油气藏评价与开发 ›› 2021, Vol. 11 ›› Issue (6): 831-836.doi: 10.13809/j.cnki.cn32-1825/te.2021.06.005

• 方法理论 • 上一篇    下一篇

致密砾岩油藏CO2吞吐提高采收率可行性研究

范希彬1(),蒲万芬2,单江涛1,杜代军2,覃建华1,高阳1   

  1. 1.中国石油新疆油田分公司勘探开发研究院,新疆 克拉玛依 834000
    2.西南石油大学油气藏地质及开发工程国家重点实验室,四川 成都 610500
  • 收稿日期:2020-06-10 出版日期:2021-12-26 发布日期:2021-12-31
  • 作者简介:范希彬(1985—),男,硕士,工程师,现从事油田开发工作。地址:新疆克拉玛依市准噶尔路勘探开发研究院,邮政编码:834000。E-mail: fanxibin@petrochina.com.cn

Feasibility of enhanced oil recovery by CO2 huff-n-puff in tight conglomerate reservoir

FAN Xibin1(),PU Wanfen2,SHAN Jiangtao1,DU Daijun2,QIN Jianhua1,GAO Yang1   

  1. 1. Research Institute of Petroleum Exploration and Development, Xinjiang Oilfield Company, PetroChina, Karamay, Xinjiang 834000, China
    2. State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, Sichuan 610500, China
  • Received:2020-06-10 Online:2021-12-26 Published:2021-12-31

摘要:

基于原油与CO2以及CO2与储层岩石相互作用,揭示环玛湖致密砾岩油藏CO2提高采收率机理。利用高温高压核磁共振系统在孔隙尺度下监测了基质岩心CO2吞吐过程中原油饱和度的变化,研究CO2吞吐提高采收率可行性。采用岩心压裂和驱替系统开展三维物理模拟实验研究,研究裂缝对CO2吞吐提高采收率的影响。实验结果表明,CO2能够有效地溶解在原油中,补充地层能量,降低原油黏度,且改善储层润湿性。基质岩心中,衰竭式开采时的原油主要产于大孔隙,CO2吞吐能有效启动中孔隙和小孔隙,衰竭式开采后,三轮次的吞吐能够提高采收率23.1 %左右,而第一轮次的贡献率最大,为15.1 %,裂缝的存在能够增大原油与CO2接触面积,减小原油渗流阻力,最终提高采收率27.1 %。实验结果从孔隙尺度揭示了CO2吞吐提高致密砾岩油藏采收率的可行性。

关键词: 提高采收率, CO2吞吐, 致密砾岩, 裂缝, 核磁共振, 三维物理模拟

Abstract:

Based on the interactions between CO2 and crude oil, CO2 and conglomerate, the enhanced oil recovery(EOR) mechanism of CO2 huff-n-puff has been revealed in Huanmahu tight conglomerate reservoir. Meanwhile, a high temperature and high pressure nuclear magnetic system was applied to monitor the change of oil saturation during experimental processes at pore scale in cores of substrates. Core fracturing and displacement system were used to investigate the effects of fractures on EOR during CO2 huff-n-puff. The experimental results indicated that CO2 could effectively dissolve in crude oil to replenish formation energy, reduce oil viscosity and improve wettability. Moreover, the crude oil produced in depletion development was in large pores, while that in medium pores and small pores could be effectively activated by CO2 huff-n-puff. After depletion development, three cycles of huff-n-puff could enhance oil recovery by 23.1 %, among which the first cycle contributed most with factor of 15.1 %. The existence of fractures could increase the contact area between crude oil and CO2 and decrease the flow resistance of crude oil, and finally the EOR is up to 27.1 %. All the results reveal the feasibility of CO2 huff-n-puff to improve oil recovery in tight conglomerate reservoirs from pore scale.

Key words: enhanced oil recovery(EOR), CO2 huff-n-puff, tight conglomerate reservoir, fractures, NMR, three-dimensional physical simulation

中图分类号: 

  • TE38