As a new artificial lift application in oil & gas industry, progressive cavity pump (PCP) becomes more and more widely used in the oilfields for its inherent advantages as energy saving, lower investment and easy maintenance. Due to the temperature limitation of stator elastomer, however, PCP has never used before in the CSS (Cyclic Steam Stimulation) application. To test the feasibility of the PCP in CSS condition, we have tried the High-Temperature-Elastomer PCP (PCM198 Elastomer PCP), manufactured by PCM, in Well Shu1-39-036 after the steam injection. The result of this trial is promising, and proves that PCM 198 PCP can tolerate the high temperature in the CSS downhole condition for the thermal recovery of heavy oil. The trial has also opened a new frontier for the PCP application in heavy oil production.
Progressive cavity pump (PCP), as a highly potential and advantageous technology, has been widely used in the world for both cold and thermal oil recovery 1–5. In China, by the end of 2007, more than 5000 wells have been installed with PCP. For PCP's application in the thermal heavy oil application, only PCM's metallic PCP (PCM Vulcain ™) has been used in North & South America 6. How to enhance the elastomer's tolerance of high temperature so as to be used in the high temperature wells has always been a hot topic. This paper is a record of our trial project with High-Temperature-Elastomer PCP (PCM 198 Elastomer PCP), and some experiences we obtained during the trial. The main purpose of this trial project is to test the reliability of this kind of special PCP when being used in 2 CSS wells.
Progressing cavity pumps are positive displacement pumps which consist of a helical steel rotor and a synthetic elastomer stator that is bonded to a steel tube. Rotation of the rotor within the fixed stator causes a series of sealed cavities to form and move axially from the pump suction to discharge (see picture 1). The resulting pumping action increases the pressure of fluid passing through the pump so that it can be produced to surface. Numerous papers 7–8, describing PC pump principles and theory have been presented.
PCPs were initially developed for the Cold Heavy Oil Production. Thanks to extensive researches, this technology has significantly widened its area of applications with the production of 8 to 43 API ° crudes. Maximum pumping fluid temperature was about 120 °C. Greater temperatures remained challenging due to the poor resistance of elastomer bonding with the stator housing.
Compared with traditional artificial oil lift technology, PCP has unique advantages from its structure and working principle. The following are some details:
Highly compatible with various reservoir, especially for the heavy oil and high sand-cut reservoir.
As a cavity pump, the adjustment of the production of PCP can be realized through the proportional increase or decrease of the pump speed through VSD.
Energy saving and higher pump efficiency.