Cold Heavy Oil Production With Sands (CHOPS)

Cold Heavy Oil Production with Sands (CHOPS) is a primary recovery technique for certain types of heavy oil deposits. This heavy oil is able to flow into the well and be pumped to surface without first being heated. This process has been economically successful in several unconsolidated heavy oil formation fields in Alberta and Saskatchewan.

The key factors in this process are: the presence of enough solution gas to move the oil (foamy oil effect); and, allowing formation sand to be produced with the oil (sand production). Allowing sand production has dramatically improved oil recovery compared to the non-sand production process. Most of the sand-oil production involves the use of progressive cavity (screw) pumping systems capable of handling significant quantities of sand with the oil and water.

The advantage of allowing sand production is that the produced sand creates cavities or wormholes (high permeability zones) for the heavy oil to flow through. This method only works well in areas where the bitumen is fluid enough to pump. It is most commonly used in Venezuela, but also in parts of the Athabasca-Wabasca region and the southern part of the Cold Lake region. This is the cheapest method but only recovers about 5-6 per cent of the bitumen.