Study of Inflow Control Device Completion in Gullfaks field

Abstract

This report is written with focus on advanced completion with Inflow Control Valves in Gullfaksfield. ICD is meant to have two effects; first is to even out the pressure difference between heel and toe of the well, which is caused by pressure drop in tubing, second is to choke back zones with dominating production. Both effects are meant to yield a more balanced inflow-profile in a well. Forstudy of these tools Gullfaks South model which has been received from Statoil has been used.

The first chapter provides a brief introduction to the Gullfaks field and production aspects regarding its thin oil column. This represents the first part of this thesis.

In later chapter the annulus flow potential in Gullfaks wells have been analyzed and evaluated based upon results from the Eclipse simulation tool. The main purpose has been to evaluate the effect of annulus flow with implemented annulus packers. In other words, evaluation of the effect of ICV with a consideration of pressure drop in a well due to friction, acceleration and phase slip which is important factor in horizontal wells has been done.

The effect of advanced completion has been studied with a use of software Petrel. Well representing Multi-lateral G-2T3H has been drilled and advanced completion was done with a use of software.

Also the effect of aquifer has been studied. The presence of active aquifer in a model with advanced completed well did not affect the cumulative oil production.

Also, attempts have been made on decreasing the number of packers in a well. However it turned outto be unsuccessful due to simulation problems. Consequently packers have been placed between each Inflow Control Valve.

Also it has been observed that, gas and water break through is found to often take place near the heel of the well. Therefore keeping the valves near the heel half or less open during the production provided relatively better drainage of oil from the toe and the branches of the well.

In final chapter for finding optimized ICV completion for a given well, various scenarios has been studied. ICV implementation showed better results with higher recovery factor. The flow of water and gas has been delayed which allowed to produce oil from toe of the well. Also, it provided better production from the branch of the well.