37 th Gas-Lift Workshop Houston, Texas, USA February 3 7, 2014 Replacement of Gas-Lift Valves in Marlim Sul Anna Luiza de Moraes y Blanco de Mattos Petroleum Engineer Fabio Paula Brum Petroleum Engineer José Ricardo Furlanetto de Azambuja Petroleum Engineer Feb. 3-7, 2014 2014 Gas-Lift Workshop 1
GOAL To prioritize rig interventions for the replacement of Gas-Lift Valves in Marlim Sul 2014 Gas-Lift Workshop 2
SUMMARY Goal Context: Marlim Sul Motivation: well 1-RJS-460 Gas-Lift Maintenance in Marlim Sul Correction, prevention and prediction Field data History of Gas-Lift Failure Installed Gas-Lift Valves Intervention plan Final comments 2014 Gas-Lift Workshop 3
CONTEXT: MARLIM SUL 2014 Gas-Lift Workshop 4
CONTEXT: MARLIM SUL 2014 Gas-Lift Workshop 5
CONTEXT: MARLIM SUL Area: 600 km² (230 mi²) Reservoir depth: 2,500-4,500 m (8,200-14,800 ft) Water depth: 800-2.500 m (2,600 8,200 ft) Oil: 13-28 API GOR: 60-200 sm³/sm³ 4 production units asset discovery P-40 FPSO-MLS P-51 P-56 1987 2001 2004 2009 2011 2014 Gas-Lift Workshop 6
CONTEXT: MARLIM SUL Gas-Lift is extremely important to us! All our production wells are equipped with Gas-Lift Valves Gas-Lift is the only artificial lift method employed in Marlim Sul Compressors discharge pressure: 195 kgf/cm² (~190 bar) Typical gas-lift rate per well: up to 200.000 Nm³/d (typically, 1.96 kg/s) Instalation depth of Gas-Lift Valves: 1,700-3,900 m (5,600 12,800 ft) 2014 Gas-Lift Workshop 7
MOTIVATION: WELL 1-RJS-460 2014 Gas-Lift Workshop 8
MOTIVATION: WELL 1-RJS-460 Completed in 2001 Connected to P-40 Producing since 2002 Gas-Lift injection since 2005 PDG signal unavailable Schlumberger Gas-Lift Valves: Orifice RDO 5/16 @-1,700 m (5,580 ft) Dummy Valve RD @-2,200 m (7,220 ft) Oil production: 830 m³/d (~5,220 bpd) in Jan, 2012 2014 Gas-Lift Workshop 9
MOTIVATION: WELL 1-RJS-460 LOSS OF GAS-LIFT INJECTIVITY Consequences of Gas-Lift Valve Failure: Unstable Gas-Lift injection Unstable multiphase flow: severe slugging! Increasing difficulties to re-establish production Scale inhibition program: reliability is key! Well testing limitation 2014 Gas-Lift Workshop 10
MOTIVATION: WELL 1-RJS-460 Extra difficulty: prioritizing workover intervention, competing against other operations 01/28/2012 01/29/2013 02/19/2013 First signs of Gas-Lift injectivity loss appeared Well was closed for Gas-Lift Valve replacement Well re-opened with a new Gas-Lift Valve Total oil loss (390 days): 56,000 m³ (~ 350,000 bbl) Gas-Lift related oil loss: 40,000 m³ (~250,000 bbl) Intervention oil loss: 13,750 m³ (~87,000 bbl) 2014 Gas-Lift Workshop 11
MOTIVATION: WELL 1-RJS-460 Intervention scope and results Replacement of Orifice Valve by a new Venturi Valve (high-reliability) Deepening of injection point Technical inspection: damage confirmed 2014 Gas-Lift Workshop 12
MOTIVATION: WELL 1-RJS-460 Intervention solved this well s problem, but...... we must prepare for similar cases in the future! Current status: corrective maintenance Goal: preventive and/or predictive maintenance, reducing intervention time if possible We needed criteria! We needed more data! 2014 Gas-Lift Workshop 13
CORRECTION, PREVENTION AND PREDICTION Oil rate (m³/d) Is it viable to intervene and replace the Gas-Lift Valve BEFORE oil loss escalates, or BEFORE it even fails? Diagnosis tools: simulation Petrobras assumption: offshore wells should operate for a period of 6 to 10 years before workover Gas-Lift Performance - 1-RJS-460 800 750 700 650 600 550 500 450 400 350 300 0 1000 2000 3000 4000 5000 6000 7000 8000 Gas-Lift injection rate (Nm³/h) 2014 Gas-Lift Workshop 14
CORRECTION, PREVENTION AND PREDICTION Is it viable to COMBINE Gas-Lift Valve replacement to some other pre-scheduled operation, so that total oil loss is reduced? Marlim Sul history: Gas-Lift Valve replacement alone: 15-25 days of rig intervention Adding Gas-Lift Valve replacement to scope: + 3-5 days 2014 Gas-Lift Workshop 15
FIELD DATA Detailed history of Gas-Lift Failure in Marlim Sul Detailed data of installed Gas-Lift Valves in Marlim Sul Intervention schedules for Marlim Sul wells 2014 Gas-Lift Workshop 16
HISTORY OF GAS-LIFT FAILURE In Marlim Sul: 10 replacements of Gas-Lift Valves since 2001 Gas-Lift Valve Replacements 30% 50% 20% Not related to Gas-Lift failure Not related to Gas-Lift Valve failure Related to Gas-Lift Valve failure 2014 Gas-Lift Workshop 17
HISTORY OF GAS-LIFT FAILURE WELL GAS-LIFT VALVE INSTALATION TIME BEFORE FAILURE WELL PRODUCTION TIME BEFORE FAILURE GAS INJECTION TIME BEFORE FAILURE 1 NOVA15 8 years 7 years 0 2 RDO 6 years 6 years 1 year 3 RDO 11 years 10 years 7 years 4 RDO 11 years 8 years 5 years 5 RDO 11 years 10 years 7 years 2014 Gas-Lift Workshop 18
HISTORY OF GAS-LIFT FAILURE Three Gas-Lift Valves failed in 2012: Orifice Valves (RDO 5/16 ) Installed for 11 years Injecting gas for over 5 years Rule: all Orifice Gas-Lift Valves with instalation time superior to 10 years shall be replaced preventively. 2014 Gas-Lift Workshop 19
INSTALLED GAS-LIFT VALVES P-40 FPSO-MLS P-51 P-56 TOTAL Number of production wells 15 7 11 8 41 Production start 2001 2004 2009 2011 - Number of Gas-Lift Valves Dummy Valves 16 8 12 5 41 Orifice Valves (instalation: 2001-2009) 11 2 3 0 16 Venturi Valves, non-qualified by Petrobras as high-reliability valves (instalation: 2003 2011) Venturi Valves, qualified by Petrobras as high-reliability valves (instalation: 2010-2013) 6 8 11 1 26 5 1 2 8 16 TOTAL 38 19 28 14 99 2014 Gas-Lift Workshop 20
INTERVENTION PLAN Search for any operations demanding long production stops and/or rig interventions 2014 Gas-Lift Workshop 21
INTERVENTION PLAN * Candidate for abandonment 2014 Gas-Lift Workshop 22
FINAL COMMENTS Rule confirmation: Three preventive replacements after 1-RJS-460 Two Orifice Valves: damaged One Venturi Valve: intact All supported the 10-year rule for Orifice Valves Next steps: Future interventions: two replacements planned for 2014 Extremely small sample: study in progress Rule for Venturi Valves 2014 Gas-Lift Workshop 23
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