Oil & Gas Geology ›› 2017, Vol. 38 ›› Issue (3): 617-625.doi: 10.11743/ogg20170322

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Biodegradation and water washing effects on oil during water flooding

Chang Xiangchun1,2, Zhao Wanchun1, Xu Youde3, Wang Tao4, Cui Jing4   

  1. 1. Shandong Provincial Key Laboratory of Depositional Mineralization and Sedimentary Minerals, Shandong University of Science and Technology, Qingdao, Shandong 266590, China;
    2. Laboratory for Marine Mineral Resources, Qingdao National Laboratory for Marine Science and Technology, Qingdao, Shandong 266071, China;
    3. Research Institute of Petroleum Exploration and Development, SINOPEC Shengli Oilfield Company, Dongying, Shandong 257001, China;
    4. Luming Oilfield Branch of SINOPEC Shengli Oilfield Company, Dongying, Shandong 257001, China
  • Received:2015-11-16 Revised:2017-01-22 Online:2017-06-28 Published:2017-07-10

Abstract: Water flooding is one of the most commonly used methods for enhancing oil recovery.About 36 oil samples from 12 waterflooded wells in Quti-9 oil reservoir of Jiyang Depression were investigated for dynamic tracking and geochemical measurements,to characterize their quality alterations and component changing patterns during the water flooding production.The results show increasing saturates and decreasing aromatics in the samples through the progress of water flooding,the typical effect of water washing during water flooding.The Pr/n-C17 and Ph/n-C18 ratios change in two different ways:decrease first and increase later or increase first and decrease later,indicating an effect of a strata chromatography adsorption,along with the water washing effect or biodegradation.The increasing C158β(H)-drimane/C168β(H)-homodrimane ratio can equally suggest an alteration by biodegradation or water washing.The obvious increase of tricyclic terpanes/17α(H)-hopane,C27-diasterane/C27-sterane,sterane/17α(H)-hopane ratios,and subtle decrease of C31R/C30H ratios,all indicate biodegradation.The MPI1,and DBT/P,C28TAS 20S/(20S+20R) and C26-/C28 TAS(20S) ratios are constant,suggesting triaromatic steroid(TAS) is unaffected by water flooding.And the phenanthrene and dibenzothiophene show no clear signs of difference in solubility or biodegradation during the waterflooding.

Key words: water flooding, water washing, biodegradation, petroleum alteration, crude oil, reservoir geochemistry, Quti oilfield, Jiyang Depression

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