Heavy Oil In Saskatchewan

Abstract

Abstract Although vast resources of heavy crude oil have been known to exist in west-central Saskatchewan for many years, until recently these resources have remained on the sidelines while the better quality crude oils of the southern part of the province were the focus of the oil industry. In recent years, however, the importance of these enormous reserves of low API gravity, high sulphur crude has been recognized, as the remaining reserves of high-quality crudes in Canada decline rapidly. In the next several decades, Saskatchewan's heavy oil will form a very significant part of the energy picture of this country as enhanced oil recovery (EOR) and heavy oil upgrading combine to unlock the potential that currently exists in this area. Although heavy oil was discovered on the Saskatchewan side of the Lloydminster area in 1936 it was not until 1944 that a commercial discovery was made. Production commenced in 1945 and in 1947 Husky Oil Ltd. constructed a refinery at Lloydminster to make asphalt from heavy oil. The early 1950s saw a flurry of activity in the area and heavy oil production reached a level of about 1 600 cubic metres per day (10,000 barrels per day) during 1956. Production continued at levels between 800 and 1 600 cubic metres per day (5,000 and 10,000 barrels per day) until 1966 when renewed interest in heavy oil sparked a mini-boom in the area which has continued to the present day. The province's recognized heavy oil deposits cover a broad area of west-central Saskatchewan known as the Lloydminster-Kindersley heavy oil belt. The present extent of heavy oil development is an area which stretches from Kindersley in the south to S1. Walburg in the north and as far east as North Battleford. The oil occurrences mostly consist of multiple zones of thin unconsolidated sandstones with high oil saturations at an average depth of 600 metres (2,000 feet). Most of the oil is found in the Mannville Formation of the Cretaceous Age. However, near Kindersley there are several Bakken Sand pools of Mississippian origin. The crude oil ranges in density from about 950 to 990 kilograms per cubic metre (11 to 17 degrees API) and is extremely viscous, resulting in very poor primary recovery (averaging less than five per cent of the oil-in-place). In response to the "re-discovery" of Saskatchewan heavy oil in recent years, the number of producing heavy oil wells in the Lloydminster-Kindersley area has risen from 840 in 1968 to a present level in excess of 3,200 wells. In the same l5-year period heavy oil production has increased from an average of 3 300 cubic metres per day to 8 700 cubic metres per day (21,000 to 55,000 barrel per day). The potential of the heavy oil belt is illustrated by Saskatchewan Energy and Mines' estimates of ultimate oil-in-place of four billion cubic metres (25 billion barrels) (nearly four times proven oil-inplace) and ultimate recovery of 600 million cubic metres (3,800 million barrels) with the implementation of EOR techniques in all suitable reservoirs.