The Mittelplate oil field is located in the Tidelands National Park in the German North Sea. Its location in an ecologically sensitive area was a challenge during well completion planning. The horizontal well A 7a penetrates the Dogger-delta sandstone in the Jurassic trough on the flank of a salt dome. The well's productivity is a very important factor in the economics of field development. The specific reservoir conditions were decisive for well design and completion fluid selection. To retain all options for future production phases, a concept using a cemented liner and subsequent perforation was selected. Formation damage control was supported by short workover time due to new completion techniques. To avoid formation damage during the initial stages of perforation and completion, a non-damaging completion fluid was evaluated in laboratory investigations. The objective was to verify the rheological properties, carrying capacity, and time stability. Minimizing fluid loss during completion guarantees optimum well productivity. A xanthan-based carrier fluid with oil-soluble resins serving as bridging agents was selected. Intensive quality control of the chemicals ensured the use of correct batches in the field, contributing to the positive results of the project.

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