基于地质工程一体化的海上低渗油田压裂实践与认识——以珠江口盆地陆丰凹陷为例  

Practice and understanding of geology and engineering integrated reservoir fracturing in offshore low-permeability oilfield:a case study of Lufeng Sag in Pearl River Mouth Basin

作　　者：罗迪 李黎 马逢源 谢明英 冯沙沙 文恒 高阳 张士诚[3] Luo Di;Li Li;Ma Fengyuan;Xie Mingying;Feng Shasha;Weng Heng;Gao Yang;Zhang Shicheng(Shenzhen Branch of CNOOC(China)Co.,Ltd.;CNOOC Research Institute Co.,Ltd.;College of Petroleum Engineering,China University of Petroleum(Beijing))

机构地区：[1]中海石油(中国)有限公司深圳分公司 [2]中海油研究总院有限责任公司 [3]中国石油大学(北京)石油工程学院

出　　处：《中国石油勘探》2024年第3期104-117,共14页China Petroleum Exploration

基　　金：中国海洋石油集团有限公司“十四五”重大科技项目“海上低渗及潜山油气田有效开发技术”(KJGG2022-0701);中海石油(中国)有限公司深圳分公司项目“陆丰14-4油田文昌组现地应力成因特征评价及不同结构储层压裂策略研究”(SCKY-2024-SZ-11)。

摘　　要：珠江口盆地作为中国海上低渗油气的重要成藏区,低渗油气资源量巨大。陆丰凹陷L44油田是南海东部首个整装压裂开发的低渗油田,为提升开发效益,采用压裂等储层改造方式,但压裂后存在改造规模未达预期、裂缝起裂机理认识不清等问题。建立了一种基于地震解释、测井、地质相结合的海上低渗油田地质工程一体化建模方法,使裂缝扩展延伸更加准确。对研究区开展了三维地质力学建模和地质工程双甜点优选,提出了适用于海上低渗油田压裂设计的储层射孔段长度上限,对C3井重新进行了压裂方案设计和产能模拟,经二次压裂投产后产量水平与设计预期基本相符。研究结果表明:(1)低排量条件下,射孔段长度由4m增至16m,单段裂缝长度平均减少30m,前5年单井累计产能减小88%;(2)射孔段长度的增大对改造规模起到抑制作用,射孔段长度大于6m时,改造范围大幅减小,射孔段长度小于6m时,改造范围减小幅度不大,最优射孔段长度不应大于6m;(3)射孔段长度小于6m时,施工排量每提升1m^(3)/min,储层改造体积平均增幅为10.97%,提高施工排量可实现进一步增大压裂改造体积的目标。建立的海上低渗油田地质工程一体化建模方法为南海东部低渗油田的开发方案和压裂方案设计提供了全新认识,有利于提升油田开发效益。Pearl River Mouth Basin is a major area for the accumulation of low-permeability oil and gas reservoirs with huge resources in the offshore China.L44 Oilfield in Lufeng Sag is the first integral low-permeability oilfield that has been fractured and developed in the eastern South China Sea.However,problems such as insufficient scale of reservoir reconstruction and unclear understanding of fracture initiation mechanism occur after fracturing.Based on seismic interpretation,logging and geological data,a geology and engineering integrated modeling method for offshore low-permeability oilfield has been established,which enables to more accurately predict fracture propagation.In addition,3D geomechanical modeling has been conducted and geological/engineering double sweet spots have optimally been selected in the study area.The upper limit of reservoir perforation interval applicable for offshore low-permeability oilfield has been proposed in fracturing design,and the new fracturing scheme design and capacity simulation have been conducted for Well C3,showing a basically consistent production level with the expectation after the secondary fracturing.The study results show that:(1)Given a low displacement,when the length of perforation interval increases from 4 m to 16 m,the fracture length in a stage decreases by 30 m on an average,and the cumulative production capacity of a single well decreases by 88%in the first five years;(2)An increase in the length of perforation interval inhibits the scale of reservoir reconstruction.When the perforation interval is more than 6 m,the scope of reservoir reconstruction greatly decreases;When the perforation interval is less than 6 m,the scope of reservoir reconstruction insignificantly decreases;As a result,the optimal length of perforation interval should be no more than 6 m;(3)Given a perforation interval of less than 6 m,the average reservoir reconstruction volume increases by 10.97%when the construction displacement increases by 1 m^(3)/min.A higher construction displacement en

关 键 词：地质工程一体化 低渗油田 裂缝扩展 压裂参数优化 陆丰凹陷 

分 类 号：TE357.1[石油与天然气工程—油气田开发工程]