海底扇浅海重力流气藏储层内部结构精细表征  

Fine characterization for inner structure of shallow-sea gravity flow gas reservoirs in submarine fan

作　　者：李佳 周伟 叶青 王玉 彭小东 彭旋 LI Jia;ZHOU Wei;YE Qing;WANG Yu;PENG Xiaodong;PENG Xuan(Hainan Branch,CNOOC China Limited,Haikou,Hainan 570312,China)

机构地区：[1]中海石油(中国)有限公司海南分公司

出　　处：《天然气勘探与开发》2023年第2期20-29,共10页Natural Gas Exploration and Development

基　　金：“十三五”国家科技重大专项“莺琼盆地高温高压天然气富集规律与勘探开发关键技术(三期)”(2016ZX05024005);中海石油(中国)有限公司重大科技专项“南海西部油田上产2000万方关键技术研究”(CNOOC-KJ135ZDXM38ZJ)。

摘　　要：南海天然气勘探在浅海重力流沉积储层中持续获得新发现,但重力流储层沉积类型特殊、沉积机制复杂,加之高温高压的储层条件,导致含气砂体叠置连通关系及气水分布极为复杂,储层内部结构精细表征缺乏有效的手段和方法。为此,精细沉积微相研究成果为指导,形成正反演结合、波形指示反演为主体的多种反演技术的方法;通过地震沉积学技术集成解释,建立研究区砂体单元叠置模式,实现复杂沉积体储层的高精度表征。研究结果表明:(1)研究区砂体展布受沉积相控制的变化,主要发育四大类成因单元砂体叠置模式,包括侵蚀水道—分流水道侧向叠置、分流水道—分流水道侧向叠置、分流水道—水道化朵体侧向接触、朵体-朵体侧向叠置;(2)进一步明确该区3种类型的主要气藏分布模式,包括统一气水界面的构造+岩性的大型整装边水气藏模式、差异充注形成的独立气水系统的小型岩性圈闭气藏模式、物性遮挡形成的局部滞留水体气藏模式;(3)研究成果适用于精细刻画复杂砂体储层的内部结构特征,并可有效地指导我国海上首个高温高压领域盆地的油气勘探开发研究。Natural gas exploration in the South China Sea makes successive discoveries in shallow-sea gravity flow sedimentary reservoirs.However,the unique sedimentary type,complex sedimentary mechanism,and the HT/HP condition of the reservoirs led to superimposed gas-bearing sand bodies,and extremely complicated gas-water distribution.There is a lack of effective techniques and methods for accurately characterizing the inner structure of reservoir.Based on the study results of detailed sedimentary microfacies,multiple inversion techniques were developed,represented by combined forward and inverse methods,and waveform inversion.By integrating interpretation of seismic sedimentology,the superimposed pattern of sand body unit was established for the study area to achieve high-precision characterization for complex sedimentary reservoirs.The following results are obtained:(i)The distribution of sand bodies is controlled by changes in sedimentary facies.There develops four superimposed patterns of genetic unit sand body,including lateral erosion channel-distributary channel superimposing,lateral distributary channel-distributary channel superimposing,lateral distributary channel-channelized lobe contact,and lateral lobe-lobe superimposing.(ii)Three main distribution models of gas reservoir in the area are clarified,including the large-scale tectonic-lithologic monolithic edge-water gas reservoir with a unified gas-water contact,small-scale lithologic-trap gas reservoir with independent gas-water system formed by differential charging,and locally retained-water gas reservoir formed by physical shielding.(iii)The study achievements are applicable to finely characterizing the inner structure of complex sand-body reservoirs,and can effectively guide the exploration and development for China’s first offshore HT/HP basin.

关 键 词：海底扇 地震沉积学 砂体刻画 内部结构特征 气水分布 气藏模式 

分 类 号：P744.4[天文地球—海洋科学] P618.13