Method for establishing single-phase unsteady seepage model based on pore network model

Abstract

The invention discloses a method for establishing a single-phase unsteady seepage model based on a pore network model. The method comprises the steps of S1, counting the coordination number and throatlength through a micro CT scanning experiment, and obtaining a rock pore throat radius frequency distribution curve through a nuclear magnetic resonance T2 spectrum; S2, based on the pore network models (SC, BCC, and FCC model), establishing a disordered structure network model through center point displacement; and S3, introducing an unsteady single-phase theory into the disordered structure network model, and obtaining an unsteady single-phase seepage equation suitable for the pore network model by combining a Poiseuille law, a Darcy law and a mass conservation law. The established unsteadysingle-phase seepage equation is closer to actual unsteady seepage, so that more accurate flow and pressure under the unsteady seepage condition can be obtained, and guidance opinions are provided for oil and gas reservoir development.

Description

technical field [0001] The invention relates to the technical field of oil and gas field development, in particular to a method for establishing a single-phase unsteady seepage model based on a pore network model. Background technique [0002] Oil and gas resources are one of the most used and most important energy sources in the world. How to develop oil and gas resources efficiently and rationally is a difficult problem faced by every reservoir engineer. The use of numerical simulation methods can assist in the study of dynamic productivity changes of oil and gas resources during the development of oil and gas reservoirs, and overcome the disadvantages of difficulty in restoring underground high temperature and high pressure conditions in the experimental process. The commonly used numerical simulation methods based on the black oil model often seldom consider the physical properties of reservoir rocks, and the simulation results often lack physical meaning; based on pore ...

AI Technical Summary

Problems solved by technology

[0003] At present, many researchers at home and abroad usually use the continuum theory to study multiphase seepage in porous media. However, due to the discontinuity of viscous force and capillary force on the pore scale, and how the seepage law changes after considering fractured media is still unclear. ; The actual fluid usually has compressibility (especially gas) inside the reservoir, which is contrary to the steady-state seepage theory that the fluid can pass from the inlet to the outlet in an instant; in the actual production situation, the seepage law of multiphase fluid is extremely complicated, conventional The advanced seepage theory cannot accurately guide the development of oil and gas reservoirs and predict its production performance, and there are still some limitations in the current research methods for unsteady single-phase seepage simulation. Conventional commercial numerical simulation software can roughly simulate single-phase seepage process, but the accuracy of calculated data and actual production is biased, which greatly limits the exploitation of oil and gas resources

Images