1. 41st Gas-Lift Workshop Houston, Texas, USA June 3 - 7, 2019
Paraffin Inhibition in the Tubing using Thermodynamics principle of Gas Lift Technology
Kenechukwu Nwankwo (Chevron Nigeria Ltd.)
2019 Gas-Lift Workshop
June 3 - 7, 2019

2. THERMODYNAMICS PARAFFIN INHIBITION
OUTLINE
Introduction
Problem Statement and Objective
Historical Performance of Case Study wells
Pertinent Data
Gas Lift Valve Design
Results
Conclusions and Recommendations
KEY MESSAGES
Currently not leveraging optimally on gas lift technology to prevent wax deposition
High temperature gas lift source stream prevented paraffin deposition in tubing
Productivity and cost management were also enhanced.
Unlike chemical, thermodynamics inhibition is free of operating challenges

3. INTRODUCTION
Gas Lift uses the principle of lowering hydrostatic head to optimize productivity.
Gas lift operations mitigate problems like sand production, SCSSV opening, flow continuity etc.
Gas lift operations have been utilized to manage wax production in the tubing by chemical paraffin inhibition
Thermodynamics principle was utilized in this study to optimally manage wax deposition with minimal cost
2019 Gas-Lift Workshop
June 3 - 7, 2019

4. INTRODUCTION – Gas Lift Principle
The operating pressures, gas lift valve positions, and gas injection rates are all monitored and controlled at the surface enabling improved reservoir production.
These values are dependent on specific well conditions.
2019 Gas-Lift Workshop
June 3 - 7, 2019

5. PROBLEM STATEMENT/OBJECTIVE
Wax deposition in tubing and flowlines is a significant contributing factor to higher operations cost in the petroleum industry (Newberry and Barker, 1985).
Remediation methods all come at periodic costs –
Intervention costs
Deferred production
which are not favorable to the oil industry at large.
Two case study wells(A-01/A-02) were used to prove the efficacy of thermodynamics inhibition.
2019 Gas-Lift Workshop
June 3 - 7, 2019

6. HISTORICAL PERFORMANCE OF CASE STUDY WELLS
PRE-PARAFFIN INHIBITION PERFORMANCE
Production trends from the wells were incoherent before paraffin inhibition
Wells were designed with Gas Lift Mandrels because the Solution GOR
2019 Gas-Lift Workshop
June 3 - 7, 2019

7. HISTORICAL PERFORMANCE OF CASE STUDY WELLS
STATIC BOTTOM HOLE ANALYSIS BEFORE GAS LIFTING
A-01 liquid level was encountered at 2200ft as seen in the plot above while that of A-02 is at the surface
A-02 dummy valve at the second position was not holding pressure as can be deduced from the profile
2019 Gas-Lift Workshop
June 3 - 7, 2019

8. PERTINENT DATA
Well fluid’s oil gravity of over 34 degree API were not typical of wax producers.
Wells were designed with Gas Lift Mandrels in the Tubing that are dummied out.
2019 Gas-Lift Workshop
June 3 - 7, 2019

9. VISCOSITY TREND
Viscosity trend from PVT models showed drastic increase with decrease in pressure and temperature
Increasing Temperature was found to be a reliable means to address Paraffin Depositional issues
2019 Gas-Lift Workshop
June 3 - 7, 2019

10. GAS LIFT VALVE DESIGN
The orifice for A-01 and A-02 are at the fifth and second mandrels positions respectively.
The remaining mandrels were dummied to replicate a one point operating gas lift system.
2019 Gas-Lift Workshop
June 3 - 7, 2019

11. RESULTS: WAT AND FLOW LINE TEMPERATURE PROFILE
Wax appearance temperature dropped due to lightening and heating of the oil column with the Gas Lift gas.
Flowline Temperature increased due to the internal heat derived from the Gas lift gas.
Flow assurance was achieved by the two processes above
2019 Gas-Lift Workshop
June 3 - 7, 2019

12. RESULTS: STATIC BOTTOM HOLE ANALYSIS AFTER GAS LIFTING
Liquid level is more distinctive(sharper front) because of the decrease in viscosity due to increased Temperature effect from the gas lift stream
Temperature gradient within the oil column was stable- implying adequate heat retention/distribution
2019 Gas-Lift Workshop
June 3 - 7, 2019

13. RESULTS: PRODUCTION IMPACT FROM FLOW ASSSURANCE
Improved productivity realized from this flow assurance strategy
Production became stable (no down time)
A total gain of 1000 BOPD realized from both wells.
Increase in water cut
Compressor pressure drop
2019 Gas-Lift Workshop
June 3 - 7, 2019

14. CONCLUSIONS AND RECOMMENDATION
Gas Lifting can also be a best Practice in flow assurance apart from Productivity optimization
Increasing Gas lift temperature for waxy well fluids can prevent wax formation
Wells with high water production and salts concentration need further analyses to manage scale and wax deposition
One-point gas lift valve injection system is recommended for flow assurance best practice because of the challenges of temperature variation across valves
Wells on chemical paraffin inhibition should be reviewed for flow optimization and cost management opportunities.
2019 Gas-Lift Workshop
June 3 - 7, 2019

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2019 Gas-Lift Workshop
June 3 - 7, 2019

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2019 Gas-Lift Workshop
June 3 - 7, 2019