Utilizing both software applications and downhole pressure and temperature gauge technology, one company is providing customers with turnkey intelligent lift systems to enhance field production.

In today's cost-conscious environment, optimizing production from maturing fields is imperative. To accomplish this, operators must employ targeted information to customize lifting solutions, helping to address the unique needs of individual fields.

This is the core of the "intelligent well" approach - monitoring and controlling the production of hydrocarbons in single or multiple wellbores in real time. Such systems can reduce interventions; production can be controlled remotely from the surface, at the well site or from a location away from the well site. Real-time data such as reservoir pressure, temperature and multiphase flow rates can be gathered from downhole monitoring devices and transmitted to the surface.

Operators also must optimize returns from their mature reservoirs. According to E. Lee Colley III, president of Weatherford Artificial Lift Systems, "Weatherford is forging new cooperative arrangements in analysis, asset management, risk-sharing and other planning technologies to help determine which artificial lift combination will add the most value to a customer's field." These partnering agreements and cooperative technology developments are bringing economically viable solutions for customers in deepwater, production enhancement and reservoir revitalization.

Automated production optimization
Utilizing both software applications and downhole pressure and temperature gauge technology, Weatherford is providing customers with turnkey intelligent lift systems to monitor, control and optimize field production. These systems also allow administration of the field from a central, remote control station (e.g., from a personal computer). "By continually monitoring every well in real time," says Colley, "these systems are able to optimize production as well as alert operators to signs of pending problems with a well."

"Life of Field" economics

Weatherford's Automated Production Optimization Systems are designed to provide unique artificial lift solutions unbiased by a particular technology. The software links hardware and instrumentation to provide the turnkey capability. The selection of beam pumps, electric submersible pumps (ESP), gas lift, plunger lift, hydraulic lift or progressing cavity pumps is based solely on what is determined to be best for the developing field. This Life of Field economics analyzes a range of technical, logistical and financial factors, as well as operating and capital costs, to determine which artificial lift system will further optimize production.

Examples of ongoing applications
Recently, Weatherford Rotaflex Pumping Units were installed with variable speed drivers (VSD) in two wells for Petrolera Perez Companc (Petrolera) in the Yacimiento Entre Lomas Field in Argentina. The long-stroke pumping units provide for improved efficiency in deep, high-volume wells. Using up to a full 251/2-foot pump stroke can result in operational savings and increased productivity. Also, the pumping unit has virtually no minimum speed, adding to the increased flexibility. The ability to adjust to slower speeds and longer strokes results in more complete barrel filling. These qualities, coupled with the automated control capabilities of the VSD, create a uniquely effective solution. The wells in this particular application are running with Rotaflex 900 pumps installed at 7,874 ft (2,402 m).

"There has already been a significant reduction in the number of sucker rod failures," said Pablo Prado, production engineer for Petrolera. In the first well, prior to VSD installation, the well averaged 60 days between interventions. After VSD installation, the well has been running for 618 days without failure. "We are pleased with the performance of the pumping units used in conjunction with the VSD in this application. The results have exceeded our expectations", stated Mario Brarda, operations manager for Petrolera Perez Companc.

In a second well, Weatherford installed a VSD with three-speed control software to increase strokes per minute (SPM) of the unit and to optimize the loads on the rod string. Production rates increased from 630 b/d to 820 b/d of oil. In addition, the loads and rod failures have been reduced.

The pumping units were also installed with the Northlander controller and software on two wells for another major operator in the Carmopolis Field in Brazil, with excellent results. "In 4 years of operation, well production has increased by more than 20% and interventions have been significantly reduced," said E. Lee Colley. "The wells are the highest producers in the field, and production is now over 1,600 b/d of oil."

PC tandem pumps

By combining automation capabilities and lifting technologies, producers can reap both cost and production advantages. For example, after assessing the performance criteria of a customer's gas-lift-assisted hydraulic jet and progressing cavity (PC) pumping combination, Weatherford reached a unique solution: hydraulically driven PC pumps in tandem, one pump acting as a driver, the other as a producer, thereby eliminating the need for sucker rods. This combination offers a substantial economic advantage offshore or on remote land areas where moving in a workover rig is cost prohibitive. Tandem PC pumps also provide advantages in situations with high rod wear.

In all of these developments, the contribution of Weatherford's Automated Production Optimization Systems provided operators with a tool for production enhancement and cost control. Some additional successful combinations of Weatherford technologies to enhance production include:
• testing a hydraulically driven progressing cavity (PC) pump developed in Brazil for Petrobras; and
• combining gas lift with ESP to reduce outlet pressure and allow greater flow through restrictions caused by small casing.

Development of Weatherford's Automation/Optimization Systems is ongoing and continues evolving with software design advances. The company is currently refining its standardized wellsite automation and optimization system, which eventually will be able to effectively manage any of its six artificial lift systems. Customers will be able to reduce costs and improve the quality of data collected, which in turn will enhance decision-making.

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