Deep shale gas resources in the Sichuan Basin have great potential,and this is a major area for future shale gas exploration and development.Deep shale gas wells face problems with liquid loading throughout the produc...Deep shale gas resources in the Sichuan Basin have great potential,and this is a major area for future shale gas exploration and development.Deep shale gas wells face problems with liquid loading throughout the production cycle.Regarding deliquification techniques,it is necessary to consider the requirements of gas wells over the full life cycle,as well as the main form of artificial lift used at different stages,to achieve economically efficient development.This paper divides the life cycle of a deep shale gas well into two stages:early production and middle/late production.Pressure-control production is conducted in the early stage of production,whereas investigations on critical liquid-carrying models,the flow distribution in the wellbore,and the main form of artificial lift are conducted in the middle and late stages of production.A recommended scheme of deliquification techniques over the full life cycle has been developed to guide the development and enhancement of artificial lift methods in deep shale gas reservoirs.As of March 2022,in the PetroChina Southwest Oil&Gasfield Company managed-pressure production has been implemented in 14 wells in the early stage of deep shale gas production.In eight wells,plunger gas lift has been implemented in the middle and late stages of production.In seven wells,foam lift has been implemented.The abovementioned techniques are effective in increasing and stabilizing production and achieving deliquification in deep shale gas reservoirs.展开更多
The inability of the gas rate to overcome the gas critical(minimum)flow rate leads to liquid loading in a gas well.To avoid premature well shut-in,the injection of surfactants is one of the standard methods used in ga...The inability of the gas rate to overcome the gas critical(minimum)flow rate leads to liquid loading in a gas well.To avoid premature well shut-in,the injection of surfactants is one of the standard methods used in gas well deliquification,although many commercial surfactants pose environmental toxicity concerns.This project investigates the suitability of biosurfactants in generating foam that will reduce the surface tension of the liquid by adsorbing at the liquid-gas interface to create a more significant mass than the liquid droplets which can be easily extracted from the walls of the wellbore.An experimental setup simulating gas well conditions introduce a surfactant derived from soybean oil,subjecting it to tests for foam stability,unloading efficiency,and dynamic surface tension.The results from the modified ASTM D-892 test show that Soybean Oil Derived Surfactant(SODS)exhibits promising surface tension reduction properties and effectively alters the gas-liquid interface.With the increase in concentration from 200 ppm,400 ppm,and 600 ppm,the expelled water increased from 17%,28%,and 70%respec-tively.Similarly,Gao-Rosen adsorption isotherms confirmed SODS appropriate for the prediction of the adsorption from solution with the R 2 values of approximately 1.0.This study introduces a cost-effective and environmentally friendly surfactant that performs favorably for gas well deliquification.展开更多
In the mid-to-late stages of gas reservoir development,liquid loading in gas wells becomes a common challenge.Plunger lift,as an intermittent production technique,is widely used for deliquification in gas wells.With t...In the mid-to-late stages of gas reservoir development,liquid loading in gas wells becomes a common challenge.Plunger lift,as an intermittent production technique,is widely used for deliquification in gas wells.With the advancement of big data and artificial intelligence,the future of oil and gas field development is trending towards intelligent,unmanned,and automated operations.Currently,the optimization of plunger lift working systems is primarily based on expert experience and manual control,focusing mainly on the success of the plunger lift without adequately considering the impact of different working systems on gas production.Additionally,liquid loading in gas wells is a dynamic process,and the intermittent nature of plunger lift requires accurate modeling;using constant inflow dynamics to describe reservoir flow introduces significant errors.To address these challenges,this study establishes a coupled wellbore-reservoir model for plunger lift wells and validates the computational wellhead pressure results against field measurements.Building on this model,a novel