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A large operator of a brown field offshore in the middle east has decided to provide full lower Completion accessibility and ensure prevention of open hole collapse as it can lead to various gains throughout the life of the well. Among those benefits, it provides a consolidated well bore for various production logging & stimulation tools to be deployed effectively, as well as full accessibility, conformance control and enable to provide production allocations for each zones. However there are multiple challenges in deploying lower completion liner in drains involving multiple reservoirs and geo steered wells: Well Bore Geometry, dog legs/ tortuosity etc. & differential sticking possibilities and of course the open hole friction. Due to the size of the open hole, restricted casing design and utilization of limited OD pipes further add to the complications of deploying the Lower completion liner in such brown Field wells.
This paper intend to review the multi-step methodology approach implemented in recent years by the company to effectively deploy 4-1/2″ Liner in 6″ Horizontal Open Hole section. Among the techniques used to assist successful deployment of lower completions are: Improving hole cleaning, ensure smooth well bore with the use of directional drilling BHA, reduction of the Open Hole friction by utilizing Lubricated brines, fit for purpose Centralizers, use of drill pipe swivel devices to increase weight available to push the liner & reduce buckling tendency.
With the length of open hole laterals reaching up to 10,000 ft for 6″ Lower drains, open hole drag, friction & cleanliness are major components that causes challenges in deploying the Liner till TD. The use of specially formulated brines with fixed percentage of lubricants proved to significant reduce friction compared to the drilling mud used for drilling the horizontal drain. The combination of low friction brine with proper centralization / standoff which resulted in reduced contact area with the formation has also shown good results in preventing differentials sticking while running the liner through multilayer reservoirs having significantly different reservoir pressures.
Another major constrain to deploy the lower completion liner in this offshore field is the very nature of the wells being primarily workover. This involves generally Tie back liners run to shallow depths to restore the integrity of wells. This limits our ability in the selection of drill pipe that can be used as only smaller OD drill pipes and HWDP can be utilized in order to deploy the Liner to bottom. On many occasions this provides only limited weight to push the Liner down to TD and impact our ability to set the liner top packer. Drill pipe rotating swivel devices have been utilized to improve our weight availability & transferability to push the liner down and to set the liner top packers. In order to provide independent deactivation mechanism for the drill pipe swivel and to have complete success in our liner deployments, a dedicated ball activated sub was designed to deactivate the swivel acting as back up in case primary deactivation methods fails during liner setting.
The combined use of all these techniques enabled the company to deploy 4.5″ Liners in 6″ Horizontal drains with high success in this offshore Brown Oil field of UAE. This resulted in better well construction and complete access to lower drains over the life of the wells.
Abstract Origin Energy Pty Ltd ("Origin") completed its first extended reach drilling (ERD) project in southeast Australia to access offshore targets from an onshore location. The project targeted the Halladale gas field which is located 5.5 km offshore and 1.8 km below the seabed. For this operator, the challenge was to access offshore reserves using onshore drilling and production infrastructure to minimize project development costs and avoid working in sensitive marine environments. To mitigate depth uncertainty at the target location, an S-shaped trajectory was selected for the Halladale-2 production well. This started with a shallow kick-off followed by a sub-horizontal section that travelled laterally offshore and ended with a drop-off section to intersect the reservoir target. Advanced drag management techniques were required to drill the 12 ¼-in. and 8 ½-in. hole intervals, install the 9 ⅝-in. production casing, 7-in. production liner, and 5 ½-in. intelligent upper completion. The 9 ⅝-in. casing was installed using the buoyancy-assisted method (floatation), such that it could be "pushed" and "reamed" in the hole beyond the point of negative weight. Due to the geological environment and potential for mud losses, special attention was required in order to have the system designed for reduced hydrodynamic loads and still maintain appropriate mud weight for wellbore stability. The 9 ⅝-in. casing was run completely empty and required rotation in order to reach total depth. During the operation of landing-out the casing on the well head, the use of rotation to overcome axial drag was not an option; therefore, adequate contingency planning was required. A casing selective floatation collar was installed to provide additional weight should it be required by filling the top portion of the string with drilling fluid as total depth was approached. This allowed the lower portion of the casing in the high angle interval of the wellbore to remain empty, and thus neutrally buoyant. This contingency was in addition to the risk assessed push-down weight that the top drive could provide. A process was adopted to ensure that every member of the team understood the program and was committed to the successful delivery of the wells. These measures resulted in significant cost savings for the project. Technical challenges were overcome with design solutions and operational practices developed with the aid of modeling and simulations performed during the planning phase. The preparation of comprehensive multi-well program, the use of real-time data to validate the engineering models and a systematic approach to well planning contributed to the success of the project. When the rig limitation is accounted for, the Halladale-2 ERD well was a world-class challenge that was successfully overcome.
