PRODUCTION CONTROL CHOKEchoke uses :- control flow : achieve liquid lift- maximize use : best use gas (lift?)- protect equipment : abrasion and erosion- cleanup : best use of back flow energy- control circulation : holds a back pressure- control pressure at surface (during flow)- control injection : on injection linewhat happens as choke provides a pressure drop and what happens to the pressure ?Energy from pressure drop is lost in :- increase velocity ( from gas expansion)- vaporization ( flashing ) of light ( short carbon chain ) hydrocarbon liquid to gas- vaporization of water- cavitation- heat production ( usually liquid friction )Detriments ( kondisi dimana mengalami penurunan ):- flashing : hydrocarbon light ends lost ( value lost )- cavitation : erosion of surface in and around choke ( kondisi mekanis dimana terjadi tekanan permukaan )- erosion : solids, droplets and bubbles in high velocity flow- freezing : expansion of gasses cools the area - refrigeration principle. penjelasan detriments diatas merupakan kondisi dimana aplikasi choke digunakan.semakin besar bukaan chokenya maka erosi nya semakin banyak , jika dikurangi akan terjadi freezing pada sumur gas, maka harus digunakan pada kondisi optimal.Pada Vena contracta, semakin tinggi nilai Pressure nya, teknologi choke nya maka semakin banyakVENA CONTRACTA : simulasi flow dari fluida , yang mana nanti akan menentukan teknologi apa yang akan dipilih.choke trim types : throttling methods, anara lain :fixed bean, needle seat, multiple orifice.problem yang dihadapi pada pengoperasian coke:- the larger the difference between the inlet and outlet pressure- cavitation, terjadi pada waktu pengoperasian choke dengan kecepataan yang sangat tinggi, maka akan terjadi vakum. jika kecepatanya tinggi, maka tekanannya akan menurun. apabila vakum terjadi, maka akan terjadi tegangan permukaan yang mempunyai frekuensi tertentu yang menyebabkan kavitasi.- freezing- mekanikal : erosi dan vibrasi. JIka turbulensi terjadi, maka akan menyebabkan kerusakan yang sangat tinggi. Dan biasanya kerusakan terjadi pada bagian outlet nya.pada choke yang biasanya di kondisi rasio 0.6 keatas, figurasi tinggi, velocity tinggi, suara nya jadi lebih berisik, otomatis equipment nya umurnya sebentar. Choke Selection Based on :- application ( lift, deliquifying the well, erosion control solids production prevention)- rate or flow and range of flow rate- presence of solids- maximum velocity- total pressure drop- fluid - liquid, gas or FOR of mix- pressure - both pressure drop and total pressure- temperature - range of acceptable temperatures during services- occurances and timing of solid in flow- droplets, bubbles- scale and organic deposit potentialchoke sizing : - control the flow : maximize production- minimized vibration damage- minimize erosion damage- CV = coefficient value :- number of gallons of water per minute what will pas through a restriction with a pressure drop at 1 psi at 600 F- used as the flow capacity indexchoke conclusion :- production chokes help unload and produce the well through pressure management--------------------------------------------------------------------------------------------------------20-12-2014laminar flow :- where the fluid moves slowly un layers in a pipe, without much mixing among the layersTurbulent flow :- opposite of laminer flow, where considerable mixing occurs, velocity are high.laminer and turbulent can be characterized and quantified using reynolds numberNR < 2000 - laminerNR > 4000 - turbulentfor 2000