摘要
通过对鄂尔多斯盆地深层煤岩气开展系统研究,落实盆地上古生界全煤层段煤岩厚度分布特征和典型地区(盆地东部以榆林为中心的面积12000 km2的矩形区块)煤岩气资源量、赋存规律与气井关键开发指标,明确关键开发技术迭代优化方向。研究表明:①资源量评估区块内上古生界1^(#)—10^(#)煤层煤岩气总资源量为5.66×10^(12) m^(3),其中8^(#)煤层资源量为3.08×10^(12) m^(3),约占总资源量的54%,是目前开发动用的主要层段;②深层煤岩气具有游离气占比高的特点,取煤岩埋深2000 m、孔隙度6.35%、游离气含气饱和度95%、总含气量22.13 m^(3)/t,评价认为煤岩气游离气含量约占40%;③构建了煤岩气水平井三角、上凸、下凹3种产能评价模型,其中三角模型可作为气井全生命周期最终累计产气量(EUR)预测的基础评价模型,取煤岩厚度7 m、水平井有效水平段长1500 m、井距400 m,三角模型评价单井EUR值为4621.28×10^(4) m^(3);④8^(#)煤层宜采用水平井、控压生产方式开发,同时要充分借鉴苏里格气田低成本开发路径;⑤提高一次采收率,实现效益开发,须紧密围绕钻井提速、有效水平段长提升、储层高强度改造、优化井网部署等进行关键技术不断迭代升级。
Through systematic investigation of deep coal-rock gas in the Ordos Basin,NW China,this work analysed the thickness distribution of the entire Upper Paleozoic coal-rock intervals,quantified the resource potential of representative areas(a 12000 km2 rectangular block in the eastern Ordos Basin roughly centered on Yulin City),clarified the occurrence characteristics of coal-rock gas,and identified key development indicators for gas wells,thereby defining the direction for iterative optimization of key technologies.(1)The total coal-rock gas in-place of the Upper Paleozoic coal seams 1^(#)–10^(#)in the reserve evaluation region is assessed at 5.66×10^(12) m^(3),of which coal seam 8^(#),currently the main target interval,contains about 3.08×10^(12) m^(3),accounting for roughly 54%of the total.(2)Deep coal-rock gas is characterized by a high ratio of free gas.Under the conditions of 2000 m burial depth,6.35%porosity,95%free gas saturation,and 22.13 m^(3)/t total gas content,the free gas content of the reservoir is estimated to be ca.40%of the total gas.(3)Three productivity evaluation models(triangular,convex,concave)are developed for horizontal wells,of which the triangular model can serve as the reference model for predicting the estimated ultimate recovery(EUR)throughout the lifecycle of coal-rock gas wells.Using the triangular model with a 7 m coal thickness,1500 m effective lateral length and 400 m well spacing,the average single-well EUR is determined to be 4621.28×10^(4) m^(3).(4)Development of the coal seam 8^(#)should employ horizontal wells with pressure-controlled production.Meanwhile,it can be further optimized by adopting the cost-effective strategies of the Sulige Gas Field in the Ordos Basin,China.(5)To achieve cost-effective development and increase primary recovery factor,key technologies must undergo continuous iteration and upgrading,focusing on accelerating drilling,extending effective lateral lengths,high-intensity reservoir stimulation,and well-pattern optimization.
作者
贾爱林
王国亭
万能
孟德伟
JIA Ailin;WANG Guoting;WAN Neng;MENG Dewei(PetroChina Research Institute of Petroleum Exploration&Development,Beijing 100083,China)
出处
《石油勘探与开发》
北大核心
2025年第6期1377-1387,共11页
Petroleum Exploration and Development
基金
中国石油天然气股份有限公司科学研究与技术开发项目“老气田‘压舱石工程’关键技术研究与示范”(2023YQX103)
中国石油天然气集团有限公司科学研究与技术开发项目“气藏采收率标定方法与复杂气藏提高采收率新技术研究”(2024DJ86)。
关键词
鄂尔多斯盆地
深层煤岩气
资源潜力
游离气占比
产能评价
开发技术政策
关键技术
迭代升级
Ordos Basin
deep coal-rock gas
resource potential
proportion of free gas
productivity estimation
policy on development technologies
key technology
iteration and upgrading