Copyright 2011, SPE/IADC Drilling Conference and Exhibition This paper was prepared for presentation at the SPE/IADC Drilling Conference and Exhibition held in Amsterdam, The Netherlands, 1-3 March 2011. This paper was selected for presentation by an SPE/IADC program committee following review of information contained in an abstract submitted by the author(s). Contents of the paper have not been reviewed by the Society of Petroleum Engineers or the International Association of Drilling Contractors and are subject to correction by the author(s). The material does not necessarily reflect any position of the Society of Petroleum Engineers or the International Association of Drilling Contractors, its officers, or members. Electronic reproduction, distribution, or storage of any part of this paper without the written consent of the Society of Petroleum Engineers or the International Association of Drilling Contractors is prohibited. Permission to reproduce in print is restricted to an abstract of not more than 300 words; illustrations may not be copied. The abstract must contain conspicuous acknowledgment of SPE/IADC copyright. Abstract El Capitan is the latest extended reach drilling (ERD) well to be drilled from the Heritage Platform into the Sacate Field, offshore California. The application of learnings from previous wells enabled El Capitan to be drilled to a total depth of 37,165 ft measured depth (MD) / 6,938 ft true vertical depth (TVD) with 33,682 ft of horizontal displacement (HD). The most challenging phases of the well will be described in this paper, concentrating on the main engineering focus areas during planning and execution.
Singh, Rudra Pratap (ADNOC Offshore) | Paila, Phalgun (Baker Hughes, a GE company) | Al-Kindi, Rashid Khudaim (ADNOC Offshore) | Al-Wahedi, Khalid Ahmed (ADNOC Offshore) | Kirby, Cliff (Baker Hughes, a GE company) | Blakely, Michael (Rubicon Oilfield International) | Christie, George (Rubicon Oilfield International)
Abstract Extended Reach Drilling (ERD) from the artificial island is particularly challenging for anti-collision, directional drilling and wellbore construction; facing various issues including but not limited to wellbore instability, hole cleaning, tortuosity, torque and drag etc., affecting the completion liner running and its ability to reach the setting depth especially in the smaller hole sizes. This paper describes the application of ground-breaking technology that enables completion liner with multiple ICDs and Swell Packers to be deployed at setting depth in ERD well maximizing oil reservoir production and saving cost. In 3D complex well profiles, while running conventional completion liner string, frictional drag is cumulated along the string, exposing the same to sinusoidal buckling which is further elevated to helical buckling and consuming the load available from surface to transfer to shoe, ultimately preventing the string to reach the setting depth. The buckling is even more severe in smaller hole sizes like 6" hole section where tapered drill string with 4" DP against 7" liner is used to run lower completion. By allowing a portion of the string to be rotated, significant amount of axial friction is converted from drag to torque and provides additional hookload at surface to push the string to TD. This selective rotation is enabled by the integration of a Swiveling Tool into the string above the Liner Hanger. The tool has been tested in a development well in an artificial island of offshore Abu Dhabi. This was the longest well drilled by operator with measured depth of 24,414 ft (Horizontal departure +/− 20,000 ft, 6" drain hole length +/− 5,200 ft). Later this technology was implemented in most of the challenging 3D complex wells and the Swiveling Tool became part of completion running string (4-1/2" Liner with ICD's and swell-able packers) based on the T&D simulation results if they indicated very little or no margin of drag available prior to string lock up which might make it impossible to reach setting depth. This paper describes a structural approach towards running 4-1/2" lower completion with ICD and swell packer in 3D-complex ERD well utilizing swiveling tool to ensure completion is run to the desired setting depth. The proposed tool can be implemented any project worldwide where buckling could prevent running lower completion and there is restriction to rotate the lower part of completion or if there are chances of having obstructions due to hole condition/geometry.
Abstract Optimizing resources and pushing the drilling limits to tap into deeper reservoirs at minimal cost has always been the primary objective of many operators worldwide. Moreover, the prolonged current market conditions are pressurizing every stakeholder involved within the well-delivery process to reduce time and the associated costs like never before. This paper deals with an Offshore Artificial Island project where the drilling limits were constantly challenged by adopting new technologies and practices in an extended-reach drilling (ERD) campaign. The complexity of these extended-reach wells was managed effectively with excellent planning and execution. Implementation of new and existing technologies and the adoption of revamped operational practices has managed the challenges of equipment capabilities, torque and drag, ECD, wellbore stability, hole cleaning and stuck pipe avoidance to name a few. The project drilled longer wells at less costs. This approach has resulted in drilling and completion of wells comfortably within the equipment-rating envelope. Additional technological means such as newly developed lubricant and mechanical drill pipe torque reducer subs helped reduce the friction factor and eliminate drill string buckling. Existing technology in the bottom-hole assembly (BHA) minimized the tortuosity in the wellbore, along with transmitted real-time downhole drilling data (Torque, Weight on Bit, Mechanical Specific Energy, and Equivalent Circulating Density) which helped in active drilling parameters optimization for efficient drilling. Similar technologies and practices were used in landing the completion string. The geo-mechanical studies undertaken at the concept stage and later revised against the offset well information helped in drilling the troublesome shale formations with no associated events. Specific importance was given to maximizing the hole cleaning by having the right tools in the BHA that could accommodate higher flow rates while using a tandem drill string for lower hydraulics. In addition, the newly formulated field / formation specific drilling and reaming practices minimized the stuck pipe, saving approximately 10% in overall well costs. This paper discusses the successful drilling of a number of offshore ERD wells with various complexities and tailored solutions with minimal downhole problems and within continuously revising planned times and budgets. The lessons learned and techniques associated with drilling of extended-reach wells at lower costs will be detailed in this paper. This information would give insights and considerations to all stakeholders who intend to drill extended reach wells or challenge their current limiters. This proven successful methodology and its results are considered a benchmark for the nearby fields in the region.