Operator's continuing success depends on the ability to manage its reservoirs and to exploit them in the most efficient manner to sustain production targets, while maintaining a high level of safety performance. Ensuring the integrity of wells is essential to achieve these requirements. Some of operated wells are reaching an age where an increasing frequency of integrity issues is becoming a concern. In addition, new wells may face greater threats to their integrity, for example due to the more corrosive reservoir fluids often encountered in existing and new developments. Wells operating under high annulus pressure are at risk of loss of pressure containment either in the form of releasing formation fluids to atmosphere or cross flow and charging up shallow reservoirs or aquifers. When monitoring trends of annulus pressures it should be taken into account that even with relatively low sustainable pressure there is a possibility that cross flow to shallow reservoirs could be taking place. This is especially true for C-C annulus "B" of most oil and water injection wells where shallow water reservoirs are straddled by one casing. Any sustainable annulus pressure on this annulus is undesirable and is to be critically reviewed.

Shallow casing corrosion in onshore wells is a well-known phenomenon throughout the Arabian Peninsula. It happens when the carbon steel is exposed to corrosive environment (including moisture and oxygen) due to insufficient barrier protection and isolation. The issue requires periodical casing excavation and inspection which are time-consuming operations with different teams involved. This document describes successful field validation of the alternative cost-efficient method of casing inspection using corrosion logging technology. The method of individual electromagnetic metal loss logging for 3 barriers became recently available. It is electromagnetic-based technology which was modified to be able to provide multiple barrier evaluation. 3 wells were selected for trial logging and later were excavated to compare the logging results with actual findings (physical check). Results of the trial test confirmed applicability of this costefficient technology for Company Surface Casing Inspection. The new method allows extending casing inspection to unlimited depth with less time required and less risks associated. The opportunity to evaluate conditions of all three barriers without retrieving the tubing gives a lot of benefits for the entire Well Integrity Management process; it may include actual corrosion rate measurements of all effective barriers, SAP (Sustained Annulus Pressure) investigations, and risk assessments. Field validation of this technology had a positive impact on Operator's Well Integrity process, giving more options for proactive Well Integrity Management and resulting in total cost reduction and improved HSE (Health, Safety and Environment) performance. Additionally, it helped to identify a serious gap in the existing conventional process of Surface Casing Inspection. This document presents the results of technology validation performed in the third barrier of a producing well in real field conditions. Additionally, it contains specific recommendations for other areas of application of this technology for maximum benefits, like three-barrier evaluation prior to workover and multiple barrier time lapse corrosion monitoring.

Well integrity is a combination of several disciplines integrated into the different phases of the well lifecycle with ultimate objective to prevent well control incidents. The subject of this paper is about effectiveness of various well integrity monitoring techniques at different stages of the field life. It is based on actual Company lessons learned and recent experience in managing well integrity incidents, when all barriers got lost. Wellhead pressure monitoring is one of the most popular methods of well integrity surveillance. It is based on the double barrier envelope concept: primary barrier envelope is the one exposed to pressure; secondary barrier envelope is the one that will be exposed to pressure if primary barrier fails. Therefore, once the primary barrier fails, it is expected to observe pressure at surface as an indication of the failure. Therefore each well operator has internal fit for purpose wellhead pressure monitoring system. Some specific well categories might be monitored more frequently than another due to higher risks associated with these wells. Double barrier policy is a well integrity requirement well-known world-wide. This policy applies to wells with positive pressure at surface capable to flow naturally. This policy is the basement for wellhead pressure monitoring system. However, based on the latest Company’s well integrity experience, this system is applicable for green fields only, with brand new barriers installed and tested. In case of mature brown fields after several decades of production this system may not always work perfectly. It may happen that failure of the primary barrier envelope occurs in the wells with already failed secondary barrier envelope. In this case there is no any "grace" period to respond to the failure and we immediately get a well control incident reflecting in uncontrolled release of well media through failed barriers. Therefore at some point of field development the time comes when secondary barrier envelope is not reliable anymore and additional surveillance activity has to be implemented to ensure safe operating conditions in the fields. This paper warns well operators on the potential gaps in the well integrity monitoring that may lead to the severe incidents. Those gaps may not exist at the early stages of development but appears during the "transition from green to brown" field. The paper helps to recognize the period for activating additional surveillance techniques avoiding unnecessary OPEX impact. It also describes various surveillance techniques for secondary barrier envelope including leak detection, corrosion logging and pressure testing.

