection type exhibit high water yield and unstable gas production.Therefore,it is recommended that no CBM wells should be arranged in these areas;(4)For areas with surrounding rock water recharge of the interlayer breakthrough type,the optimization of fracturing parameters and the synergistic drainage-based depressurization of the well pattern hold the key to high gas production;(5)For areas with no recharge,it is prone to achieve drainage-based depressurization,and the optimization of fracturing and production processes plays an import-ant role in guaranteeing high CBM production in this area;(6)For areas with multiple recharge water types,it is diffi-cult to develop CBM,and it is necessary to arrange CBM wells prudently in these areas.
作者
杜丰丰
倪小明
张亚飞
刘玉茹
王文升
DU Fengfeng;NI Xiaoming;ZHANG Yafei;LIU Yuru;WANG Wensheng(School of Energy Science and Engineering,Henan Polytechnic University,Jiaozuo 454003,China;China United Coalbed Methane Corp.,Ltd.,Beijing 100011,China;CNOOC Energy Tech-Drilling&Production Co.,Tianjin 300452,China)
出处
《煤田地质与勘探》
EI
CAS
CSCD
北大核心
2023年第6期74-84,共11页
Coal Geology & Exploration
基金
河南省高校科技创新团队项目(21IRTSTHN007)
中国海洋石油集团有限公司重大科研专项项目(CNOOC-KJ135ZDXM40ZL01)。
关键词
补给水类型
煤层气
高产水
水动力场
控制因素
recharge water type
coalbed methane
high water yield
hydrodynamic field
controlling factor
