Horizontal well strategies for steamflooding oil formations with a communicating water zone.

摘要

In view of the remarkable success of steam injection for heavy oil recovery, it is important to seek techniques for using steam in marginal reservoirs. This was the underlying objective of the research reported here.;A heavy oil reservoir in Saskatchewan, the Aberfeldy reservoir in Lloydminster, was selected as the prototype for the scaled model steamflooding experiments.;Base case waterfloods and steamfloods were established for reference. Gas and solvent additives were investigated for homogeneous and bottom water formations. The effect of solvent slug size on recovery was also investigated for a thin bottom water case.;Steam injection experiments were conducted in four combinations of vertical and horizontal wells (injectors and producers) using two bottom water thicknesses. The use of a small volume of solvent with steam was also examined.;Temperature measurements and theoretical analyses were used to interpret the results obtained. There is an optimal bottom water thickness, below which formation heating by conduction is far more useful than use of gas or solvent additives. An optimal bottom water thickness value was determined to be between 7-10% of gross formation thickness. The application of horizontal injectors and producers in marginal reservoirs subjected to steamfloods seems to be the best strategy. (Abstract shortened by UMI.)