织金工区煤层气定向井产能影响因素分析  

Productivity controls in CBM directional wells,Zhijin block

作　　者：金鑫[1] 李佳欣 刘念肖 裴颖杰[1,2] JIN Xin;LI Jiaxin;LIU Nianxiao;and PEI Yingjie(Sinopec East China Oil&Gas Company,Nanjing,Jiangsu 210019,China;Sinopec Chongqing Shale Gas Co.,Ltd.,Chongqing 408400,China)

机构地区：[1]中国石化华东油气分公司,江苏南京210019 [2]中国石化重庆页岩气有限公司,重庆408400

出　　处：《天然气技术与经济》2024年第5期29-35,共7页Natural Gas Technology and Economy

基　　金：中国石化科技部科研项目“低压煤系气藏地质工程一体化高效开发技术”(编号:P20074-1);“中国石化煤层气勘探战略选区研究”(编号:P21086-5)。

摘　　要：为了解决织金工区煤层气定向井产能差异大、稳产时间短、产能影响因素认识不清等问题,以工区大、小井组共23口定向井为研究对象,从地质和工程角度出发,分析了地质条件及施工参数对气井产能的影响规律,指出了不同地质情况及工艺措施对气井产能的影响程度。研究结果表明:①影响织金工区煤层气定向井产能的主要因素有解吸压力、煤层厚度、施工液量、前置液量和施工排量;②地质上大井组平均开发层位约为小井组的4倍,16、17、21号煤层在沉积环境、保存条件和储层构造上好于其他煤层;③工程上施工液量、前置液量和施工排量对压裂改造有较大的影响,结合工区施工数据,当排量一定,施工液量约为前置液量的5倍时,储层改造效果较好。结论认为:①织金工区煤层具有多、薄等特点,且层间距、纵向非均质差异小,采用定向井开发多层合采效果较好,中、下煤组整体开发效果优于上、中煤组;②不同储层改造规模及方法对气井产能影响大,织金工区煤层煤化程度强,脆性低于其他煤层及页岩等储层,提高前置液量比重有助于更好地打开裂缝,增大储层改造体积。Most coalbed methane(CBM)directional wells in Zhijin block are confronted with challenges,such as significant difference in the productivity,short time in the stable production,and unclear productivity controls.So,23 directional wells deployed at large and small well groups in the study area were taken as examples to analyze the effect of both geological conditions and operational parameters on the productivity.Moreover,the influential degree of different geological conditions and technological measures on the productivity was pointed out for these wells.Results show that(i)the controls mainly include desorption pressure,coal seam thickness,working-fluid volume,lead volume and displacement;(ii)geologically,the average development horizons in large well groups are about 4 times those in small ones.And No.16,17 and 21 coal seams are better than others in terms of sedimentary environment,preservation conditions and reservoir structure;and(iii)the working-fluid volume,lead volume and displacement have a great impact on fracturing stimulation.Practical data indicates that,at a certain displacement,the stimulation effect is better when the working-fluid volume is about 5 times of the lead volume.Two conclusions are made.In addition to great in quantity,the coal seams in Zhijin block feature small in thickness,layer spacing and heterogeneity difference in vertical.Thus,a better effect may been achieved from multilayer commingled production by directional wells,and the overall effect in the lower to middle coal groups is better than that in the middle to upper groups.What's more,various stimulation scale and methods have a great impact on the productivity.For the Zhijin coal seams which are provided with high coalification and less brittle than the other seams or shale reservoirs,to raise the proportion of lead volume is helpful to induce fractures better,thus to scale up the stimulated reservoir volume.

关 键 词：织金区块 煤层气 灰色关联 数值模拟 影响因素 

分 类 号：TE328[石油与天然气工程—油气田开发工程]