A Study On Percolation Mechanism Of Low Permeability Reservoir And Recovery Technology

A comprehensive study has been made on the problems of low permeability reservoir. This dissertation presents the development of a study on percolation mechanism of low permeability reservoir and recovery technology.The specific tasks achieve in this work include the following:1. Theory study of flow through the low-permeability porous media has been made by utilizing similarity theory and dimensional analysis in this thesis. The equations of motion about flow through very low permeability porous media are established. A critical condition has been modeled to describe low velocity non-Darcy flow in porous media. The equations among start-up pressure gradient, water breakthrough time, oil recovery rate and injector-producer distance are established.2. Some new shop experimental methods of low permeability reservoir evaluation have been offered in this dissertation by combining percolation mechanism of low permeability reservoir and some new experimental methods such as constant velocity mercury penetration experiment, scanning electron microscopy experiment, conventional mercury penetration experiment, NMR, etc. A method of removable reserves of low permeability reservoir is given to make evaluation. The relation between this evaluation method and displacement efficiency is studied in this thesis.3. The third part of this research is focus on how to enhance oil recovery(EOR). (1) Oil-displacement mechanism of activity water is studied by utilizing shop experiment of activity water and numerical reservoir simulation. (2) The influence of water quality on injection pressure, stratum damage, productivity and well pattern designing of very low permeability reservoir is studied by shop experiment, petroleum reservoir engineering and numerical simulation. (3) Economic production rate limit of bailing recovery and containing water formula have been given. Dynamic liquid level fitted model, feed flow ability and bailing recovery production rate fitted model are also given in this thesis. (4) Hydraulic fracturing technology being suitable to very low permeability reservoir is discussed. Damage mechanism of fracturing fluid and methods of reducing damage has been developed to optimize the parameters of hydraulic fracturing treatment. This dissertation presents an academic basis for the hydraulic fracturing improvement of a very low permeability reservoir.