Gas Lift Valves Replacement in Norway Field Using Riserless Light Well Intervention Vessel

Abstract

Abstract Scope of this paper is to describe the Riserless Well Intervention campaign carried out on Norwegian Barents Sea field in 2019. The intervention campaign was carried out with a Light Well Intervention (LWI) vessel and consisted in the replacement of failed Down Hole Gas Lift Valve (DH-GLV) on six oil producer wells. Three oil producer wells experienced a DH-GLV failure between 2018-2019 and were consequently shut in due to the loss of the first well barrier envelope. The Riserless well intervention campaign was carried out in October 2019. The subsea equipment supplied for the campaign was deployed on the X-Tree, acting as well control device and thus allowing the re-entry of the well granting well access from the LWI vessel. The DH-GLV replacement was successfully achieved by wireline operations. The first DH-GLV replacement confirmed a constructive failure of the valves, therefore the campaign scope of work was extended to all the oil producers of the field where the same type of valve was installed (six wells). The campaign successfully replaced all the DH-GLV of the field with an average time of six days/well. The first well barrier envelope was re-established, and production restored. The engineered solution that was adopted allowed to carry out the intervention campaign with a LWI vessel, avoiding the mobilization of a winterized rig and consequent IWOCS commissioning, resulting in a sensible OPEX reduction.