The paper will present lessons learnt to mitigate the stabilization of the air/gas entering into lubricious biopolymer water-based system which decreased density of mud while drilling. The system selected for its highly lubricious properties and formation damage free properties to accommodate the usage of resistivity equipment provided excellent results in the field. Performance was almost equivalent to non-aqueous drilling fluid. However, the stabilization of gas/air entering the mud was encountered generating drilling troubles and risk of well control problems. An extensive study performed, consisted of assessing interactions between components and containments of the mud system with gas/air, crude-oil and drill solids introduced from the reservoir. The testing involved the adding of air from air-compressor for 60-second while mud sample is sheared at 6000 rpm. The mud weights of samples were measured before addition of air, right after and 60-second after the aeration. The percentage of density drop was calculated. Target value was maximum drop of 5% within 60 second after stopping the addition of air. Several combinations of polymers, lubricants, contaminants and other additives were evaluated. The study demonstrated that the interactions between crude-oil, polymers and lubricants can highly stabilize air/gas entrapment in the biopolymer water base mud system. The phenomena led to significant density decrease, drilling troubles, well control and safety issue in the field. They can also increase the viscosity of the biopolymer mud system. However, highly stabilized air/gas entrapment can be removed by the addition of emulsion breaker at concentration less than 1.5%vol of mud. In addition, the type and nature of the lubricant plays a major role in the stabilization of air/gas entrapment. The selection of the polymers should be combined with the choice of lubricant during the design phase to minimize the gas entrapment. Knowledge gained from the study establish a new testing protocol to assess in the laboratory the air/gas entrapment close to field shear conditions. The testing protocol showed good correlation with the field. The testing protocol can be used during the design phase or for investigations. It will improve the overall design of mud system where highly lubricious fluid is needed. Combination of polymers and lubricants did also provide low air/gas entrapment tendency.

ADMA-OPCO has undertaken a prestigious campaign to drill a large number of wells from artificial island in ABC field, most of these wells are extended reach drilling (ERD) wells with step-out up to around 18,000 ft. Operational efficiency/costs for drilling ERD wells is highly dependent on the wellbore stability, especially while drilling through the problematic Nahr Umr shale at different deviations and azimuths. Nahr Umr shale has a known history of causing wellbore instability in UAE and the surrounding countries and therefore a geomechanical study was initiated to understand the geomechanical setting in ABC field as well as fluid-rock interaction between drilling fluid and Nahr Umr shale formation. The main objectives of this geomechanical study were to optimize well design and drilling fluids in order to drill through Nahr Umr shale interval efficiently, additionally estimation of sustainable pressure variation that major faults can take without being reactivated was also performed. An integrated geomechanical study including a 3D geomechanical modeling was carried out, in order to ensure drilling through Nahr Umr shale formation efficiently. This study covered formation petrophysical characterization, chemical tests on cuttings from Nahr Umr shale, chemo-poroelastic modeling, weak bedding analysis and also faults reactivation analysis. Based on the study mentioned above, both customized drilling fluids program and suitable mud weights were optimized to stabilize Nahr Umr shale, and mitigate different types of wellbore instability issues. In addition to mud fluid optimization, the sustainable pore pressure variation was also estimated for several major faults. A successful drilling campaign is in progress; so far many deviated wells have been completed without any noticeable troubles while drilling through Nahr Umr shale. This geomechanical model is helping to implement an effective drilling program for a smooth well placement. A learning curve has been building up continuously for handling more complex well trajectories successfully in the future. From this study, it was realized that, not only fluid-rock interaction and geomechanics related factors need to be taken into consideration for stabilizing a wellbore, but also special attention is needed for the existing micro-fractures within the formation, where increase in mud weight may make hole condition worse. A balanced approach has been adopted including drilling fluid optimization in order to avoid possible multiple failure mechanisms.

