Extended Reach Drilling (ERD) and Maximum Reservoir Contact (MRC) well design can drastically decrease development costs. A critical ERD and MRC challenge is frictional drag encountered when running long casing and liner strings. If the frictional drag becomes too great the string will stall before reaching total depth (TD), severely compromising the completion of the well. This paper presents the implementation of the casing swivel tool to effectively mitigate this friction risk. String rotation can provide a large reduction in axial drag by shifting the friction vector to primarily affect the torsional direction. Full string rotation offers the largest benefit, but the torque required often exceeds both the casing connection rating and top drive capability. The use of a swivel enables partial string rotation above the swivel to reduce the torque requirement. With increasing production lateral lengths the swivel was moved from the running string into the liner to increase the rotating length of pipe while managing rotational torque. The drill pipe swivel has a long history of effectively providing a reduction in axial drag by allowing for the running string to be rotated when running long MRC lower completion liners. As lateral lengths have increased from 10,000 feet up to 20,000 feet in Extended MRC (EMRC) wells, the ratio of liner length to running string length has greatly increased. To accommodate this shift in well design the swiveling point needed to be pushed deeper into the well, from running string to the liner. The fit-for-purpose design of the sacrificial casing swivel allows it to be integrated permanently into the completion and enables increased partial string rotation. To date the casing swivel has been deployed on eight wells, including a world record single-run 6-5/8″ production liner. In one well, the liner stalled and only reached TD after engaging the swivel. The use of the casing swivel has reduced the required well count and capital investment by enabling lateral sections of up to 20,000 feet while also decreasing drilling risk due to less overburden drilling. The application of casing swivel in the Giant Offshore Oilfield Abu Dhabi was a first for this size and length of lower completion liner. The casing swivel has become a key enabler to maximizing the length of production laterals resulting in substantial well construction cost savings.

The long term development from four artificial islands of this giant offshore field in the United Arab Emirates (UAE) is requiring longer and longer ERD wells. This can only be achieved by drilling higher angle, higher departure and increasing lateral lengths. Horizontal departure ratios have increased from 2:1 to 3:1 and will, before the development has finished approach 4:1. Maximum Reservoir Contact (MRC) lateral lengths at the beginning of the development were planned to average 10,000ft but are already being lengthened to 20,000ft, and beyond. This paper describes the many challenges that have arisen and have been successfully overcome to enable deployment of 6 5/8" horizontal lower completions of lengths up to 20,000ft into wells that are greater than 30,000ft MD. These challenges have been surmounted through the use of proprietary in-house software, leveraging partner resources and global experience, close collaboration between drilling, completion and field development teams, new technology equipment development and deployment methodologies. Several case histories will be presented and discussed at length in this paper. These will focus on specific aspects for each of the wells such as the; high strength liner connections, high load liner running tools, reservoir drilling fluid composition, swellpacker design, use of drillpipe or casing swivels, centraliser type and the effect of dog leg severity in the long reservoir lateral.

This Extended Reach Drilling (ERD) field re-development predominantly from four artificial islands of a giant offshore field in the United Arab Emirates (UAE) requires in most cases extremely long laterals in order to reach the defined reservoir targets, by the field development team. The giant offshore field can be effectively split in to two (2) geographical sections; East and West. The East portion of the field has been developed extensively and is considered to have good reservoir properties. The West portion of the field has much lower quality reservoir properties and requires an engineered lower completion liner in order to deliver the required well performance that will adequately produce and sweep the reservoir. The engineered liner along with the extremely long laterals means significant time is spent switching the well from reservoir drilling fluid (RDF) non-aqueous fluid (NAF) to an aqueous completion brine. In order to reduce the amount of rig time spent on the displacement portion of the completion phase, technologies have been developed to provide a method of switching the well from RDF NAF drilling fluid to an aqueous completion brine, without the associated rig time of the current displacement method. This technique eliminates the use of a dedicated inner displacement string and allows for the displacement to be performed with the liner running string, saving on average five (5) days per well. In this paper the authors will demonstrate the technology and system developed to perform this operation, as well as the qualification, testing, field installations and lessons learned that were required to take this solution from concept to successful performance improvement initiative.