A Study On Pore Structure And Seepage Characteristics Of Reservoir In Area 76 Of Xing

In this paper,the low-permeability field of Fuyuite in the Block A76 is considered as the research object,and the combination of lithology analysis,casting thin section,conventional mercury intrusion,nuclear magnetic resonance,starting pressure gradient,wettability,and seepage and oil displacement experiments are used.From qualitative analysis to quantitative characterization,from the macroscopic experiment to the microscopic mechanism,the characteristics of microscopic pore structure,single-phase percolation mechanism,and oil-water two-phase flow characteristics of ultra-low permeability reservoirs were systematically described.Research indicates :1.The Fuyu oil layer in the 76 th area of the apricot is characterized by low porosity and ultra-low permeability reservoirs,with an average permeability of 2.30×10-3?m2 and an average porosity of 14.91%.In semi-logarithmic coordinates,the porosity and permeability of the core of the Fuyu oil layer have a good linear relationship;the main components of the rock skeleton are quartz,albite,plagioclase and calcite,and contain a small amount of iron minerals,so it exists.Speed-sensitive,water-sensitive,acid-sensitive and alkali-sensitive hazards;reservoirs are characterized by fine sandy siltstone and feldspathic lithic sandstones,with a maximum particle size range of 0.24 mm to 0.56 mm and a main particle size range of0.04 mm to 0.40 mm,with the increase of permeability,the maximum particle size and the main particle size range showed an increasing trend.2.The mercury intrusion parameter shows that the discharge pressure and the saturation median pressure increase with the decrease of permeability.When the air permeability is less than 1×10-3?m2,the pressure of the displacement and saturation medium pressure increase rapidly;The pore throat radius decreases rapidly with the decrease of permeability,and the pore-throat ratio increases rapidly.Therefore,the specific surface area of the reservoir is large,the solid-liquid coupling effect and the Jiamin effect are strong,and the remaining oil droplets are difficult to start.3.Through the reservoir engineering calculation method,the pressure gradient and critical initial permeability of the interwell displacement of the reservoir are analyzed.The maximum water injection pressure is consumed near the injection well and the production well,and the larger displacement pressure gradient makes the critical initial permeability.Smaller,in accordance with the current production system can be effectively used conditions.4.The percolation curve can be seen that the two iso-osmotic points of the Fuyu oil layerare between 53.53% and 61.39%,the average isotonic point is 57.13%,and the span of the two-phase seepage zone is between 13.37% and 32.63%.It is 23.65%;the irreducible water saturation is between 32.74% and 51.95% with an average of 41.51%;the residual oil saturation is between 32.27% and 39.21%,the average residual oil saturation is 34.84%,and the curve is linear on Convex type.5.The reservoir wettability is strong water and wet,and the average Amott wettability index is 0.39;the permeability oil recovery increases with the increase of the wetting index,with an average of 4.89%;the same physical rock samples have different water saturation conditions.In the following,the infiltration rate is different,and the infiltration rate decreases with the increase of water saturation in the core;comparing with conventional infiltration experiments and high pressure dynamic infiltration experiments,the rock skeleton is further compressed with the increase of fluid pressure,and the pore volume is slightly increased.At an environmental pressure of 10 MPa,the osmotic oil recovery averaged 0.27%.6.The results of NMR T2 spectroscopy in the test of imbibition show that the degree of mobilization of the crude oil in the pores during the imbibition process decreases with the increase of microscopic geometry of the pores,and the extent of the pores with T2 ? 2ms is the largest,being 84.85%,T2?10ms.The fluid in the pores has the lowest degree of utilization,being 0.88%.