Oil & Gas Geology ›› 2021, Vol. 42 ›› Issue (5): 1234-1242.doi: 10.11743/ogg20210520

• Methods and Technologies • Previous Articles     Next Articles

Time-varying permeability of sandstone reservoirs under waterflooding of different water quality

Jianzhong Wang(), Xiankun Song, Yingchao Fu, Lianting Sun, Jinjie Xu   

  1. Petroleum Engineering College, China University of Petroleum (East China), Qingdao, Shandong 266580, China
  • Received:2019-04-19 Online:2021-10-28 Published:2021-10-26

Abstract:

Water injection may lead to a chronical reduction of reservoir permeability due to the blockage of formation pores by suspended solid particles, oil, bacteria, and other impurities in the injected water.For fields under water flooding for quite a long time, it is not wise to continue sticking to the water quality determined on originally measured formation permeability.This study investigates possible formation damage caused by water injection through laboratory experiments on sandstone cores of different permeability from wells with long water injection history according to 5 different standards of water quality(SY/T 5329-2012), and put forward a concept of water quality-sensitive permeability.And through theoretical derivation, a mathematical expression describing the attenuation law of permeability is established to describe changing sandstone reservoir permeability with time during injection of water of different qualities.The criteria for water and reservoir selection are determined for better decision making on injection water quality for high water-cut wells.It provides a theoretical basis for achieving better performance of wells with long-time water flooding through water quality adjustment.

Key words: waterflooding, water injcetion history, permeability retention, water quality-sensitivity, formation damage simulation, waterflooding, sandstone reservoirs, Gudong Oilfield

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