Conventional Versus Unconventional Scale Management, a Sustainable Approach to Assure Well Integrity and Productivity in Giant Offshore Field in Abu Dhabi

Abstract

Abstract An effective Scale Management is applied in a giant offshore field in Abu Dhabi for monitoring and mitigating the formation/deposition of inorganic scale on the tubing, to eliminate potential impacts to well integrity and production. With the increasing demand of maximizing well productivity as part of future field development plans and the drilling of unconventional Extended Reach Wells emerges challenges in scale management strategies. In the conventional vertical wells, scale monitoring and mitigation has been applied successfully through the application of scale inhibitor squeeze chemical treatments into the reservoir to prevent scale formation. In addition, scale monitoring techniques to confirm well accessibility aided in controlling scale and applying proper treatment of scale dissolver and scale inhibition. However, in comparison to what is typically applied in conventional vertical wells, the scale management strategies applied in unconventional Extended Reach Wells will be much more challenging. In Abu Dhabi Extended Reach Wells range with an averaging total depth 20,000-30,000 feet. Several factors encountered effects in the implementation of scale chemical treatment due to the well design and water injection strategies. Such factors include chemical placement for targeting zones in long horizontal wells, limited inhibitor lifetime where scale inhibitor residual analysis return profile demonstrate an average of 3-5 months minimum inhibition concentration (MIC). Also, enormous chemical consumption around 6-12 times greater than volumes required for conventional wells is needed. By implementing scale management, a strategy has been developed to thoroughly monitor and manage scale issues in such wells. Moreover, studies and revalidation are conducted as part of scale management which are mainly covering chemical selection for successful chemicals in terms of performance. Furthermore, exploring the market for suitable technologies that can help in minimizing scale risks such as chemical diverter and enhancer while looking into the application of nonmetallic (GRE). This paper will present a technical overview of scale management applied in conventional and unconventional wells and focus on the scale management strategy to monitor and mitigate scale risks over the lifetime of producer wells. Filed case treatment application provided will demonstrate the effectiveness of the implementation of scale management and the added value of different strategies.