Xinjiang Petroleum Geology ›› 2022, Vol. 43 ›› Issue (1): 107-114.doi: 10.7657/XJPG20220116

• APPLICATION OF TECHNOLOGY • Previous Articles     Next Articles

Reservoir Damage Mechanism for Upper Wuerhe Formation in Southern Mahu Area, Junggar Basin

ZHOU Wei1(), SHEN Xiulun2, KOU Gen1, WEI Yun1, JIANG Guancheng2(), YANG Lili2, ZHANG Yuankai1   

  1. 1. PetroChina Xinjiang Oilfield Company, a.Research Institute of Experiment and Detection; b.Key Laboratory of Conglomerate Oil and Gas Reservoir Exploration and Development, Karamay, Xinjiang 834000, China
    2. School of Petroleum Engineering, China University of Petroleum, Beijing 102249, China
  • Received:2021-06-03 Revised:2021-08-09 Online:2022-02-01 Published:2022-01-24
  • Contact: JIANG Guancheng E-mail:1013095722@qq.com;m15600263100_1@163.com

Abstract:

The core of the conglomerate reservoir from upper Wuerhe formation of Permian is very easy to break after immersed in fluids, so that it is difficult to evaluate how gel-breaking fracturing fluid damages the reservoir, and it is impossible to determine the factors controlling reservoir damage in the southern Mahu area, Junggar basin. This study used X-ray Micro-CT technology to scan core samples and reconstructed the three-dimensional pore structure, and then characterized the pore changes on different sections by the ball-stick model and the threshold segmentation method. The results show that, after the reservoir was damaged by gel-breaking fracturing fluid, the average pore radius, average throat radius, average throat length, average pore-to-throat ratio, porosity and permeability were reduced by 42.1%, 32.7%, 19.1%, 45.3%, 7.7% and 33.8%, respectively. After fractured by gel-breaking fracturing fluid, the reservoir was damaged, resulting in reduced porosity and permeability, especially a significant change in permeability. Swelling montmorillonite in the clay minerals and particle migration are the factors that can cause damage to the reservoir, and the interaction between gel-breaking fracturing fluid and the reservoir is the primary factor causing reservoir damage.

Key words: Junggar basin, Mahu sag, southern Mahu area, Wellblock Mahu-1, upper Wuerhe formation, conglomerate, gel-breaking fracturing fluid, reservoir damage, clay mineral

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