Analysis method and system for early water production data of coalbed methane wells considering anisotropy

Abstract

The invention discloses a method and system for analyzing early water production data of coalbed methane wells considering anisotropy. Homogeneous permeability k in homogeneous coal seam i ; Carry out linearization processing to the water production equation of coalbed methane wells considering anisotropy, and calculate the values ​​of the independent variable X and the dependent variable Y in the linearization equation; put the X and Y values ​​in the above steps into the same rectangular coordinate system In , the permeability k is obtained according to the slope of the linear relationship; the k and k i For comparison, if the relative error between the two is within 1%, it is considered that k i is correct; otherwise, continue to assume homogeneous permeability k i ; Calculate the permeability k in the cleat direction of the coal seam according to the intercept and slope in the linearized equation of the coalbed methane well water production equation considering anisotropy x and the permeability k in the cleat direction of the coal seam end y .

Description

Method and system for early water production data analysis of coalbed methane wells considering anisotropy technical field The present invention relates to the field of oil and gas field development engineering, in particular to a consideration for the development of unconventional oil and gas reservoirs. Anisotropic coalbed methane well early water production data analysis method and system. Background technique The production data analysis method is to analyze the actual production data of oil (gas) well by mathematical model and then reverse the reservoir parameters. The mathematical model used is generally derived based on the fluid seepage equation and boundary conditions in the oil (gas) reservoir. pregnancy The production data analysis method can theoretically restore the fluid seepage state of the reservoir as much as possible, which has clear physical meaning and theoretical background. In practice, based on the actual production data of oil (gas) wells, in...

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Problems solved by technology

[0009] Existing CBM well "single-phase water stage" analysis methods can be subdivided into two categories. One category refers to the production data analysis methods of conventional oil and gas reservoirs, replacing the oil phase and gas phase with water phase, and still assumes that the reservoir has permeability. The other type considers the rock mechanical properties and low permeability characteristics of coal rock itself, and considers the stress sensitivity effect and pressure propagation distance on the basis of the first type of method, but this type of method still does not consider anisotropy Effect on fluid seepage in reservoir

[0010] In general, most of the existing production data analysis methods for coalbed methane wells are aimed at the "gas-water two-phase flow" stage of coal seams, and a small number of production data analysis methods for the "single-phase water" stage of coal seams have not considered the impact of heterogeneity on single-phase flow in coal seams. The effect of phase water seepage

Moreover, the production data of the coalbed gas-water two-phase flow stage are affected by various factors such as profit sensitivity, matrix shrinkage, and gas-water two-phase flow. Therefore, it is difficult to invert formation parameters based on the two-phase flow data, and the reliability is questionable.

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