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With today's low energy prices and with the increasing drive towards sustainability, it is essential to develop more economically efficient and ecofriendly technologies in oil and gas field development. Such a technology is self-healing cement, which was successfully applied in a large project in northern Italy in the conversion of a gas field to a gas storage field. During the construction phase of gas production and storage wells, one of the critical goals is to achieve competent hydraulic isolation between the surface and the casing to reach the reservoir. There are several cases documented in the literature where poor isolation has resulted in gas flow to surface, thereby polluting water reserves, greenbelts, and populated areas. Improper isolation can also result in interzonal communication, production of unwanted fluids, gas migration, casing corrosion, and sustained casing pressure. These can have significant health, environmental, and economic impact. Additionally, the impending need for well intervention, along with high re-entry costs, will further weaken revenue margins. Breaking through conventional cementing solutions, a global oilfield service company had established an active cement technology to improve annular isolation in gas wells. This technology is capable of self-healing when exposed to hydrocarbons of any type, unlike other self-healing systems that are limited by the level of methane (CH4) in the gas reservoir. The new system allows universal coverage for any concentration of CH4. Because the concentration of CH4 in different gas reservoirs can vary significantly, the self-healing "protection" against different levels of CH4 is tailored to suit different reservoirs. This field-proven technology, in use for more than 10 years, stemmed from the original self-healing technology commercialized more than a decade ago. Subsequently, an opportunity arose to apply this technology in a large project in the north of Italy. The project would exploit a depleted gas field by conversion to a gas storage field with the drilling of 14 wells from two clusters above the reservoir. The product testing and implementation, job execution, and results evaluation brought several benefits with positive impact to the service company and the owner/operator of the field. A higher level of isolation significantly decreases the need for future well integrity and repair, which provides medium- to long-term benefit for the operator—an added value that is sometimes omitted in well construction design. Using a zonal isolation technology, such as the self-healing cement system described here, inherently places the service company and operator in a much more secure position for the future. Furthermore, in the current industry climate, saving 30 to 40 days of rig time and the cost of remedial operations and achieving important mitigation against health and environmental impact pose a significant economic advantage.

Current oil and gas volatile market environment and the increase focus towards sustainability, it is essential to develop more economically and ecofriendly technologies in oil and gas industry environment. Maintain well integrity is mandatory towards developing oilfields to contain the reservoir fluids within the wellbore, however it becomes more critical in developing new underground gas storage reservoir in Italy. During construction phase of gas production and storage wells, one goal, besides hydraulic isolation of the production casing with cement, is the sand production containment during production cycle of the field. Sand production, even in small quantities, will eventually erode downhole and surface equipment leading to potential catastrophic scenarios of uncontrol reservoir fluid reaching surface. These can have significant health, environmental, and economic impact. Additionally, the impending need for well intervention, along with high re-entry costs, will further weaken revenue margins. In high permeability reservoirs required for underground gas storage projects, the injection and production cycles can lead to stresses applied in nearby wellbore formation which will destabilize the sandstone grains leading to sand production. To mitigate the sand production into the wellbore, a gravel pack operation will support the wellbore, consolidating the space behind the production screens. In this field, a high-risk failure was identified for traditional alpha-beta gravel pack methodology. This could lead to expensive recovery operations for the client and service provider to restore the well and re-perform the gravel pack. To tap different part of the reservoir, one well in particular had to be sidetracked from 9-5/8in casing resulting in a long clay interval being exposed susceptible of instability. It was required to isolate this interval to avoid disturbing the clay interval during gravel pack operations, however, to accommodate the completion, the optimum solution was to use expandable liner. Using this zonal isolation technique to regain well integrity, along with redesign of gravel pack carrier fluid technology led to a successful job securing client position as a reliable field operator. The field operator was committed for high level of safety during operations, starting from design phase through the execution, to achieve long-term well integrity and performance.

Abu Dhabi National Oil Company (ADNOC) offshore and Schlumberger jointly initiated a project to drill the longest 12¼-in section ever drilled in United Arabs Emirates (UAE) as part of the integrated drilling service for an extended-reach project. The plan involved drilling 14,400 ft in an extended-reach drilling (ERD) well in the field. The objective was to reach section TD in one run, drilling from 5,194-ft MD and reaching TD at 19,494 ft MD. In the well in study, Well 29, the trajectory crossed different formations—including limestones, shales, and dolomites—and built inclination from 30° to 78° to achieve an optimal step-out for the following sections to reach the boundaries of the reservoir at 27,000 ft. Different formation challenges throughout the section required a step change in engineering to complete the objective successfully. ADNOC needed a robust steerable system selection with metal-to-metal sealing that would be exposed to severe downhole conditions, a new bit technology design, anti-collision analysis to help reduce additional gyroscopic operations, and optimized drilling parameters with an enhanced drillstring design. The section was planned to drill in 17.7 days. The total section was finished 10 days ahead of planned AFE, setting the record for the longest 12¼-in section ever drilled in ADNOC and UAE of 14,400 ft, which was 58% longer lateral than field average. Through increased cutting efficiency and superior impact resistance, the new bit design with ridged diamond elements drilled the fastest 12¼-in section on the field in 0.91 d/1,000 ft. Good hole conditions facilitated successfully running and cementing the longest 9⅝-in casing, meeting ADNOC well integrity barrier requirements. The 12¼-in section had the fastest IADC-recorded ROP in the field, with an on-bottom ROP of 105 ft/h, which was 110% faster than the field average. The Geomagnetic Reference Service correction was implemented for the first time and was allowed to drill in proximity with a high anti-collision risk well, eliminating a gyro trip in the middle of the run. Downhole drilling parameters analysis from the drilling mechanics module was crucial for understanding downhole energy transmission and implementation of efficient drilling strategy and reducing shocks and vibrations. The drillstring was redesigned, replacing the traditional 5-in × 5⅞-in drillpipe and enabling a stiffer BHA, which helped maximize the bit performance.