CN-122021978-A - Shale oil well productivity prediction method, system and electronic equipment based on different flow states

CN122021978ACN 122021978 ACN122021978 ACN 122021978ACN-122021978-A

Abstract

The invention belongs to the technical field of oil and natural gas self-injection drainage and production processes, in particular relates to a shale oil well productivity prediction method, system and electronic equipment based on different flow states, and aims to solve the problems of larger error and poor adaptability of the shale oil well productivity prediction method in the prior art. The method comprises the steps of collecting oil well production data in a historical production time period, calculating bottom hole flow pressure by using RTA software based on the oil well production data, calculating yield normalized pressure based on wellhead pressure, bottom hole flow pressure and oil well yield, making a double-log diagnosis chart by taking the logarithm of the yield normalized pressure as an ordinate and the logarithm of material balance time as an abscissa, determining unstable linear flow and quasi-steady flow based on the slope of the double-log diagnosis chart, and adding the productivity condition of the unstable linear flow and the productivity condition of the quasi-steady flow to obtain final productivity. The method improves the productivity prediction accuracy of the shale oil well.

Inventors

Wang Miaodi
TANG QING
LI SHAOFU
LIU CHENGYUAN
WANG DONG
ZHOU JUNJIE
HAN TAO
XIA WEI

Assignees

中国石油天然气股份有限公司

Dates

Publication Date: 20260512
Application Date: 20241111

Claims (9)

1. A shale oil well productivity prediction method based on different flow regimes, the method comprising: acquiring well production data over a historical production time period, the well production data including wellhead pressure, material balance time, well production, wellbore depth, fluid density and friction loss of the shale well; Calculating a bottom hole flow pressure using RTA software based on the well production data; Calculating a production normalized pressure based on wellhead pressure, bottom hole flow pressure, and well production; taking the logarithm of the yield normalized pressure as an ordinate and the logarithm of the material balance time as an abscissa, and making a double-logarithm diagnosis chart; determining an unsteady linear flow and a quasi-steady flow based on the slope of the log-log diagnostic map; and adding the capacity condition of the unstable linear flow and the capacity condition of the quasi-steady flow to obtain the final capacity.
2. The method for predicting the productivity of a shale oil well based on different flow states according to claim 1, wherein the method for calculating the bottom hole flow pressure is as follows: W 2 ＝W 1 +ρ·g·h+ΔP; Wherein, W 2 is bottom hole flow pressure, W 1 is wellhead pressure, ρ is fluid density, g is gravitational acceleration, h is wellbore depth, and ΔP is friction loss.
3. The method for predicting the productivity of a shale oil well based on different flow regimes according to claim 2, wherein the method for calculating the normalized pressure of the productivity is as follows: And dividing the first difference value at the current moment by the oil well yield at the current moment to obtain the yield normalized pressure at the current moment.
4. A method of predicting shale well productivity based on different flowstates as claimed in claim 3, wherein the method of determining the unsteady linear flow and the pseudo steady flow based on the slope of the double log diagnostic map is: When the slope of the double-logarithmic diagnosis chart is 0.5 and the length of the abscissa corresponding to the slope of 0.5 is greater than a first threshold, the material balance time corresponding to the slope of 0.5 is an unstable linear flow; And when the slope of the double-log diagnostic chart is 1 and the length of the abscissa corresponding to the slope 1 is greater than a second threshold value, the material balance time corresponding to the slope 1 is quasi-steady-state flow.
5. The method for predicting the capacity of a shale oil well based on different flow regimes according to claim 4, wherein the method for calculating the capacity condition of the unsteady state linear flow is as follows: And accumulating and superposing the oil well production corresponding to the material balance time of the unstable linear flow to obtain the productivity condition of the unstable linear flow.
6. The method for predicting capacity of a shale oil well based on different flow regimes of claim 5, wherein the method for calculating the capacity status of the quasi-steady-state flow is: And in the quasi-steady-state flow stage, fitting the capacity condition by using Arps recursive method to obtain the capacity condition of the quasi-steady-state flow.
7. A shale oil well productivity prediction system based on different flowstates, the system comprising: the system comprises a data acquisition module, a data acquisition module and a data processing module, wherein the data acquisition module is used for acquiring oil well production data in a historical production time period, and the oil well production data comprise wellhead pressure, material balance time, oil well yield, shaft depth, fluid density and friction loss of a shale oil well; the bottom hole flow pressure calculation module is used for calculating bottom hole flow pressure by using RTA software based on the oil well production data; The output pressure calculation module is used for calculating output normalized pressure based on wellhead pressure, bottom hole flow pressure and oil well output; the diagnostic chart module is used for making a double-logarithmic diagnostic chart by taking the logarithm of the yield normalized pressure as an ordinate and the logarithm of the material balance time as an abscissa; The flow state determining module is used for determining an unstable state linear flow and a quasi-steady state flow based on the slope of the double-logarithmic diagnosis chart; the capacity calculation module is used for calculating the capacity condition of the unstable linear flow and the capacity condition of the quasi-steady flow respectively, and adding the capacity condition of the unstable linear flow and the capacity condition of the quasi-steady flow to obtain the final capacity.
8. An electronic device, comprising: the system comprises at least one processor and a memory communicatively connected to the at least one processor, wherein the memory stores instructions executable by the processor for execution by the processor to implement the different flow regime based shale well productivity prediction method of any of claims 1-6.
9. A computer readable storage medium having stored thereon computer instructions for execution by the computer to implement the different flow regime based shale well productivity prediction method of any of claims 1-6.

