Recent laboratory and field testing enabled Total Exploration and Production Norway (TEPN) to optimize the shaped charge design and gun system used for perforating an appraisal well test in the high pressure high temperature (HPHT) Victoria field, offshore Norway.
The laboratory testing consisted of two different phases; penetration tests under downhole conditions into stressed rock, and a temperature test to evaluate any degradation in shaped charge performance.
Test shots into stressed Nugget and Crab Orchard Sandstone rock targets were used to identify which of the four charge designs being proposed would provide the best downhole penetration performance. Charge D, a 28 gram, deep penetrating, high temperature charge designed for 3.50 inch gun systems, provided the deepest penetration into the stressed rock targets.
The temperature test subjected both the charges and gun system to the high end of the reservoir temperature for the worst case expected time required to run both guns and test string into the wellbore. Results indicated that the heated charges provided penetration performance into steel bars substantially matching unheated charge penetration.
This paper discusses a recommended test methodology to qualify perforators for high temperature wells, and the importance of conducting such a test program in close collaboration with field operations.