High Bitumen Research Articles

Organic Geochemistry and Petroleum Exploration--Problems?: ABSTRACT

Results of organic-geochemical studies of deep well bores contradict current concepts on the generation, maturation, and thermal destruction of hydrocarbons. Main-phase hydrocarbon generation (high bitumen coefficients) apparently occurs between 190 and 250°C in Lower Cretaceous to Devonian rocks in five separate well bores. In these same rocks, the kerogen still retains high values of pyrolyzable hydrocarbons normalized to organic carbon. All five well bores have had higher than 250°C paleotemperatures. These results indicate that much higher temperatures than those commonly accepted are required for the complete generation and thermal destruction of hydrocarbons. Other results from these studies contradict the following accepted organic-geochemical trends vers s depth: (1) maturation of saturated hydrocarbons; (2) the S1/S1 + S2 ratio (S1 = extractable bitumens and S2 = pyrolyzable hydrocarbons per thermal analysis); (3) the temperature at the maximum of the S2 peak; (4) the thermal phaseout of C15 + hydrocarbons; and (5) correlation of elemental kerogen composition and vitrinite reflectance with extractable and pyrolyzable hydrocarbons. Laboratory duplication of generation-maturation reactions in closed, pressurized, water-wet systems shows that the controlling parameters of these reactions are not as described in the accepted mathematical formulas modeling these reactions. Concepts concerning the generation and thermal destruction of hydrocarbons apparently have bee greatly oversimplified. End_of_Article - Last_Page 1363------------

The Alsands Project--A Challenge in Petroleum and Mining Geology: ABSTRACT

A third mining operation in the Athabasca oil sands area of northern Alberta is planned by the Alsands Project Group, a consortium of nine petroleum companies. The group is considering the use of large draglines to excavate oil sands from an open pit mine. This project contemplates separation of the bitumen and sand by a hot water process, followed by upgrading to synthetic crude oil. Production will begin in 1986; when design capacity of 140,000 b/d (22,250 m3/d) is reached, this project will supply over 10% of Canada's forecast crude producibility. The bitumen occurs in a 300 ft (90 m) sequence of unconsolidated sands and clays of the Lower Cretaceous McMurray Formation, at or near the surface. A thin veneer of Recent and Pleistocene aeolian and glacial deposits overlie the McMurray. Devonian carbonates and evaporites occur below the Cretaceous. McMurray deposition took place in a mesotidal, coastal environment. The lowermost sands are fluvial, upper delta plain, overlain by tidal channel and tidal flat sands and muds of the lower delta plain. Some marine barrier bars and beaches have been identified. The highest bitumen saturations occur in the fluvial and tidal channel sands. However, the lowermost sands are frequently water saturated under artesian conditions. The rugged paleotopography of the Devonian erosional surface has s gnificantly influenced the depositional pattern of the overlying McMurray. This relief is, in part, due to the solution of Middle Devonian salt beds, with subsequent collapse of the overlying units. This complex sequence of depositional patterns, varying lithologies, and fluid contents, combined with salt tectonics, has created the need for detailed geological and geotechnical studies to interface with mining engineering in developing a viable mine plan. End_of_Article - Last_Page 960------------

PERSPECTIVES FOR THE UTILIZATION OF GEOBOTANICAL GUIDES IN THE DETECTION OF SALT-DOME STRUCTURES

In a hot, dry climate the presence of salt-loving vegetation (halophytes) may serve as a supplementary indicator of the presence of a salt-dome structure. Deep-seated oily water apparently forces the highly saline waters to the surface, where vegetation indicators may take two forms: where drainage is poor, the halophytes will be found along the anticline itself, but where drainage is good, the salt-loving plants concentrate along the perimeter of the salt-dome structure, sometimes virtually outlining it. In addition, the presence of gigantic and deformed plants in the area may indicate a high bitumen content. However, the influence of the deep oily water on the salinity of overlying deposits, soil and ground water varies with geologic conditions, depth and chemical composition of the ground water, conditions for its ascendance and conditions determining soil formation. The authors caution against over-simplification, since not every halophytic association indicates a buried salt dome; the specie composition of the association and presence or absence of bitumen-indicating forms must also be considered. --A. Eustus.