摘要
惠州26洼是中国南海海域最富的生油气洼陷之一,勘探开发潜力巨大。近年来,位于洼陷东南部的惠州27-W构造在古潜山花岗岩以及古近系三角洲砂体中取得了重大突破,但该区域“富油贫气”分布特征,致使油气成藏主控因素模糊不清,极大地制约了油气勘探开发的进程。破解这一难题,深入剖析惠州27-W构造深层油气成藏条件,精准揭示主控因素,构建成藏模式,对油气勘探开发意义非凡。本文依据地质、钻井、测井及地震等资料,明确该构造深层油气成藏的关键地质要素:优质湖相烃源岩,具备早油晚气、近源持续供烃的特性;古潜山经风化改造、古近系砂砾岩体规模性成储;薄泥岩叠置与断裂面应力封堵,形成有效盖层;多期隆升造就圈闭,断裂与岩性组合控圈;深缝浅砂实现侧向差异运移。惠州27-W构造具有充足的烃源岩供烃,但晚期缺少断裂对天然气的调节及输导作用,古潜山、古近系整体上经历了油驱水三期的原油充注成藏过程,形成了现今大规模的油藏。
Huizhou 26 Sag is one of the richest oil-producing Sags in the South China Sea,with enormous potential for exploration and development.In recent years,Huizhou 27-W structure,located in the southeastern part,has made breakthroughs in paleo-buried hill granite and Paleogene delta sand bodies.However,the distribution characteristics of"rich oil and poor gas"led to unclear main controlling factors for accumulation,greatly restricting the process of exploration and development.In order to solve the problems,it is meaningful to analyze the accumulation conditions,reveal the main controlling factors,and establish an accumulation mode.Based on geological,drilling,logging,and seismic data,the key geological elements for accumulation are identified.High-quality lacustrine source rocks possess the characteristics of early oil and late gas generation,as well as continuous hydrocarbon supply from the near source.The paleo-buried hill has been transformed by weathering,and the large-scale sand-gravel rock bodies in the Paleogene have formed reservoirs.The superposition of thin-bedded mudstone layers and the stress-based sealing effect of fault planes jointly contribute to the establishment of highly effective cap rocks.Multiple episodic uplifts have created traps,and the combination of faults and lithology controls the traps,the deep fractures and shallow sands have realized lateral differential migration.The Huizhou 27-W structure has an abundant hydrocarbon supply from source rocks,yet it lacks the regulation and migration-conducting functions for natural gas in the late stage.The paleo-buried hill and the Paleogene as a whole have experienced a three-stage crude oil charging and accumulation process of oil displacing water,forming the large-scale oil reservoirs today.
作者
龚鑫
郑立庆
熊万林
曹雨菡
宋朋霖
何莹
李智超
杨沂川
GONG Xin;ZHENG Liqing;XIONG Wanlin;CAO Yuhan;SONG Penglin;HE Ying;LI Zhichao;YANG Yichuan(National Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Chengdu University of Technology,Chengdu 610059,Sichuan,China;Deep-Sea Development Co.,Ltd,CNOOC(China),Shenzhen 518054,Guangdong,China;Shenzhen Company of CNOOC(China)Co.,Ltd.,Shenzhen 518054,Guangdong,China)
出处
《石油地质与工程》
2025年第2期59-64,72,共7页
Petroleum Geology and Engineering
关键词
惠州26洼
古潜山
古近系
成藏条件
成藏模式
Huizhou 26 Sag
paleo-buried hill
paleogene
accumulation conditions
accumulation modes
作者简介
龚鑫(1998-),男,在读硕士研究生,现从事油气成藏动力学研究。E-mail:gx09109418@163.com。
