CN-121993124-A - Shale gas cage sleeve type throttle valve control method and system

CN121993124ACN 121993124 ACN121993124 ACN 121993124ACN-121993124-A

Abstract

The invention discloses a shale gas cage sleeve type throttle valve control method and system, and relates to the technical field of oil and gas field development. The method comprises the steps of collecting production data before and after a cage type throttle valve in a set control period, screening out production data in a subcritical state, predicting the production of a gas well in the subcritical state of the cage type throttle valve, obtaining a corrected Cv curve under the condition of the current pressure difference according to the predicted instantaneous production, a specific Cv curve of the valve and pressure data before and after the valve, obtaining a valve adjusting opening corresponding to the current control period according to the corrected Cv curve, adjusting the cage type throttle valve, and repeating the adjusting process until a pressure control target is achieved. According to the invention, the subcritical state gas well yield is predicted through the model, and the Cv curve is corrected in real time, so that the fine control is realized, the pressure control target is approached more quickly, and the control response speed is accelerated.

Inventors

YANG JIAN
YU YANG
ZHOU WEI
WANG WEILIN
CHEN CHAO
XIE BO

Assignees

中国石油天然气股份有限公司

Dates

Publication Date: 20260508
Application Date: 20241106

Claims (11)

1. The shale gas cage sleeve type throttle valve control method is characterized by comprising the following steps of: S1, setting a pressure control target and a control period; S2, collecting production data before and after the cage type throttle valve in the control period; S3, predicting and obtaining the subcritical state gas well yield of the cage type throttle valve according to the subcritical state production data; S4, correcting a flow coefficient Cv curve of the regulating valve according to the subcritical state gas well yield and the pressure data before and after the valve to obtain a corrected Cv curve under the current pressure difference condition; s5, obtaining the valve adjusting opening corresponding to the current control period according to the corrected Cv curve; and S6, adjusting the cage type throttle valve according to the valve adjusting opening degree, and repeating the adjusting process of S2-S6 until the pressure control target is achieved.
2. The shale gas cage-type throttle valve control method as claimed in claim 1, wherein S3 comprises: Taking pre-valve production data samples and post-valve production data samples in subcritical states as inputs of a neural network prediction model, taking shale gas well yield samples as prediction targets, and training a subcritical state gas well yield prediction model; and predicting the collected production data in the subcritical state through the subcritical state gas well yield prediction model to obtain the subcritical state gas well yield of the cage type throttle valve.
3. The shale gas cage-type choke control method according to claim 1 or 2, wherein the production data comprises temperature, pressure, oil pressure, casing pressure, instantaneous gas production and instantaneous water production before and after the valve.
4. The method of claim 3, further comprising detecting water production of the shale gas well with an acoustic probe, and rejecting pre-valve and post-valve temperature and pressure data when water production is detected.
5. The control method of the shale gas cage type throttle valve according to claim 4, wherein the step of detecting the water outlet condition of the shale gas well by using an acoustic probe comprises the steps of detecting and obtaining gas-liquid two-phase flow noise by adding the acoustic probe at the cage type throttle valve, and inputting the gas-liquid two-phase flow noise and the production data into a water production judging model to obtain a water production judging result.
6. The method of claim 5, further comprising marking the production data with a sample tag of whether water is produced, obtaining a water production discrimination sample, and training the water production discrimination model based on the water production discrimination sample.
7. The shale gas cage type throttle valve control method according to claim 1, wherein before S6, the method further comprises the steps of judging whether the valve adjusting opening is within a preset opening adjusting range, if so, executing the adjusting step of S6, and if not, executing the adjusting of the next control period.
8. The shale gas cage type throttle valve control method according to claim 1, wherein S5 comprises the steps of calculating gas well yield change after the pre-valve pressure change in real time according to pre-valve pressure data and post-valve pressure data, making a horizontal line according to the changed gas well yield, and determining valve opening corresponding to an intersection point of the corrected Cv curve and the horizontal line as valve adjustment opening of the current control period.
9. A shale gas cage-type choke control system, comprising: The parameter setting module is used for setting a pressure control target and a control period; The data acquisition module is used for acquiring production data before and after the valve of the cage type throttle valve in the control period; the production prediction module is used for predicting and obtaining the production of the gas well in the subcritical state of the cage-type throttle valve according to the production data in the subcritical state; The output correction module is used for correcting the flow coefficient Cv curve of the regulating valve according to the subcritical state gas well output and the pressure data before and after the valve to obtain a corrected Cv curve under the current pressure difference condition; And the adjusting module is used for obtaining the valve adjusting opening corresponding to the current control period according to the corrected Cv curve, adjusting the cage-type throttle valve according to the valve adjusting opening, and repeatedly executing the adjusting process until the pressure control target is realized.
10. The shale gas cage type throttle valve control system according to claim 9, wherein the parameter setting module is further used for setting an opening adjustment range, the adjustment module is further used for judging whether the valve adjustment opening is within the opening adjustment range, if so, the cage type throttle valve is adjusted according to the valve adjustment opening, and if not, the next control period is adjusted.
11. The shale gas cage-type choke control system of claim 9, further comprising a water production discrimination module for detecting water production of the shale gas well, and rejecting pre-valve and post-valve temperature and pressure data when water production is detected.

