Longer Tiebacks by Electrification and Remote Power

Abstract

Standard field architecture is generally based on topsides production and distribution of power and chemicals necessary to operate equipment in drill centers. The paper will present efficient field architectures adapted to operate remote tie-backs with different combinations of subsea electrical power distribution, remote power generation and storage, and improved ways to mitigate corrosion, hydrates and wax issues for long tie-backs. Developing remote resources requires several technology bricks that enable a cost effective and reliable technical solution. To reduce the CAPEX, the main objective is to reduce the number of tubes typically with one single heated flowline to avoid a long and costly service line or with one small power cable and local distribution of power to avoid a heavy and expensive large umbilical. Alternatively, power can be generated and stored at drill center location and chemicals can also be managed locally with limited OPEX. A significant focus was done recently on technology developments enabling long distance tie-back developments. Domain of application and interest of each technology is generally well known and the delivered value is well presented. Looking for the most appropriate combination of technologies on a new field development is now the new challenge to figure out new opportunities. This paper proposes to group the long distance tie-backs fields in three main categories based on extensive studies done for several operators and to present the best architecture for each category. The first category groups very long distance single end tie-backs for which a cold flow system combined with full electrical equipment at drill center location is adapted. The second one is applicable for more consequent development where several drill centers are combined to one long and heated export line; with subsea electrical distribution to power each branch of the remote field and local management of chemicals at each drill center. The third category groups all daisy chain developments for which a heated line gathers the production coming from each fully electrical drill center. Each field development can generally be categorized in one out of the three categories presented in this paper. Based on this categorization, the right combination of low carbon and reliable new technologies enables valuable development of long tie-backs and then increases utilization area of each existing asset.