With the ability to handle high volumes of liquid and operate in deeper wells with more free gas than rod pumps, electrical submersible pumps (ESPs) are proven to be an effective and versatile artificial lift solution for E&P companies around the world. ESPs can be very cost effective tools, but only if they are properly optimized and monitored. A well optimized ESP can quickly payout the capital spent on it, however keeping ESPs running under optimal parameters is often easier said than done. At OVS Group we have created a workflow that will allow for more comprehensive and efficient surveillance of ESP operations to ensure that production teams make the best operational and fiscal decisions.
The Challenge
Production represents the cash flow for an oil and gas company. Keeping production high and operating costs low directly impact the profitability of the organization, as artificial lift optimization plays a key role in regards to both costs and maintaining adequate production. In the end, an operator must perform a balancing act—running equipment harder to increase production, while keeping in mind the cost of replacing worn out equipment.
Especially in today’s economic environment, a typical production team may be responsible for hundreds of wells using a variety of lift mechanisms. Wells equipped with electrical submersible pumps (ESP) represent a very large portion of active wells today—about 150,000 to 200,000 worldwide. ESPs represent a significant capital investment for companies that use them, and protecting that investment requires constant surveillance to avoid costly replacement, downtime, or inefficient pump operations. Ideally, a team would monitor each ESP on a daily basis, taking the pressure, temperature, and flow rate data gathered from the field and plotting the data on each pump’s performance curve. Gathering all of this data, loading it into the well-model, and validating ESP performance can take hours of valuable time, and since issues do not occur often, teams might find it easier to rely solely on monitors, such as temperature alerts, or reports of declines in production in order to identify when attention is necessary. Simply put, optimizing ESPs, or manually performing trend analyses are necessary actions, but can take more time than a production team typically has. Without regular analysis, issues may go overlooked, resulting in decreased production, shortened pump life, increased downtime, and increased operational costs.
The need for more efficient ESP surveillance goes even deeper than dealing with well-to-well maintenance issues. ESPs also provide a broad level of control throughout the production network. Engineers can control volume brought to the surface, pressure drop at the formation or implement reservoir management decisions by changing the operating parameters for the pumps. In order to maintain that level of control, production teams need quicker, and easier-to-access information to make decisions involving an entire fleet of pumps. For instance:
- Temporary flow restrictions in the production system may require a reduction in flow rates. Should the operator shut-in one particular well or reduce the flow from a number of wells? Which wells should be prioritized and what is the long-term impact on the pump fleet?
- Increasing water disposal costs may require a reduction in produced water. Which well or wells should be affected?
- A well may be down for work, but production targets need to be maintained. Which group of pumps can be pushed to make up that lost production?
With large well counts and short decision-making windows, operators frequently make hastier decisions than they should. This is partly driven by the lack of readily accessible data that would help operators make the most optimal choice.
The One Virtual Source Solution
OVS Group provides an automated ESP Surveillance workflow within its Well Performance Analysis (WPA) offering. OVS ESP Surveillance connects to data from the field using automated data gathering equipment in conjunction with well-models, historical performance data, and recommended pump operating specifications. The workflow automatically compares the most recently collected data from the field with the most recent well-model, and responds to any discrepancies found between the two.
Typically graphed on a pump performance curve, OVS ESP Surveillance displays the pump’s current operating conditions along with the pump’s corresponding efficiency. The workflow automatically checks that the current operating conditions are within the previously established tolerances generated by the production engineering team or the pump manufacturer. If current operating conditions fall outside these predefined tolerances, the software will notify the production engineering team of this potential issue to ensure that immediate action is taken. Alerts are commonly configured for pump supply voltage, motor temperature, pump vibration, pressure intake, and other operational parameters. Additional systems can be configured that analyze the short and long-term trends of these same parameters and alert the user accordingly. Incorporating data from historical performance or forecasted production allows for more advanced alerting capabilities, such as future pump capacity concerns. These exception-based alerts allow for production teams to focus their efforts on the items that need attention first and foremost.
ESP Surveillance also allows the user to perform sensitivity analyses in order to predict the consequences resulting from changes made to a pump’s operating parameters and their effects on production and the pump itself. A pump may be operating within its efficiency envelope, but by adjusting something as simple as its frequency, operators can maximize production output while ensuring the pump does not get overworked. A sensitivity analysis like this can be incorporated into the larger strategy of optimizing the entire operation around certain production goals. If for instance, an operator finds it necessary to keep water volumes below a particular threshold in some areas, the operator would need to decide where water production could be reduced while minimizing the resulting drop in oil rates and keeping the fleet of ESPs operating in a healthy manner. By running sensitivity analyses on the ESPs in the area, the production team can determine the optimal decision to match the desired water rate.
Workflow in Action
Case Study: Large National Oil Company
In a large National Oil Company, ESP Surveillance was implemented as the primary tool for daily operations for 60+ wells using ESPs. This implementation allowed a single individual, in a control center, to monitor and optimize the entire fleet of pumps while also managing other operational duties. The result was a significant reduction in manpower needed to operate the ESPs. At the same time, the number of occurrences of pumps operating outside of the design parameters were reduced with expectations of an increase in service life. The company also found opportunities to improve production by pushing under-capacity pumps harder.
Upon installation at another oil and gas company – a large, US-based independent – ESP Surveillance allowed the company to identify and rectify 5 ESPs that were being over-worked within one day of implementation.
Requirements
- Remotely Gathered Pressure Data
- Well Models
- Well Specifications
• Wellhead Pressure
• Pump & Tubing Specifications
• Wellbore Schematics
• Reservoir Conditions
• Production Fluid Specifications
• Productivity Index
- Performance Tolerances & Alarm Presets
Deliverables
- Pump Performance Curves
- IPR/VLP Curves
- Automatic model validation (depending on predefined tolerances)
- Automatic alarms
• Sub-optimal pump performance
• Pump supply voltage
• Motor temperature
• Pump vibration
• Pump intake pressure
• Others… - Tools for performing sensitivity analyses on the current model within the same interface
Expected Benefits
- Consolidates important ESP data, making it easier to see important information so that personnel can make informed decisions in a timely manner.
- Massive reduction in time spent validating models
- Decreased downtime for ESP maintenance
- Increased average ESP run life
Final Thoughts
With the current markets for oil and gas being how they are, it remains paramount that a production engineer has the best tools to make effective decisions in a timely and cost-efficient manner. One Virtual Source offers a whole suite of workflows, in addition to ESP Surveillance, to expedite a production engineer’s duties. Utilizing our software, production engineers can spend less time sifting through data to determine what is important, and more time engineering solutions.
