Evaluation of Completion Damage to High Permeability Non-Consolidated Formations
Authors: Prachner William 
Published: December 2007

American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc.
This paper was prepared for the Society of Petroleum Engineers of AIME Symposium on Formation Damage Control, to be held in Houston, Tx., Jan 29–30, 1976. Permission to copy is restricted to an abstract of not more than 300 words. Illustrations may not be copied. The abstract should contain conspicuous acknowledgment of where and by whom the paper is presented. Publication elsewhere after publication in the JOURNAL paper is presented. Publication elsewhere after publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF PETROLEUM ENGINEERS JOURNAL is usually granted upon request to the Editor of the appropriate journal, provided agreement to give proper credit is made. provided agreement to give proper credit is made. Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers office. Such discussion may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines.

Abstract
An endeavor is made to identify the major causes of completion damage experienced in high capacity producers with sand control installations, and to quantify their impact on well performance.
The Total Skin reflecting the combined effect of all parameters influencing the initial inflow potential was determined parameters influencing the initial inflow potential was determined from flowing build-up surveys and segregated mathematically into the components due to partial penetration and completion damage, respectively. Taking into account the pressure losses in the flow string and assuming damage free completions, the wellhead flowing capacities were then determined theoretically for all nonrestricted producers and compared with the actual wellhead potentials observed producers and compared with the actual wellhead potentials observed in the field.
Additionally, the completion efficiencies of all wells investigated were calculated.
Of the 28 underream gravel pack completions investigated, only 11 were free from rate restrictions due to the risks of coning and erosive velocities and, therefore, could be allowed to produce at the full flowing potential.
These included 7 wells with a combined actual maximum rate of 17800 b/d (i.e., 2.543 b/d/well) lower than the theoretical damage free capacity. Additionally, there was a combined capacity reduction of 9493 b/d (i.e., 1356 b/d/well) ascribable to partial penetration. penetration. The review includes one plastic consolidation with a relatively satisfactory completion efficiency of 32% as compared with an average of 27% for the 28 gravel packed wells.
Regarding the effect on productivity of the main causes of completion damage it was found that:A comparatively moderate degree of permeability impairment has a severe effect on inflow performance if it occurs in a partially penetrating completion. penetrating completion.Cement squeezing may result in a serious reduction in productivity. productivity.Skin damage can be eliminated if an invert emulsion free from plugging material is used as a completion fluid.