中国中西部典型前陆盆地超压体系形成机制与大气田关系  

Formation of overpressure system and its relationship with the distribution of large gas fields in typical foreland basins in central and western China

作　　者：李伟[1] 陈竹新[1] 黄平辉[2] 于志超[1] 闵磊[3] 鲁雪松[1] LI Wei;CHEN Zhuxin;HUANG Pinghui;YU Zhichao;MIN Lei;LU Xuesong(PetroChina Research Institute of Petroleum Exploration&Development,Beijing 100083,China;PetroChina Southwest Oil&Gas Field Company,Chengdu 610051,China;PetroChina Tarim Oilfield Company,Korla 841000,China)

机构地区：[1]中国石油勘探开发研究院,北京100083 [2]中国石油西南油气田公司,成都610051 [3]中国石油塔里木油田公司,新疆库尔勒841000

出　　处：《石油勘探与开发》2021年第3期536-548,共13页Petroleum Exploration and Development

基　　金：中国石油天然气股份有限公司重大科技攻关项目(2016B-05)。

摘　　要：基于实测地层压力、重点探井钻井液密度、测井计算压力等资料的研究,结合天然气地质条件分析,探讨不同前陆盆地地层流体超压体系特征与形成机制以及超压体系与大规模天然气聚集的关系。研究结果表明,①不同前陆盆地地层超压形成机制存在较大差异,库车前陆盆地主要是塑性盐膏层超压封闭与深层—超深层的生烃增压,准南前陆盆地主要是生烃增压与欠压实封闭,川西前陆盆地主要是生烃增压与古流体超压封存;②前陆盆地存在多类型超压与多层位超压叠置发育、封闭性前陆冲断构造带发育强超压—极强超压、前陆隆起区深层发育强超压—极强超压等3个方面的共性特征;③存在塑性盐膏层超压、生烃增压形成的超压、喜马拉雅期隆升剥蚀后的封存超压、欠压实超压等4种对大气田起重要控制作用的区域性超压封盖与封存机制;④区域性超压是大气田形成的重要保障,超压体系中充足的气源、大规模储集体与圈闭发育是大气田形成的基本条件,超压体系有利于深层—超深层大气田的形成。Based on the data of measured formation pressure,drilling fluid density of key exploration wells and calculated pressure by well logging,combined with the analysis of natural gas geological conditions,the characteristics and formation mechanisms of formation fluid overpressure systems in different foreland basins and the relationship between overpressure systems and large-scale gas accumulation are discussed.(1)The formation mechanisms of formation overpressure in different foreland basins are different.The formation mechanism of overpressure in the Kuqa foreland basin is mainly the overpressure sealing of plastic salt gypsum layer and hydrocarbon generation pressurization in deep-ultra-deep layers,that in the southern Junggar foreland basin is mainly hydrocarbon generation pressurization and under-compaction sealing,and that in the western Sichuan foreland basin is mainly hydrocarbon generation pressurization and paleo-fluid overpressure storage.(2)There are three common characteristics in foreland basins,i.e.superimposed development of multi-type overpressure and multi-layer overpressure,strong-extremely strong overpressure developed in a closed foreland thrust belt,and strong-extremely strong overpressure developed in a deep foreland uplift area.(3)There are four regional overpressure sealing and storage mechanisms,which play an important role in controlling large gas fields,such as the overpressure of plastic salt gypsum layer,the overpressure formed by hydrocarbon generation pressurization,the residual overpressure after Himalayan uplift and denudation,and the under-compaction overpressure.(4)Regional overpressure is an important guarantee for forming large gas fields,the sufficient gas source,large-scale reservoir and trap development in overpressure system are the basic conditions for forming large gas fields,and the overpressure system is conducive to forming deep to ultra-deep large gas fields.

关 键 词：中国中西部 前陆盆地 超压体系 大气田 生烃增压 欠压实 盐膏层 超压封闭 超压封存 

分 类 号：TE122[石油与天然气工程—油气勘探]