As reserves become harder to recover, operators need answers that solve their challenging production demands and help maximize reservoir deliverability. In the past, methods for producing heavy oil were expensive and ineffective at best. With the advent of horizontal wells and later multilateral wells, heavy oil production efficiency increased; however, these recovery methods still left most of the reserves in the ground.
With the introduction of the steam-assisted gravity drainage (SAGD) drilling technique, production efficiencies of 60 percent or better are now possible in heavy oil reserves. Originally developed by the Alberta, Canada Department of Energy (formerly AOSTRA), Sperry Drilling’s SAGD technique utilizes twin horizontal wells, one drilled above the other, and steam injection to enhance the recovery of heavy oil. Steam is injected to the upper well, and the heated heavy oil and condensed steam are produced from the lower well. Reduced oil viscosity, along with improved sweep and displacement efficiency, provides a higher percentage of recovery than other traditional methods.
Instrumental to Halliburton's nearly two decades of SAGD leadership and success is its proprietary magnetic ranging technology used on more than 700 SAGD well pairs and in numerous nonconventional applications. By allowing two or more wellbores to be positioned within extremely tight tolerances, magnetic ranging technology helps eliminate the positional uncertainty of conventional surveys and provides more precise tolerance needed for SAGD wells.