optimization control algorithm based on the deep deterministic policy gradient(DDPG)framework is proposed.The algorithm aims to optimize plunger lift working systems to balance overall reservoir pressure,stabilize gas-water ratios,and maximize gas production.Through simulation experiments in three different production optimization scenarios,the effectiveness of reinforcement learning algorithms(including RL,PPO,DQN,and the proposed DDPG)and traditional optimization algorithms(including GA,PSO,and Bayesian optimization)in enhancing production efficiency is compared.The results demonstrate that the coupled model provides highly accurate calculations and can precisely describe the transient production of wellbore and gas reservoir systems.The proposed DDPG algorithm achieves the highest reward value during training with minimal error,leading to a potential increase in cumulative gas production by up to 5%and cumulative liquid production by 252%.The DDPG algorithm exhibits robustness across different optimization scenarios,showcasing excellent adaptability and generalization capabilities.展开更多
As a necessary step,removing liquid in the wellbore plays an important role during the production of gas wells.Plunger lift is a widely-used intermittent deliquification process for gas wells.However,the manual contro...As a necessary step,removing liquid in the wellbore plays an important role during the production of gas wells.Plunger lift is a widely-used intermittent deliquification process for gas wells.However,the manual control way and wire logging are still utilized as a downhole monitoring way for plunger lift,which is not efficient in terms of interrupting the production.This paper presents an improved solution that logging instruments canister are deployed and retrieved by means of a new assembly.With the reciprocating plunger,logging instruments canister can be carried and deployed to the bottom of a gas well to carry out logging and sampling tasks on the production demand of a field.After the deployment and logging tasks are performed,logging instruments canister is carried back to the surface by the plunger and then data is transferred to the wellhead device near field wireless communication technology.This newly developed plunger lift system comprises plunger body,deployment sub-assembly,retrieve sub-assembly and logging instruments canister.The surface device comprises RF antenna,reader and writer.Based upon the method of deployment-retrieve integration,the new deliquification process is introduced and on-line monitoring of production dynamics can be performed including P/T measurement,downhole fluid sampling,pressure build-up,etc.without interrupting production.The general solution and engineering design parameters have been confirmed by research teams,while system prototype manufacture and workbench tests are being performed.The cost-effective way combining deliquification with dynamic monitoring is developed and contributes to increasing production and the stable productivity of gas wells.It is very significant for low-pressure and low-production gas fields to achieve automation production and management.展开更多
文摘Deep shale gas resources in the Sichuan Basin have great potential,and this is a major area for future shale gas exploration and development.Deep shale gas wells face problems with liquid loading throughout the production cycle.Regarding deliquification techniques,it is necessary to consider the requirements of gas wells over the full life cycle,as well as the main form of artificial lift used at different stages,to achieve economically efficient development.This paper divides the life cycle of a deep shale gas well into two stages:early production and middle/late production.Pressure-control production is conducted in the early stage of production,whereas investigations on critical liquid-carrying models,the flow distribution in the wellbore,and the main form of artificial lift are conducted in the middle and late stages of production.A recommended scheme of deliquification techniques over the full life cycle has been developed to guide the development and enhancement of artificial lift methods in deep shale gas reservoirs.As of March 2022,in the PetroChina Southwest Oil&Gasfield Company managed-pressure production has been implemented in 14 wells in the early stage of deep shale gas production.In eight wells,plunger gas lift has been implemented in the middle and late stages of production.In seven wells,foam lift has been implemented.The abovementioned techniques are effective in increasing and stabilizing production and achieving deliquification in deep shale gas reservoirs.
