Introduction There are three major tar-sand areas in Alberta: the Alberta Tar Sands, the Cold Lake Tar Sands, and the Peace River Tar Sands. The total reserves in place are estimated at 1,000 billion barrels, and recoverable reserves are estimated at 400 billion barrels. The Alberta Tar Sand area is the largest of the three. It covers 5.75 million acres. As shown in Fig. 1, it is located in the northeast part of Alberta, between Township lines 77 and 103 and between Range lines 6 and 20, west of the Fourth Meridian. The estimated reserves in place, in terms of the depths from which they have to be recovered, are tabulated below: Reserves Depth (billions of barrels) 0 to 100 ft 45.1100 to 1,000 ft 373.9Deeper than 1,000 ft 207.0 Total Resreves in Place 626.0 The Tar Sands belong to the early Cretaceous. Fig. 2 shows the simplified geological cross section' along the dashed line in Fig. 1 from A to B. As the Elk Point salt (fine cross-hatch on Fig. 2) collapsed, the overlying Beaverhill Lake limestone formed a basin for Cretaceous sediments. The overlying tar sands (in black) are unconformable to the limestone. The tar-sand sediments are deposited in predeltaic, deltaic, and post-deltaic environments, Pre-deltaic and deltaic sediments are rich in tar, and their matrix materials contain 90 to 95 percent by weight of quartz. The post-deltaic deposits are poor in tar and their matrix materials contain only 50-percent quartz by weight. The tar differs from conventional oils. It has low gravity (6 degrees API at 60 degrees F), high viscosity (3,000 to 300,000 poise at 60 degrees F), and is undersaturated in hydrogen. The bituminous tar sand will be mined and physically removed to an extraction plant. There, it will be processed and upgraded to produce "synthetic" crude. This mining and processing operation involves a large capital investment in the plant and equipment. Also considerable are the daily costs of mining and transporting large quantities of tar-sand ore. It is important, therefore, to have an accurate evaluation of the tar-sand deposit before so great an investment is committed. This requires a large number of test holes from which the needed information can be derived. An evaluation system involving the analysis of a suite of well logs from each test hole can be used to appraise these ore bodies. Such analyses of the large volumes of data available from logging programs in many test holes are best handled by computer. Also, use of the computer makes possible an evaluation system which has a high capability possible an evaluation system which has a high capability for producing all of the desired answers. Furthermore, machine computation of well logs is fast and minimizes the problems associated with laborious intensive-evaluation problems associated with laborious intensive-evaluation systems done manually.