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Upstream pressure must be more then twice downstream pressure . PSIG
Acoustic Velocity (From Petroleum Engineers Handbook) A wellhead choke is used to control the production rate from a well. In the design of tubing and well completions (perforations, etc.), the engineer must ensure that neither tubing nor perforations control the production from the well the flow capacity of the tubing and perforation should always be grater than the flow performance behavior of the reservoir. Wellhead chokes are selected so that fluctuation in the line pressure downstream of the choke have no effect on the well flow rate to ensure this condition, flow through the choke must be at critical flow conditions; this is, flow through the choke is at the acoustic velocity. For this condition to exist, downstream pressure must be approximately 0.55 or less of the tubing or upstream pressure. Under these conditions, the flow rate is a function of the upstream or tubing pressure only. |