南海北部深水区油气成藏理论技术创新与勘探重大突破

南海北部深水区油气资源丰富,是我国重要的油气勘探开发领域,历经20年的科技攻关与应用实践,形成了一系列的理论和技术。研究成果表明：①南海北部陆缘大型拆离作用控制了深水盆地的形成和演化,在陆缘深水区形成了始新世湖相、渐新世海陆过渡相和渐新世—中新世海相3套烃源岩;②陆缘岩石圈强烈薄化带控制了南海北部的古地貌与沉积环境,在珠江口盆地白云凹陷与琼东南盆地深水区形成了陆架边缘三角洲—深水扇体系和大型中央峡谷沉积体系的优质储层,上述3套烃源岩与多类型储集体之间由不同的输导系统构成了3种油气成藏模式;③针对深水区中深层地震成像差、储层预测与流体识别难的问题,研发了“犁式”电缆宽频和立体震源采集技术、三维空间高精度重磁震联合反演技术、深水油气勘探海底检波器地震处理和纵横波联合反演技术、深水储层物性—含油气性定量评价技术;④针对深水钻完井与测试关键技术缺乏等难题,研发了一种深水探井井壁主动强化技术、深水表层集束批钻模式、深水大产能安全高效测试模块化技术。结论认为：①建立了南海北部深水油气成藏理论、深水区油气勘探地球物理技术体系和深水安全高效钻完井测试技术,形成了配套的深水油气勘探技术体系,有效地指导和发现了一批大中型商业油气田,探明天然气地质储量超过3 000×108 m3,实现了我国深水油气勘探历史性重大突破;②油气地质理论认识创新、地球物理和钻采关键瓶颈技术突破,是南海北部深水区持续获得重大油气发现的必要条件。

Theoretical and technological innovation of oil and gas accumulation and major exploration breakthroughs in deep-water areas,northern South China Sea

The deep-water areas in the northern South China Sea are rich in oil and gas resources, and is an important oil and gas exploration and development region of China. Over two decades of scientific and technological researches and practices in this region, a series of theories and technologies has been formed. The research results were achieved as follows. (1) The large-scale detachment of the northern continental margin of the South China Sea controlled the formation and evolution of deep-water basins, forming three sets of source rocks (Eocene lacustrine facies, Oligocene marine–continental transitional facies and Oligocene–Miocene marine facies) in the deep-water area of the continental margin. The strong thinning zone of the continental margin lithosphere controlled the paleogeomorphology and sedimentary environment of the northern South China Sea. In the deep-water areas of the Baiyun sag in the Pearl River Mouth Basin and the Qiongdongnan Basin, high-quality reservoirs of continental shelf marginal delta-deep-water fan systems and large-scale central-canyon sedimentary systems were formed. The above three sets of source rocks and multi-types of reservoirs constitute three kinds of oil and gas accumulation models by different transport systems. (2) In view of the problems of poor seismic imaging, difficult reservoir prediction and fluid identification in middle–deep layers of the deep-water area, a set of targeted technologies has been researched and developed, including the "plough-type" cable broadband and stereo vibrator acquisition technology, three-dimensional high-precision gravity, magnetic and seismic joint inversion technology, subsea geophone seismic processing technology and P–S wave joint inversion technology for deep-water oil and gas exploration, and quantitative evaluation technology for deep-water reservoir physical properties and petroleum properties. (3) For lack of key technologies for deep-water drilling, completion and testing, a kind of deep-water exploratory well sidewall active strengthening technology, deep-water surface cluster batch drilling mode, and deep-water large-scale safe and efficient testing modular technology have been thus developed. It is concluded that: (1) the deep-water oil and gas accumulation theory in the northern South China Sea, the geophysical technology system for oil and gas exploration in deep-water area, and the safe and efficient drilling, completion and testing technology in deep-water area have been innovated and established, forming a supporting deep-water oil and gas exploration technology system, which has effectively guided and helped to discover a number of large and medium-sized commercial oil and gas fields, with proved geological reserves of natural gas more than 3 000×108 m3, achieving a historic breakthrough in deep-water oil and gas exploration in China, and (2) the innovation of oil and gas geological theory, the breakthroughs in key bottleneck technologies for geophysics, drilling and production are the necessary conditions for continuous major oil and gas discoveries in the deep-water area of the northern South China Sea.