The use of an innovative wireless bottom hole pressure/temperature telemetryacquisition system in artificial lift operations can dramatically improveefficiency and optimize fluid producing rates in those wells. The tool isinstalled into the producing well in the vicinity of the perforations, measuring and transmitting the producing bottom hole pressures and temperaturesto the surface for instantaneous control of the surface pumping motor speedthis insures the lowest possible fluid level back pressures, this allowing forthe highest possible fluid entry into the wellbore from that reservoir'scapacity. Operating costs per barrel are lowered since the maximum oilproduction can now be realized from existing wells.
The telemetry tool is deployed with standard slick line equipment and isinstalled inside a well in a manner similar to ordinary pressure recordertools. Several unique advantages of the tool are:
no moving parts;
nowire line to the surface;
real time measurement of bottom hole data; and
slick line retrievable.
Future versions of the acquisition system tool willimprove operating efficiency in the following ways:
Temperature monitoring and control of perforation scaling, tubular waxing, and tubular hydrating plugs.
Provide data necessary to create diagnostically predictive IPR curvesthrough monitoring of reservoir in-flow rates.
Enabling early warning of water encroachment or lensing through fluidresistivity monitoring.
A field demonstration of the application of the bottom hole pressure data, asreceived from Real Time Diagnostics' wireless pressure transmission system, improved the efficiency of PanCanadian Petroleum Limited's 8A-I9–38-0I-W4m wellin the North Bodo field of northeast Alberta, Canada. An illustration ofservicing a typical North Bodo slant well on a pad of wells is shown in Figure1. The Telemetry Acquisition Tool (TAS ®) device, developed by Real TimeDiagnostics (RTD), was installed in the production tubing below the producingzone perforations, where it was able to measure and accurately transmit bottomhole production pressures and temperatures of the well's producing horizon tothe surface. The real time pressure data was relayed into a voltage loop and asurface computer which contained software designed to output an analog processsignal. This signal was then sent to the Wermac Electric Limited's Variable Frequency Drive (VFD), which controls the speed and torque of the electricmotor powering the bottom hole progressive cavity pump (PCP) system. PanCanadian was able to both increase the oil production and decrease thelifting costs per barrel by utilizing the actual bottom hole pressure responseof the reservoir fluids flowing into the wellbore to optimize the daily rate ofproduction.
Basic theory of signal transmission through electromagnetic wave propagation isnot unique or novel; in fact, it has been around for many years. A typical oilfield telemetry system includes a down hole frequency transmitter, whichcontains measurement sensors and a receiver located at the surface. A speciallymodulated electromagnetic frequency signal, representative of the measurementsperformed by the sensors located in the down hole transmitter, is injected intothe formation where it propagates upward to the surface along the outside ofthe casing string, essentially creating a two wire path for the current flow tofollow.
