Quantitative evaluation method for single well yield contribution rate of fracture and matrix to super-low permeability reservoir

Abstract

The invention relates to a quantitative evaluation method for a contribution rate of fractures and a matrix to single well yield of a super-low permeability reservoir. The method comprises the steps of step 1, establishing a reservoir matrix geologic model; step 2, establishing a reservoir fracture geologic model; step 3, combining the reservoir matrix geologic model with the reservoir fracture geologic model through geologic modeling software comprising matrix and fracture modules, and establishing a preliminary reservoir geologic model considering a natural fracture; step 4, performing analog computation of an influence of the matrix on single well yield; step 5, performing analog computation of an influence of the matrix and an artificial fracture on the single well yield; step 6, performing analog computation of an influence of the matrix, the artificial fracture and the natural fracture on the single well yield; and step 7, performing quantitative evaluation on the contribution rate of the fractures and the matrix to the single well yield. According to the method, the contribution degree of the fractures and the matrix to the single well yield of the super-low permeability reservoir is given out and the advantages of seepage capabilities of the matrix and the fractures are pointedly exerted, so that the method plays a vital role in improving development effects.

Description

technical field [0001] The invention belongs to the technical field of single-well production evaluation of ultra-low permeability tight oil reservoirs, and particularly relates to a quantitative evaluation method for the contribution rate of fractures and matrix to ultra-low permeability oil reservoir single-well production. Background technique [0002] According to the Petroleum and Natural Gas Industry Standard of the People's Republic of China "Evaluation Method for Oil and Gas Reservoirs" (SY / T628521997), which was implemented in 1998, ultra-low permeability oil reservoirs refer to oil reservoirs with surface air permeability less than 1.0mD. The layers are characterized by poor physical properties and the development of natural micro-fractures. The primary problem in the economic and effective development of such reservoirs is how to increase the single-well production. The study believes that the main factors affecting the single-well production of ultra-low permeabi...

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Problems solved by technology

Which injection medium to choose for evaluation was considered in the early stage by water injection, but the study found that when water injection was used to evaluate the contribution of the matrix to the average single well production, when the water injection volume was the same as the injection volume of the actual production block, the simulated well bottom The water injection pressure often reaches above 100.0MPa, which is much higher than the actual bottom hole water injection pressure of various ultra-low permeability oil fields that have been put into development blocks, and is also far higher than the formation fracture pressure; if the stress sensitivity of the rock is considered, adjust the stress sensitivity coefficient, although It can better fit the bottom hole water injection pressure in actual production, but it will change the permeability of the entire matrix core and cannot truly reflect the actual production capacity of the matrix. Therefore, the water injection method can only evaluate the average value of natural fractures and artificial fractures. Contribution to single well production

In order to overcome the limitations of the quantitative evaluation of the contribution rate of fractures and matrix to the average single well production by the water injection method, an evaluation method for gas injection was proposed. The quantitative evaluation method of well production impact has not been carried out by scholars so far.

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