Since the drilling started on the remote artificial islands located in UAE the operator used multiple initiatives to enhance the performance. One of them was the development of Operational Performance Improvement Plan(OPIP) targeting key aspects of the well planning and construction with an aim to improve the performance and reduce cost. The paper describes the thought process and steps taken to implement the OPIP and bring the performance to the new level for the operator. The main objective in harsh economic conditions was to construct the wells safer, with less cost and more efficiently. To achieve the goal, several well construction optimization workshops were organized aiming to change the drilling processes, operations procedures, tools, equipment and well design, as well as to have a clear plan on smooth expanding the extended reach drilling envelop. As a result, the operational performance improvement planwas developed and joint well engineering, subsurface and operations team was set to ensure the implementation. The main purpose of the plan was the standardization of all processes between few rigs, elimination of non-necessary activities and utilization of fit-for-purpose tools during execution phase. The OPIP had over80 items, and everyone of them was targeting specific drilling / completion activities. As part of the implementation, the process required a multi-discipline approach including but not limited to drilling, completions, equipment, subsurface, production, rig and service contractors with subsequent small task forces and focal point assigned to each individual action for time delivery, follow up and closure. At the same time not all the initiatives were implemented – some were rejected due to significant increase of operational risks and / or due to HSE associated risks. The process uses a live tracker and it resulted in significant performance improvements, when time for some operations decreased by 25%(i.e. blow out preventer test time), some activities were eliminated (i.e. wiper trips), drilling practices were completely changed (i.e. use of integral packer) and as a result, the project duration was reduced by one year as of to date. The manuscript describes a structural approach to the optimization of the well construction process with an objective to improve time and cost associated. The proposed ideas can be used at any project worldwide, especially on high cost, extended reach wells drilling projects.

From the start of the drilling campaign on the remote Satah Al Razboot (SARB) artificial islands located in United Arab Emirated (UAE) the operator used multiple optimization initiatives to enhance drilling performance and well delivery. Even though the complexity of the wells increased over time, when extended reach drilling (ERD) envelop started to expand, with the implementation of optimization initiatives the well construction time significantly decreased. This paper describes the way of thinking and steps taken to boost the performance to the absolutely new level for the operator. The main objective in actual harsh economic conditions was to drill the wells under the budget without jeopardizing well integrity, service quality and HSE. The ultimate goal was to decrease well construction time by 25%. To achieve this goal, several well construction optimization workshops were organized aiming to challenge and find improved drilling processes, operations procedures, tools, equipment and well design, as well as to have a clear plan on smooth expanding ERD envelop. In addition with the workshop initiatives, an Operational Performance Improvement Plan was developed aiming to analyzed all operational opportunities to reduce time; a dedicated well engineering, subsurface and operations team was set up to lead the feasibility studies and ensure the implementation of the approved initiatives. Implementation of all performance improvement initiatives required a balance between all involved parties. Every decision should be verified by multiple teams, included but not limited by drilling, equipment, completion, subsurface, production and intervention. Once the approval is obtained then the initiative is implemented and analyzed, taking into account increasing complexity of the wells and lesson learnt captured. At the same time not all the initiatives were implemented – some were rejected due to significant increase of service quality risk; some due to HSE associated risks. The implementation of the initiates and ideas contributed to the reduction of flat time, elimination of online operations, etc. The manuscript describes the steps taken to drill extended wells within shorter time compare to standard deviate and horizontal wells. It highlights main challenges faced during implementation of the performance improvement plan and describes techniques and technologies used to overcome them.

The paper describes deployment phase of a smart circulating sub in offshore Abu Dhabi field as an effort to improve efficiency and flexibility in tackling operational drilling risk and minimize associated NPT. It will describe the pre-campaign technical assessment and preparation, the field operation summary, the detail activation record, and the trial statistics including the activation success ratio including also some reliability milestones that will beneficial to be reference in term of tool functionality and reliability. The smart sub offers practicality to select three different flow path mode on top of the isolation mode without any necessity to pull out of hole nor to disconnect the pipe at surface. Different from any other conventional tool, the command to change the flow path mode is fully achieved only by manipulating absolute pressure or pipe rotation speed. Thus, it will save time, lower the operational risk as well as increase flexibility. As part of new technology implementation, a set of factory test and field trial run were conducted to evaluate its operability, reliability, and also to define its technical limit. A total of 8 field trial runs with 38 activation in more than 800 running hours has proved the system's the reliability through the field trial. And through the paper, some feedback from the field trial runs that is aimed to raise a design and operational improvement towards a more robust tool functionality.