Deepwater Dry Tree Semi Technology Readiness: Perspectives of Operator and Classification Society

Lu, Jenny Yan; Lee, Ming-Yao; Huyse, Luc; Hansen, Vigleik L.; Viteri, Martha

doi:10.4043/23919-ms

Cited by 9 publications

(4 citation statements)

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“…A more thorough overview of dry tree semi concepts emerging in the market is included in an OTC paper by J. Lu et al [1]. A few examples of these new concepts are discussed in the following text.…”

Section: Closer Look At Dry Tree Conceptmentioning

confidence: 99%

Dry Tree Solutions for Ultra-Deepwater in Offshore Brazil

Davis

Raposo

et al. 2013

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With Pre-salt area being a massive new offshore oil frontier, there is a high demand for deepwater floaters for both drilling and production. There are some unique challenges related to the ultra-deepwater (water depth beyond 1500m) and the Brazilian environment for the pre-salt area. Various floater concepts have been evaluated with specific focus for Offshore Brazil applications.This paper provides an overview of the current technology related to dry tree solutions as well as discussion of the pros and cons of various concepts. The paper also discusses some new concepts emerging in the industry attractive for Offshore Brazil.A dry tree solution has the advantage of direct access into reservoirs from the floaters. This allows the operators to drill, complete and workover the well directly from the same hosting unit. The result could be increased reserves and productions in Offshore Brazil as well as significant cost reduction. Proper validation of the concepts and technology qualification of all the systems/components associated with novel technology, establish the basis for a safe and successful project implementation while reducing potential risk to personnel, environment and property.DNV has established processes to systematically evaluate new concepts and new technologies, e.g. Approval in Principle (AiP) and Technology Qualification (TQ). A brief introduction to these processes is included in the paper and how they support the development of these new concepts.

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Section: Closer Look At Dry Tree Conceptmentioning

confidence: 99%

Dry Tree Solutions for Ultra-Deepwater in Offshore Brazil

Davis

Raposo

et al. 2013

All Days

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“…Therefore, optimization of the hull form to reach better global motion performance is critical to the development of a SEMI FPU or a drilling platform. In addition, the recent research and development on dry-tree SEMI also requires a concept with better heave motion performance (Lu et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

Global motion and airgap computations for semi-submersible floating production unit in waves

et al. 2017

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We study the global hydrodynamic performance of a semi-submersible floating platform unit in order to optimize the hull form in the future. The hydrodynamic problem is solved by employing potential flow theory and Morison equation for modelling of the viscous effects. The added mass and damping coefficients, as well as the first-order motion responses, second-order mean drift forces, diffracted and radiated wave field, and airgap are computed to examine the hydrodynamic behavior of the floating production unit. The computational results show that the motion responses in short-crested waves are mostly smaller than those in long-crested waves. The maximum wave elevation occurs at WP45 in 45°45° wave heading in long-crested waves. In addition, the minimum airgap occurs at AG45 in 45°45° wave heading in linear waves, while the worst airgap point in nonlinear waves is AG0 in 0°0° wave heading. Extensive parametric studies have been performed to examine the dependence of the motion responses and the other key design criteria on the principal dimensions including hull draft, column width, column spacing, column corner radius, pontoon height, pontoon width, and the size of cakepiece. By comprehensive and systematic hydrodynamic computations and analyses, it is revealed that the combined vertical motion at the worst airgap location is almost in phase with the wave elevation in extreme wave condition with a peak wave period around 14–15 s. Moreover, it is found that the most efficient way to reduce the motion is to increase the hull draft, though the airgap may also decrease. Besides, reducing the pontoon height can achieve better motion performance and larger airgap simultaneously. This paper aims to provide a benchmark for future studies on automatic hull form optimization

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“…[7,8] The feasibility of several of these novel designs to provide an economic solution for development of deepwater marginal fields is unknown. Some of these have been evaluated as dry tree solutions for development of large fields with 12 production risers and a large drilling rig for deeper reservoirs and for two novel hull designs efforts have been undertaken in RPSEA funded projects to increase their technology readiness levels (TRL).…”

Section: Introductionmentioning

confidence: 99%

Alternative Direct Vertical Access Solutions for Development of Marginal Assets in Deepwater - a DeepStar Study

et al. 2015

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This paper is based on a DeepStar study undertaken to evaluate innovative deepwater floating platforms and riser systems, with dry tree (DT) or direct vertical access (DVA) capability, for development of marginal fields and benchmarking with proven dry tree platform concepts [1][2][3]. The spread moored semi-sub shaped and hybrid novel hull designs with top tension risers (TTRs) and quayside integration of topsides overcome key concerns with both TLP and Truss Spar with TTRs and provide cost effective solutions for ultra-deepwater marginal fields.The designs were developed for three regions (Gulf of Mexico, West of Africa, and Offshore Western Australia) and three water depths (3,000 ft, 6,000 ft, and 8,000 ft) for a common design basis with defined topsides and riser payloads, and specified design constraints. The estimates for novel designs were obtained from eight Concept Owners, and a comparative assessment was performed for 13 designs in three groups for nine combinations of regions and water depths. Coupled analysis was performed for most novel designs for GoM 6,000 and WoA 6,000.The five field development themes with DT benchmarks, novel hull, novel riser, drilling or process will be described. The key design, global performance, and constructability features of alternative concepts will be discussed. The variability in key estimates for three groups will be identified. The novel hull designs evaluated enable integration of topsides at quayside or by floatover and provide ability to support DTs and long stroke RAM tensioners. For designs evaluated with a modular drilling rig and upto six TTRs, lower CAPEX is estimated.The ranges of key design data, tensioner stroke, and global performance for each group have distinct variations. The novel riser design considered is Compliant Vertical Access Riser (CVAR), which is an offset riser with no tensioners, thus it enables use of semi-sub design with lesser draft. The development themes with wet trees and a drilling riser reduce the payload on hull.Technology readiness level (TRL) varies for the novel concepts. The detailed comparative assessment undertaken showed high potential for standardization of hull designs. In ultra-deepwater regions with harsh metocean conditions, several of these novel hull designs provide enabling solutions. This is the first major effort undertaken with evaluation of 13 alternative design cases with DT or DVA capability. The evaluations done for three regions would also be applicable in many other regions. The documentation of estimates in three groups identifies benefits from novel designs over benchmarks designs in each group, and distinct variations among groups. These results would help in selection of specific concepts for a region for further qualification and project readiness for development of worldwide marginal deepwater and ultra-deepwater fields.

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Deepwater Dry Tree Semi Technology Readiness: Perspectives of Operator and Classification Society

Cited by 9 publications

References 0 publications

Dry Tree Solutions for Ultra-Deepwater in Offshore Brazil

Dry Tree Solutions for Ultra-Deepwater in Offshore Brazil

Global motion and airgap computations for semi-submersible floating production unit in waves

Alternative Direct Vertical Access Solutions for Development of Marginal Assets in Deepwater - a DeepStar Study

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