About This Item

Share This Item

The AAPG/Datapages Combined Publications Database

AAPG Bulletin

Abstract

AAPG Bulletin, V. 105, No. 12 (December 2021), P. 2477-2518.

Copyright ©2021. The American Association of Petroleum Geologists. All rights reserved.

DOI: 10.1306/06222118094

Depositional conditions and accumulation models of tight oils in the middle Permian Lucaogou Formation in Junggar Basin, northwestern China: New insights from geochemical analysis

Haiguang Wu,1 Wenxuan Hu,2 Yuce Wang,3 Keyu Tao,4 Yong Tang,5 Jian Cao,6 Xiaolin Wang,7 and Xun Kang8

1School of Earth Sciences, Northeast Petroleum University, Daqing, China; State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, Nanjing, Jiangsu, People’s Republic of China; [email protected]
2State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, Nanjing, Jiangsu, People’s Republic of China; [email protected]
3State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, Nanjing, Jiangsu, People’s Republic of China; [email protected]
4State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, Nanjing, Jiangsu, People’s Republic of China; [email protected]
5PetroChina Xinjiang Oilfield Company, Karamay, People’s Republic of China; [email protected]
6State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, Nanjing, Jiangsu, People’s Republic of China; [email protected]
7State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, Nanjing, Jiangsu, People’s Republic of China; [email protected]
8State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, Nanjing, Jiangsu, People’s Republic of China; [email protected]

ABSTRACT

Recent discoveries of huge tight oil resources in the middle Permian Lucaogou Formation within the Jimusaer sag in the Junggar Basin in northwestern China have aroused numerous studies on this unconventional petroleum system. However, depositional conditions of the source rocks and the accumulation models of the oils are still unclear because of the complexity of the petroleum system. In view of this, systematic geochemical investigations on 120 samples covering a whole variety of source and reservoir rocks in the Lucaogou Formation were carried out. Based on the results, two types of depositional conditions were identified for the five sections of source rocks (denoted A–E), with sections A, C, and D deposited under hypersaline and reducing conditions, and sections B and E under brackish and relatively oxidizing conditions. Oil-source rock correlation results demonstrated that four groups of oils (denoted 1–4) with distinctive geochemical signatures from the formation finally accumulated in three relatively independent subsystems (labeled Sub-I to Sub-III). Groups 2–4 oils (Sub-II and Sub-III) originated solely from interbedded mudstone, so the accumulation model is highly interbedded and nearby accumulation. Group 1 oils (Sub-I) are originated from the vertical mixing of hydrocarbons produced by multiple mudstone beds at greater depths followed by lateral migration, thus called vertical-lateral mixing accumulation model. This study highlights the importance of lateral migration in tight oil accumulation and will benefit future tight oil exploration in the Junggar Basin, such as the Permian Feng Cheng Formation, and other areas worldwide.

Pay-Per-View Purchase Options

The article is available through a document delivery service. Explain these Purchase Options.

Watermarked PDF Document: $14
Open PDF Document: $24

AAPG Member?

Please login with your Member username and password.

Members of AAPG receive access to the full AAPG Bulletin Archives as part of their membership. For more information, contact the AAPG Membership Department at [email protected].