Liquid Management on Canyon Express

摘要

The Canyon Express (operated by Total E&P USA Inc.)subsea development consists of 10 subsea wells each tied intoone of two 57 mile, 12” flowlines, that extend from thedeepest wells at 7250 foot water depth to a shallow water hostplatform at 300 foot water depth. Although the production is arelatively dry gas, there exists some volume of liquid thatreturns to the platform with the gas as a result of producedliquids and return of methanol injected for hydrateremediation. Because of the extreme lengths and depths of theCanyon Express flowlines liquid management has been asignificant concern with extensive transient and steady stateanalysis being performed throughout the project design phaseto evaluate the behavior of the liquid in the flowlines.Complex transient flow models, including flow line andtopside facilities characteristics, were developed andnumerous simulations executed to determine the optimal andfeasible operation for the multiphase fluid Canyon Expressflowlines under various conditions during field life. Duringstart up and the early operation of the Canyon Express systemthe actual results for liquid holdup and flow were documentedfor various well ramp-up scenarios. The purpose of this paperis to compare results from the design phase for liquidmanagement on Canyon Express with actual operatingconditions and summarize the evolution of the currentoperating philosophy. The original transient and steady stateanalysis will be compared to the actual conditions experiencedin the operation highlighting lessons learned in flow modelingand other assumptions made. This paper will demonstrate theusefulness of extensive transient and steady state analysis onprojects with complex flow conditions and the importance ofincorporating the conclusions of the analysis intoimplementation plans that can be subsequently adjusted toreflect the actual field conditions.