Horizontal well transient pressure rapid calculation model establishing method capable of improving near-wellbore pressure drop

Abstract

The method discloses a horizontal well transient pressure rapid calculation model establishing method capable of improving the near-wellbore pressure drop. The method comprises steps as follows: S1, calculating the Laplace space solution of a horizontal well under the infinite oil reservoir and uniform flow rate distribution condition; S2 decomposing the Laplace space solution of the horizontal well under the infinite oil reservoir and uniform flow rate distribution condition into a planar flow part of a stratum and a mirror superposition part of a top and bottom closed boundary effect; S3, calculating the near-wellbore flow pressure drop of the horizontal well; S4, replacing the mirror superposition part of the top and bottom closed boundary effect in the Laplace space solution of the horizontal well under the infinite oil reservoir and uniform flow rate distribution condition with the near-wellbore flow pressure drop of the horizontal well to obtain a shaft pressure calculation model of the horizontal well. The pressure drop response composition of the horizontal well is decomposed, the near-wellbore flow pressure drop of the horizontal well is reasonably described by using a near-wellbore radial flow mechanism, and effects of vertical permeability, shaft position, positive and negative skins and shaft radius are reflected truly.

Description

technical field [0001] The invention relates to the technical field of horizontal well transient pressure, in particular to a method for establishing a fast calculation model of horizontal well transient pressure for improving near-well pressure drop. Background technique [0002] Horizontal well technology has become the main method for efficient development of oil and gas reservoirs, and transient pressure analysis is the basic way to evaluate the productivity of horizontal wells and reservoirs. Since well test interpretation requires real-time calculation and fast response, the analytical solution of seepage mathematical model is still the main tool for well test evaluation. Ozkan & Raghavan (1991) obtained the pressure response calculation model of the line source horizontal well by integrating the point source response along the axis of the wellbore of the horizontal well according to the superposition principle. This model is simple in calculation and widely used, and ...

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Problems solved by technology

[0003] Although the Ozkan point source superimposed horizontal well pressure degradation generally reflects the pressure drop dynamics of horizontal wells, the description of the pressure drop near the wellbore (corresponding to the early stage of the typical curve) is distorted: the model is not sensitive to the change of the wellbore radius and cannot describe The effect of measures to expand the effective well diameter; the model is not sensitive to the change of vertical permeability, which often leads to the low vertical-horizontal permeability ratio estimated by well test interpretation, which is seriously inconsistent with the actual core data

In addition, the model has a large amount of calculation in the mirror superposition part of the top and bottom edge sealing boundary effect, and the history fitting is too time-consuming

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