Improving the Profitability of Sucker- Rod Pumped Wells in a Mature - PowerPoint PPT Presentation

Sucker Rod Pumping Workshop Houston, Texas September 12 – 15, 2006 Improving the Profitability of Sucker- Rod Pumped Wells in a Mature Field Gábor Takács, Ph.D. University of Miskolc, Hungary

Paper Outline • Field Description • Project Objectives • Measurement Program • Operational Problems Detected • Pumping Mode Optimization • Maximizing Liquid Rates • Conclusions 2006 Sucker Rod Pumping Workshop 2 Sept. 12 - 15, 2006

Field Description • North African Mature Oilfield • 70+ Rod Pumped Wells • Field Production 35,000 BLPD • Average Water Cut 60% • Reservoir Pressure 1,500 – 1,800 psig • Average Well Depth 5,000 ft • Light Oil, Negligible Gas Production 2006 Sucker Rod Pumping Workshop 3 Sept. 12 - 15, 2006

Project Objectives • Assessment of Operating Conditions • Detection of Problem Areas • Determination of Optimum Pumping Modes • Maximizing Liquid Production 2006 Sucker Rod Pumping Workshop 4 Sept. 12 - 15, 2006

Portable Measuring System Used 2006 Sucker Rod Pumping Workshop 5 Sept. 12 - 15, 2006

Measurement Program • Well Analysis Sequence – Dynamic Liquid Level – Annular Gas Rate from Pressure Buildup – Dynamometer Survey – TV, SV Tests – Electrical Measurements • Measurements Conducted on >50% of Wells 2006 Sucker Rod Pumping Workshop 6 Sept. 12 - 15, 2006

Operational Problems Detected Problem Wells Impossible to Balance Pumping Unit 53% (Units Weight Heavy w. no CW) Lifting Efficiency Less than 75% 56% (Improper Pumping Mode Selected) Rod String Loading Less than 60% 91% (Rod Strings Oversized) Surface Efficiency Less than 60% 100% (Pumping Units Extremely Oversized) 2006 Sucker Rod Pumping Workshop 7 Sept. 12 - 15, 2006

Pumping Mode Optimization • Definition of Pumping Mode – Combination of • Pump Size • Polished Rod Stroke Length • Pumping Speed • Optimum Pumping Mode – Ensures the Best Energy Efficiency – Found at the Maximum of Lifting Efficiency 2006 Sucker Rod Pumping Workshop 8 Sept. 12 - 15, 2006

Pumping Mode Optimization • Definition of Lifting Efficiency P η = hydr 100 lift PRHP • Maximum Lifting Efficiency Ensures: – Minimum of Polished Rod Horsepower – Minimum of Electric Costs – Maximum of Power Efficiency 2006 Sucker Rod Pumping Workshop 9 Sept. 12 - 15, 2006

Pumping Mode Optimization • Optimization Strategy – Current Liquid Rates – Present Surface Equipment – Current Pump Setting Depths • Optimization Results – Field-Wide Savings on Electric Power: 17% 2006 Sucker Rod Pumping Workshop 10 Sept. 12 - 15, 2006

Optimization Examples Well ID A B C D E Present Pumping Mode Plunger Size, in 2.5 2.5 2 2.5 2.25 Stroke Length, in 124 88 106 124 88 Pumping Speed, SPM 9.5 9.5 9 9 10 Optimum Pumping Mode Plunger Size, in 2.75 2.75 2.75 2.75 2.75 Stroke Length, in 124 88 88 106 88 Pumping Speed, SPM 7.6 7 6.1 8.2 6.7 Improvements Rel. Lifting Efficiency Increase, % 20.2 14.9 80.0 16.8 42.1 Rel. Energy Saving, % 16.8 13.0 44.4 14.4 29.6 2006 Sucker Rod Pumping Workshop 11 Sept. 12 - 15, 2006

Maximizing Liquid Production • Calculations Made for Key Wells – Assuming Pumped-Off Conditions – Using Pumping Unit Present on Well – Achieving Optimum Pumping Mode • Main Achievements – Average Liquid Rate Increase: around 70% – Lifting Efficiencies in Optimum Range (70 – 85%) – Properly Loaded Surface Equipment – Increased System Efficiencies 2006 Sucker Rod Pumping Workshop 12 Sept. 12 - 15, 2006

Conclusions • Portable Equipment Ideal for Field Evaluations • Problem Areas Easy to Detect • Optimum Pumping Modes Decrease Total Energy Requirements • Increased Liquid Rates Improve Energy Efficiency for Key Wells 2006 Sucker Rod Pumping Workshop 13 Sept. 12 - 15, 2006