从油气成藏过程分析探井失利原因

Reasons for the failure of petroleum exploration wells from the process of hydrocarbon accumulation

金强 程付启 王秋彤 王铜山

JIN Qiang CHENG Fuqi WANG Qiutong WANG Tongshan

1. 中国石油大学(华东) 地球科学与技术学院, 山东 青岛 266580; 2. 中国石油勘探开发研究院 石油地质研究所, 北京 100083

1. School of Geosciences, China University of Petroleum(East China), Qingdao, Shandong 26580 China; 2. Geological Branch, Institute of Petroleum Exploration and Development, PetroChina, Beijing, 100083, China

探井失利的原因包括地质、工程或管理等问题，其中地质问题最为常见，常常从构造、储层等方面定性分析，结果不了了之。四川盆地H探井目的是勘探灯影组天然气，这里背斜构造很落实、储层很发育，可是失利了。通过有限的灯影组岩心，开展白云岩溶蚀孔缝洞充填的沥青光学分析、孔缝洞充填白云石的包裹体均一温度和气体组成分析等，试图揭示有无原油成藏、天然气成藏和天然气保存过程：发现H井灯影组在中三叠世—早侏罗世原油（沥青）成藏过程正常，可与区域成藏相对比；在中侏罗世—白垩纪原油裂解成天然气过程中沥青受到氧化和水洗作用，原因是该井所在背斜发生倾斜和断裂，天然气成藏时没有圈闭，造成天然气没有聚集；在之后的喜马拉雅构造运动期间该井所在又恢复了背斜形态，但是没有天然气充注，导致H井失利。具有正常的原油和天然气成藏，且在新构造运动中保持稳定的构造应当是有利的勘探目标。

There are various reasons for subeconomic wells in oil and gas exploration, including the problems of geology, engineering and management, among which the most common problem is geology. The lack of oil and gas accumulation in the lost well H drilled for natural gas in the Dengying Formation (pre-Cambrian) in the western Sichuan Basin was considered using geochemical tools, which include the optical analysis of bitumen and homogenization temperatures and gas compositions of fluid inclusions in dolomites filled in the dissolved fractures and pores. Oil accumulation in the well H area was normal from the Middle Triassic to the Early Jurassic. Bitumen was oxidized and washed by flowing waters in the period of oil cracking to gas from the Middle Jurassic to Cretaceous. As a result, there was no natural gas accumulation in the well H anticlinal area since the anticline was tilted and cut by a fault. The well H anticline was restored again during neotectonics in the Cenozoic, but there was no gas charging in the anticline because no gas was generated from oil-cracking or source rocks. Therefore, the well H was dry. Structures or traps with normal oil charging and normal gas charging and neotectonic stability are potential targets for gas exploration in the Dengying Formation in the Sichuan Basin.

国家油气重大专项“深层油气资源预测”（ZX201705008-06）和国家自然科学基金“岩溶相储层缝洞形成机制”（U1663204）联合资助。

https://doi.org/10.11781/sysydz201905621