Progress In The Development Of Submersible Pump Power Cables
Authors: Tijunelis Donatas , Vandevier Joe E. 
Published: December 2007

The use of submersible motor driven pumps to lift oil from its reservoir is on an increase. It will mean a significant use of cables capable of withstanding the chemical attack, high temperature, and pressure of the bottom-hole environment in an oil well. During the past decade, considerable research and development has been directed to this objective through the initiative of the oil production equipment manufacturers. There have been production equipment manufacturers. There have been both failures and successes. This paper summarizes and traces the developments, discussing new insulation material properties, specific cable designs, and testing techniques for service in oil at temperatures of 275 degrees F+ and more than 4,000 psi+ of hydrostatic pressure. Splicing, as well as psi+ of hydrostatic pressure. Splicing, as well as probable targets of future cable developments, are probable targets of future cable developments, are also covered.

Introduction

Secondary recovery of oil is going to submersible, electric motor driven pumps. This will be the way of the future. Worldwide, the switch to electric submersible systems has more than doubled in the past decade. The trend has been closely linked to improvements in reliability and extended life of the submersible system in spite of the severe bottom-hole conditions. These improvements have not just evolved, but rather have been the result of intense developmental efforts.

The submersible power cable developments for oil production has lagged the development of pumps and motors until late 1960's. Until then, partially because the total footage used was still low, the oil production equipment manufacturers relied on an adaptation of the conventional power cables - such as were used in the mining industry. Under the circumstances, these did a fair job. Many of the early applications for the submersible lift systems were relatively simple - low bottom-hole temperatures, moderate pressures, and low gas content.

With success came more attention as well as a demand to fulfill more difficult applications. On one hand, the cable manufacturers began to recognize business volume potential and thus justification for innovation. Cable quality destined for oil field use began to be tightly controlled. As new applications brought with them deeper, more severe bottom-hole conditions, the requirements of the materials used began to significantly deviate from those suitable for the more conventional surface and mining applications. The initial target for development was oil resistance and higher temperature insensitivity.

Although many industry sectors had an interest in an improved cable, it was the submersible equipment manufacturers like CENTRILIFT and Reda Pump Companies who provided the momentum. In the case of CENTRILIFT, they contracted their Corporate Research Center to the task of inventing new compounds, working with material suppliers, cable manufacturers, and the oil production people to design and develop power cables specific to the new bottom-hole applications.

DEVELOPMENT OF POWER CABLES FOR HIGHER TEMPERATURE AID OIL RESISTANCE

As mentioned, the first steps in developing an oil well cable were to improve temperature and oil resistance. From a starting point of the existing cables shown in Figure 1, developments took the form of a search for higher temperature, oil resistance rubbers, as well as copper resistance in the thermoplastic insulation. The result was several patented new material compositions and cable constructions.