Sucker Rod Pumping WorkshopHouston, Texas

September 12 – 15, 2006

Improving the Profitability of Sucker-Rod Pumped Wells in a Mature FieldGábor Takács, Ph.D.

University of Miskolc, Hungary

Sept. 12 - 15, 2006 2006 Sucker Rod Pumping Workshop 2

Paper Outline

• Field Description• Project Objectives• Measurement Program• Operational Problems Detected• Pumping Mode Optimization• Maximizing Liquid Rates• Conclusions

Sept. 12 - 15, 2006 2006 Sucker Rod Pumping Workshop 3

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

Sept. 12 - 15, 2006 2006 Sucker Rod Pumping Workshop 4

Project Objectives

• Assessment of Operating Conditions• Detection of Problem Areas• Determination of

Optimum Pumping Modes• Maximizing Liquid Production

Sept. 12 - 15, 2006 2006 Sucker Rod Pumping Workshop 5

Portable Measuring System Used

Sept. 12 - 15, 2006 2006 Sucker Rod Pumping Workshop 6

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

Sept. 12 - 15, 2006 2006 Sucker Rod Pumping Workshop 7

Operational Problems Detected

100%Surface Efficiency Less than 60%(Pumping Units Extremely Oversized)

91%Rod String Loading Less than 60%(Rod Strings Oversized)

56%Lifting Efficiency Less than 75%(Improper Pumping Mode Selected)

53%Impossible to Balance Pumping Unit(Units Weight Heavy w. no CW)

WellsProblem

Sept. 12 - 15, 2006 2006 Sucker Rod Pumping Workshop 8

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

Sept. 12 - 15, 2006 2006 Sucker Rod Pumping Workshop 9

Pumping Mode Optimization

• Definition of Lifting Efficiency

• Maximum Lifting Efficiency Ensures:– Minimum of Polished Rod Horsepower– Minimum of Electric Costs– Maximum of Power Efficiency

PRHPPhydr

lift 100=η

Sept. 12 - 15, 2006 2006 Sucker Rod Pumping Workshop 10

Pumping Mode Optimization

• Optimization Strategy– Current Liquid Rates– Present Surface Equipment– Current Pump Setting Depths

• Optimization Results– Field-Wide Savings on Electric Power: 17%

Sept. 12 - 15, 2006 2006 Sucker Rod Pumping Workshop 11

29.614.444.413.016.8Rel. Energy Saving, %42.116.880.014.920.2Rel. Lifting Efficiency Increase, %

Improvements6.78.26.177.6Pumping Speed, SPM881068888124Stroke Length, in

2.752.752.752.752.75Plunger Size, inOptimum Pumping Mode

10999.59.5Pumping Speed, SPM8812410688124Stroke Length, in

2.252.522.52.5Plunger Size, in Present Pumping Mode

EDCBAWell ID

Optimization Examples

Sept. 12 - 15, 2006 2006 Sucker Rod Pumping Workshop 12

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

Sept. 12 - 15, 2006 2006 Sucker Rod Pumping Workshop 13

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