This paper presents field results and lessons learned from aNorth Sea field where a combined scale and corrosioninhibitor has been applied using a single formulation to controlboth the deposition of scale and associated corrosion. TheGalley field is a subsea development within the UK sector ofthe North Sea. The use of a single product has facilitated areduction in the number of umbilical lines to be used toprovide flow assurance on the subsea flow lines and process ofthis facility.The paper outlines the problems encountered when the initialformulation was deployed in the field and the steps taken todevelop and monitor an improved formulation. Problems thatcan affect product application in a subsea environment,including deposition of suspended solids within the chemical,hydrate formation, incompatibility of the chemicals withumbilical material and produced fluid, will all be addressed.The laboratory methods used to select the product along withmeasurement methods used in the field are also discussed.The validation of the laboratory selection methods in the fieldrequired the development of a monitoring program to establishbase line control and to assess the degree of protection fromscale deposition and corrosion across the process.The changing physical conditions within the flow lines andacross the topside process will be described, as well as thechanges in brine chemistry within the field, as injection waterbreakthrough occurred. The use of novel real timemonitoring, as well as water chemistry tracking and analysisof suspended solids within the produced fluids across theprocess will prove vital to the understanding of the efficiencyof flow assurance within the processes was and how treatmentrates and products could be optimised. This paper will outline in detail the particular issues associatedwith chemical injection to a subsea facility, many of which arecurrently being developed in the Gulf of Mexico and is a goodexample of lessons learned and sharing of best practice fromanother oil basin.
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