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Abstract
A novel timer activated sandface valve was developed that has significant impact on wellbore productivity by enabling improved wellbore clean up, particularly in high angle and open hole completions. This technology has been field trialled and proven in three wells in a North Sea field. The tool was developed from concept to installation in less than nine months including detailed engineering review and assurance.

Negative impact to productivity due to inefficient wellbore clean up of high angle completions is a common situation for production wells. The current solution can be complex completion architecture or extensive clean up procedures that are both expensive and difficult to implement. The consequence of a poor clean up can be loss in well productivity, access to reserves or a requirement to sidetrack the well.

Poor clean up was observed in several wells in a North Sea field. The wells exhibited high skin and no flow from the toe sections of the well due to the dominance of high productive intervals subject to high drawdown at the heel of the well. The timer activated sand face valve was developed with the key objective to deliver sequential clean up from the toe of the reservoir section without intervention or incremental rig time. The valves also deliver the functionality of a sliding side door for future water shut-off capability along the well bore.

The paper will present an overview of the technical challenge, detail development of the tool and processes used for assurance and include results of the field trial. The valve development combines a field proven timer activation mechanism with conventional sliding sleeve technology. The tool was developed without incremental resource and cost often required for product development utilising specifically designed lean technical assurance tools and failure mode and effects analysis processes. The result is a successfully field proven completion tool that is the basis for a new completion technique that has application in high angle wells in all oilfield applications.

Introduction
The project to design, develop, manufacture and install a novel timer activated valve was initiated in response to poor clean up observed in wells drilled in a North Sea development. Flow contribution from wells drilled in the field had been restricted to small sections of the wellbore. This was determined by pressure transient analysis and confirmed by results of production logging. The flow was shown to be coming predominantly from the heel of the well and in some cases the flowing length was less than 20% of the overall reservoir section drilled. Log data acquired during drilling, and data gathered from offset appraisal wells showed that the wells were capable of producing from the entire section. Considerable value in terms of increased production and reservoir access could be gained if the wells could be designed or modified to increase the flowing interval.

Analysis of conventional and established techniques for improving clean up in open hole wells was undertaken. Poor clean up of high angle wells, particularly with open hole completions is common. Despite poor clean up, the wells drilled in the field were high rate producers. The aim was to establish the most cost effective method of increasing the flowing interval without risking base production. Remedial techniques were also investigated and a trial was conducted of most appropriate selected intervention. This was not successful in improving production and resulted in a collapsed wellbore.