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The well-control stack system is a critical part of the coiled tubing (CT) unit pressure containment package and is composed of a stripper assembly and hydraulically operated rams, which perform the functions described next. Figure 1--Typical quad-ram well-control stack configuration (courtesy of SAS Industries Inc.). The blind rams are used to seal the wellbore off at the surface when well control is lost. Sealing of the blind rams occurs when the elastomer elements in the rams are compressed against each other. For the blind rams to work properly, the tubing or other obstructions across the ram bonnets must be removed.
Abstract A proprietary design using a pyro-mechanical, electrically initiated, kinetic energy enabled shearing action has safely and reliably delivered on the promise of "Shear Anything" and seal successfully. The kinetic blowout stopper (K-BOS) will shear anything in the well above the bit thus eliminating non-shearables from the oil & gas lexicon. Further a superior clean fish with minimal deformation is produced by the kinetic shearing action. The K-BOS will shut-in full flow and pressure blowouts in milliseconds with its simple protected hermetically sealed construction for unparalleled post–shearing sealing performance and dramatically reduce extremely deadly and damaging flammable and/or toxic gas releases. With unrivalled confidence and reliability with best-in-industry control system monitoring and function testing and actuation techniques, the K-BOS requires virtually zero maintenance because of its simple construction where the working components are not wetted by wellbore fluids until actuation, meaning lower costs and reduced NPT and downtime. Like the automotive air bag, the K-BOS is self-contained and meets US and International deregulation requirements regarding safety and logistics of pyrotechnic devices. Starting with ballistic modeling technology developed for the military, the models were adapted to the K-BOS application and predicted the outcomes of shearing tests with different common tubulars including traditional "unshearables." A testing regime has been conducted to validate the models, demonstrate repeatability of the results, and demonstrate that a post shear seal could be achieved. More than 30 test serials with the K-BOS 4-1/16″ prototype including empty well-bore tests, shear tests ranging from 5/16″ wireline to 3-1/2″ Drill Collar with a 1″ Wall Thickness. All tests to date have sheared the target tubular without failure. Multiple materials and configurations have been tested. In all the shearing tests, the K-BOS successfully sheared the target while achieving all safety objectives. The shear test program has validated the models and has also provided validation data allowing for adjustments to the modeling technology for this specific application and resulting in a high level of accuracy and precision in design and shear performance expectations. The shear testing also showed that the K-BOS can shear without damaging the seals and provides an adequate sealing surface after shearing. The K-BOS has successfully met technical readiness level 5 (API 17N scale) and is ready to move on to in the field scale shear and seal testing. These results and the continuation to continuing development further the prospects of ensuring the K-BOS achieves its mission to strengthen the industry's social license to operate.
Abstract The rig start-up process that was used for the semi submersible tender assist rig was successful in mitigating schedule and cost risks associated with readiness of the rig and the complex interface with other contractors located around the world. The Malaysian team successfully delivered the rig start up from 1 year cold stack mode change of ownership, turned around the rig into a fully functional one, on cost, schedule and incident free. It was an extremely challenging timeline from contract award to securing rig modification, interface upgrades and equipment delivery to meet the operators’ "First Oil" date. Multiple stakeholders were engaged to identify & build up a credible rig start action plan to deliver the required upgrades, reactivation and repairs in a timely manner. A technical queries process was used to manage the information exchange, captured decision and way forward. The successful rig start-up required Integrating new team members from various parties onshore & offshore integration, and familiarised the team with operators’ ways of working on safety including managing parties with limited rig start-up experience. The process needed an intensive interface management with multiple organizations within country and outside. The rig start-up was successfully completion on schedule, below planned budget and most importantly safely. The modification was aimed at allowing a coupled body action between the semi sub tender assisted rig and tension leg platform, allowing for drilling, completion, hook up and commissioning and production to be carried out simultaneously. Ultimately it allowed for a safe and efficient well delivery campaign and meeting the production targets from a new facility. With the action plan in place, the operator and contractor successfully closed out on audit findings & action items (> 1700 audit actions) from various aspects of HSE Technical safety, Rig Startup Audits, Marine, Aviation, Lifting & Hoisting, Health, Dropped Objects Prevention Scheme (DROPS), 3rd party commissioning & project interfaces to sail away from shipyard on time. A structured systems integration test was carried out in shipyard to qualify and commissioning new and existing drilling rig systems. Well control systems were also confirmed functional and a blowout preventer shear test was carried out using the original equipment manufacturer (OEM) and operator guidelines. Once the rig was sailed to location and set up alongside the tension leg platform, the remainder of the systems integration test was completed on site. The result of this was a flawless startup and transition into drilling and completion operations with minimal downtime to the operator and rig contractor.
