Asset Integrity Management, Engineering and Risk Assessment

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Engineering and Risk Assessment

ABS Consulting has conducted third party analysis services to evaluate new design concepts, proposed additions, repairs and damage conditions for a variety of offshore floating facilities. Some of these services include:

Hull FEM Analysis
Fatigue Analysis
Crack Propagation Analysis
Buckling Analysis
Vibration Analysis (Accommodation, Frames, etc.)
Stability Analysis
Hydrodynamic Analysis

Additionally, ABS Consulting can provide support services related to mechanical, piping, and electrical systems design such as mechanical and process design review, fire and safety systems analysis, or instrumentation and automation analysis and review.

Analysis Capability

ABS Consulting has a vast capability within the field of development of analytical models for many types of analysis and applications. These models have been utilized by clients as elements of integrated solution or as stand-alone studies.

Environmental Loading

The primary activity of ABS Consulting's Specialized Engineering Group is the analysis of the response of offshore structures and ships to environmental loading both for strength assessment and fatigue assessment. A key input into such analyses is a model of the working environment. ABS Consulting delivered numerous projects requiring load prediction and is experienced with modeling environmental for both the frequency and time domains, using measured data as well as data from standard references.

The primary tools used in this work include for wave load and motion prediction:

PRECAL
AQWA

and if non-linear effects are significant, the following software tools are used:

LAMP
SWAN

For sloshing analysis a computational fluid dynamics code, FLOW3D, is employed. In wave impact analysis both commercial codes, such as CRSLAM, and other in-house programs are used.

Global and Local Structure

We have considerable experience building structural models, using finite element methods, of offshore structures and ships. The finite element models are used for a variety of assessments including the evaluation of strength, fatigue performance and vibration performance. The models range from global models in which the entire structure is represented, to local fine mesh models designed for investigating fatigue.

Strength Analysis

For strength analysis our procedures are based on the Dynamic Loading Approach (DLA) which is a first-principles analysis methodology in which wave and motion-induced loads are explicitly calculated and applied to finite element models of the structure and then analyzed. Spectral fatigue analysis procedures are applied when a rigorous assessment of fatigue performance is required. In the same vein, vibration analysis can be performed on the same models. The models developed for strength analysis are modified to render them suitable for vibration analysis. The analysis will typically entail a free vibration analysis, followed by a forced vibration analysis.

Intact and Damaged Stability

Assessment of the intact and damaged stability of a wide variety of ships and offshore structures has been undertaken. Generally a quasi-static approach has been employed in the stability analysis. Other related tasks include preparation of trim and stability booklets for a wide range of loading conditions. Damage stability analysis of monohull ships considering the dynamics of flood water, ingress and egress of flood water through damage openings of different sizes and ships has also been undertaken.

Mooring/Tendon Dynamics and Statics

ABS Consulting has vast experience in the analysis of shallow-water catenary moorings as well as deep-water synthetic moorings. Recent experience includes analysis of single-point moorings of tankers, spread moorings of drill ships and cruise ships and DP-assisted moorings. ABS Consulting is knowledgeable and experienced in the use of many mooring analysis programs, such as the AQWA suite, MORA, DMOOR, etc., that utilize both coupled and completely decoupled analysis methods.

Fracture Mechanics Assessments

ABS Consulting has utilized Fracture Mechanics to plan inspections for structures. We have carried out defect assessments in accordance with BS7910 and API-579 on both structures with existing defects and also on new structures by growing defects to critical size from an initial defect size set by the fabrication NDE acceptance criteria. For a recent CNG gas vessel project, we have also coupled such analysis work with state of the art NDE methods such as Acoustic Emission Testing to arrive at a full on-line monitoring system transferring real data back to the operator at any point in time.

In addition, ABS Consulting has also used a simplified Fracture Mechanics approach involving the creation of "Defect Imbedded" S-N curved, thus enabling such an approach as specified above to be utilized on a large number of connections without the need to run BS7910 calculations and which can be easily used with any FEA structural analysis post processing capability.

Riser Analysis

ABS Consulting not only has capability within this field (working on many operational projects but also has an existing working relationship with MCS International (specialists in the field of riser design). This relationship may be drawn upon where specific additional expertise is required to augment ABS Consulting existing in-house experience.

Risk Engineering

ABS Consulting has extensive capabilities and provides a vast range of services with respect to safety, risk and reliability engineering in the offshore oil and gas industry. They are at the forefront in the development and independent review of Health, Safety & Environment (HSE) Cases for different types of facilities or assets, and apply and utilize a variety of sophisticated software tools and products to assist in the effective and efficient management of hazards and risk.

In particular, with the legislative/regulatory requirement to produce an HSE Case for an offshore facility, they are continually looking to enhance the techniques and methodologies they adopt in helping organizations and operators manage risk to a level that is 'As Low as Reasonably Practicable' (ALARP).

Services:

Developing, producing, reviewing and maintaining HSE Cases for the different phases (Design, Commissioning, Operational, etc.) of a facility's or asset's life cycle including the application of THESIS;
Providing a portfolio of services for the formal, systematic and comprehensive identification of hazards to which an asset or facility is exposed;
Conducting and reviewing Quantitative and Qualitative Risk Assessments via the application of techniques such as Event Tree and Fault Tree Analyses;
Developing, producing, reviewing and maintaining Health, Safety & Environment Management Systems;
Developing and producing Environmental Management Systems to comply with ISO 14001 requirements;
Designing, developing and delivering training courses to cover the range of our specialist consulting services and software products;
Developing and producing Emergency Response Plans and Procedures for effective response to a variety of emergency scenarios;
Facilitating performing and undertaking emergency response training, drills and exercises.

Hazard Identification

Hazard Identification is the first and, in many ways, the most important step in a risk assessment. If a hazard is not identified, its contribution to the risk cannot be estimated. Only those hazards that are identified are likely to be controlled with any confidence. Some of the techniques applied by ABS Consulting to assist in the identification of hazards include:

Hazard & Operability Studies (HAZOP)
Hazard Identification Studies (HAZID)
Hazard Checklists
Failure Modes, Effects and Criticality Analyses (FMECA)
Hazard Registers & Fault Schedules

Quantitative Risk Assessment (QRA)

ABS Consulting are specialists in performing Quantitative and Qualitative Risk Assessments. Specifically, in QRA, the systematic identification and evaluation of the likely consequences and frequency of possible hazards associated with facilities and operations are a major input to the risk management decision-making process.

Qualitative Risk Assessment

Often, it is inappropriate to perform an in-depth QRA, and coarse or qualitative risk calculations may be sufficient and more effective.

For more information, contact:

Brian Gibbs
Director - Asset Integrity Management
1-281-673-2765 | bgibbs@absconsulting.com

Tom Nolan
Director - Oil & Gas Services, North America
1-281-673-2740 | tnolan@absconsulting.com