Description

Shale gas cage sleeve type throttle valve control method and system Technical Field The invention relates to the technical field of oil and gas field development, in particular to a shale gas cage sleeve type throttle valve control method and system. Background In the oil and gas recovery process, the downhole high pressure gas needs to be depressurized to a pressure value allowed by the delivery pipeline before being delivered to the central processing plant. The throttle valve is used as key regulating equipment and has 2 main functions of throttling and depressurizing petroleum and natural gas produced by a wellhead, controlling the pressure of the wellhead, thereby meeting the requirement of ground conveying equipment on the pressure of produced fluid, controlling the yield of petroleum and natural gas, and keeping the bottom hole pressure stable, thereby achieving the purpose of protecting the petroleum and gas well. The cage type throttle valve achieves the purposes of throttling and depressurization by controlling the exposed area of the throttle hole on the valve sleeve, and compared with a common throttle valve, the cage type throttle valve can effectively delay the rate of reducing the shale gas yield and improve the final recoverable reserve of a shale gas single well. However, the currently adopted calculation formula of the yield of the throttling valve in the subcritical state cannot be directly applied to the shale gas cage type throttling valve, and the response speed of a common adjusting control method is low, so that fine control of pressure and yield is difficult to realize, and the control requirements of high pressure and small fluctuation are difficult to adapt. In addition, pressure fluctuation before and after the valve is abnormal due to gas-liquid two-phase flow of the cage type throttle valve, and fine control difficulty is increased. Disclosure of Invention The invention provides a control method and a control system for a shale gas cage type throttle valve, which are used for solving the problem that the pressure and yield of the cage type throttle valve are difficult to control finely in the existing throttle valve adjusting control scheme. The invention is realized by the following technical scheme: the invention provides a shale gas cage type throttle valve control method, which comprises the following steps: S1, setting a pressure control target and a control period; S2, collecting production data before and after the cage type throttle valve in the control period; S3, predicting and obtaining the subcritical state gas well yield of the cage type throttle valve according to the subcritical state production data; S4, correcting a flow coefficient Cv curve of the regulating valve according to the subcritical state gas well yield and the pressure data before and after the valve to obtain a corrected Cv curve under the current pressure difference condition; s5, obtaining the valve adjusting opening corresponding to the current control period according to the corrected Cv curve; and S6, adjusting the cage type throttle valve according to the valve adjusting opening degree, and repeating the adjusting process of S2-S6 until the pressure control target is achieved. According to the invention, the subcritical state gas well yield of the cage-type throttle valve is predicted through the real-time production data before and after the valve, the Cv curve of the valve is corrected according to the real-time yield and the pressure data before and after the valve, the corrected Cv curve of the cage-type throttle valve under the real-time pressure difference is obtained, and the more accurate adjustment opening degree can be obtained according to the corrected Cv curve, so that the adjustment control process is more approximate to the pressure control target. In addition, the lack of subcritical state yield calculation formulas applicable to the cage-type throttle valve is compensated based on model prediction, and the response speed is further improved. Further, S3, taking pre-valve production data samples and post-valve production data samples in subcritical states as input of a neural network prediction model, taking shale gas well yield samples as prediction targets, and training a subcritical state gas well yield prediction model; and predicting the collected production data in the subcritical state through the subcritical state gas well yield prediction model to obtain the subcritical state gas well yield of the cage type throttle valve. Further, the production data includes pre-valve and post-valve temperatures, pressures, oil pressures, casing pressures, instantaneous gas production, and instantaneous water production. Further, the method comprises the steps of detecting the water production condition of the shale gas well by adopting an acoustic probe, and eliminating the temperature and pressure data before and after the valve in the water production process when the water produ