东濮凹陷文留气藏天然气成因与成藏史分析  

Gas genesis and accumulation history of Wenliu gas pool in Dongpu Sag, Center China

作　　者：许化政[1] 周新科[1] 

机构地区：[1]中国石化石油勘探开发研究院

出　　处：《石油勘探与开发》2005年第4期118-124,共7页Petroleum Exploration and Development

基　　金：中国石化科技项目"中国石化环渤海湾地区前第三系油气资源前景"(P03076)

摘　　要：文留构造是在东濮凹陷中央隆起带背景上因盐聚集而形成的背斜构造,构造翼部因盐滑塌而使圈闭幅度加大。构造圈闭内沙四段产状平缓,储集层累计厚度大,含气丰度高。地球化学特征显示天然气为典型煤成气藏,成藏类型为“古生新储”。石炭二叠系煤系在中、下三叠统沉积后完成第一次生烃过程,Ro、磷灰石裂变径迹等资料证实,当时煤系的古埋深约为3500m,古地温为118℃,Ro值为0.85%;中生代该区以抬升剥蚀为主,煤系生烃中止;古近纪裂谷发育期间,煤系埋深加大,进入二次生气期,东营组沉积后达到生气峰值阶段。其后东营运动的抬升剥蚀加速了煤成气的扩散、运移和聚集成藏。二次运移的主动力为其自身的高浓度和高压力潜能,运移的主通道是裂隙断裂系统。Wenliu structure is an anticline caused by salt- accumulation in the background of center mole track in Dongpu Sag with the trap extent enlarged by salt-slumping in the wings. The reservoir is thick with gentle occurrence and high gas abundance. The geochemical characteristics of the gases reveal that it is a typical coal-derived gas reservoir formed from pre- Mesozoic source rocks and accumulated in Cenozoic pool. The first hydrocarbon generating process occurred after Early-Middle Triassic sedimentation. According to the Ro values and apatite fission track, the paleo-burial depth of the coal formation was about 3500m at that time, the palaeo-temperature was 118℃, and the Ro reached 0. 85M. Then after 180 million years of interruption caused by uplift and erosion, the coal formation began secondary hydrocarbon generating in the Eogene rifting period because of the increase of burial depth. The generation peak appeared after Dongying Formation was deposited. The later uplift and erosion during Dongying Movement accelerated the diffusing, migration and accumulation of the coal derived gases. The high concentration and pressure formed the main power for the secondary migration, and the fracture-fauh system acted as the major channels.

关 键 词：文留气藏 C-P煤系 二次生烃 古地温 成藏史 

分 类 号：TE122.1[石油与天然气工程—油气勘探]