Description

Shale oil well productivity prediction method, system and electronic equipment based on different flow states Technical Field The invention belongs to the technical field of oil and natural gas self-injection drainage and production processes, and particularly relates to a shale oil well productivity prediction method, system, electronic equipment and storage medium based on different flow states. Background Along with the gradual expansion of the scale of the domestic shale oil exploration and development, the accuracy of the productivity prediction method is crucial to the benefit development. However, the problems of quick initial oil yield, quick pressure drop, large drop amplitude, large difference among different layers, complex production dynamic characteristics and the like exist in the exploration and development process. At present, scholars at home and abroad conduct a great deal of researches on productivity decreasing rules and productivity prediction of the fracturing horizontal well, wherein the methods comprise an analysis model, a semi-analysis model, numerical simulation and the like, and dynamic rules of various production indexes of the horizontal well are analyzed from different angles. However, the method is mostly macroscopic, analysis on different flow states is lacking, and even if the different flow states are considered, the method is only used by a formula, so that the prediction error is larger. The existing shale oil well productivity prediction method has the following limitations that (1) the existing productivity prediction method is mainly aimed at shale gas wells, has low adaptability to shale oil wells and needs to be further researched, and (2) after multi-stage fracturing completion is carried out on the shale oil wells, different flow characteristics of fluid can be generated. If only one method is used for predicting the whole production process of the horizontal well, the method is not suitable for different flow states of shale oil well fluid, and (3) fitting is carried out by using different formula methods based on the flow state, and only the formula is used for applying, so that the prediction error is large. Therefore, the shale oil well productivity prediction method in the prior art has the problems of larger error and poor adaptability. Disclosure of Invention In order to solve the problems in the prior art, namely the problem of larger error in the shale oil well productivity prediction method in the prior art, the invention provides a shale oil well productivity prediction method based on different flow states, which comprises the following steps: acquiring well production data over a historical production time period, the well production data including wellhead pressure, material balance time, well production, wellbore depth, fluid density and friction loss of the shale well; Calculating a bottom hole flow pressure using RTA software based on the well production data; Calculating a production normalized pressure based on wellhead pressure, bottom hole flow pressure, and well production; taking the logarithm of the yield normalized pressure as an ordinate and the logarithm of the material balance time as an abscissa, and making a double-logarithm diagnosis chart; determining an unsteady linear flow and a quasi-steady flow based on the slope of the log-log diagnostic map; and adding the capacity condition of the unstable linear flow and the capacity condition of the quasi-steady flow to obtain the final capacity. In a preferred embodiment, the method of calculating the bottom hole flow pressure is: W2＝W1+ρ·g·h+ΔP; Wherein, W 2 is bottom hole flow pressure, W 1 is wellhead pressure, ρ is fluid density, g is gravitational acceleration, h is wellbore depth, and ΔP is friction loss. In a preferred embodiment, the method of calculating the yield normalization pressure is: And dividing the first difference value at the current moment by the oil well yield at the current moment to obtain the yield normalized pressure at the current moment. In a preferred embodiment, the method for determining the unsteady linear flow and the quasi-steady flow based on the slope of the double-log diagnostic map is as follows: When the slope of the double-logarithmic diagnosis chart is 0.5 and the length of the abscissa corresponding to the slope of 0.5 is greater than a first threshold, the material balance time corresponding to the slope of 0.5 is an unstable linear flow; And when the slope of the double-log diagnostic chart is 1 and the length of the abscissa corresponding to the slope 1 is greater than a second threshold value, the material balance time corresponding to the slope 1 is quasi-steady-state flow. In a preferred embodiment, the method for calculating the capacity of the unsteady linear flow is as follows: And accumulating and superposing the oil well production corresponding to the material balance time of the unstable linear flow to obtain the productivity condition