Abstract This paper describes the successful application of a rigless well abandonment method that isolated the well's production interval using resin-based sealant, without cement and without latching a conventional subsea blowout preventer (BOP). An offshore operator needed to permanently abandon a subsea well that had become uneconomic due to excessive sand production. Several subsea wellhead and downhole conditions would have made killing the well by conventional means difficult if not impossible. Wellhead fatigue and soil erosion around the wellhead meant that a conventional drilling BOP could not be used in the operation due to the equipment's weight. Fluids to kill the well and permanently seal the formation could only be pumped down the tubing, and an obstruction in the flow path would limit the injection rate. Typical wireline and coiled tubing intervention tooling and circulation could not be used. Cement and micro-cement have particles that could potentially bridge at the downhole obstruction, preventing it from sealing the formation. Considering these factors, the operator and service provider designed, tested, obtained regulatory approval, and successfully implemented a rigless abandonment operation using a service vessel and well stimulation tool to inject resin-based sealant into the well to seal the formation and enable safe final abandonment and tree removal using a light intervention vessel. These results suggest that this method can potentially be used during abandonment of subsea wells with smaller trees and wellheads that have experienced fatigue.
Abstract As the use of electric submersible pumps (ESPs) increases in critical production operations, i.e., offshore and high production wells, the need for more efficient systems to replace the traditional jointed pipe installation and retrieval process becomes more relevant. Methods such as coiled tubing (CT) and wireline deployment have been used in the past with varying degrees of success and deployment with power cable is making its way into mainstream ESP applications. All alternative ESP deployment methods face issues when it comes to wellbore control, especially in applications where ESPs are installed to boost production in naturally flowing wells. This paper examines well control challenges associated with cable deployed ESP (CDESP) installation and retrieval, and provides strategies to carry out these operations safely. Careful review of current ESP change out operations with workover rigs leads to the development of an equivalent well control strategy for rigless CDESPs. Well permanent completion design, the required components on the blowout preventer's (BOP) stack, and deployment and retrieval procedures are established. This strategy eliminates the use of expensive and duplicative well control barriers with no operational safety being compromised. Moving from workover rig-based ESP change out to through tubing rigless operation is a major undertaking with many challenges of which well control is a key element. This paper provides a comprehensive review of all relevant issues and presents a practical strategy to ensure safe and economical field operations.
The adoption of segregated drilling campaigns is commonplace in an effort to harness economies of scale and reduce well construction costs. In an attempt to increase the financial efficiency of drilling campaigns, the division of the well construction and completions operations can be segregated into two distinct phases. A drilling and casing phase leaving a cased well in a Temporary Abandonment (TA) status, followed by a phase consisting of clean-up, completion and stimulation operations resulting in the handover of the well to production to bring hydrocarbon production online. As such an Intervention and Completion Unit (ICU) with the capability to perform perforation, multi-zone completion installation, stimulation, clean-up operations and well testing has significant advantages when deployed in the later phase of a segregated multi-phase drilling campaign. This paper describes the collaborative development of an ICU that facilitates the installation of multi-zone and smart well completions, conveyance for well servicing operations, well bore clean-up (WBC) activities, well testing and stimulation activities. The challenge of undertaking traditional drilling phase activities with a technically capable, yet cost effective ICU is discussed, particularly the core areas where the reduction in specification through it being redundant for the phased operations. The key parameters driving the ICU development and design are presented from the operator's perspective, based on prior campaign experience utilizing this approach with alternative technology. The process identifying the key requirements of the completion and well servicing operations is described with the selection of implementing new technology solutions in the design. The avoidance of Non-Productive Time (NPT) is a core aspiration in making incremental cost efficiencies. The identification of operations not on the critical path that can be performed simultaneously or as an offline activity, have the potential to make high cost impacts. Through innovative design and the implementation of novel and field tested technology, allied to extensive use of offline activities as concurrent operations, the ICU has the potential to make significant cost savings in a segregated well construction project. Collaboration between the operator and service provider drives a design which provides a technically pragmatic and capable ICU and as such attracting project cost savings allied to lower support equipment costs. Further, the deployment flexibility of the ICU allows it to perform operations ranging from well construction activities such as well slot preparation, completions and intervention, to well deconstruction activities such as heavy workover, Permanent Abandonment (PA) phases and slot recovery. The ability to perform multi-phase operations whilst mobilized to a platform brings further cost benefits and operational flexibility.
