湘中坳陷海相油气勘探前景再认识

RECONSIDERATION ON MARINE PETROLEUM EXPLORATION PROSPECTS IN THE MIDDLE HUNAN DEPRESSION

湘中坳陷海相油气勘查区块与南方其他区块相比,具有较为明显的成藏条件优势:1)烃源岩演化程度相对最低,龙潭煤系现今仍以烟煤为主;2)测水、龙潭2套煤系在区域上连片分布,封盖能力较强,钻井证实其下油气显示异常活跃;3)湘中在古生代时地处赤道附近,广泛发育的风暴岩有利于油气及时运移与聚集;4)早期形成的江南雪峰古隆起为油气藏的保存和重建创造了有利条件。因此,湘中坳陷具有较好的勘探前景,根据勘探现状,应以涟源凹陷下组合为主攻目标,依次向江南雪峰古陆推进。

Compared with other exploration areas in south China, the Middle Hunan depression has fairly superior conditions for petroleum accumulation. 1） Evolution degree of hydrocarbon source rocks is relatively lower and the Longtan coal series are still dominated by soft coal. 2） Regionally, two sets of coal series, the Ceshui and the Longtan, are distributed continuously with fairly good covering ability. Drilling data has proved that oil and gas shows are very active. 3） The Middle Hunan depression was located near equator in Paleozoic and the storm rocks developed widely is favorable for oil and gas migration and accumulation. 4） The Jiangnan Xuefeng Palaeo-lifts formed early support condition for preservation and rebuilding of oil and gas accumulation. Therefore, the Middle Hunan depression has fairly good exploration prospects. According to present exploration status, exploration targets should be the lower combinations in the Lianyuan depression, advancing toward the Jiangnan Xuefeng Palaeocontinent gradually.