CASING HEAD PRESSURE FINE TUNING in Dual String Gas Lift Well With Injection Pressure Operated Valve,By: Gatut Widianoko ( Weatherford ) Herry Subekti ( BP Indonesia ) Wahyu Jatmiko ( BP Indonesia ),ASME WORK SHOP - KUALA LUMPUR 2003,Abstract,After two ( 2 ) years gas lift optimization performed with concentrated in gas lift change out, starting this year 2003, Bp -Indonesia begin to focus on Casing Head Pressure Tuning. The first year, the gas lift optimization had made 3500 bopd oil gain, and the second year had made 4000 bopd oil gains. This year, up-to the second quarter 2003, BP had made 4500 bopd oil gains. This total gains is came from 40 % gas lift change out, and 60 % from Casing Head Pressure Tuning. Today we are going to talk about the steps of casing head pressure tuning of the BP-Indonesia gas lift optimization on dual string gas lift well as follow : 1) Identify the gas lift well problems ; 2) Nodal analyzing to determine the well potential ; 3) Optimize point of injection of both string by gas lift change out ; 4) Perform Tuning Casing Head Pressure to optimize both string.,Offshore North West Java Oil Field,Old Oil Field with more than 30 years old High FGOR with 1000 : 1 or more Low PI with only about 1 3 blpd / psi Low Production with about 200 - 500 blpd Low Static Pressure with average 600 psi Limited Casing Pressure with 600 psi only Flowing Tubing Pressure is about 180 psi Shallow well - reservoir depth 3000 ft TVD Limited data (SBHP and PI is normally unknown) Old wells - may have leaking valve or tubing Some gas lift valves installed 5-10 years ago Some gas lift header choke stuck open/close,BP Wells General Conditions,CHP Fine Tuning Candidates Wells ( Gas Lift Optimization ),Suddenly production rate drop Suddenly the well dead Casing Head Pressure unstable Suddenly gas injection rate increase/decrease Inaccurate gas rate measure Robbing, and cause one (1) string dead or drop The well shutdown under maintenance The well shut-in while service status Gas lift Change out is being perform Suddenly Casing Head Pressure Increase Suddenly Casing Head Pressure decrease Suddenly Flowing Tubing Head Pressure increase,Casing Head Pressure Tuning Steps in Dual Gas Lift well,Use graphical method to construct the well condition. Draw the static and flowing pressure gradient, etc. Select Kick Off and best Operating pressure available. Use 90% (max) off Kick Off as Operating pressure. Select best point of injection of both string ( close or same depth ) and operating port size (close or same size). Use same surface opening and closing pressure for both string valve. Perform gas lift well performance by software on each string to determine optimum condition . Perform CHP tuning by open the Gas Lift Header Choke and set at the kick off pressure selected. Adjusts the CHP slowly to reach the Best Surface Operating Pressure selected. Record the Rates. Select the best rate and keep best CHP.,Graphical Method,0,500,1000,1000,1500,2000,3000,4000,D E P T H Ft T V D,PRESSURE (p s i),FTP,CHP,1200 p s i,Casing Pressure,Echo- Wells,Mid Perforation,Tubing Pressure,#1,#2,#3,#7,0.45 p s i / ft,0.1 p s I / ft,FL,FBHP,Kick Off,Operating Pres.,(To determine best Point of Injection, KO and OP),Gas Lift Well Performance,Gas Injection Rate Vs Production Rate,Q l,Q i,Q I : Gas in Rate mscfd,Q l : Prod. Rate blpd,Optimum Point,Why Do Casing Head Pressure tuning instead of Gas Injection Rate Tuning ?,Gas Measurement Problems,Not each platform has a good measurement facilities Some Gas Measuring inaccurate Gas Injection rate not recorded Gas in VS CHP does not make sense We Decided Using CHP as parameter to optimize gas injection Adjust CHP to find a best production rate of both String Measure Gas In, after best CHP reached / selected Record and keep best CHP of each Well,WHAT IS BEST CHP,Where is the existing CHP ? Is it too high ? Any un-loader valve reopen? Is the existing gas in too much ? Do We need to decrease it ? OR Is it too low ? Is the existing gas in too low ? Can the existing CHP pressure reach the operating valve ? Do we need to Increase it ? Any actions needs to be done ?,Back to The Original Operating Pressure Design,Decreasing CHP,0,500,1000,1000,1500,2000,3000,4000,D E P T H Ft T V D,PRESSURE (p s i),FTP,CHP,1200 p s i,Casing Pressure,Echo- Wells,Mid Perforation,Tubing Pressure,#1,#2,#3,#7,0.45 p s i / ft,0.1 p s I / ft,FL,FBHP,Kick Off,Best Operating Pres.,(To determine Best Operating Pressure),Existing CHP Too High,Increasing CHP,0,500,1000,1000,1500,2000,3000,4000,D E P T H Ft T V D,PRESSURE (p s i),FTP,CHP,1200 p s i,Casing Pressure,Echo- Wells,Mid Perforation,Tubing Pressure,#1,#2,#3,#7,0.45 p s i / ft,0.1 p s I / ft,FL,FBHP,Kick Off,Operating Pres.,(To determine Best Operating Pressure),Existing CHP Too Low,Some Wells Sample of CHP tuning at BP-Indonesia,Oil Gains : 250 b o p d,Sample : A,Best CHP,Best C