A Single-Phase Unsteady Seepage Model Establishment Method 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, comprising the following steps: S1: counting the coordination number and throat length through a micro-CT scanning experiment; obtaining rock pore throats through nuclear magnetic resonance T2 spectrum Radius frequency distribution curve; S2: Based on the pore network model (SC, BCC, and FCC model), the disordered structure network model is established through the displacement of the center point; S3: The unsteady single state is introduced into the disordered structure network model Phase theory, combined with Poiseuille's law, Darcy's law, and mass conservation law, obtains the unsteady single-phase seepage equation suitable for the pore network model. The unsteady single-phase seepage equation established by the invention is closer to the actual unsteady seepage, and can obtain more accurate flow and pressure in the case of unsteady seepage, and provide guidance 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 ...

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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

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