By H. J. WEBBER''
(18th Amm.al Technical illeeti·,~g, The Pet?·oleu.m Soc-iety of C.l.Jlf., Ba'Jiff, Alta, illuy, 1967}
ABSTRACT tant Cold Lake depo::;its and with minster area to the south. For pur selected observations on the nature poses of uniformity, the term bitu Downloaded from http://onepetro.org/JCPT/article-pdf/6/04/146/2167092/petsoc-67-04-04.pdf by guest on 26 September 2021 The heavy h}•drocarbon deposits m and properties of the other Alberta men will be used to describe lhe the C11ld Lake area of Alberta are de deposits, particularly the Athabas Cold Lake heavy hydrocarbons. scriUed, and ~orne observations on other Alberta oil sands, particularly ca deposit. The Cold Lal~e oil sands occur the Athabasca deposit, are presented. The terms ·'oil sand" as used within the Mannville Group of Low here and "tar sand" as used in the er Cretaceous age, and are of ~lp Congress papers are defined as a proximately the same geologicnl sand containing a highly viscous age as the Grand Rapids deposits INTRODUCTION crude hydrocarbon material not re to the north and the reservoirs in coverable in its natural state the Lloydminster Field to the HIS contribution was presented through a well by ordinary produc south. FignTe 1 is a schematic T in a slightly different form at tion methods. cross section showing the strati the Seventh \Vorld Petroleum Con graphic relationship of the Athn gress in Mexico City in April, 1967 basca, Cold Lake and Lloydminster as a discussion under Panel Discus COLD LAKE AREA accumulations. sion No. 13, "Occunenee and Pros The Mannville Group at Cold pects of Tar Sands," oj: a paper b;~r In addition to the deposits dis Lake is approximately 660 feel Dr. P. H. Phizackerley and Miss cussed by Dr. Phizackerle~r and thick and is overlain by 900 to 1.- L. 0. Scott entitled "The i\Iajor Miss Scott in their paper, there is 600 feet of sediments. It is com Tar Sand Deposits of the 'iVorld." another major area of Alberta con posed of interbedded sand, silt and In accordance with Congress rules tr~ining heavy hydrocarbon depo shale, with minor stringers of coni. against printing of discussions, this sits which are considered by the The depositional environment contribution is not being published Alberta Oil and Gas Conservation ranges from continental through in th~ Proceedings of the Congress. Board to be oil sands. This area is deltaic to near-shore marine. Imli located about 125 miles northeast The purpose of this presenta vidual oil sands range up to 100 of the citJ.• of Edmonton, and is tion is to supplement the recorded feet or more in thiclmess. The generally referred to as the Cold summary of ''torld oil sands depo main bitumen accumulations are Lake area. The heavy hydrocar sits with a discussion of the impor- related to a large Paleozoic Htruc bons in this area are transitional tural high. The bitumen may occm· in properties between the bitumen in any sand in the sequence, and 7 Oil and Gas Conserva,tion Board, of the oil sands to the north and may or may not be underlain by Calga1·y, A.lberta the heavy crude oil of the Llo~·d- an aquifer.
