Pressure reduction coefficient-based calculation method for maximum distance of natural gas lateral migration

Abstract

The invention relates to the field of natural gas reservoir forming and discloses a calculation method for a maximum distance of natural gas lateral migration. Specifically, the method comprises the following steps of (1) determining a key reservoir forming period; (2) determining a natural gas lateral migration starting point and a migration path; (3) determining natural gas lateral migration power, migration resistance and a pressure reduction coefficient; and (4) in combination with the steps, gradually reducing the migration power according to an influence of the migration resistance in the lateral migration process of natural gas. When the migration power is smaller than the migration resistance, oil and gas cannot be migrated, and at the moment, a distance from the natural gas to themigration starting point is the maximum distance of the natural gas migration. Through the method provided by the invention, the maximum distance of the natural gas lateral migration can be quantitatively calculated; and the distribution range of a gas reservoir can be determined, thereby better guiding the selection of exploration targets and increasing the success rate of natural gas drill-up targets.

Description

technical field [0001] The invention relates to the field of oil and natural gas accumulation, in particular to a method for calculating the maximum distance of lateral migration of natural gas based on the pressure drop coefficient. Background technique [0002] The study of natural gas migration characteristics shows that natural gas migrates in two different directions, vertical and lateral. Vertically, natural gas mainly migrates vertically along the hydrocarbon source faults connecting the source layer and the reservoir, resulting in the heterogeneity of the distribution of gas reservoirs in the vertical direction; laterally, natural gas mainly migrates along the The lateral migration of sand bodies leads to the heterogeneity of the distribution of gas reservoirs on the plane. The longer the lateral migration distance of natural gas along the sand body, the larger the gas-bearing area of ​​the gas reservoir. Therefore, the maximum distance of lateral migration of natur...

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Problems solved by technology

There are several problems in these methods: 1) The first method is mainly a statistical and analogy method, which has great uncertainty, and the accuracy of the result is the lowest; 2) The second method is mainly to analyze the existing Knowing the distance of oil and gas lateral migration in the well, the calculation results of this method are highly accurate, but not predictable, and have little guiding significance for oil and gas exploration deployment; 3) The third method is mainly a basin simulation method, but This method does not take into account the influence of capillary pressure on oil and gas migration, so the accuracy of the simulation results is low