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Geoscience ›› 2022, Vol. 36 ›› Issue (06): 1563-1573.DOI: 10.19657/j.geoscience.1000-8527.2022.221

• Oil and Gas Exploration and Development • Previous Articles     Next Articles

Influence of Cenozoic Diabase Intrusion on Reservoir Properties of Mudstone Wallrocks in the Yangxin Sub-depression, Subei Basin

WANG Kai1,2(), LIU Huichuan1,2(), REN Weiwei1,2, LI Wenqi1,2, YU Zhiqi1,2   

  1. 1. State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum (Beijing), Beijing 102249, China
    2. College of Geosciences, China University of Petroleum (Beijing), Beijing 102249, China
  • Received:2021-12-25 Revised:2022-04-25 Online:2022-12-10 Published:2023-01-11
  • Contact: LIU Huichuan

Abstract:

Traditional view holds that magmatic active area is non-permissive for oil and gas exploration, but theoretical study and exploration practices reveal that magmatism may greatly improve their reservoir properties. Up until recently, the magmatic influence on sedimentary wallrocks is unclear, and thus it is important to investigate such influence (e.g., for diabase intrusion) for oil and gas exploration. This study took well Fengye 1 of Yangxin sub-depression in the Subei Basin as an example, with the aim to investigate the influence of diabase intrusion on reservoir properties of the mudstone wallrock. Based on the core, seismic and logging data, we carried out detailed investigations on the reservoir open-space and reservoir physical properties of diabase and its contact metamorphic zone, and discussed the lithofacies, physical properties and influence on the wallrock reservoirs. Diabase intrusion in northern Jiangsu began during the Wubao Movement (ca.59 Ma). The diabase intrusive-metamorphic complex comprises four layers: central gabbro, marginal diabase, slate wallrock, and unmetamorphosed mudstone wallrock. In the slate, the im-permeable mudstones has been transformed into oil and gas reservoir. The reservoir open-space includes all kinds of pores and fractures formed by intrusion and metamorphism, as well as dissolution (dominant). The upper contact zone is thicker than the lower contact zone. Formation of the contact metamorphic mudstone reservoir was mainly controlled by the diabase intrusion, and its influence includes metamorphic consolidation, hydrothermal fracturing, condensation shrinkage and dissolution, among which dissolution may have played a key role.

Key words: Subei Basin, igneous intrusion, thermal metamorphic reservoir, properties

CLC Number: