Deep Downhole Chemical Injection on BP-Operated Miller: Experience and Learning

摘要

The BP-operated Miller field poses a unique chemical challenge because it has arguably the harshest oilfield scaling regime in the North Sea, if not the world. An average of three to four squeeze treatments per week are performed across the online wells, creating tremendous operational, chemical, and logistical challenges. This produces the ideal environment in which to evaluate new technologies and engineering solutions in an attempt to increase the wells' overall efficiency. Deep downhole chemical injection (DDHCI) was installed on Well A26/08 and brought on line in July 2003. The Miller DDHCI is unique to the industry because it allows the injection of a scale inhibitor at the perforations by means of a tail pipe, essentially protecting the whole of the tubing from scale deposition. This approach has the potential to reduce the need for additional scale control through squeeze treatments. Much emphasis has been placed on the efficiency of scale protection that DDHCI offers. A year of flowing the well under the protection of the continuous-injection chemical has yielded much information about the nature of the chemical delivery and inhibitor efficiency. Much also has been learned about the pumping hardware required to ensure continued performance. Further information has been provided by two intensive sampling exercises that have allowed independent analysis of the squeeze chemicals and the injected chemical. This paper details the design criteria of the DDHCI completion as well as the philosophy of installing such a device. It then gives details on the management strategy of using DDHCI in a proactive manner to maximize the time between squeeze treatments.