天然气勘探与开发2025，Vol.48Issue(5)：37-47,11.DOI:10.12055/gaskk.issn.1673-3177.2025.05.004
致密砂岩储层远端裂缝识别方法及裂缝评价
Identification and evaluation of fractures outside wellbores in tight sandstone reservoirs:A case study of Triassic Xujiahe Formation in Hexingchang area,western Sichuan Basin
摘要
Abstract
It is challenging to identify fractures outside wellbores in the tight sandstone reservoirs with ultra-low porosity and permeability in the upper submember of the second member of the Upper Triassic Xujiahe Formation(hereinafter referred to as T3x23)in the Hexingchang area of the Western Sichuan Depression of the Sichuan Basin.To address the challenge,and clarify the controlling mechanism of fractures on gas-well productivity in this area,electrical imaging identification charts for natural fractures were established by comparing genetic mechanisms,occurrences and image characteristics of natural versus induced fractures,based on core fracture observations,thin-section micro-fracture analyses,and electrical imaging log data.Moreover,the consistency between fracture strike and current in-situ stress direction,as well as the correlation between fracture parameters and open flow potential(OFP)of gas wells were investigated,thereby defining a workflow for identifying near-wellbore geological bodies using acoustic remote detection technology.The results are obtained in four aspects.(i)T3x23 in the study area is dominated by low-angle fractures(55.9%),followed by high-angle fractures(27.5%)and oblique fractures(16.6%).The latter two are mostly open,indicating good effectiveness.(ii)Well productivity is controlled by fracture strike.Fractures oriented near E-W and NW-SE align with the direction of current maximum principal stress,resulting in single-well OFP up to 52.95×10⁴ m3/d,whereas wells with N-S-strike fractures have productivity less than 5×10⁴ m3/d.Effective fracture density shows a positive correlation with the OFP.(iii)The acoustic remote detection technology for identifying fractures outside wellbores can accurately characterize the fractures within 40 m around the wellbore.It is concluded that the established geology-engineering integrated fracture-evaluation system effectively enables the identification of fractures outside wellbores,thereby facilitating the optimization of development planning for fault-fracture reservoirs.The zones with developed near E-W-strike fractures are the targets for horizontal well trajectory optimization in this area.关键词
声波远探测/远端裂缝识别/气井无阻流量/致密砂岩储层/三叠系上统须家河组/四川盆地西部坳陷/合兴场地区Key words
Acoustic remote detection/Identification for fractures outside wellbore/OFP of gas well/Tight sandstone reservoir/Upper Triassic Xujiahe Formation/Western Sichuan Depression of Sichuan Basin/Hexingchang area分类
能源科技引用本文复制引用
彭婷婷,秦启荣,何传亮,吴燕辉,王志文..致密砂岩储层远端裂缝识别方法及裂缝评价[J].天然气勘探与开发,2025,48(5):37-47,11.基金项目
中石化经纬有限公司科研项目"合兴场地区测井—地震—地质一体化解释研究及应用"(编号:JWKT2212). （编号:JWKT2212）
