渤南洼陷古近系天然气成藏条件

 渤南洼陷古近系天然气呈现良好的勘探前景。研究天然气成藏条件，有助于认识天然气的成藏过程和成藏机理，为今后的天然气勘探提供理论依据。综合利用地质、地震、测井和录井等资料，系统分析了该区的有利成藏条件。研究表明，渤南洼陷气源灶以沙四上亚段为主，热演化程度高，晚期成藏，具有优越的气源条件；各类扇体及次生孔隙形成古近系天然气较好的储集条件；沙三中、下亚段泥岩及沙四上的膏盐层与泥岩互层，共同构成了优质区域盖层与天然气保存条件；各成藏地质条件的有效配置是天然气聚集成藏的关键因素；渤南洼陷深层发育的膏盐层，相应形成盐间及盐下两套天然气成藏系统。生气中心及周缘广泛分布的各类扇体为该区下一步的勘探目标。

The Reservoir Forming Conditions for Natural Gas in Paleogene Formation, Bonan Sag

The prospect of natural gas exploration in Paleogene, Bonan sag is very promising. The study on the gas reservoir forming conditions will help to understand the forming process and the mechanism of the gas reservoirs, and to provide a theoretical basis for future gas exploration. It is carried out in this paper, based on geological, seismic and logging data in this area. It is shown that the main gas generating bed is the upper Sha4, with high thermal evolution degree, as a late accumulation, and with advantageous gas source conditions. All kinds of fans and secondary pores create favorable reservoir conditions of Eogene. Mudstone in middle and lower Sha3, together with salt bed and mudstone in upper Sha4, form a favorable regional cap bed and reservoir bed. The effective configuration of reservoir-forming and geologic conditions is the key factor of the natural gas accumulation. Deep Bonan sag correspondingly forms an inter and below salt bed natural gas reservoir-forming system. The gas generation center and the areas surrounding all kinds of fans are the next exploration targets.