Assessment of Barite Scaling Potentials, Sulfate Removal Options, and Chemical Treating Strategies for the Tombua-Landana Development

Abstract

fax 01-972-952-9435. AbstractThis paper discusses the development of a holistic water and scale management plan for a green-field development, which faces a new order of scale management challenges. Specifically, this paper documents a scale risk assessment and the development of a scale management plan during the frontend engineering design of the Tombua-Landana development in West Africa. The complexity of scale management is compounded by the presence of multiple reservoirs with very different scaling potentials and by the plans for produced water reinjection. The objective of the study was to define a complete scale management plan, which incorporates flexibility for future unknowns and minimizes the total cost of scale management, without over-capitalization.The Tombua-Landana field will produce from multiple reservoirs that incorporate several distinct formation waters with barium content as high as 800 mg/l and will require seawater injection for reservoir pressure maintenance from day one. Scaling tendency predictions were made for the major groups of formation water, both with and without seawater injection. In addition, a variety of produced water reinjection scenarios were investigated. This field study typifies several industry trends in inorganic scale management: (i) Deepwater West Africa is emerging as a new focus area for sulfate scaling; (ii) Deepwater economics require co-production of multiple reservoirs in order to reach threshold reserves and will necessitate the installation of major infrastructures; (iii) Economic and environmental drivers support the use of produced water reinjection, even though this exacerbates water compatibility problems and creates new challenges for reservoir monitoring.