Analytical Study of Oil Recovery on Gas Lift and ESP Methods

In addition, the selection of this artificial lift method will maximize potential oil recovery from developing oil fields. Gas lift and ESP (Electric submersible pump) are widely used in oil and gas industry. As a result, a thorough evaluation of this artificial lift method is critical to long-term profitability.

Thus, this study aims at an in-depth analysis of oil well behavior, which requires gas lift and ESP to achieve optimized oil production. This will be based on a stable simulation of oil production in the Sarawak field, courtesy of PETRONAS Carigali Sdn. Together with the simulation results, a comparison between gas lift and ESP will be identified and analyzed.

This thesis would not have been accomplished without the guidance and assistance of several individuals who contributed in one way or another and provided their valuable assistance in the preparation and completion of this research. During the implementation of the project, we received a lot of input and ideas from them, which greatly benefits the progress of the project.

INTRODUCTION

Background of Study
Problem Statement
Objective and Scope of Study

Objective
Scope of Study

The Relevancy of the Project
Feasibility of the Project within the Scope and Time Frame

As part of the study, an in-depth analysis of the behavior of an oil well requiring gas lift and ESP will be developed based on steady-state well simulation using PROSPER software to ensure optimized oil production. The gas lift method and ESP are the two most common artificial lift methods that are widely used and are chosen for primary enhancement of oil recovery. Apart from that, a comparative study between gas lift and ESP has not yet been done.

And therefore, a strategy to optimize throttle lift and ESP needs to be further investigated on this study by using steady state simulation software such as PROSPER. Therefore, this study will help to focus on the selection of artificial lift, especially on gas lift and ESP, which are most widely used in oil and gas industry operations. This comparative study of gas lift and ESP requires reliable results of pressure or flow rate diagrams that combine the relationship between well inflow and vertical lift capacity curves.

In addition, this study is conducted in 2 phases; the first phase involves the primary research on gas lift and ESP method to maximize its ultimate potential for production and profitability. And as a result, a comparison between gas lift and ESP is then developed to deliver an optimized oil well production.

LITERATURE REVIEW

Artificial Lift

Artificial Lift Feasibility
Types of Artificial Lift

Gas Lift

Gas Lift System
Golden Rules of Gas Lift
Limitations of Gas Lift
Gas Lift Strength
Gas Lift Overview

ESP (Electrical Submersible Pump)

ESP System
Advantages and Disadvantages of ESP
ESP Overview

PROSPER Software

PROSPER Application

Production Optimization

Production Optimization by Artificial Lift

Summary

But most importantly, the artificial lift method can produce the well at the desired rate and for the required time. In the oil and gas industry, gas lift and ESP are most commonly used in artificial lift methods. Gaslift and ESP have overcome such production engineering challenges in the Stag oilfield.

Gas lift is widely used in the artificial lifting methods due to its utility and versatility and therefore it is widely used and known as the most flexible artificial lifting method. Through the overall review of gas lift, it can be concluded that gas lift deserves serious consideration in the artificial lifting method. Another artificial lifting method that plays a major role in increasing oil production is the Electrical Submersible Pump (ESP).

Looking at the overall overview of ESP, it can be concluded that ESP is considered an effective and economical artificial light method to improve oil recovery. In addition, there are certain environmental and geographic considerations that may be predominant in the implementation of artificial lift methods such as gas lift and ESP.

Figure 2: A typical continuous gas lift system [11]

METHODOLOGY

Project Activities

Data Gathering and Analysis
Case Study of Optimization of an Oil Well using PROSPER
Well Modeling
Discussion

Important Dates
Key Milestone and Gantt-Chart
Tools Required
Data Required

This reflected that the increase in water cut and the drop in reservoir pressure will have a significant impact on oil production. In this case study, the minimum recovery of oil is set to be no less than 1500 stb/day. This means that any well producing an oil rate of less than 1500 stb/day will not be considered an economic oil well producer.

The technical data required are laboratory PVT data, well test data, VLP data and IPR data. This IPR curve plays an important role in understanding the relationship between downhole fluid pressure and oil production rate. The comparison should identify the optimum and maximum production rate achieved by each artificial lift method, as well as the key performance indicator (KPI) that influences the final choice of gas lift and ESP.

3 Preparation of oral defense 4 Review of literature 5 Procurement of software 6 Collection of data about the plant 7 Preparation of draft interim report 8 Preparation of final interim report 9 Laboratory activities 1 (in half break): Gas lift BETWEEN SEMESTER. The requested data is obtained from an oil production well in the Sarawak field, courtesy of PETRONAS Carigali Sdn.

RESULT AND DISCUSSION

Data Gathering and Analysis

Case Study of Optimization of an Oil Well Using PROSPER

Well Modeling

Developing a Well Performance Model Using PROSPER
Well A
Simulate Base Case Forecast under Various Operating Conditions 43
Well B
Simulate Base Case Forecast under Various Operating Conditions 63
Well C
Well D
Simulate Base Case Forecast under Various Operating Conditions
Evaluate Various Development Options to Optimize Oil
Well E
Simulate Base Case Forecast under Various Operating Conditions
Evaluate Various Development Options to Optimize Oil

Discussion

From the obtained result, it follows that the reduction of the pressure in the well head causes the increase of the withdrawal. The effect of increasing pipe size is to give a higher junction pressure for a given flow rate because the pressure drop across the pipe is reduced. Changing the gas injection rate and pump operating frequency in gas lift and ESP is also performed to perform sensitivity analysis on the artificial lift parameter.

From the obtained result, an increase in gas injection rate gas lift will result in an increase in oil rate production. The result is shown that increase in pumps operating frequency ESP will result in increase in oil rate production. Although ESP tends to be more expensive, ESP offers a potential flow rate that is better than gas lift.

Well depth determines how much surface energy is required to move fluids to the surface and can place limits on gas lift and ESP. When designing a gas lift and ESP, the availability of electricity or natural gas determines the type of artificial lift chosen, whether gas lift or ESP. Gas lift can operate over a wide range of production conditions and can be used for any well configuration (deviation, horizontal and double completion).

Gas lift operating costs are generally low compared to ESP and are directly dependent on fuel costs and system reliability or integrity. For the 500-200scf/stb range, the achievable pumping rate will be limited by the amount of gas emerging from the solution in the pump area. Greater than 2000scf/stb, the FBHP will need to remain above bubble pressure to prevent gas cavitation in the pump.

This is because the gas lift does not depend on the bubble pressure, so it is suitable for any range. ESP is not recommended for high bubble point as this will limit maximum pumping in the well due to the detrimental effects of free gas in the pump. Looking at the general situation, the efficiency of a gas lift system is about 10-30%, while ESP is about 35-60%.

CONCLUSION AND RECOMMENDATION

Conclusion

Recommendation to Future Work