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• ClM Figw·e 1.--Schematic C1·oss Section oj the .4.liH:t'la Oil Sands and A.ssociatl'cl Forma.fiom·. 146 The Journal of Canadian Petroleum The quantity of bitumen in place in the evaluated area outlined in Figure 2 has been preliminarily es timated at about 75 billion barrels. The Cold Lake deposits therefore rank as the third largest in- the world, behind the Athabasca depo sit and Venezuela's Orinoco oil sands. The quantity of· bitumen which might eventually be recov ered at Cold Lake is not known at this time, but is expected to be of the order of 30 billion barrels. There are minor reserves of natu ral gas in some of the sands, par ticularly the upper sand in the group. It is probable that major bitumen accumulations underlie the Downloaded from http://onepetro.org/JCPT/article-pdf/6/04/146/2167092/petsoc-67-04-04.pdf by guest on 26 September 2021 military area to the north of the evalUated area. Minor accumula r. '\ tions occur to the south of the out lined area, and unevaluated occur rences to the east in Saskatchewan would further contribute to esti mates of the total bitumen-in-place in the Cold Lake region. Much of the bitumen at Cold L~ke is of 10 to 12" API gravity. The reported viscosities of these bitumens range from 4,000 to 100,- 000 cp at 100"F. Some of the hy drocarbon material is lighter, rang ing up to 14.5" API gravity with viscosities as low as 250 cp at 100"F. A shortage of reliable data prevents further elaboration re garding bitumen density and visco sity. The sulphur content of the bitumen is generally 3 to 4 weight per cent. The mode of occurrence of bitu men in the Cold Lake deposits is FIG_ 2 also shown by Figure 2. The "mas EVALUATED..... " COLD LAKE HEAVY HYD.OCAUON Ai.fA --Maui~ sive" category is arbitrarily ap MASSIVENESS OF PAY ZONE lli!iiS:i-IM••....-:Iialo plied to those wells at which more ~-DII5'11"1.d than two-thirds of the total oil Figun3 fl.-Massiveness of the Pay Zone in the Cold Lake Heavy Hyd1·ocaTbon sand pay occurs in one or more A~·ca. "thick" sands. A "thick" sand is de fined as one that is thicker than 40 feet, and, for the purpose of this definition, a shale break thick this part generalhr contains only but are not considered to be se er than 10 feet is considered to one or two thin sands. riously outdated.) The northwest ',, separate the overlying and under The success with primary pro and south portions of the Athabas lying sands into separate entities. duction in the Cold Lake area has ca deposit are overlain by 1,00() to The 1'intermediate" category em been minimal. At the time of writ 1,900 feet of overburden, and con braces those '\Yells at which one ing, there are seven experimental tain one-third of the bitumen-in third to two-thirds of the total subsurface enhanced-recovery pro place_ A northeast area, holding oil-sand pay exists in "thick'' sands, jects in progress in the general about one-sixth of the bitumen-in and the 1'dispersed" category en area. place, has zero to 200 feet of over compasses the wells at which less burden and contains a number of than one-third or none of the total potential mining areas. The re oil-sand pay occurs within "thick" ATHABASKA AND OTHER AREAS maining half of the bitumen is sands. The areas designated as mas overlain by 200 to 1,000 feet of sive and intermediate appear to OverbU'rden overburden. coincide fairly well with the areas having the greatest bitumen-in The overburden thickness varies Satu?·ation place. Locally. the bitumen-in significantly in the Athabasca de place may exceed 400,000 barrels posit, as illustrated in Figu1·e S. The Board's 1963 evaluation re per acre_ Some 85 per cent of the (Data for Figures 3 and 4 were port (1) indicates that the Atha total deposit area of 2,900 square obtained from the Oil and Gas Con basca oil sands have a high hydro miles is classed as dispersed, and servation Board's study of 1963, carbon saturation. The average bi- . .'· . Technology, October-December, 1967, Montreal 147 tumen saturation is 11.5 weight per cent or 1,700 barrels per acre foot: 70 per cent of the bitumen in-place is contained in sands with a bitumen content greater than 10 weight per cent or 1,500 barrels pet· acre foot. Bitumen Pay Thickness and Dish·ib1dion It should be noted that the pay thicknes~ shown in Table I in the paper br Dr. Phizacl~erley and iVIi.s:.; Scott may be in error due to a misunderstanding of Lhe Board's stud.r of 19G3. Gross oil-sand pay thicknesses were not established by the Board for the Athabasca depo Downloaded from http://onepetro.org/JCPT/article-pdf/6/04/146/2167092/petsoc-67-04-04.pdf by guest on 26 September 2021 sit, but the net pay for sands ric.h et· than 5 weight per cent bitumen wa::: recentb· estimated to average GO feet and to reach .a maximum of 270 feet. The maximum gross pay thicknesses for the Bluesky Gething and Grand Rapids depo sits are about 125 feet ~md 90 feet. t·e::;pecti vel3·. The bitumen di~tribution in the Athabasca deposit is illustrated in Fiyul'e .'1, where average township ( 31i square miles 1 values ha\·e been used. The bitumen-in-place ex ceeds 100,000 barrels pet· acre in an area of 3.1 million acres, or slightly more than half of the de posit area. In ten tcw:nships, or :~GO square miles, the bitumen-in place exceed::; an average of 200.