沁水盆地南部中深部煤层气富集高产控制因素与有利区评价  

Evaluation of controlling factors and favorable zones for coalbed methane enrichment and high production in the mid-deep southern Qinshui Basin

作　　者：杨延辉 李梦溪 张辉[1] 米忠波 彭传利 王宁 缠玉慧 YANG Yanhui;LI Mengxi;ZHANG Hui;MI Zhongbo;PENG Chuanli;WANG Ning;CHAN Yuhui(PetroChina Huabei Oilfield Company,Renqiu 062552,China;Beijing Aoneng Hengye Energy Technology Company,Beijing 100089,China)

机构地区：[1]中国石油华北油田分公司,河北任丘062552 [2]北京奥能恒业能源技术有限公司,北京100089

出　　处：《天然气地球科学》2024年第10期1740-1749,共10页Natural Gas Geoscience

基　　金：中国石油华北油田公司技术攻关项目“沁水盆地沁南区块煤层气潜力目标评价与地质工程一体化研究”;中国石油前瞻性、基础性技术攻关项目“深层煤层气富集成藏与高产基础理论研究”(编号:2021DJ2301)联合资助。

摘　　要：中深部煤层气具有高含气、高饱和、含游离气的特征,采用新型井震标定和多属性联合构造解释技术,精细认识构造、标定解释层位,准确识别断层和陷落柱。沁水盆地南部西翼安泽区块安13井储量区单位涌水量为4 m^(3)/(m·d)以下,主体在1 m^(3)/(m·d)以下,水动力条件较弱。评价井取心资料统计结果表明:(1)研究区裂缝比较发育,裂缝发育区每点处各向异性较强,近南北、近东西向的裂缝相对发育,属于走滑断层应力机制,最大水平主应力方向为NNE向,有利于压裂裂缝的延伸。(2)3#煤层孔隙度平均为4.48%~4.5%。在构造形成过程中,背斜部位由于地层抬升,地层压力下降,甲烷通过孔隙和裂隙等通道由构造低部位向高部位运移,煤层水受重力作用,由高处向低处渗流,逐步形成“构造顶部富气贫水,腰部气、水共存,底部富水贫气”的煤层气富集模式,要获得较高产气量,须寻找煤层含气饱和度大于70%,含气量大于14 m^(3)/t的储层有利区。(3)对于有外水补给的储层开放体系,供给边界压力不变,外水补给造成泄流范围内压力降低缓慢;当储层为封闭体系时,储层水体为滞留型;当储层为半封闭体系时,储层水体为弱径流型。(4)沁水盆地南部西翼马必东区块煤层气井深度普遍为800~1 200 m,平均压裂液量为946.5 m^(3),返排后单相流期采用定产水量、定流压降速生产,单相流流压降幅保持在0.05~0.1 MPa/d之间,单相期平均时间为108 d,累计排水量为560 m^(3),平均解吸压力为4 MPa,排采曲线呈产水上升型,解吸前出现尖峰,稳产期长。The mid-deep CBM has the characteristics of high gas content,high saturation,and contains free gas.New well seismic calibration and multi-attribute joint tectonic interpretation techniques are adopted to finely understand the tectonics,calibrate the interpreted layers,and accurately identify the faults and trapped columns.The unit water influx in An13 reservoir area of Anze block of the west wing of southern Qinshui Basin is below 4 m^(3)/(m·d)in the area,and the main body is below 1 m^(3)/(m·d),with weak hydrodynamic conditions.The statistical results of the coring data of the evaluation wells show that:(1)The cracks in the study area are rela⁃tively developed,the west is more developed than the east,the anisotropy is stronger at each point in the crack development area,the cracks in the direction of near north-south and near east-west are relatively developed,which belongs to the stress mechanism of the strike-slip faults,and the direction of the maximum horizontal prin⁃cipal stress NNE is favorable for the extension of fracturing cracks.(2)The porosity of the 3#coal seam averag⁃es 4.48%-4.5%.In the process of tectonic folding,due to the uplift of strata in the dorsal part,the pressure of strata decreases,methane is transported from the low part of the tectonics to the high part of the tectonics through the channels of pore space and fissure,etc.,and the water of the coal seam seeps from the high to the low part of the tectonics due to the effect of gravity,and the coal seam gas enrichment mode of“the top of the tectonics is rich in gas and poor in water,the waist gas and water coexist,the bottom of the gas rich in water and poor in gas”is formed step by step.In order to obtain high gas production,it is necessary to find a favorable area in the reservoir where the gas saturation of the coal bed is more than 70%and the gas content is more than 14 m^(3)/t.(3)For the open system of the reservoir with external water recharge,the supply boundary pressure re⁃mains unchanged,and the pressure within the d

关 键 词：中深部煤层 富集高产 开发单元 地质—工程一体化 压裂返排 

分 类 号：TE121.1[石油与天然气工程—油气勘探]