Novel Design for Enhancing Oil Well Pump Performance through Elimination of Paraffin Buildup

Physical Sciences : Petroleum

Available for licensing

Inventors

  • Mukul Sharma, Ph.D. , Petroleum and Geosystems Engineering
  • Raymond Zowarka, Jr. , Center for Electromechanics
  • Siddharth Pratap, Ph.D. , University of Texas at Austin
  • Michael Werst, B.S. , Center for Electromechanics
  • Clay Hearn, B.S. , Center for Electromechanics
  • Michael Worthington, B.S.
  • Jonathan Hahne, B.S. , Center for Electromechanics
  • Hsing-Pang Liu, Ph.D. , Center for Electromechanics
  • Bryan Bunkowski , Center for Electromechanics

Background/unmet need

One of the major maintenance headaches that adds cost to the production of mature oil wells is the elimination of wax and paraffin buildup in the drill pipe. The accumulation over time of non-volatile compounds in "cold spots" in the tubing creates high pressures and flow constrictions that at the very least contribute to accelerated pump wear, and at worst constrict the flow altogether.

Standard treatment methods include the circulation of hot drilling fluid through the drill string to melt buildup spots and circulate the melted material out. Downhole heater elements can also be used, but require separate power supplies and inevitably result in loss of heat to the well. These methods must be used several times per year, taking production off-line in order to clean out the wax buildup. Current heating methods lead to additional resource costs and inefficient use of time. A mechanism that is more cost-effective and energy-efficient for well heating could significantly improve well performance.

Invention Description

Inventors at The University of Texas at Austin developed a prototype that generates heat at a localized spot in the production tubing string. No external power supply is required, as the heat is generated from magnetically induced currents. The level of heat can also be controlled to keep the oil temperature from dropping below the critical temperature of paraffin formation, guaranteeing the prevention of wax buildup and restricted flow.

The infrastructure of the proposed heating system is simple and does not interfere with existing pump equipment at the surface of the well, as opposed to current methods that require extensive modification of pump equipment. The energy input to the unit can be provided by a sucker-rod pump, downhole motor, or any other energy source. However, the use of power provided by the well’s sucker rod for pumping oil eliminates the need for any other power source for the heating system.

Benefits/Advantages

  • Energy-efficient
  • Direct installation of elements in flow path eliminates initial wax buildup
  • Prevents heat loss from the surface of the well
  • No interference with other well maintenance procedures
  • Eliminates subsurface cabling
  • Eliminates additional infrastructure at well surface; simpler design
  • No external power requirement

Features

  • Prevents formation of wax and paraffin buildup in flow path
  • Integrates directly with existing well infrastructure
  • Simple installation, as if installing a length of production tubing
  • Generates heat at specific locations in the well
  • Functions independently of other well maintenance procedures
  • Pumping unit can be removed from the well for service without removing the heating unit.
  • Utilizes same power provided by well’s sucker rod for pumping oil
  • Requires no modifications to well head, tubing hanger, and method of oil delivery

Market potential/applications

There are over two million producing oil wells worldwide. One million of those use some form of artificial lift equipment. It is estimated that at least 750,000 of those lifted wells use sucker-rod pumps. Approximately 80% of all oil wells in the US are stripper wells, the vast majority of which also use sucker-rod pumps.

Wells that already utilize sucker-rod pumps for oil delivery can increase their production by using these pumps to simultaneously power the proposed heating system to prevent wax formation in the flow path. The current downturn in oil price creates a unique opportunity for low-cost solutions to existing pumping problems, such as wax buildup preventing efficient well flow. This invention provides an elegant solution that can be employed by oil and gas companies that perform well cleaning or maintenance in order to achieve optimal well performance.

Development Stage

Lab/bench prototype

IP Status

  • 1 U.S. patent application filed
  • 1 U.S. patent issued: 10,125,589