The objective of this work is to create an automatic control system (ACS) which stabilizes operation of pipeline system of reservoir pressure maintenance (RPM) for a large oil field. Injection in regime of miscible displacement is planned to be used as a method of stimulation of reservoir system in considered oil field. In this case water and associated petroleum gas are injected to reservoir through injection wells in the form of water-gas mixture. RPM pipeline system consists of two parallel pipelines which provide water and gas delivery to injection wells. Project total number of injection wells is more than 50. The mixture is formed in special mixing units located at wellheads of injection wells. Fr om control point of view described object is a complex dynamic system. The problem of control system design is complicated by the fact that it is planned injection not of a single-phase liquid, but two-phase water-gas mixture in required ratio. Prior to ACS development, the study of transient processes in RPM pipeline system was performed using mathematical model. Based on analysis of simulation results cascade ACS was formed wh ere water and gas flow rates are regulated and pressure drop on regulation valves is controlled. When testing the developed ACS on a real object, the problem of possible water ingress into gas line was identified at low valve opening and low pressure drop on gas valve. In order to avoid the occurrence of such situations, control algorithm was corrected accordingly. Further approbation showed operability of developed ACS.
References
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