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

• 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)

Wells Problem

• 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

PRHP P

hydr 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

29.6 14.4 44.4 13.0 16.8

• Rel. Energy Saving, %

42.1 16.8 80.0 14.9 20.2

• Rel. Lifting Efficiency Increase, %

Improvements 6.7 8.2 6.1 7 7.6 Pumping Speed, SPM 88 106 88 88 124 Stroke Length, in 2.75 2.75 2.75 2.75 2.75 Plunger Size, in Optimum Pumping Mode 10 9 9 9.5 9.5 Pumping Speed, SPM 88 124 106 88 124 Stroke Length, in 2.25 2.5 2 2.5 2.5 Plunger Size, in Present Pumping Mode

E D C B A Well 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