The company introduced a new era of Well Integrity Management system as a continuous assessment and verification process to ensure the integrity of the wells is designed, monitored and maintained throughout the well life cycle.Failure of any well barriers is not allowed. If a barrier fail , an immediate action should be taken to restore the well integrity, which is one of the important business elements in oil and gas fields; and hence according to well integrity standards utilizing well control devices are mandatory to protect human life, and reduce the potential for environmental pollution in addition to minimize the loss of production.The surface control subsurface safety valve (SC-SSSV) is an integral part of the overall safety system of any well and it is the only method that provides sub-surface isolation in case of emergency due to uncontrolled surface or sub-surface event. Therefore it is mandatory to have functional SC-SSSV installed in the production tubing in all gas and oil wells, irrespective of their location, to stop the flow in case of a catastrophic failure.The SC-SSSV is adjusted to be held in the open position by hydraulic positive pressure from surface. This pressure is applied through a control line in the tubing-casing annulus running from the valve to the surface. In case of an emergency shutdown the hydraulic pressure will be released forcing the safety valve to close. However the control lines could leak, plug or break leading to losing the functionality of the safety valves. The only way to rectify SC-SSSV C/L problems is by a rig work-over to replace with new C/L. This paper describes the innovative methodology, which is the first application in the UAE & Middle East, to install Baker Hughes system "Inject-safe" controlled sub-surface safety valve which has a similar operating philosophy to the conventional SC-SSSV. The "Inject-safe" C/L deployment is on the inside of the tubing which drastically reduces the cost. This unique approach has been successfully executed in one of the super giant onshore fields in Abu Dhabi through an extensive techno-economical study.The paper goes through the methodology of candidates' selection, the system requirements and modification in wellhead and the trial results through specific testing criteria in one of the wells as part of a field pilot. The risk assessment is also discussed along with the execution process.The cost impact of installing the new system as proved in the pilot through a techno-economical evaluation well will be highlighted, in addition to well performance pre/post installation combined with the project conclusion and recommendation for future implementation.

Well Integrity issues associated with barrier degradation due to corrosion could significantly impact on production results in mature fields. Sometimes those issues may lead to the severe well control incidents during production phase affecting on the performance of the facilities nearby. This paper describes the negative trend of well control incidents, which was changed, by using innovative approach of secondary barrier evaluation for wells with compromised primary barrier envelope. The objective is to share with the audience special practice of well integrity management using multiple barrier evaluation technology to prevent loss of pressure containment (LOPC) incidents. In addition, the method allows to extend the production life of wells with sustained annulus pressure (SAP) and continue operating those wells under specific conditions and periodic monitoring instead of immediate killing and securing. This "grace period" could be granted based on the known conditions of the secondary barrier envelope until the rig become available to fix the integrity issue and restore the well barriers. Company started drilling activity in 1960's and since that time more than 4,000 wells have been drilled. All wells have carbon steel casings which serves as secondary barrier envelope in case primary barrier fail. Carbon steel easily gets corroded with time in case of insufficient protection and isolation from corrosive environment. Failure of both well barrier envelopes results in well control incidents. Uncontrolled release of hydrocarbons and other reservoir media to surface or aquifers has a strong negative HSE impact: it could be a reason for human injuries and deaths due to pressure, fire and H2S release, environment pollution, deferred production. Additionally, it is associated with unplanned increase in CAPEX and OPEX, reduction of business targets and KPI's, may cause negative impact on Company image and reputation. Innovative proactive method of secondary well barrier evaluation, successfully used to prevent well control incidents, allows Operators to find the right balance between safety and operation, and extend the production life of the wells with integrity issues without jeopardizing safety and integrity conditions in the fields. Paper illustrates how 9 well control incidents have been prevented and 14 wells with compromised primary barrier envelope were allowed to operate for a limited period of time, until the integrity issues have been fixed.