Mechanisms of Formation Damage & Permeability Impairment Associated with Drilling, Completion & Production of Low API Gravity Oil Reservoirs

R. David Shaw, Rod Doane, Brant Bennion, Mimi Reichenbach, and Alan Gordon

The economic production of heavy oil reservoirs requires an in-depth understanding of the specific mechanisms of formation damage that are unique to these types of formations. This paper provides a brief description of some of the dominant mechanisms of permeability impairment which can occur in low API gravity oil-producing zones. These include:

1. Drilling induced damage

-- solids entrainment

-- fines migration

-- rock/fluid incompatibilities

-- fluid/fluid incompatibilities

2. Reactive clay-induced damage

3. Formation of emulsions (water-oil, oil-water)

4. Foamy oil phenomena

5. Sand control and consolidation issues

6. Completion induced damage, acidizing, solvent injection, etc.

7. Thermally induced damage

-- mineral transformations

-- mineral dissolution

-- wettability alterations

8. Biologically induced damage

9. Formation damage issues peculiar to the drilling and completion of horizontal wells in heavy oil producing zones

This paper provides a general overview of many types of formation damage which engineers and geologists should be aware of when planning exploitation programs for heavy oil plays.

AAPG Search and Discover Article #91019©1996 AAPG Convention and Exhibition 19-22 May 1996, San Diego, California