Porous Flow Mechanics For Low Permeability Reservoirs And Its Application

In this paper, porous flow mechanics in low permeability and fractured reservoirs is studied for the practical problems that occurred during the development of reservoir, which is accomplished on the base of predecessors' work. the main research results we get are as following:1 , From the porous flow experiments by cores form low permeability reservoirs, nonlinear porous flow mechanics in the core of low permeability reservoirs is found; the relationships between real start-up pressure gradient, pseudo start-up pressure gradient, pressure gradient of pseudo liner porous flow and permeability are analyzed; dead oil area, nonlinear porous flow area and liner porous flow area are confirmed.2, Flow profile of fluid in low permeability reservoir is confirmed. New concepts such as overall criterion, low-permeability criterion and low-velocity criterion are brought forward, which have been testified by experiments. The relationships between different porous-flow criterion and pressure gradient are analyzed, the relationships between 1 ow p ermeability reservoirs o verall c riterion and different p ressure gradients are also confirmed. what's more, viscosity of flowing fluid in porous media is calculated with porous flow experiment data.3, Influence on production capacity by various factors are analyzed, and a new concept of effective drive factor is brought forward. According to the chara-cteristics and porous flow theory of low permeability reservoir, oil production decline equation, water cut equation and waterflooding character equation for waterflooding low permeability reservoir are derived, the influence on low permeability reservoir development effect by effective drive factor is analyzed.4, Through analyzing the relationship between percentage of mobile fluid in different cores and porosity, permeability, it's necessary to introduce into a new evaluation index factor for low permeability reservoir evaluation, percentage of mobile fluid in low permeability reservoir and classifying limits of start-up pressure gradient grade are brought forward.5 , Influence on self-imbibition by various factors is analyzed, imbibition experiments data of low permeability reservoir is fitted with improved ternary exponential function model. The imbibition experiment result in lab is applied in reservoir condition by magnifying according to similarity theory, influence on Toutai low permeability and fractured reservoir by various factors is analyzed. A production decline model which is fit for water huff and puff well is established based on the in-site production data and imbibition experiment in lab.