文摘The inability of the gas rate to overcome the gas critical(minimum)flow rate leads to liquid loading in a gas well.To avoid premature well shut-in,the injection of surfactants is one of the standard methods used in gas well deliquification,although many commercial surfactants pose environmental toxicity concerns.This project investigates the suitability of biosurfactants in generating foam that will reduce the surface tension of the liquid by adsorbing at the liquid-gas interface to create a more significant mass than the liquid droplets which can be easily extracted from the walls of the wellbore.An experimental setup simulating gas well conditions introduce a surfactant derived from soybean oil,subjecting it to tests for foam stability,unloading efficiency,and dynamic surface tension.The results from the modified ASTM D-892 test show that Soybean Oil Derived Surfactant(SODS)exhibits promising surface tension reduction properties and effectively alters the gas-liquid interface.With the increase in concentration from 200 ppm,400 ppm,and 600 ppm,the expelled water increased from 17%,28%,and 70%respec-tively.Similarly,Gao-Rosen adsorption isotherms confirmed SODS appropriate for the prediction of the adsorption from solution with the R 2 values of approximately 1.0.This study introduces a cost-effective and environmentally friendly surfactant that performs favorably for gas well deliquification.
基金support from Science Foundation of China University of Petroleum,Beijing(No.2462023YJRC019)National Natural Science Foundation of China(No.52204059)Key Core Technology Research Project Foundation of PetroChina Group(No.2023ZG18).
文摘In the mid-to-late stages of gas reservoir development,liquid loading in gas wells becomes a common challenge.Plunger lift,as an intermittent production technique,is widely used for deliquification in gas wells.With the advancement of big data and artificial intelligence,the future of oil and gas field development is trending towards intelligent,unmanned,and automated operations.Currently,the optimization of plunger lift working systems is primarily based on expert experience and manual control,focusing mainly on the success of the plunger lift without adequately considering the impact of different working systems on gas production.Additionally,liquid loading in gas wells is a dynamic process,and the intermittent nature of plunger lift requires accurate modeling;using constant inflow dynamics to describe reservoir flow introduces significant errors.To address these challenges,this study establishes a coupled wellbore-reservoir model for plunger lift wells and validates the computational wellhead pressure results against field measurements.Building on this model,a novel optimization control algorithm based on the deep deterministic policy gradient(DDPG)framework is proposed.The algorithm aims to optimize plunger lift working systems to balance overall reservoir pressure,stabilize gas-water ratios,and maximize gas production.Through simulation experiments in three different production optimization scenarios,the effectiveness of reinforcement learning algorithms(including RL,PPO,DQN,and the proposed DDPG)and traditional optimization algorithms(including GA,PSO,and Bayesian optimization)in enhancing production efficiency is compared.The results demonstrate that the coupled model provides highly accurate calculations and can precisely describe the transient production of wellbore and gas reservoir systems.The proposed DDPG algorithm achieves the highest reward value during training with minimal error,leading to a potential increase in cumulative gas production by up to 5%and cumulative liquid production by 252%.The DDPG algorithm exhibits robustness across different optimization scenarios,showcasing excellent adaptability and generalization capabilities.
文摘As a necessary step,removing liquid in the wellbore plays an important role during the production of gas wells.Plunger lift is a widely-used intermittent deliquification process for gas wells.However,the manual control way and wire logging are still utilized as a downhole monitoring way for plunger lift,which is not efficient in terms of interrupting the production.This paper presents an improved solution that logging instruments canister are deployed and retrieved by means of a new assembly.With the reciprocating plunger,logging instruments canister can be carried and deployed to the bottom of a gas well to carry out logging and sampling tasks on the production demand of a field.After the deployment and logging tasks are performed,logging instruments canister is carried back to the surface by the plunger and then data is transferred to the wellhead device near field wireless communication technology.This newly developed plunger lift system comprises plunger body,deployment sub-assembly,retrieve sub-assembly and logging instruments canister.The surface device comprises RF antenna,reader and writer.Based upon the method of deployment-retrieve integration,the new deliquification process is introduced and on-line monitoring of production dynamics can be performed including P/T measurement,downhole fluid sampling,pressure build-up,etc.without interrupting production.The general solution and engineering design parameters have been confirmed by research teams,while system prototype manufacture and workbench tests are being performed.The cost-effective way combining deliquification with dynamic monitoring is developed and contributes to increasing production and the stable productivity of gas wells.It is very significant for low-pressure and low-production gas fields to achieve automation production and management.
