Evaluation and Modification of the Means San Andres Unit Waterflood

Detailed engineering and geologic studies were conducted in 1968 and 1969 for the Means San Andres Unit by Humble as unit operator. As a result of this work, the unit injection scheme has been expanded to include interior injection as well as the original peripheral injection. The Means field is divided by a dense saddle into 2 producing areas called N. and S. domes. In the N. Dome, pressure correlations dovetailed with the geologic interpretation to identify 3 San Andres intervals: Upper San Andres, Lower San Andres Oil Zone, and Lower San Andres Aquifer. The principal response from previous injection had been caused by aquifer injection which migrated vertically through a semipermeable barrier to the Lower San Andres Oil Zone. Interior injection was started in 1970 to flood the Upper San Andres and provide direct support to the Lower San Andres Oil Zone. In the S. Dome, a pressure survey utilizing short-term buildup testing techniques identified an area which had not been efficiently flooded. The previous peripheral injection has been effective for the rest of the S. Dome. Interior injection started in 1970 to flood the low pressure area.