Ramesh Ramasamy - Academia.edu (original) (raw)

Uploads

Papers by Ramesh Ramasamy

MATEC Web of Conferences, 2018

The catastrophic failure of an offshore water injector well is presented in this paper. The failu... more The catastrophic failure of an offshore water injector well is presented in this paper. The failure mode was determined from the final collapsed state of the conductor pipe which resulted in the surface Xmas tree and wellhead to drop vertically down onto the platform deck. Various inspections and assessments are carried out to determine the integrity of the well structure and compared against the original drilling records. Stability evaluations of the casing is also carried out to account for the loss of annular cement which resulted in loss of centralisation. The analyses conclude that various sequence of events have contributed towards the failure of this well. The lack of intermediate inspections and monitoring have resulted in uninhibited corrosion and pitting on the conductor pipe. Some considerations on the necessity of an effective inspections strategy and rationalisations of a robust integrity screening are also drawn.

The increase in ageing offshore wells and the continued requirement to maintain operations beyond... more The increase in ageing offshore wells and the continued requirement to maintain operations beyond their original design life is beginning to be a major challenge faced by operators worldwide. This problem is further compounded by the limited availability of well construction records, unknown operational conditions and inadequate through life maintenance. In many cases the large number of wells which may be required to be evaluated can also make the process of developing acceptable integrity procedures challenging. Defining an accurate understanding of the present condition of these assets is essential to ensure that the structural integrity of the well can be confirmed, and the acceptability of extending the life of the asset can be evaluated. This papers focuses on the criticality of the well integrity specifically of the conductor and surface casing corrosion and the deterioration of the annular cement due to ageing on shallow water injector wells. Several structural assessments t...

MATEC Web of Conferences, 2014

The worldwide exploration and development of subsea and deepwater reservoirs has laid down some n... more The worldwide exploration and development of subsea and deepwater reservoirs has laid down some new and old engineering challenges to the offshore pipeline industry. This requires large D/t pipelines to be installed at water depths in the vicinity of up to 2700m. The deepwater collapse and buckle propagation event is almost unavoidable as the pipe wall thickness cannot be always determined from the codes and standards due to the limit state criteria. These codes also do not consider any fabrication imperfections and sustained damages emanating from transportation and handling. The objective of this paper is to present the Finite Element Analysis (FEA) of dented pipes with D/t ratio more than 45, which is outside the applicability of current design codes, and to investigate the effects on installation capacity of these various damage sizes in terms of collapse and buckle propagation.

The offshore construction environment can be very difficult to be accurately predicted, due to va... more The offshore construction environment can be very difficult to be accurately predicted, due to various uncertainties in the geotechnical elements, and highly probabilistic events at which ocean conditions govern the design. The integrity assessment and life extension activities towards end of field life is becoming very common in older fields surrounding Malaysia, and other areas such as the Arabian Gulf and the North Sea. The in-line measurement of the existing residual stresses on these assets is very critical for the remaining life assessments, and also to categorise assets for shutdown to undergo rehabilitation work. The novel idea of using ultrasonic waves is developed and explained in detail in this paper. This method is based on the measurement of the time of propagation of the critically refracted longitudinal wave components travelling along the subsurface region of the specimen. Numerical validation is backed up by experimental work to verify this method to be fit-for-purp...

Journal of Physics: Conference Series, 2017

Internal stresses or residual stresses in the structural elements are very crucial in carrying ou... more Internal stresses or residual stresses in the structural elements are very crucial in carrying out in-service evaluations and fitness-for-purpose assessments. The generation of these internal stresses can occur as result of the fabrication of the steel members, installation sequence or other ad-hoc events such as accidents or impact. The accurate prediction of the internal stresses will contribute towards estimating the integrity state of the structural elements, with respect to their material allowable stresses. This paper investigates the explicit FE based numerical modelling of the ultrasonic based non-destructive technique, utilising the measurable longitudinal critical refracted wave (LCR) and relating these to the internal stresses within the structural elements by the evaluation of the material dependent acoustoelastic factors. The subsurface travel path of the LCR wave inside the structural elements makes it a sub-surface stress measurement technique and the linearised relat...

