Effect of absorption boundary layer on nonlinear flow in low permeability porous media

Abstract

Taking low permeability cores of Daqing oilfield for example, the flow characteristics at low velocity were studied with the self-designed micro-flux measuring instrument. Considering the throat distribution and capillary model, the thickness of fluid boundary layer under different pressure gradients was calculated, and the mechanism and influencing factors of nonlinear percolation were discussed. The results show that the percolation curve of ultra-low rocks is nonlinear, and apparent permeability is not a constant which increases with pressure gradient. The absorption boundary layer decreases with the increase of pressure gradient, and changes significantly especially in low pressure gradient, which is the essence of nonlinear percolation. The absorption boundary layer is also found to be impacted by the surface property of rocks.

Keywords

low permeability reservoirs / percolation / absorption boundary layer / capillary model

References

[1] WangD.-fu.Ordos basin extra-low permeability oilfield development [M], 2007, Beijing, Petroleum Industry Press: 1-3

[2] HuangY.-zhang.Fluid mechanics in low-permeability reservoir [M], 1998, Beijing, Petroleum Industry Press: 80-86

[3] Miller-bownlieT. A.. Subsoil water in relation to tube wells [J]. Indian & Eastern Engineer, 1919, 42(2): 116-131

[4] von EngelhardtW., TunnW. L. M.. The flow of fluids through sandstones [J]. Heidelberger Beitrage zur Mineralogie und Petrographie, 1954, 2(1): 12-25

[5] IrmayS.. On the theoretical derivation of darcy and forchheimer formulas [J]. J Geophys Res, 1958, 64(4): 485-486

[6] DudgeonC. R.. An experimental study of the flow of water through coarse granular media [J]. La Houille Blanche, 1966, 21(7): 785-801

[7] BasakP.. Non-Darcy flow and its implications to seepage problems [J]. Journal of the Irrigation & Drainage Division, American Society of Civil Engineers, 1970, 103(4): 459-473

[8] RussellD. A., SwartzendruberD.. Flux-gradient relationships for saturated flow of water through mixtures of sand, silt, & clay [J]. Soil Science Society of America Proceedings, 1971, 35(1): 21-26

[9] CarverR. E.. Studies on the validity of Darcy’s law for flow in natural sands [R]. Technical Completion Report USDI/OWRR Project No. A-037-GA, 1973, Athens GA, University of Georgia

[10] KececiogluI., JiangY.. Flow through porous media of packed spheres saturated with water [J]. Journal of Fluids Engineering-Transactions of the American Society of Mechanical Engineers, 1994, 116(1): 164-170

[11] PradaA., CivanF.. Modification of Darcy’s law for the threshold pressure gradient [J]. Journal of Petroleum Science & Engineering, 1999, 22(4): 237-240

[12] WangS.-j., HuangY.-z., CivanF.. Experimental and theoretical investigation of the Zaoyuan field heavy oil flow through porous media [J]. Journal of Petroleum Science and Engineering, 2006, 50(2): 83-101

[13] HaoF., ChengL.-s., HassanO., HouJ., LiuC. Z., FengJ. D.. Threshold pressure gradient in ultra-low permeability reservoirs [J]. Petroleum Science and Technology, 2008, 26(9): 1024-1035

[14] Polubarinova-KochinaP. Y.Theory of ground water movement [M], 1962, Princeton N J, Princeton University Press: 20-24

[15] XuS.-l., YueX.-an.. Experimental research on nonlinear flow characteristics at low velocity [J]. Journal of China University of Petroleum: Natural Science Edition, 2007, 31(5): 60-63

[16] LiZ.-f., HeS.-li.. Influence of boundary layers upon filtration law in low-permeability oil reservoirs [J]. Petroleum Geology & Oilfield Development in Daqing, 2005, 24(2): 57-59

[17] CoatesG. R., XiaoL. Z., PrammerM. G.NMR logging principles and applications [M], 1999, Texas, Gulf Publishing Company: 7