A Case Study of Asset Integrity and Risk Assessment for Subsea Facilities and Equipment Life Extension

Abstract

The ever increasing oil and gas exploration and production cost requires highly efficient and safe operation of the existing offshore and subsea equipment and facilities. At the same time, a large number of facilities and parts of the existing infrastructure are quickly approaching or have exceeded their originally designed service life. Many fields, however, still have large amount of remaining recoverable oil and gas reserve which can be profitable if current production equipment's service life can be extended beyond their nominal design, otherwise economic penalty of stopping production or installing new equipment will be too high.On the other hand, once existing equipment have been operating beyond their design life, unforeseen failure and integrity problems can occur that site personnel may have not previously encountered. In many cases this can cause production to cease unexpectedly, and result in costly emergency repairs to get the asset back online.To extend asset life and push the design envelop, operators must prove to themselves and often their regulators that the assets are safe to operate with limited and controlled risks. In a scenario like this, the subsea integrity management of ageing assets has become a key issue for the oil and gas industry.This paper provides an actual case study for asset integrity assessment of subsea facilities life extension, performed by DNV GL and the O&G asset operator team. The study includes the asset integrity condition assessment based on equipment design documentation, operations data, maintenance and inspection analysis data, risk assessment and recommended mitigation of identified threats, engineering critical analysis of high risk equipment, and proposed destructive lab testing of parts retrieved from subsea.

Condition assessment, remaining useful life prediction and life extension decision making for offshore oil and gas assets

“…" As depicted in Table 3, three colour codes are used to indicate potential courses of action. This colour coding methodology has so far used as an equipment condition acceptance criteria for some industries such as electric power, offshore oil and gas and petrochemical industries (Amir and Muttalib, 2014;Hameed and Khan, 2014;Carvalho et al, 2015).…”

Development of a techno-economic framework for life extension decision making of safety critical installations

“…The technical assessment module involves the application of condition assessment tools to determine current physical and functional health status of an asset. Risk assessment methodologies have widely been used for this purpose in some industries (e.g., see Palkar and Markeset, 2012;Liu et al, 2014;Carvalho et al, 2015). On the other hand, probabilistic safety assessment (PSA) models such as analytical unavailability and unreliability models have also been employed in the nuclear industry to determine current health status of safety related systems (e.g., see Martorell et al, 1999;Kancev et al, 2011;Kancev and Cepin, 2012;Martón et al 2015).…”

“…Ramuhalli et al (2012) applied PHM techniques to assess and predict the RUL of nuclear reactor components. Our proposed framework adopts an assessment rating approach as in references Palkar and Markeset, 2012;Liu et al, 2014 andCarvalho et al, 2015. However, the approach utilized in this study is more quantitative and accounts for greater number of key factors in LE technical assessment.…”

Techno-economic feasibility assessment of life extension decision for safety critical assets

“…The technical assessment module involves the application of condition assessment tools to determine current physical and functional health status of an asset. Risk assessment methodologies have widely been used for this purpose in some industries (see Palkar and Markeset, 2012;Shafiee et al, 2013;Carvalho et al, 2015). On the other hand, probabilistic safety assessment (PSA) models have also been employed in the nuclear industry to determine current health status of safety related systems (Martorell et al, 1999;Kancev et al, 2011;Martón et al, 2015).…”

“…Ramuhalli et al (2012) applied PHM techniques to predict the RUL of nuclear reactor components. Our proposed framework adopts an assessment rating approach as in references Palkar and Markeset, 2012;Liu et al, 2014;Carvalho et al, 2015. However, the approach utilized in this study is more quantitative and accounts for greater number of factors influencing the LE technical assessment.…”