Texaco Canada Petroleum Inc., (TCPI) has successfully conducted a 10-horizontal well primary production pilot project at Frog Lake, Alberta, Canada, where the heavy oil gravity ranges from 10 to 14 API, and the oil viscosity ranges from 20,000 to 50,000 cp. These 10 wells were completed in the Lower Waseca formation (one of five prospective formations in the field) and produced using the primary production technique of "cold production", which is the coproduction of sand and oil from the reservoir at ambient temperatures. These wells were very successful with most wells displaying productive capabilities in excess of 100 barrels of oil per day. Based on the success of the 10-well pilot, a long term staged development plan was established that will allow resolution of some technical challenges also identified by the 10-well project. This paper summarizes "cold production" technology, the history of the Frog Lake field, completion and production techniques, and some of the operational and technical challenges encountered. A field wide development strategy and enhanced oil recovery potential are also discussed. Cold Production Technology A number of heavy oil and oil sand reservoirs in Alberta, Canada have been successfully produced under primary production at rates far in excess of the predictions based on radial Darcy flow. The primary heavy oil production is possible by allowing formation sand to be produced along with reservoir fluids using a progressive cavity (PC) pump. This process is called "cold" production because heat, such as steam, is not introduced into the reservoir to effect production of the heavy oil. Figure 1 shows a PC pump which can carry reservoir fluids and sand to surface through the rotational action of a rotor housed in a flexible rubber stator. Typically, a cold production well will produce oil and water at sand cuts as high as 30 to 40% initially, which gradually decrease over time to stabilize at between 1 to 5% after one year of production. Cold production technology has been applied to many heavy oil and oil sand reservoirs in the Cold Lake region of Alberta, Canada with economic success. Figure 2 shows a representative cold production project with a six year production history. The range of reservoir characteristics and fluid properties amenable to cold production are shown in Table 1. Currently, the two generally accepted theories on the dynamics of cold production are:sand production creates "wormholes" in the reservoir thereby increasing both the effective permeability and well bore radius, and;the oil flows due to the "foamy oil" phenomena, a type of reservoir drive mechanism involving the retention of solution gas by the viscous oil. Other factors contributing to cold production may include increased drainage radius, gas expansion, and continuous pore de-blocking. Higher quality PC pumps allow co-production of the sand with the heavy oil. Sand production is encouraged through large diameter perforations in vertical wells and wide slots in horizontal well liners. Anticipated recoveries are increased to 8 to 12% of the original oil in place from negligible levels if the wells were produced without the co-production of the sand. As horizontal well technology developed, demonstrated increases in oil production from three to four times that of conventional vertical wells were common. Although the cold production mechanism is not fully understood, a combination of horizontal wells and cold production does have the potential to economically produce many heavy oil fields. History of Frog Lake Property Texaco Canada Petroleum Inc. (TCPI) is a 100% working interest owner of a 34,000 acre 53 section oil sand lease located at Frog Lake, Alberta. P. 279^
This paper (SPE 52636) was revised for publication from paper SPE 37545, first presented at the 1997 SPE International Thermal Operations & Heavy Oil Symposium, Bakersfield, California, 10-12 February. Original manuscript received for review 15 January 1997. Revised manuscript received 10 August 1998. Paper peer approved 1 September 1998. Summary Texaco Canada Petroleum Inc. (TCPI) has successfully conducted a 10-horizontal well primary production pilot project at Frog Lake, Alberta, Canada. The gravity of the heavy oil ranges from 10 to 14 API, and the oil viscosity ranges from 20,000 to 50,000 cp. These 10 wells were completed in the Lower Waseca formation (one of five prospective formations in the field) and were produced by use of a coproduction of sand and oil from the reservoir at ambient temperatures, known as cold production. These wells were very successful, with most wells displaying productive capabilities in excess of 100 B/D. Based on the technical success of the 10-well pilot, a long-term staged development plan was established to resolve some technical challenges identified by the 10-well project. These challenges include reduction of operating costs and improvement of artificial lift and well reliability. As part of the development plan, over 70 horizontal wells have been drilled and production has peaked at 3,000 BOPD. This paper summarizes the history of the Frog Lake field, completion and production techniques for the pilot project, and some of the operational and technical challenges encountered. A field-wide development strategy and potential for enhanced oil recovery (EOR) are also discussed. P. 551
An improved method was developed to obtain the complete characteristic of centrifugal pump. The conversion formula of complete characteristics is established based on the normal performance curve. An example was presented to illuminate the new method, and the complete characteristic curves of 14SA-10 centrifugal pump were obtained by the new method. The hydraulic transient of the centrifugal pump failure and start-up was simulated by method of characteristics (MOC), which quote the complete characteristics data. The results show that the inversion method is available to obtain the complete pump characteristic curves provided the normal performance curve. For hydraulic transient simulation, more accurate numerical result can be obtained, if the new model is adopted to convert the experimental normal performance curve to complete characteristics curve of centrifugal pump.
A pressure vessel is installed to prevent transient vacuum and overpressure in centrifugal pump integrated system. In order to study the transient response of the pressure vessel with multichannels and improve design approach, an integrated system with two centrifugal pumps and a pressure vessel is presented. Based on the water hammer method of characteristics (MOC), the integrated numerical model and program are established by combining pumps, valves and pressure vessels in the integrated systems. Transient pressure process and gas volume variation are simulated for the pressure vessel. The Oscillation amplitude and frequency are obtained, and then the extreme hydraulic transient pressures are analyzed and compared. An optimal design method is provided to determine the safe and economic mass (SEM) of gas (nitrogen) and corresponding optimal safe and economic volume (SEV) of pressure vessel.
Pressure vessels can greatly protect a water supply pipeline system from water hammer damages. In order to improve the performance of a pressure vessel, a strainer is proposed to compensate the resistance of the connecting pipe. A numerical model and program is established for a pressure vessel with an independent compensation strainer based on the method of characteristics (MOC). Using the proposed model, the hydraulic transient processes are simulated for a pressure vessel with various strainer resistances, and the hydraulic pressure and volume fluctuations are obtained by the proposed model. The influences of resistance on the transient process are analyzed and an optimal approach is suggested to determine the suitable compensation strainer for the pressure vessel. A water hammer protection system is optimized based on the proposed method. The result shows that the compensation strainer can largely affect both positive and negative water hammer pressure. If a suitable strainer is selected based on the proposed approach, the transient surge and extreme pressure distribution will decrease. To some degree, it is simple and convenient to improve a pressure vessel by employing an additional compensation strainer in the pipeline system for water hammer protection.
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