Research On Reasonable Under-voltage Monitoring And Control System For Underbalanced Safe Drilling

Maintaining a reasonable and steady state in the process of underbalanced drilling has been in the favor of reducing drilling risk,increasing the drilling rate and protecting reservoir and so on.The embodiment of advantages depend on a certain way or method of controlling the stability of underground pressure timely by the existing well equipment and instrumentation when the underground pressure changes in the process of underbalanced drilling.To realize real-time monitoring and controlling of the key control factors of the reasonable underbalanced pressure drop in underbalanced drilling,the control of throttle valve needs to be studied by relying on the ground chock manifold to establish the corresponding monitoring and control system.Therefore,based on ground equipment and instrumentation of underbalanced drilling,a monitoring and system for reasonable underbalanced pressure drop of underbalanced drilling has been researched and developed.The following results mainly achieved:1.According to the ground equipment and instrumentation of underbalanced drilling,the designing scheme of realizing the monitoring and controlling for a reasonable underbalanced pressure drop is designed.In addition,monitoring and control principle of the reasonable underbalanced pressure drop is analyzed,monitoring adaptability and control effectiveness is realized.The monitoring and control scheme of underbalanced pressure drop is analyzed and demonstrated,which provides the design basis for the development of monitoring and control system of a reasonable underbalanced pressure drop.2.The influencing factors of underbalanced pressure drop changes are analyzed,and the physical model of wellbore fluid in underbalanced drilling is established.The model is used to the parameter sensitivity analysis for the influence factors of ground control,and predict the reasonable underbalanced pressure drop.That means it can provide a theoretical basis for realizing the control.3.Based on the throttle backpressure control mode,the time series neural network prediction method is studied.The method is used to establish and analyze the predictive control model of the bottom hole underbalanced pressure drop.4.The monitoring and control system of a reasonable underbalanced pressure drop is developed,achieving the real-time monitoring and control of the scene.The system is applied to two wells with better application effect.Results of predictive control meet the expectations,which can guarantee the bottom hole underbalanced pressure drop is within the scope of reasonable control,reducing drilling risk.In this paper,the design of monitoring and control system of a reasonable underbalanced pressure drop in the process of safe underbalanced drilling can realize the prediction and control of underbalanced pressure drop changes,reducing the drilling risk.It has an important guiding significance and promotional value for improving the level of underbalanced drilling in China.