摘要
为了破解四川盆地南部威远地区下志留统龙马溪组斜坡型强非均质性页岩气藏高效开发所面临的钻井周期长、形成复杂缝网难度大、单井产量低等难题,经过多年的技术创新、科技攻关与生产实践,形成了“1套理论、4项关键技术”,有效地支撑了威远国家级页岩气示范区的高效建成。研究结果表明:①创新提出了古隆起背景下“沉积选区、构造分带、保存控藏”的斜坡型页岩气藏差异富集理论,形成了多期构造叠加海相页岩气区带评价与甜点优选技术,明确了纵向上最优靶体为龙一_(1)^(1)层中下部富有机质硅质页岩,落实核心建产区面积为165 km^(2),该区域内部署井井均测试日产气量达到27×10^(4) m^(3)、EUR超过1.1×10^(8) m^(3);②形成了以地质工程一体化导向技术、长水平段高效钻井技术为核心的窄箱体水平井高效导向钻井技术,并且建立了页岩气井钻井提速模版,钻井周期较之前期缩短约33.1%,优质页岩储层钻遇率提升至97.2%,水平段延伸能力突破3000 m;③基于压裂缝网动态扩展模型,形成了强非均质页岩储层体积压裂优化技术,实现了对压裂缝网改造区几何尺寸、储层增产改造体积、有效改造体积、支撑裂缝面积等关键评价指标的定量预测,加砂强度由1.3 t/m增至2.7 t/m,提升了改造效果;④影响威远页岩气井产能的主控因素包括龙一_(1)^(1)储层厚度、压力系数、总含气量、射孔簇数、加砂强度、压裂水平段长度等6项,采用基于广义回归神经网络与改进的嵌入式离散裂缝模型的页岩气井生产动态预测方法,使得页岩气井生产动态预测结果符合率接近甚至超过95%。
The efficient development of the slope-type strongly heterogeneous shale gas reservoir of Lower Silurian Longmaxi Formation in the Weiyuan area of the southern Sichuan Basin faces several difficulties,such as long drilling cycle,difficult formation of complex fracture network,and low single well production.In view of this,one theory and four key technologies are developed after years of technological innovation,technological research and production practice,which provide effective support for the efficient construction of the Weiyuan National Shale Gas Demonstration Area.And the following research results were obtained.First,the differential enrichment theory of slope-type shale gas reservoir in the setting of paleouplift is put forward,namely"sedimentation area selection,tectonic zonation and preservation controlling reservoir".The multi-stage structure superimposed marine shale gas zone evaluation and sweet spot selection technology is developed.The organic-rich siliceous shale in the middle and lower parts of S_(1)l_(1) layer is determined to be the optimal target in the vertical direction.The core productivity construction area covers 165 km^(2),where the deployed wells have an average daily gas production of 27×10^(4) m^(3) during the testing and the EUR is more than 1.1×10^(8) m^(3).Second,the efficient navigational drilling technology with geology-engineering integration guided technology and efficient long horizontal section drilling technology as the core for the horizontal well with a narrow target is developed,and the rate of penetration(ROP)improvement model of shale gas well is established.The drilling cycle is shortened by 33.1%,the drilling rate of quality shale reservoir is increased to 97.2%,and the extension capacity of horizontal section exceeds 3000 m.Third,based on the dynamic propagation model of hydraulic fracture network,the volume fracturing optimization technology for strongly heterogeneous shale reservoir is developed,and the key evaluation indexes can be predicted quantitatively,including net fracturing stimulation area dimension,stimulated reservoir volume,effective stimulation volume and propped fracture area.The sanding intensity is increased from 1.3 t/m to 2.7 t/m,and the stimulation effect is improved.Fourth,the main factors controlling the productivity of shale gas wells in the Weiyuan area include Long_(1)^(11) reservoir thickness,pressure coefficient,total gas content,perforation cluster quantity,sanding intensity and fracturing horizontal section length.Thanks to the application of the shale gas well production performance prediction method based on general regression neural network and modified embedded discrete fracture model,the coincidence rate of shale gas well production performance prediction result is close to and even higher than 95%.
作者
王治平
张庆
刘子平
李彦超
李宜真
何封
赵晗
WANG Zhiping;ZHANG Qing;LIU Ziping;LI Yanchao;LI Yizhen;HE Feng;ZHAO Han(CNPC Chuanqing Drilling Engineering Co.,Ltd.,Chengdu,Sichuan 610051,China;Shale Gas Exploration and Development Department,CNPC Chuanqing Drilling Engineering Co.,Ltd.,Chengdu,Sichuan 610051,China)
出处
《天然气工业》
EI
CAS
CSCD
北大核心
2021年第4期72-81,共10页
Natural Gas Industry
基金
国家科技重大专项“水平井压裂设计优化系统”(编号:2016ZX05023-001)。
关键词
四川盆地南部
威远地区
斜坡型强非均质性页岩气藏
高效开发
评层选区
导向钻井
体积压裂
生产动态预测
Southern Sichuan Basin
Weiyuan area
Slope-type strongly heterogeneous shale gas reservoir
Efficient development
Layer evaluation and zone selection
Navigational drilling
Volume fracturing
Production performance prediction
