Improving the Closing Characteristics of Subsurface Safety Valve with Combined FEAand CFD Modeling/Numerical Analysis

摘要

Surface-Controlled Subsurface Safety Valves (SCSSVs) arerndesigned to automatically shut-in a well below the earth’srnsurface in the event of damage to the wellhead or other keyrncomponents of a completion string. Flow rates in highlyrnproductive gas wells can produce stresses that exceed therndesign limits of a typical subsurface safety valve duringrnclosure in blowout conditions. High-rate uncontrolled flowrnconditions can act to prevent a SCSSV from closing or canrnsubject the valve to stresses that the valve cannot withstand.rnFlow tests conducted to verify valve performance underrncertain flow conditions are often not capable of predictingrnvalve performance when the valves are subjected to flowrnconditions different from the test conditions. Because the netrnforce on the flapper is a function of the flow parameters, arnvalve that tests successfully at one set of conditions is notrnguaranteed to perform successfully in a different set ofrnconditions.rnThis paper will discuss the use of Finite Element Analysisrn(FEA) combined with Computational Fluid Dynamics (CFD)rnto economically and effectively determine 1) if a SCSSV willrnclose under various flow conditions, and 2) whether it willrnwithstand the associated forces generated during the closure.rnIf this method is used, the flow tests could then be used tornverify the accuracy and confirm results of the FEA and CFDrnanalyses. After the FEA/CFD models are validated throughrnflow testing, the performance of the valve in response tornchanges within the flow parameters or safety valvernconfiguration can then be predicted using FEA/CFD models.rnActual testing can be performed only to confirm the results ofrnFEA/CFD or may be avoided completely.