南海北部自营深水天然气勘探重大突破及其启示

2014年9月15日中海油宣布,该公司在南海北部LS17-2-1井测试获得160×104 m3/d的高产油气流,这是我国发现的第一个自营勘探的深水高产气田。该区的勘探经历了3个阶段:1在普查勘探阶段(2002年以前)受技术的限制主要勘探工作集中在浅水区;2对外合作勘探阶段(2002年—2012年),由于勘探发现储量规模小、开发无经济性,合作伙伴相继放弃了南海西部深水勘探权益,但证实了南海深水区发育优质烃源岩和储层,揭开了南海深水区油气勘探的面纱;3自营勘探阶段(2013年至今),中海石油(中国)有限公司湛江分公司依托国家科技重大专项和自身生产科研能力,先后开展了深水地震资料采集和处理、深水优质储层分布、深水区油气成藏关键因素等多项科研攻关,优选并确定了钻探的首选目标——陵水17-2构造,取得了天然气勘探的重大突破。陵水17-2构造位于中央峡谷乐东—陵水段内,主要目的层新近系上中新统黄流组总厚度超过150m,砂岩占比为75.4%,单层最大厚度可达52m,孔隙度介于30.0%~33.7%,平均为31.5%,渗透率介于293~2 512mD,平均为633mD,为特高孔、高—特高渗储层。陵水17-2气田的勘探突破,展现了该深水区域油气勘探的巨大潜力。

A major breakthrough in deepwater natural gas exploration in a self-run oil/gas field in the northern South China Sea and its enlightenment

A commercial natural gas flow in the Upper Miocene Huangliu Fm was obtained in Well LS17-2-1, northern South China Sea, and its tested daily production reached up to 1.6 million m³/d. This occurred in the first deepwater oil/gas field independently explored and operated by CNOOC Zhanjiang Branch. This exploration project has experienced three stages in this study area. On the first overall survey stage prior to 2002, early exploration only focused on shallow water areas so we had a superficial understanding of deepwater fields for lack of enough exploration data. On the second foreign cooperation stage from 2002 to 2012, foreign partners quit successively due to small scales of the discovered hydrocarbon reserves and the unworthiness of further exploitation in the deepwater domain there. On the third self-run stage from 2013 to present, by virtue of national key technological research and development programs during the 11^th and 12^th Five-Year Plans, CNOOC Zhanjiang Branch has tackled a series of key scientific research projects such as seismic data acquisition and processing, high quality reservoir distribution, key controlling factors of hydrocarbon accumulation in deepwater areas. On this basis, Lingshui 17-2 was selected as the first target for deepwater drilling, which is situated in the Ledong Lingshui section of the central trench with the Huangliu Fm as the ultra-high porosity and high & ultra high permeability pay zone (the total thickness: 150 m; sandstone percentage: 75.4%; the maximum thickness of a single layer: 52 m; porosity: 30.0% ~ 33.7% and 31.5% on average; permeability: 293 ~ 2 512 mD and 633 mD on average). The exploration breakthrough of Well Lingshui 17-2 not only opens a door to hydrocarbon 'treasures' but demonstrates the great potential of oil and gas exploration in the deepwater of the South China Sea.