Conoco has completed and tested a series of high rate, gravel-packed oil wells. Analysis of the well test data for the first completion indicated significant formation/completion damage had been caused during the gravel-packing process. Extensive laboratory testing designed to closely simulate the completion procedure was performed in conjunction with detailed completion pressure loss evaluation. The studies identified the LCM pill used during completion operations as the primary source of damage. A new. self-breaking, LCM composition was designed that provided fluid-loss control with minimum formation/completion damage. This LCM system and a number of other design improvements were then used in the field's remaining gravel-packed completions.
This paper describes the analysis of well test data and the application of this information to evaluate completion procedures for these high rate, cased-hole, gravel-packed completions. The analysis technique used is unique in that it uses a combination of laboratory, analytical, and operational data to quantify individual components of the total measured pressure drop across the completion. This approach provides a significantly better insight into completion performance than merely stating an overall completion pressure drop, skin value, or well flow efficiency.
This systematic analysis of pressure losses resulted in a better understanding of "formation damage" effects and the factors that influenced them during the completion process. This in turn allowed completion procedures to be modified to target specific areas for improvement.