Abstract Plug and Abandonment (P&A) is the largest category in Decommissioning expenditures, representing 40-44 percent of the total investment that basically comes as mandatory cost with no expected return. If the well operator gets P&A inadequate, results may include water flows, gas or oil seeps from the seabed, or underground cross flow between formations with huge impact on environment and marine life. The objective of this paper is plasma-based technology for enhanced casing section milling addressing the P&A challenges. According to some oilfield service providers, two main P&A challenges are as follows: Time and expense of casing milling - for example, Norwegian regulations call for cementing two 50-meter sections of casing above and below each hydrocarbon-bearing zone. Each section may take more than 10 days to mill and may generate four tons of swarf. The second challenge is swarf damaging blow out preventer (BOP) - Milling generates swarf, which then must be removed before cementing. However, swarf removal can damage the BOP. To avoid well integrity issues, BOP has to be dismantled, inspected and repaired at considerable expense. The presented paper is focused on technology eliminating the P&A challenges. The core of the technology is based on plasma generator producing high temperature water steam plasma for rapid steel structural degradation. This approach brings a radical abandonment of the classic rotary approaches with connected tubes in long strings and generation of swarf which need to be removed. Besides elimination of aforementioned challenges, the technology advantages include also rigless operation since the system is designed for coiled tubing solution. This feature brings additional cost savings using Light Weight Intervention Vessel (LWIV). Moreover, fully automated coiled tubing goes hand in hand with enhanced safety of the operational staff. Impact and potential of the technology is to change, simplify the process of P&A and therefore significantly cut the time of whole P&A. The technology is currently under development with expected commercialization within three-year period.
The realization associated with Macondo is that loss of well control (blowouts) can still occur in the drilling equipment and procedures in unanticipated ways. The oil and gas industry, the regulators and the public must understand the potential and the preparations. The industry and the regulators are collaborating and investing in improved methods, practices and equipment necessary to continue to conduct ever safer exploitation of hydrocarbons. This paper describes how the global oil and gas industry is developing specific ability to close off wells with a secondary "capping system" that can shut off entirely and/or flow to offshore collection vessels. Capping systems can be installed in various configurations for deepwater, ice-infested locations, multi-well installations beneath a floating facility, well intervention scenarios, and wells with limited downhole pressure integrity.
Abstract This paper details a case history of a recent HPHT CT well intervention operation to gain access to a suspended subsea well, in order to finally abandon the well including wellhead removal from seabed. There was a need to mill out the shallow set environmental cement plug to allow section milling and cement plug setting on well that had been originally suspended in 1997. The absolute worst case predicted pressure trapped below the shallow set cement plug was 12,500psi. This paper will take the reader through the full life cycle of the CT well intervention project. Starting with the initial feasibility study that lead to the selection of CT as the most viable option, moving onto the two sets of trials on test wells verifying the milling parameters and BHA selection. There will then be details on the 15,000psi live well intervention landing string that had to be manufactured to act as a conduit for the milling operations and also having the capability to shear the 2″ QT1000 0.203″ CT. The paper covers a review of the actual versus planned operations and captures high level lessons that would benefit future similar operations. The requirement to enter old wells that have been previously suspended / abandoned to fully abandon to current standards is an area of increasing interest. The use of CT to re-enter a HPHT subsea well has proven its versatility in comparison to alternatives such as costly relief well or HP interface equipment to allow jack up operations that could facilitate a snubbing unit.
Expectations and requirements for that is placed over the blown-out well as subsea-well emergency response a "cap." Its purpose is to stop or redirect preparedness were stepped up as a the flow of hydrocarbons and to buy time result of the Macondo blowout and oil for engineers to permanently seal the spill that began 20 April 2010 in the US well. It is massive and can weigh as much Gulf of Mexico. A key change is the as 50 to 100 tons, presenting logistical requirement to have subsea capping challenges in quickly transporting it to stacks ready to be deployed that are the emergency occurring at the blownout capable of handling the specific blowout offshore well. Then debris is name of each piece of equipment gives removed and the wellhead is prepared.