Reservoir Evaluation and Development ›› 2020, Vol. 10 ›› Issue (6): 24-32.doi: 10.13809/j.cnki.cn32-1825/te.2020.06.004

• Methodological and Theory • Previous Articles     Next Articles

Synthesis of associative polymer for flooding in low permeability reservoir and its reservoir adaptability

LI Huabing1(),LI Jianting2,LI Wenhong3,HU Jun1,YUAN Guowei3,LIANG Yan4,5,ZHANG Xinmin1,4,GUO Yongjun1,4,5()   

  1. 1.Sichuan Guangya Polymer Chemical Co., Ltd., Nanchong, Sichuan 637900, China
    2.No.2 Oil Production Plant, PCOC, Qingcheng, Gansu 745100, China
    3.Exploration and Development Research Institute, Changqing Oilfield Branch Company, PetroChina, Xi’an, Shaanxi 710018, China
    4.State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, Sichuan 610500, China
    5.College of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu, Sichuan 610500, China
  • Received:2020-11-03 Online:2020-12-26 Published:2021-01-07
  • Contact: GUO Yongjun E-mail:gyfzlhb@126.com;gyfzgyj@126.com

Abstract:

In view of the reservoir conditions in a block of Changqing Oilfield with medium temperature, high salinity and low permeability, different temperature-salt resistant associative polymers(HAWSP series) with low relative molecular weight(720.42×104 ~ 982.55×104) and different contents of dodecylallyl tetramethyl ethylene diammonium bromide(TDAD) have been designed and synthesized. Then the molecular structure of the polymer has been confirmed by infrared spectroscopy. Under the conditions of this block, the reservoir adaptability of HAWSP series involving solution properties and application performance have been studied, and the field test has been carried out in this block. The results show that, compared with the salt-resistant partially hydrolyzed polyacrylamide(HPAM), HAWSP series has better thickening capacity and similar aging stability(viscosity retention rate is greater than 85 % after aging for 60 days). When the gas permeability is of 50×10-3 μm2, the associative polymer HAWSP-850 not only exhibits good injectability and conductivity, but also could present stronger sweeping ability in heterogeneous core with a permeability contrast of 4 times(low permeability is of 25×10-3 μm2), which can enhance the oil recovery by another 3.29 percentage points. Field tests show that the temperature-salt resistant associative polymer has better field adaptability. Compared with the conventional HPAM flooding system, it has a significant effect of reducing pressure and improving injection capacity and oil recovery. Associative polymer has important promotion significance of chemical flooding in low permeability reservoirs.

Key words: low permeability, low molecular weight, associative polymer, reservoir adaptability, field test

CLC Number: 

  • TE357