Deployment of Emulsified Scale – Inhibitor Squeeze to control Sulphate/Carbonate Scales within Subsea Facilities in the North Sea Basin

Abstract

Abstract This paper presents laboratory/field results and lessons learned from a North Sea field where a novel emulsified scale inhibitor was deployed via bullhead squeeze treatments in four low water cut, sand screened wells. The field is a subsea development within the UK sector of the North Sea. These were the first squeeze treatments to be performed on the field. The remote location of the production wells relative to the production vessel and their high production levels meant that scale management was critical to the effective recovery of hydrocarbon from the field. The risk of scale formation even at low water cut was deemed sufficiency high for a scale inhibitor squeeze application to be applied. The decision to use emulsified scale inhibitor for treating such low water cut wells was arrived at after an extensive series of laboratory tests including formation damage coreflood studies and assessment of chemical retention. The risk of fines mobilisation when deploying water based chemicals in low water cut, poorly consolidated reservoir will be outlined. The challenges with the deployment of the chemical package via a diving support vessel (DSV) and gas lift line will also be outlined along with the performance of the wells following the treatment and the effectiveness of this scale control method. This paper will outline in detail the particular issues associated with chemical injection to a subsea facility, many of which are currently being developed in the Gulf of Mexico and is a good example of lessons learned and sharing best practice from another oil basin.