Bowen盆地北部M煤层气田水平井生产差异特征与主控因素分析  

Analysis on the difference of production characteristics and main factors for horizontal well in M coalbed methane field of Northern Bowen Basin

作　　者：崔泽宏[1] 王建俊 刘玲莉[1] 夏朝辉[1] 张铭[1] 杨勇[1] 段利江[1] CUI Zehong;WANG Jianjun;LIU Lingli;XIA Zhaohui;ZHANG Ming;YANG Yong;DUAN Lijiang(Petro China Research Institute of Petroleum Exploration & Development,Beijing 100083,China)

机构地区：[1]中国石油勘探开发研究院,北京100083

出　　处：《煤炭学报》2021年第5期1660-1669,共10页Journal of China Coal Society

基　　金：国家科技重大专项基金资助项目(2016ZX05029005)。

摘　　要：Bowen盆地北部上二叠统煤系地层煤层气资源丰富,但勘探开发程度低,为指导有利开发选区,需厘清已开发煤层气田生产特征差异与主控因素。以M煤层气田实际生产数据为基础,从静、动态资料研究入手,根据开发井高峰产气量和产气曲线形态划分4类产气模式:Ⅰ型,高峰产气量>4万m^(3)/d,产气陡升—陡降—后期平缓递减型,该型产气模式高峰产气量高,高峰稳产期短,为3~7个月,递减阶段早期递减快,年递减速度为30%~35%,后期递减缓慢;Ⅱ型,高峰产气量介于2万~4万m^(3)/d,产气陡升—后期缓慢递减型,该型产气模式高峰产气量中等,高峰稳产期相对较长,为10~12个月,递减阶段递减相对缓慢,年递减速度为8%~10%;Ⅲ型,高峰产气量<2万m^(3)/d,产气缓升—后期平稳型,该型产气模式产气相对较低,但产气平稳,无明显递减期;Ⅳ型,高峰产气量<1万m^(3)/d,低产不连续型,该型产气模式产气低或无自然产能。通过动、静态资料综合分析,明确了影响M煤层气田上述产气差异特征主控因素:①受埋深、构造控制,浅埋藏(<350 m)、高构造区域,煤层渗透性高,又是煤层气解吸、扩散、运聚的主要方向,高峰产气量高,主要分布于气田西部,为Ⅰ型产气模式;随埋藏变深(350~500 m)、构造变低,逐渐过渡为Ⅱ型产气模式,分布于气田中部;当埋深>500 m,煤层渗透性<1×10^(-15) m^(2),自然产能低,分布于气田东部,为Ⅳ型产气模式。②受局部低幅微凸起构造控制,高峰产气量高,仅分布气田东部局部区域,为Ⅰ-Ⅱ型产气模式。③受顶板封盖性差和煤层分叉变薄、夹矸的影响,开发井高峰产气量相对较低,分布于气田北部和南部,主要为Ⅲ型和Ⅳ型产气模式。基于上述结论,Bowen盆地北部浅埋藏、高构造斜坡区域仍是新区优先水平井开发的有利区域,但须优化浅层开发井网、井距,制定合理排采制度,避免产气大起大落,力求实�The coalbed methane is rich in Permian coal seams of the Northern Bowen basin,but the degree of exploration and development is low.In order to select the favorable development area and to clarify the production characteristics and the main influential factors,based on the static and dynamic production data in M coalbed methane gas field,and according to the peak gas rate and gas rate curve of the development well,four gas production types are established.For typeⅠ,the peak gas rate is higher than 4×104 m^(3)/d and the gas rate curve has a sharp rise-steep drop-slow decline trend.The peak gas is high and the peak gas time is short about three to seven months.The early decline phase has a high annual decline rate about 30%-35%,and the decline rate becomes slower in the later decline phase.For typeⅡ,the peak gas rate is 2×104-4×104 m^(3)/d and the gas rate curve has a sharp rise-slow decline trend.The peak gas is medium and the peak gas time is relatively long about ten to twelve months,and the decline is relatively slow with annual decline rate about 8%-10%.For typeⅢ,the peak gas rate is lower than 2×104 m^(3)/d and the gas rate curve has a slow rise-steady trend.The gas rate is relatively low but steady,so there is no apparent decline.For typeⅣ,the peak gas rate is lower than 1×104 m^(3)/d with a discontinuous production.Moreover,the main influential factors for the above different production characteristics are specified.Firstly,under the control of coal seam depth and geological structure,the area with relatively shallow depth(<350 m)and high permeability is the major region for the migration of desorbed and diffused coalbed methane,and it has a high peak gas rate,mainly in the west of the gas field with gas production typeⅠ.As the increase of coal seam depth,in the depth range of 350 to 500 m,at the lower location of the geological structure,the gas production typeⅡdistributes in the middle of the gas field.When the depth of coal seam is deeper than 500 m with permeability lower than 1×10^(-15

关 键 词：Bowen盆地北部 煤层气 水平井 生产差异特征 高峰产气量 主控因素 

分 类 号：P618.11[天文地球—矿床学]