大佛寺井田煤层气井压裂参数优化方案

(1.西安科技大学 地质与环境学院,陕西 西安 710054; 2.西安科技大学 煤炭绿色开采地质研究院,陕西 西安 710054; 3.陕西新泰能源有限公司,陕西 咸阳 712000; 4.国土资源部煤炭资源勘查与综合利用重点实验室,陕西 西安 710021)

压裂参数; 大佛寺井田; 参数优化

Optimization program of fracturing parameters for coalbed methane wells in Dafosi Minefield
MA Dong-min1,2,4,WANG Chuan-tao1,XIA Yu-cheng1,ZHANG Jia-rui1,SHAO Kai3,YANG Pu4

(1.College of Geology and Environment,Xi'an University of Science and Technology,Xi'an 710054,China; 2.Geological Research Institute for Coal Greey Mining,Xi'an University of Science and Technology,710054,China; 3.Shaanxi Xintai Energy Company Limited,Xianyang 712000,China; 4.Key Laboratory of Coal Resources Exploration and Comprehensive Utilization Ministry of Land and Resources,Xi'an 710021,China)

fracturing parameters; Dafosi Minefield; parameter optimization

DOI: 10.13800/j.cnki.xakjdxxb.2019.0212

备注

为有效优化彬长矿区大佛寺井田煤层气井压裂施工工艺,对井田内24口煤层气直井产气情况和压裂施工参数进行统计分析,研究了煤层气直井压裂施工对其产能的影响,并将产能效果较好的气井压裂施工参数进行了分析对比。研究发现,在煤储层地质因素一致的情况下,影响压裂效果的主要工程参数有施工排量、压裂液用量、加砂强度以及砂比等。大佛寺井田煤层气直井采用活性水压裂液,支撑剂为石英砂,压裂施工排量为5.4~8.5 m3/min,压裂液用量616.00~1 193.25 m3,加砂强度为3.26~13.00 m3/m,砂比为6.9%~17.1%.结合气井历史排采资料和相关地质资料,以日均产气量和稳定日产量1 000 m3为压裂效果产能下限,得到适合大佛寺井田煤层气直井的压裂参数优化配置,建议压裂工艺优化方案设计如下:施工排量建议为8~10 m3/min; 细砂段塞1~2个; 压裂液用量建议为950~1 100 m3(前置液占25%~40%); 加砂强度建议为5~7 m3/m(煤厚>12 m)或8~9 m3/m(煤厚<12 m); 砂比建议为10%~11%; 支撑剂中中砂/粗砂比值建议为2~3.该方案可为井田后期煤层气井的压裂施工提供一定的工程依据。

In order to optimize the fracturing effect of coalbed methane(CBM)wells in Dafosi mine field of Binchang mining area,the gas production and fracturing parameters of 24 CBM vertical wells were analyzed statistically.The influence of fracturing on the productivity of CBM vertical wells was studied,and the fracturing parameters of wells with better production were compared.It is found that the main engineering parameters affecting fracturing effect are operational discharge capacity,fracturing fluid dosage,sand strength and sand ratio under the same geological factors of coal reservoir.The CBM vertical wells in Dafosi mine field adopts reactive water fracturing with quartz sand as proppant,the operational discharge capacity was 5.4~8.5 m3/min,the fracturing fluid dosage was 616.00~1 193.25 m3,the sand strength was 3.26~13.00 m3/m and the sand ratio was 6.9%~17.1%.Taking the average daily and steady gas production of 1 000 m3 as the lower limit of productivity,optimized fracturing parameters are obtained by comparative analysis of the data of historical production and related geology.The optimized fracturing scheme is suggested as follows: operational discharge capacity is suggested to be 8~10 m3/min; 1 or 2 fine sand plugs are added in preflush stage; total volume of fracturing fluid is set between 950 and 1 100 m3(with 25%~40% preflush fluid); sand strength is suggested to be 5~7 m3/m when coal seam thickness excesses 12 m or 8~9 m3/m when thickness was less than 12 m; sand ratio is suggested 6.9%~17.1%; the medium/coarse sand ratio in propping agents is set 2~3.Meanwhile,the scheme can provide certain engineering basis for the fracturing construction of later CBM wells.