Oil & Gas Geology ›› 2019, Vol. 40 ›› Issue (6): 1197-1204,1214.doi: 10.11743/ogg20190604

• Petroleum Geology • Previous Articles     Next Articles

Microscope dynamic process and controlling factors of oil charging in tight reservoir

Huang Wenbiao1, Zhan Zhuochen1, Lu Ruijing2, Gao Yang3, Lu Shuangfang1, Bai Zhenhua4, Yang Liang5   

  1. 1. School of Geosciences, China University of Petroleum(East China), Qingdao, Shandong 266580, China;
    2. No.4 Oil Production Plant of Daqing Oilfield Company Ltd., PetroChina, Daqing, Heilongjiang 163511, China;
    3. Research Institute of Petroleum Exploration and Development of Xinjiang Oilfield Company Ltd., PetroChina, Karamay, Xinjiang 834000, China;
    4. Research Institute of Petroleum Exploration and Development of Daqing Oilfield Company Ltd., PetroChina, Daqing, Heilongjiang 163712, China;
    5. Research Institute of Petroleum Exploration and Development of Jilin Oilfield Company Ltd., PetroChina, Songyuan, Jilin 138000, China
  • Received:2018-11-21 Revised:2019-08-02 Online:2019-12-28 Published:2019-10-15

Abstract: The microstructure of tight reservoir affects the charging efficiency of crude oil,and restricts the abundance and distribution of tight oil.Based on experiments including the physical simulation of tight oil charging,stable rate mercury injection,Scanning Electron Microscopy (SEM) and nuclear magnetic resonance (NMR),the charging process of crude oil and structural characteristics of pore throats of the tight reservoir were quantitatively characterized,and the effects of diagenesis,authigenic mineral growth patterns and pore throat structural features on oil charging in tight reservoirs were discussed.The results show that the oil charging process can be divided into three stages:initial stage,rapid-increase stage and slow-increase stage.This is a result of the dynamic balance between displacement pressure and capillary pressure during the charging process and the distribution of main reservoir space.In detail,there are two increasing modes in the rapid-increase stage,namely,the sustained rapid-increase and rapid-increase by pulses.The two modes reveal the differences in the distribution characteristics of mainstream throat radii in these samples.It is found that diagenesis,including compaction,cementation,dissolution,and authigenic mineral growth,has greatly affected the size and distribution of reservoir space and throat radius,and determined the quality of tight reservoir.Therefore,under the condition of abundant oil source,the key to tight oil enrichment lies in the sufficient driving force and high-quality reservoir,and thus the sand bodies near the open faults/micro-fractures are concluded to be the favorable zones for hydrocarbon exploration.

Key words: rate-controlled injection mercury, pore-throat structure, diagenesis, tight oil charging, tight reservoir

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