Physical simulation experimental device for determining the lower limit of buoyancy and dynamic balance, and method for determining the lower limit of buoyancy and dynamic balance

Abstract

The invention discloses a physical simulation experiment device and method for determining the buoyancy lower limit and power balance, and belongs to the field of petroleum geology. The physical simulation experiment technology is utilized for determining buoyancy lower limit change features and the power balance relation at the lower limit on the condition of tight sandstone reservoirs of petroliferous basins. The deep basin gas accumulation physical simulation experiment device simulates piston-type boosting of natural gas on the condition of the tight reservoirs. The sizes of a critical pore throat when buoyancy acts or not on the conditions of different water column weights and different charge pressures are simulated, and under the buoyancy lower limit, natural gas does not generate gas-water replacement and gathers to form deep basin gas accumulation. Experimental data are utilized for fitting of the relation between the diameter of the critical pore throat and the water column heights, a force balance relation among the expansive force of natural gas, capillary force and hydrostatic pressure on the critical condition is built, and a calculation mode of the radius of the critical pore throat is determined. The physical simulation experiment device and method deepen search on tight sandstone gas reservoir accumulation mechanisms, and provide an effective means for prediction of the entrapment range of tight sandstone gas reservoirs.

Description

technical field [0001] The present invention relates to an experimental device in the field of petroleum geological research, its use method and experimental results, in particular to a method of determining the lower limit change characteristics of buoyancy under the condition of tight sandstone reservoirs in oil and gas basins and the lower limit by means of physical simulation experiment technology. dynamic equilibrium relationship. Background technique [0002] Tight sandstone gas reservoirs are an important exploration field for current and future oil and gas resources, and deep basin gas reservoirs are the most important type of tight sandstone gas reservoirs. The accumulation mechanism of deep basin gas is the primary problem to be solved. From the current literature, the representative physical simulation experiments and accumulation mechanism studies include the physical simulation experiments and research results of Robert M. Gies in 1982, the physical simulation ...

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Problems solved by technology

The advantages and existing problems of this simulation experiment and the understanding obtained are as follows: ① It is recognized that the critical pore-throat diameter for the formation of deep basin gas reservoirs is not a fixed value, and the gas supply rate and reservoir characteristics are two of the influencing factors, but there is no A comprehensive understanding of the factors affecting the critical pore-throat diameter, without simulating the influence of the hydrostatic pressure on the critical pore-throat diameter under the buried depth of the reservoir; However, the range of deep basin gas reservoirs, i.e. the change mechanism of the top boundary, has not been explained dynamically

The problem is that such a model has only been established, and the critical geological conditions and influencing factors of "buoyancy does not work" have not been studied in depth

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