IMPERIAL, CITIES SERVICE, RICHFIELD & ROYALITE JOIN FOR COMPREHENSIVE RESEARCH IN ATHABASCA TAR SANDS...
January 15, 1960
The most comprehensive research project ever undertaken to release liquid hydrocarbons from the Athabasca oil sands of northern Alberta was announced today coincident with the formation of a four company partnership to carry forward the enterprise.
The four companies are IMPERIAL OIL LIMITED, CITIES SERVICE ATHABASCA, INC., a subsidiary of Cities Service Company, which will operate the project, RICHFIELD OIL CORPORATION OF LOS ANGELES and ROYALITE OIL COMPANY LTD.
Imperial, Cities Service and Richfield will each hold a 30 per cent interest in the partnership. Royalite's interest will be 10 per cent.
The Athabasca oil sands comprise the world's largest known reserves of hydrocarbons. They are located some 300 miles north of Edmonton along the banks of the Athabasca River. Areas in which these sands are at or near the surface contain in excess of 40 billion barrels of recoverable oil, about the same amount as the proved crude oil reserves of North America. In other areas, the sands, deeper under the surface and with varying depths of overburden, contain vast additional reserves.
Existence of tremendous hydrocarbon deposits along the Athabasca River has been known to petroleum scientists for many decades. Many unsuccessful efforts have been made to separate oil from the sands on a basis which would be commercially competitive with other means of producing oil. The new partnership believes the problems can be solved by new techniques.
Research activities have been carried on individually by the partners for several years, searching for a method of extraction of oil from the Athabasca sands on a commercially feasible basis. The present research program was begun two years ago by Cities Service. Subsequently, a $ 31,500,000 pilot plant was built at Mildred Lake, roughly 30 miles north of McMurray.
The plant includes a 3,000 barrel per day distillation unit, extensive separation equipment and numerous collateral facilities. A unique mining "wheel", which his proved highly successful in the surface mining of coal in Europe, strips the sand from the surface. In the Athabasca Project, the sands are put through a series of processes, which remove the oil and return clean white sand to the mined areas.
As operator of the project, Cities Service Athabasca, Inc has established headquarters in Edmonton. President of this subsidiary is A. P. FRAME, senior vice president of Cities Service Company. LEE N. HAUGEN, for many years a leading Cities Service executive in refinery construction and operation and recently vice president in charge of research, will be vice president and general manager, with headquarters in Mildred Lake and Edmonton.
BACKGROUND INFORMATION ATHABASCA OIL SANDS, RESEARCH PROJECT.
The Athabasca oil sands are located along the banks of the Athabasca River, some 300 miles north and slightly east of Edmonton, Alta.
They comprise in estimated 30,000 square miles of oilsoaked sands in the McMurray formation, and contain what are believed to be the world's largest hydrocarbon deposits. Numerous theories have been advanced as to their origin, but scientific opinion continues to differ in this respect.
The sands at or near the surface are estimated to contain some 40 billion barrels of hydrocarbon reserves. This is approximately equal to the total proved crude oil reserves of North America.
In other areas, the oil sands are too deep under the surface to be reached by surface mining methods. These deep sands contain vast additional reserves.
The crux of the oil sand problem has been in economically mining the sand and extracting the liquid hydrocarbons.
In 1957, Cities Service Company and Royalite Oil Company Ltd. undertook an extensive examination of the problem. Royalite had conducted extensive core hole drilling on a 50,000 acre lease at Mildred Lake, about 30 miles north of McMurray. Cities Service subsequently undertook laboratory and bench scale studies of various extraction methods. Encouraged by the results of these studies, Cities Service acquired 186,000 acres of Athabasca oil sands in the areas where the sands were at or near the surface.
In September 1958, work was begun on design for a pilot plant at Mildred Lake. This plant went into operation in August 1959. Richfield Oil Corporation joined the project in December 1958. Imperial Oil limited entered the partnership in October 1959. An agreement was reached whereby Imperial, Richfield and Cities Service will each hold a 30 per cent interest in the project, and Royalite 10 percent.
At the Mildred Lake pilot plant site, the oil sands lie partially exposed along the banks of the Athabasca River. Specially constructed mining equipment was brought in to strip the oil sands from the escarpment and convey them to a mobile extraction unit. The extraction unit returns clean sand to the escarpment area and forwards the liquid hydrocarbons to the pilot refinery built nearby.
In this area the sands range from 150 to 200 feet in thickness and are located on top of limestone. The overburden on top of the sands in the menial areas ranges from 25 to 100 feet.
The oil sand deposit consists of rounded, unconsolidated sand grains. About five per cent of this material is finer than 200 mesh and consists of fine sand, clay and silt.
The average hydrocarbon content of the deposit is about 10 per cent by weight. The hydrocarbons are approximately 7.5 A.P.I. gravity and solid atmospheric temperature. About 50 per cent of the hydrocarbon boils below 1,000 degrees F. The sulphur content is roughly five per cent, with vanadium running about 200 parts per million.
In the surface formations, there are relatively thin clay lenses practically barren of hydrocarbon. Other areas are almost pure bitumen.
Economic studies had indicated that a commercially attractive venture in the Athabasca oil sands would require largescale operations. As a result the cost of mining the tar sands became a paramount factor in determining their successful economic exploitation.
The Athabasca group's executive engineers scoured both the U. S. and Europe for suitable mining machinery. They found the most promising device in the Ruhr Valley in Germany. Here German fabricators had engineered and built gigantic mining wheels for the commercial exploitation of brown coal.
