Without the application of innovative equipment and operating techniques, a reservoir containing an estimated 40 million m3 (250 × 106 bbl) of heavy oil-in-place would have remained unproducible. The use of conventional pumping techniques would not have been able to handle the 60 000 mPa.s (centipoise) oil which averages 40% to 50% formation sand by volume in the first few weeks of production. Progressive cavity pumps provided the most flexible, cost-effective option to exploit this difficult formation. Through the optimization of this unique equipment and associated operating techniques by both the producing and service companies involved, economic development has been made possible.
This paper will describe the evolution a/the progressive cavity pump system in the development of the Clearwater Formation in the Lindbergh-Elk Point field. Modifications made 10 the equipment design and techniques to optimize pump sizing and pump run lives will be discussed.
The Lindbergh-Elk Point field is located approximately 165 km east of Edmonton and just south of the town of Elk Point as shown in Figure 1. Amoco Canada holds a 100% working interest in 6090 ha (23.5 sections) in the Lindbergh field. Development of the field began in December 1981 with the drilling of the first well in the Lower Cummings Formation of the Mannville Group. The successful production of this first well prompted the drilling of additional wells in 1983 and again in 1984. The drilling of these wells resulted in the delineation of the Sparky and Clearwater formations. Testing of the Clearwater Formation showed its prolific producing capabilities despite its high viscosity and produced sand volumes. Previous experience and the characteristics of the reservoir fluids indicated that conventional methods of surface lift would not be successful in this application. As a result, progressive cavity pumps were employed due to their ability to pump viscous fluid with a high solids content.
The Clearwater Formation is 25 m 10 30 in (82 ft to 99 ft) thick and consists of a moderately well sorted litharenitic sand. The sand coarsens upward in the deposit and is made up of very fine to medium-grained and subangular to subrounded particles. This continuous body of sand was deposited along a prograding shoreline in a northwesterly direction. A series of shale-silt laminations were later deposited over a portion of the area now overlain by the reservoir due to the occurrence of a minor marine transgression. A calcite cemented sand is often associated with this zone. The sand is overlain by a I m (3 ft) thick lignitic coal seam which, in turn, is capped by a Lower Sparky marine shale. A typical set of well logs of the formation is shown in Figure 2.
A major system, consisting of long, sinuous channels, removed and reworked the Clearwater sand as a result of regression during Upper Sparky time. A marine incursion of the Clearwater sea supplied mud which infilled these channels forming updip seals for hydrocarbon reservoirs.
