CN-122021979-A - Method and system for rapidly predicting gas-water two-phase yield of tight water-containing gas reservoir fracturing well

CN122021979ACN 122021979 ACN122021979 ACN 122021979ACN-122021979-A

Abstract

The invention provides a method and a system for rapidly predicting gas-water two-phase yield of a tight water-containing gas reservoir fracturing well, wherein the method comprehensively considers the influence of slip effect, stress sensitivity effect, starting pressure gradient and gas high-pressure physical property on a seepage mechanism in a tight reservoir, respectively establishes gas phase correction pseudo-pressure and pseudo-time and water phase correction pseudo-pressure and pseudo-time to realize linear treatment of nonlinear factors, determines a two-phase unsteady seepage model, adopts implicit pressure and explicit saturation treatment model parameters to deduce corresponding analytical solutions, determines a tight reservoir utilization range to establish a corresponding gas-water two-phase material balance equation, and is used for solving average stratum pressure and average water saturation to update seepage model parameters, thereby realizing two-phase yield prediction of the full life cycle of the tight reservoir. The method can solve the problems of insufficient calculation precision and low efficiency in the prior art, realize accurate and rapid prediction of the two-phase yield of the compact gas fracturing well, and provide technical support for efficient development of compact water-containing gas reservoirs.

Inventors

ZHENG RONGCHEN
LI HONGTAO
JIA YING
TAN XUEQUN
JIA CHAO
LIU JIANDANG

Assignees

中国石油化工股份有限公司
中国石油化工股份有限公司石油勘探开发研究院

Dates

Publication Date: 20260512
Application Date: 20241112

Claims (10)

1. A method for rapidly predicting gas-water two-phase yield of a tight water-containing gas reservoir fracturing well is characterized by comprising the following steps: Step 100, based on setting reservoir parameters of a tight reservoir, comprehensively considering the slip effect, the stress sensitive effect, the starting pressure gradient and the influence of gas high-pressure physical properties relative to a seepage mechanism to establish a two-phase unsteady seepage operation model of the tight reservoir; step 200, determining a solution function setting principle and a two-phase analytic solution deduction mechanism matched with a two-phase unsteady state seepage operation model according to prediction time step dividing thought analysis; Step S300, determining a dynamic parameter updating model for updating model parameters around average formation pressure and average water saturation based on the solving function setting principle; and step 400, dividing a multi-prediction time step according to the requirements according to the prediction period, starting operation by taking the original stratum pressure and the original water saturation of the reservoir as the parameters of the initial model before updating, substituting the parameters into the reservoir singular of the target reservoir, combining the dynamic parameter updating model and a two-phase analytic solution deduction mechanism to calculate and determine the dynamic two-phase yield data of the target reservoir, and realizing full-period two-phase yield prediction.
2. The method according to claim 1, wherein in step S100, the set correction pseudo-pressure and correction pseudo-time function are used to simultaneously characterize the effects of the high pressure physical parameters, the reservoir stress sensitivity effect and the slip effect of the gas phase seepage related gas of the tight reservoir.
3. The method of claim 1, wherein the effect of the start-up pressure gradient on gas phase seepage is characterized by a modified start-up pressure gradient effect coefficient.
4. The method of claim 1, wherein the stress sensitivity is characterized by providing a nonlinear term around the stress sensitivity, and treating with an aqueous phase correction quasi-pressure, an aqueous phase correction quasi-time to characterize the effect of the stress sensitivity on the aqueous phase seepage.
5. The method of claim 1, wherein a two-phase unsteady state seepage operation model is established as follows: Wherein λ is the starting pressure gradient, ψ is the gas phase correction pseudo pressure, x is the x coordinate, G λ is the correction starting pressure gradient influence coefficient, φ is the reservoir porosity, k i is the reservoir absolute permeability, k rg is the gas relative permeability, c ti is the integrated compression coefficient in the original state of the reservoir, μ gi is the gas viscosity in the original state of the reservoir, t a is the gas phase correction pseudo time, For the water phase correction pseudo pressure, t w is the water phase correction pseudo time, mu w is the water phase viscosity, c tw is the reservoir water phase comprehensive compression coefficient, and k rw is the water phase relative permeability.
6. The method according to claim 1, wherein in step S200, parameters in the gas-water two-phase unsteady state seepage equation are processed by adopting an implicit pressure and explicit saturation method, and an analytical solution of the two-phase unsteady state seepage operation model is obtained by deriving by using a Laplace transformation method.
7. The method according to claim 1, wherein in step S300, the tight reservoir usage range is analyzed, a gas-water two-phase material balance equation in the usage range is established as a dynamic parameter update model, and the average formation pressure and the average water saturation in the usage range are solved as update parameters of the model.
8. The method of claim 7, wherein the method comprises calculating X, Y-directional mobility areas and calculating a mobility volume in a rectangular area using a mobility area of the water phase as a reservoir mobility area, respectively, taking into account a start pressure gradient characteristic of gas permeation flow in analyzing a mobility area of the tight reservoir.
9. A storage medium having stored thereon program code for implementing the method of any of claims 1-8.
10. A fast prediction system for gas-water two-phase production of a tight gas reservoir fracturing well, wherein the system performs the method according to any one of claims 1-8.

