Method for improving recovery ratio through nuclear magnetism online tight oil-water flooding development

Abstract

The invention belongs to the technical field of oil-gas exploration, and particularly relates to a method for improving the recovery ratio by nuclear magnetism online tight oil-water flooding development. The method comprises the following step of step 1, putting a rock core sample into a drying oven after oil washing and salt washing, adjusting the temperature of the drying oven to 60 DEG C, drying for 48 hours and taking out the rock core sample. The diameter D = 2.5 cm, the length L = 5.450 cm, the porosity phi = 15.22%, the permeability K = 0.1028 mD and the dry weight M1 = 61.8972 g of asample are measured according to industrial standards, the rock core sample after dry weight is put into a vacuum pump for vacuumizing for 4 hours, pressurizing (20MPa) of saturating simulated oil fornot less than 48 hours is carried out after no bubble overflows, the simulated oil density Rho o = 0.8g / cm<3>, the wet weight M2 is equal to 65.0846g, the initial oil saturation Soi of the sample iscalculated, the experiment error caused by oil-gas-water three-phase flow in the experiment process can be avoided only when the initial oil saturation is required to reach 98% or above, the structureis reasonable, and the displacement efficiency, the residual oil saturation, the residual oil distribution rule and other parameters of oil in the rock core sample can be accurately obtained.

Description

technical field [0001] The invention relates to the technical field of oil and gas exploration, in particular to a method for increasing the recovery rate of nuclear magnetic on-line tight oil-water flooding development. Background technique [0002] Tight oil is another new hotspot in the exploration and development of unconventional oil and gas in the world after shale oil and gas. As a typical unconventional resource, tight oil will be one of the important energy sources in my country in the future. Tight oil refers to reservoirs in overburden matrix with permeability less than or equal to 0.1×10 -3 μm 2 (air permeability is less than 1×10 -3 μm 2 ) oil in tight sandstone, tight carbonate rock and other reservoirs. Generally, a single well has no natural production capacity or natural production capacity is lower than the lower limit of industrial oil and gas flow, but industrial oil and gas production can be obtained under certain economic conditions and technical me...

AI Technical Summary

Problems solved by technology

However, due to the small pore-throat radius, poor connectivity, complex pore-throat structure, and prominent viscous and capillary forces in tight oil reservoirs, the seepage characteristics of water flooding in tight oil reservoirs are different from those of conventional oil reservoirs and shale oil reservoirs. It is difficult to directly obtain the seepage law and macroscopic properties of water flooding in tight oil reservoirs and methods.

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