中国南方海相残留盆地勘探风险分析与选区评价

中国南方发育有下海上陆的多旋回生储盖组合,总体形成了震旦系-下古生界及中-上古生界2套大的海相成藏组合;平面上形成以江绍-十万大山断裂为界的南、北两大成藏区,其中北区发育2套组合,南区发育中-上古生界1套组合。平面上古油藏与油气显示分布受古隆起控制,油气成藏经历了加里东-海西期生油、印支期裂解成气、燕山-喜马拉雅期调整与改造3期以上事件。现今保存的海相油气藏具有明显的残留特征。综合分析认为,南方海相普遍存在勘探程度低、技术尚不成熟、油气成藏规律认识局限等方面的风险,其中常规油气勘探风险相对较高,海陆叠合盆地勘探风险相对较低,非常规页岩气勘探风险最低,并由此对南方海相进行了评价与有利区带优选。 

Risk analysis and play evaluation of marine residual basins in South China

Multiple cycles of hydrocarbon generation, reserve and cap assemblages with sea at the bottom and continent at the top developed in South China. There were mainly 2 sets of marine accumulation assemblages including Sinian-the Lower Paleozoic and the Middle-Upper Paleozoic. On plane map, the study area was divided into 2 accumulation zones (the southern one and the northern one) by the Jiangshao-Shiwandashan Fault. In the northern accumulation zone, 2 sets of accumulation assemblages developed, while in the southern accumulation zone, only the Middle-Upper Paleozoic assemblage existed. The distribution of ancient reservoirs and oil-and-gas shows was controlled by ancient uplifts. Petroleum accumulation experienced over 3 stages of tectonic events, for example, oil generating in Caledonian-Hercynian stages, oil cracking to gas in Indosinian stage, and adjusting and deforming in Yanshanian-Himalayan stages. The present marine reservoirs in South China have distinctive residual features. Their exploration degrees are low, techniques are not mature, and the knowledge about accumulation rules is restricted. The risks are higher for normal petroleum explorations, lower for marine superimposed basin explorations, and the lowest for unconventional shale gas explorations. The marine strata in South China were evaluated and the favorable zones for exploration were pointed out.