- 000 barrels per acre. There are three central barren area:.; which are not shown on Fig u.re -1, but which are shown as white areas on Figm·e ~ in Town ships 86 to 92. The bitumen-in r>lace indicated for any township which is partially barren relates only to the portion of the township which contain~ oil .sands. FIG.J CONTOURS BITUME'N IN PLACE' ATHABASCA TAR SANDS Ma.~siveness of Pa!f Zmlf! fiiWI cf 0'/ ... burdon Thouurodo cl BBLS/oc,. OVERBURDEN THICKNESS ~0-.SO m.l50-200 .....__soD-- AND DISTRIBUTION OF BITUMEN t:::J50-100 - 200-'240 \Vhen considering possible re 0 6 12 18 2A 30mr,., ~K0-150 JAN.IPV covery processes for oil sands, it is important to kno\\" \"·'hether the Figlll't' .'J_-Q11erb11rdl'Ji Thickness a.11d Disl1·ibution oj Bilu/111'11 in the .flthu bitumen occurs in massive sand basca Oil Sands. unit~ or in separate, thin sand unit:; or some combination of the two. Figure 4 has been prer>ared as an attempt to describe the massive ness of the Athabasca deposit. The category definitions are consistent mining area contains massive been defined along the eastel'n edge with those used for F~guTe 2. sandg. Man}' factors besides mag of the Athabasca deposit. Although In general. the areas designated siveness must be considered, how much of the deposit c\oes not hnve as massive coincide with the areas ever, before any particular area an underlying aquifer, water-su of greatest bitumen-in-place. There may properly be considered suit turated sands are present in de are some relatively rich areas able for mining. pressions in the underlying Pnleo which fall into the dispersed cate zoic surface. gon·. and these may be detected Aquifers and Gas Zones Down-dip or edge aquifers ap by comparing Figu·res 3 and 4. pear to exist in the other major For the most part, the potential A fairly definite aquifer has oil sands deposits. 14B The Journal of Conadion Petroleum ·: l\o!iiwr gas aCcumulations occur ' in the Wabiskaw and Upper Mc j Murray sands in the south and southeastern portions of the Atha ·:. basca deposit, and insignificant r-:: . gas blows have been encountered 0 during drilling in various other '. areas of this deposit. Free gas is not known to occur in the Grand Rapids deposits, but has been locally 1·ecovered from the ~. -· Bluesky-Gething deposits. Formation Pressu.Te amd Te'm. .pe1·at1.U'B Formation pressures and tem peratures in Alberta oil sands, in cluding Cold Lake, are roughly re lated to depth in Table L Downloaded from http://onepetro.org/JCPT/article-pdf/6/04/146/2167092/petsoc-67-04-04.pdf by guest on 26 September 2021 The pressure-depth trend is com patible with heavy-gravity oil _,i fields to the south. It has been .., found to be significantly inaccurate in only a few localitieS in the oil sands areas. Individual field temperature measurements may vary by as much as 5 or even 10 degrees from those shown in the Table. AcKNOWLEDG11:ENTs This discussion was prepared with the cooperation of the Geol ogy Department of the Oil and Gas Conservation Board of Alberta. The assistance of geologists J. R. Pow, G. H. Stafford and R. R. Wil liams is gratefully acknowledged. REFERENCE (1) "A Description and Reserve Es timate of the Oil Sands of Al I'•'" berta," Rcpol·t of the Oil and I Gas Co11senJatim~ Board, Calga ry, Alberta, 1963 . .-,.,. - ...- .. ~ .... )"' FIG.d ATHABASCA TAR SANDS 191!1- Moui¥• MASSIVENESS OF PAY ZONE ~ • lnllrmedu:lll ~----1 ~-Di.ptl.....d . ------.--- 0 6 12 111 2A 30 miln I JAN. 1Pd7 I(...... , I !% . Figure -'--Massiveness of the. Pay Zone in the Athabasca- Oil Sands. !~~'1, 1 - ~ .:r l 1,~... ~--~- Harry J. Webber attended the Uni TABLE I versity of Alberto and .-eceived a B.Sc. in chemical engineering in 1951. He joined the steff of the Oil and Gas Con Depth from surface. feet. .. _...... 50-600 700 1000 1300 1600 1900 servation Boord in 1953, and served in ------9 number of Field ond heod-offfce posi Formation fluid pressure, psig. __ .... <100 100 220 350 470 600 tions prior to his oppointmei-lt as oil ------sands engineer in 1964. His duties in Formation temperature, oF._ .. _..... 35-45 46 57 65 72 clude surveillance of oil sands and heavy 5o I oil recovery projects. : ,, Technology, October-December, 1967, Mont~eal 149 . _,. ;:·.=- ;\:--,.·..