针对稠油油藏在蒸汽驱过程中易发生汽窜,导致波及系数减小、采收率降低等问题,使用化学剂辅助蒸汽驱的热化学驱油技术得到发展。针对热化学驱油体系内化学剂扩散规律不明确、矿场应用效果存在差异的问题,在物理模拟实验基础上,建立机理模型,通过定性、定量研究降黏剂和泡沫在不同体系下的扩散规律,并考虑压力影响,得以明确化学剂扩散规律。研究表明:降黏剂段塞主要沿优势通道扩散,加剧汽窜,泡沫段塞在扩散中起到封堵调剖作用,促进蒸汽腔均匀扩展;两者间存在相互影响,降黏剂段塞应置于泡沫段塞后,可使主流线方向汽窜速度降低8%,泡沫物质的量浓度提高30.0%;同时应保证一定驱替压差,压力可使化学剂波及范围、平均物质的量浓度分别提高2.3、1.0倍。研究结果对稠油油藏热化学驱方案设计具有参考价值。
It is prone to steam channeling during steam flooding in heavy oil reservoirs, which makes the sweep coefficient small and the recovery low. So, thermochemical flooding technology, chemical agent-assisted steam flooding, has been developed. The diffusion laws of chemicals in thermochemical oil displacement systems are unclear and the field application effects are different. So, a mechanism model was constructed on the basis of physical simulation experiments, the diffusion laws of viscosity reducers and foams in different systems were studied qualitatively and quantitatively, and the diffusion laws of chemicals were clarified considering the pressure effect. The study shows that the viscosity reducer plugs diffuse along the dominant channels to promote steam channeling, but foam plugs block steam channels and modify injection profiles in the diffusion, which promotes the uniform expansion of the steam chambers. There is an interplay between the two, and the viscosity reducer plug should be placed in the foam after the plug. Thus, the steam channeling speed and the molar concentration of foam in mainstream directions are reduced by 8% and 30%, respectively. At the same time, a certain displacement pressure difference should be guaranteed, and the pressure could increase the swept volume of the chemicals and average molar concentration by 2.3 times and 1.0 times, respectively. The study has a reference value for the design of thermochemical flooding programs in heavy oil reservoirs.
[1]BAGCI A S, GUMRAH F.Effects of CO2 and CH4 addition to steam on recovery of west Kozluca heavy oil[C].SPE86953, 2004:1-13.
[2]YANG J, LI X, CHEN Z, et al. Combined steam-air flooding studies: experiments, numerical simulation, and field test in the Qi-40 Block[J]. Energy & Fuels, 2016, 30(3): 2060-2065.
[3]WEI B, PANG S, PU W, et al. Mechanisms of N2 and CO2 assisted steam Huff-n-Puff process in enhancing heavy oil recovery: a case study using experimental and numerical simulation[C]. SPE201013, 2017:1-12.
[4]RABIEI F M,HARDING T G,ABEDI J, et al.Onsetof convective mixing at the edge of steam chamber in steam-Solvent Recovery of heavy oil and bitumen[C].SPE157861, 2012,1-16.
[5]ZHAO D W, WANG J, GATES I D.Solvent-aided steam-flooding strategy optimization in thin heavy oil reservoirs[C].International Petroleum Technology Conference,2013,1-15.
[6]YUAN Z, LIU P, ZHANG S, et al.Experimental study and numerical simulation of nitrogen-assisted SAGD in developing heavy oil reservoirs[J].Journal of Petroleum Science and Engineering, 2018, 162: 325-332.
[7]LI Y B, GAO H, PU W F, et al.A novel displacement mechanism of CO2-assisted steam flooding for highly acidic heavy oil reservoir: an experimental study[C].SPE188858, 2017:1-9.
[8]曹正权,马辉,姜娜,等.氮气泡沫调剖技术在孤岛油田热采井中的应用[J].油气地质与采收率, 2006,13(5):75-77.
CAO Zhengquan,MA Hui,JIANG Na,et al.Application of nitrogen-foam profile control technology in thermal recovery wells of Gudao Oilfield[J].Petroleum Geology and Recovery Efficiency,2006,13(5):75-77.
[9] EMADI A, SOHRABI M, JAMIOLAHMADY M, et al.Mechanistic study of improved heavy oil recovery by CO2-foam injection[C].SPE143013, 2011,1-19.
[10] LI Z, LU T, TAO L, et al.CO2 and viscosity breaker assisted steam huff and puff technology for horizontal wells in a super-heavy oil reservoir[J].Petroleum Exploration and Development, 2011, 38(5): 600-605.
[11] WANG X, WANG J, QIAO M.Horizontal well nitrogen and viscosity reducer assisted steam huff and puff technology: taking super heavy oil in shallow and thin beds, Chunfeng Oilfield, Junggar Basin, NW China, as an example[J].Petroleum Exploration and Development, 2013, 40(1): 104-110.
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