南海西部海域宝岛21-1气田的发现与成藏模式  

Discovery and hydrocarbon accumulation models of Baodao 21-1 gas field in the western South China Sea

作　　者：邓勇 裴健翔 胡林 尤丽 DENG Yong;PEI Jianxiang;HU Lin;YOU Li(CNOOC China Limited,Zhanjiang Branch,Zhanjiang,Gruangdong 524057,China;CNOOC China Limited,Hainan Branch,Haikou,Hainan 570100,China)

机构地区：[1]中海石油(中国)有限公司湛江分公司,广东湛江524057 [2]中海石油(中国)有限公司海南分公司,海南海口570100

出　　处：《中国海上油气》2022年第5期13-22,共10页China Offshore Oil and Gas

基　　金：中海石油(中国)有限公司重大科技项目“南海大中型天然气田形成条件、勘探潜力与突破方向(编号:2016ZX05026-002)”部分研究成果。

摘　　要：琼东南盆地是南海西部海域天然气勘探主战场之一,目前已发现的大中型气田,主要集中于西部崖南凹陷浅水区与乐东-陵水凹陷深水区,东部松南-宝岛凹陷发现的气藏规模小、非烃含量普遍较高,一直未获得规模商业性突破。近年来,基于新一轮油气地质研究,转变勘探思路,认为宝岛21断阶带紧邻生烃中心,发育近物源大型三角洲储集体,主通源断裂与凹陷边界深大断裂呈平行关系,且活动停止时间早,预测CO含量低,为烃类气的有利汇聚区,可作为宝岛北坡突破的首选方向。据此实施钻探,在宝岛凹陷成功发现古近系深水气田—宝岛21-1气田,实现宝岛凹陷勘探半个世纪以来首个重大突破。宝岛21-1气田的发现证实宝岛凹陷北部断阶带具有“转换断阶控源、控储、控聚”天然气高效成藏模式。同时,认为富烃凹陷的转换断阶带与古近系陵水组和崖城组三角洲构成的良好耦合区,是南海北部天然气勘探的重点方向。The Qiongdongnan basin is one of the main battle-fields for natural gas exploration in the western South China Sea. The large and medium-sized gas fields that have been discovered so far are mainly distributed in the shallow water area of the Yanan sag and the deep water area of the Ledong-Lingshui sag in the west area. The gas reservoirs discovered in the Songnan-Baodao sag in the east area are of small scale and generally have high non-hydrocarbon content, and no large-scale commercial breakthrough has been achieved. In recent years, a new round of petroleum geological research has been carried out, with the exploration ideas changed. It is considered that the Baodao 21 fault-step belt is close to the hydrocarbon generation center, and large-scale near-source delta reservoirs are developed. The main source faults are in a parallel relationship with the deep and large boundary faults on the sag, the activity of source faults stopped early, and predicted COcontent is low, which is favorable for hydrocarbon gas accumulation. It can be the preferred direction for breakthroughs on the north slope of the Baodao sag. Drilling was carried out accordingly, and the Paleogene deep water gas field(Baodao 21-1 gas field) was successfully discovered in the Baodao sag, achieving the first breakthrough in the exploration of Baodao sag for half a century. The discovery of the Baodao 21-1 gas field confirms that the fault-step belt in the northern Baodao sag has an efficient gas accumulation model of “transition fault-step source, storage, and accumulation”. At the same time, it is considered that the transition fault-step belt in the hydrocarbon-rich sag and the Paleogene Lingshui Formation and Yacheng Formation deltas constitute a good coupling area, which is the key direction of natural gas exploration in the northern South China Sea.

关 键 词：南海西部海域 深水区 断阶带 宝岛21-1 构造-岩性气田 勘探思路 

分 类 号：TE122.1[石油与天然气工程—油气勘探]