One such typical wheel mines 143,000 cubic yards of coal per day. Buckets fastened to a huge wheel dig into the mining face, and drop their load upon a conveyor belt, which transfers it, in the case of the tar sands, to an extraction unit.
The wheel itself rests on tractor treads. Each tread has its own drive. A control cabin moves up and down to permit the operator to be close to the cutting face. The machine is ingeniously constructed in terms of counterbalancing and the independent drives of all the operating equipment make it an exceedingly flexible device.
Convinced that the mining wheel offered the greatest potentiality, the Athabasca engineers ordered a smaller version that would be suitable for pilot plant research and operation. German engineers came to the oil sand area, in various tests, and designed a suitable machine, which was assembled and is now in operation at Mildred Lake.
The diesel electric experimental wheel now being used can handle 9,600 cubic yards of material per day. The nine-foot diameter-digging wheel is installed on a 20.5foot boom capable of covering a wide area. On this wheel are fastened six 1. 8 cubic foot buckets with hardsurfaced, erosionresistant, cutting edges. The machine also has a tail boom, 38 feet long, carrying the far end of the conveyor belt. Current for this unit is produced by a Deutz diesel generator setmounted on a trailer.
The present extraction equipment has been designed as a portable, self propelled unit, which will operate in the field along with the mining equipment.
The sequence of operations is as follows: The bituminous sands are delivered by the belt conveyor from the bucket wheel to the extraction unit. Here the first step consists of separating rocks and foreign material. The second and basic extraction process consists of using a diluent produced from the bitumen itself to reduce the viscosity and specific gravity of the bitumen. Water is then added, causing the sand to precipitate, freeing the diluted bitumen for subsequent processing. The precipitated, oilfree sand is discharged to the escarpment area.
Leaving the extraction unit, the mixture of water, diluent and bitumen passes through a separation plant. The oily mixture is decanted from the water.
The water is recycled to the extraction unit, and a small quantity of make up water is added. Flow and temperature of the recycle water is controlled by the separation unit operator, while the temperature of the make up water is regulated automatically by means of 100 p. s. i. steam injection.
The diluent recovery unit, which then separates the bitumen from the diluent, has been designed to process 39,000 B/D of a mixture of 67 per cent diluent and 33 per cent bitumen by volume. The recovery of the diluent is accomplished by heating the mixture in a furnace and flashing it at high temperature and at atmospheric pressure.
The diluent is returned to the extraction process, while the virgin bitumen is split into two streams, one that goes to storage for subsequent use as fuel, while the other is charged into a visbreaking unit which is actually a simplified thermal cracking unit. The unit was prefabricated by M. W. Kellog Co., and shipped to Mildred Lake.
The bitumen passes successively through two oilfired furnaces. The effluent is quenched in a soaking drum, then collected in a receiver, from which the tail gas is vented to a flare.
Some coke is unavoidably formed in the furnaces and the soaker drum. It must be spalled and burned, with the help of steam and air, as part of a regular schedule.
The net liquid is pumped from the receiver drum as the final product.
Temperatures and pressures, as well as proportions of recycled fluids, must be carefully controlled in this visbreaking operation.
Products emerging from the combination diluent recovery and visbreaking units are finally: diluent, overhead naphtha, bitumen, and visbreaker liquid.
The furnace of the diluent recovery unit and the two-visbreaker furnaces are of the single upfired helical coil oilburning type.
The diluent recovery furnace is the largest: it has four burners each capable of delivering 5.7 million b. t. u. /hr. It is also equipped, near the bottom, with an extra steamcoil for the production of superheated steam. Each of the two visbreaker furnaces has two burners each capable of delivering 1.65 million b. t. u. /hr. Diluent, or diesel fuel, is used for starting, and steamatomized bitumen as regular fuel.
Electric power for the Mildred Lake project is supplied by two Caterpillar diesel generator sets.
Threephase 60 cy. 440 volt power is supplied to the many pumps and compressors. Singlephase 60 cy. 115 volt current is supplied for the light and for instrumentation. Batteries are provided for emergency lighting, and an extra standby generator to feed the boiler, in case of emergency.
Water from the Athabasca River is carefully treated for human consumption as well as for steam production, for process and for cooling water.
After having settled in a pond, the water is flocculated with alum and filtered through two anthracite filters. Drinking water is then chlorinated, while the plant water is treated with zeolite to reduce its hardness. Then it is de-aerated to minimize its corrosion tendencies. Finally, suitable phosphate compounds, sodium sulfite and an antifoam agent are added to it, as extra precautions.
The water, being returned to the river, is free of oil, and contains nothing injurious to plant or marine life.
Two Foster Wheeler boilers, each producing 21,500 lb/hr. of saturated steam at 100 p. s. i., supply the steam for the plant and for domestic heating.
An elaborate fire protection system consisting high pressure water distribution, dry chemicals and portable extinguishers covers every portion of the Athabasca installation, from the mining area to the living quarters.
Based on bench scale results and engineering estimates to date, Athabasca researchers believe that it should be possible to design facilities to separate the bitumen at a reasonable cost.
Should pilot plant studies substantiate this estimate, the major hurdles are still to come. For the extracted bitumen, in itself, is certainly no conventional article of commerce. This bitumen, as mentioned earlier, is solid at atmospheric temperatures. It is a crude product of 7.5 A. P. I. gravity containing five percent sulphur.
