SPE 30123

Utilization of Biologically Generated Acid for Drilling Fluid Damage Removal and Uniform Acid Placement Across Long Formation Intervals.

Almond, Stephen W., Stim-Lab UK Ltd.; Harris, Ralph E., Cleansorb Ltd.; Penny, Glenn S., Stim-Lab, Inc.

Paper presented at the SPE European Formation Damage Conference held in The Hague, The Netherlands, 15-16 May 1995. Copyright 1995, Society of Petroleum Engineers, Inc. (reproduction of abstract is permissible).

ABSTRACT

A method of drilling damage removal is presented which uses biologically generated acid (BGA) as the stimulation fluid.  The BGA solution is not reactive during the actual pumping stage which allows its displacement into the reservoir to be controlled by the relatively low permeability of the near well-bore damage.  Catalytic generation of acid occurs at a controlled rate once the BGA has been injected into the formation and results in uniform damage removal around the near well-bore region.

The ability of BGA to be generated under a variety of temperature and pressure conditions and the compatibility evaluation of BGA with a variety of commonly used oil and water based drilling muds is first presented to establish some of the operational guidelines for BGA use. Drilling damage removal studies utilizing the modified API linear conductivity flow cell and carbonate material with BGA is presented to demonstrate the effectiveness of this stimulation fluid.  Dual core flow test data is then presented which shows BGA's ability and HCl's inability to remove drilling damage over long horizontal intervals in carbonate formations.

To order a copy of the above SPE paper visit: The Society of Petroleum Engineers web site