Description

Method and system for rapidly predicting gas-water two-phase yield of tight water-containing gas reservoir fracturing well Technical Field The invention relates to the technical field of oil and gas exploration and development data prediction, in particular to a method and a system for rapidly predicting gas-water two-phase yield of a compact water-containing gas reservoir fracturing well. Background The existing productivity prediction method is mainly realized based on three methods of an empirical formula, an analytical model and numerical simulation. The empirical formula method is mainly calculated through an Arps formula (crude oil recovery empirical formula) and other yield decreasing curve fitting formulas, the analytical model method is mainly realized based on a linear flow model and a partitioned linear flow model, and the numerical simulation method is mainly based on tool operation processing such as commercial numerical simulation software t-Navigator, CMG, eclipse. The problems of the prior art are mainly characterized in that the problem of variable production flow pressure output prediction cannot be solved by an empirical formula method, the variable production flow pressure output prediction is difficult to be suitable for field application, the prediction of the production capacity by a numerical simulation method is time-consuming, the parameter input is overlarge, the prediction is usually carried out by adopting a rapid calculation analysis model, but the existing analysis model has larger defects, the influence factors related to model operation are not comprehensive enough, the calculated result is inconsistent with the authenticity, in addition, the water saturation of a tight gas reservoir is higher, the used seepage model is basically limited to the single-phase seepage problem, and the model operation is based on steady-state and quasi-steady-state assumptions. Therefore, the existing analytical model has the problems of low efficiency, low calculation precision and the like when predicting the gas-water two-phase yield of the compact gas well. The information disclosed in the background section of the invention is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art. Disclosure of Invention The invention provides a method for rapidly predicting the gas-water two-phase yield of a tight gas reservoir fracturing well, which can effectively solve the problems of insufficient calculation precision and low efficiency in the prior art, realize accurate and rapid prediction of the gas-water two-phase yield of the tight gas fracturing well, provide technical support for efficient development of the tight gas reservoir, respectively establish gas phase correction quasi-pressure and quasi-time, water phase correction quasi-pressure and quasi-time to realize linear treatment of nonlinear factors by comprehensively considering the slippage effect, stress sensitivity effect, starting pressure gradient and gas high-pressure physical property in the tight reservoir on a seepage mechanism, determine a two-phase unsteady seepage model, adopt implicit pressure and explicit saturation processing model parameters to deduce corresponding analytic solutions, determine the dynamic range of the tight reservoir to establish a corresponding gas-water two-phase material balance equation for solving average stratum pressure and average water saturation updating seepage model parameters, and further realize the two-phase prediction of the full life cycle of the tight reservoir. Preferably, in one embodiment, the method comprises: Step 100, based on setting reservoir parameters of a tight reservoir, comprehensively considering the slip effect, the stress sensitive effect, the starting pressure gradient and the influence of gas high-pressure physical properties relative to a seepage mechanism to establish a two-phase unsteady seepage operation model of the tight reservoir; step 200, determining a solution function setting principle and a two-phase analytic solution deduction mechanism matched with a two-phase unsteady state seepage operation model according to prediction time step dividing thought analysis; Step S300, determining a dynamic parameter updating model for updating model parameters around average formation pressure and average water saturation based on the solving function setting principle; and step 400, dividing a multi-prediction time step according to the requirements according to the prediction period, starting operation by taking the original stratum pressure and the original water saturation of the reservoir as the parameters of the initial model before updating, substituting the parameters into the reservoir singular of the target reservoir, combining the dynamic parameter updating model and a two-phase an