Abstract
Developing a cost-effective scale management strategy as early as possible during field development planning is imperative to allow informed decision making. In the past, strategy selection was commonly based on static scaling risk assessment. However, the trend over the years has shifted to incorporate dynamic aspects, notably in-situ scale precipitation in a time lapse manner and coupling this with scaling risk assessments. More recently, streamline simulation techniques have been applied to support the prediction of scale precipitation in the reservoir and consequent in-situ stripping of scaling ions. It remains pertinent to extend the use of these dynamic tools to properly assess the impact of reservoir scaling reactions on scale management economics and the subsequent adoption of an optimum strategy.
A robust and systematic approach has been developed to combine the use of dynamic models in scaling risk assessment with envisaged production improvement processes and integration of disciplines in the decision analysis process. Reservoir scaling reactions are modeled using streamline simulation. Examinations have been extended to cover the impact of in-situ scale precipitation, taking into account changes in drainage radius in the presence of hydraulic fractures and different sandface completions. Emphasis is also placed on conducting analyses to address field complexities ranging from a variety of potential field development concepts, injection water alternatives, and drainage and completion options to uncertainties in formation water composition.
Workflows developed on a North Sea green field development are described, including results from analog/synthetic datasets as examples for this paper. Our work indicates that both in-situ ion stripping and drainage patterns significantly influence chemical requirements and treatment frequencies for squeeze treatments following in-situ scale deposition. Based on this information, comparative scale management costs are developed to help select the most appropriate scale management option. Finally, we highlight limitations in current industry tools and workflows and what can be done to reduce uncertainties during the development of a scale management strategy.