Marine Structures, 2018

Most of the major oilfields in the North Sea, Persian Gulf and South China Sea are becoming very ... more Most of the major oilfields in the North Sea, Persian Gulf and South China Sea are becoming very mature, with their assets exceeding their calculated design life. The severe corrosionSevere corrosions on the metallic structures of oil wells consisting of the conductor and casings, combined with spalling of annular cement forming the barriers can result in catastrophic events leading to structural collapse and wellhead vertically dropping onto the platform deck. With the collected inspection records, a systematic approach is deemed essential to assess the in-place condition of these wells and to categorise them for life extension works. This paper presents a simplified screening method for the structural integrity assessment of platform conductors towards the end of their design life and the prioritisation which follows thereafter for life extension operations by bridging the gap between design data and inspection records. The deterministic and probabilistic integrated approach is taken to address this problem, by considering the information collected from the as-built design records to the in-place inspections, coupled with the operating and metocean loads. The pragmatic and novel conductor operating guideline curves are proposed and constructed to present the evaluated integrity states, which will enable operators to rapidly categorise conductors for rehabilitation. TheThis screening method is applied to a group of 40-year old water injection wells, and is demonstrated to have the practical prospect, and can be automated to provide a robust and effective assessment technique.

Abu Dhabi International Petroleum Exhibition & Conference, 2017

The Arabian Gulf and the surrounding GCC regions have some of the world's oldest oil and gas ... more The Arabian Gulf and the surrounding GCC regions have some of the world's oldest oil and gas fields dating back to the 1930s and 1940s, some of which are still actively producing. From a design perspective, the oil wells in these fields have operated beyond their design lives. However, due to the recent decline in oil prices, there is an ever increasing demand to keep these assets producing for the foreseeable future. It is therefore critical that the asset owners/operators develop a thorough understanding in the health conditions of these aged wells and also to put in place an effective well integrity management system to ensure the longevity of these assets. This paper presents a novel approach towards well integrity management utilising advanced modelling of the well structure coupled with a newly developed non-destructive examination technique to provide the best possible assessment of the health condition of the well system. An accurate assessment is paramount for operators...

Applied Ocean Research, 2017

The life extension of ageing oil wells is becoming an ever more crucial part of an operator's act... more The life extension of ageing oil wells is becoming an ever more crucial part of an operator's activities in recent years, mainly due to slumping oil price which discourages new exploration and the potential extended operation of some older fields with sufficient producing capacity still remaining. The conductor forms one of the primary structural components of wells and its deterioration over time warrants immediate integrity assessment and rehabilitation plans. The construction residual loading or preloads on the conductor are calculated as per standard guidelines and by analytical means during its design and installation phase, but may not be realistic when assessing aged conductors, due to the high levels of over-conservatism built in to address the various uncertainties during the well drilling phase, hence a more practical means of evaluating this residual load is required in carrying out the integrity assessments. This papers presents the novel use of ultrasonic based non-destructive technique (NDT) to measure the conductor preload by observing the travel time of the longitudinal critical refracted (LCR) waves and employing the acoustoelastic method to determine the structural stresses. The measurement of the time of flight (TOF) of this wave component is evaluated from the signals measurement under a range of preload stresses induced into the specimen, and the acoustoelastic calibration curve is obtained as a result, for various section geometries and dimensions. Numerical analyses are also carried out to correlate and validate the magnitude order of the acoustoelastic constant of typical conductor steel grade (Grade-B). These are in good agreement with each other and can be a very reliable tool for the on-site preload measurements during oil well integrity assessment. This measurement of conductor preload results in minimising any associated uncertainties, assumptions and the corresponding over-conservatisms carried over from the design stage, hence streamlining the repair and rehabilitation strategies to the most critical well-conductor groups in the field, thus significantly reducing the costs and resources for operators in extending life of aged wells.

2005 1st International Conference on Computers, Communications, & Signal Processing with Special Track on Biomedical Engineering, 2005

Abstract - The intention of this article is to introduce and overview Pneumatic Artificial Muscle... more Abstract - The intention of this article is to introduce and overview Pneumatic Artificial Muscles (PAMs) as whole and to discuss on its numerical modelling, namely using the Finite Element (FE) Method, to understand more on its behaviour in generating force for actuation. The ...

de.manu-systems.com

- The intention of this article is to introduce and overview Pneumatic Artificial Muscles (PAMs).... more - The intention of this article is to introduce and overview Pneumatic Artificial Muscles (PAMs). The construction of PAMS mainly consist of flexible, inflatable membranes, having orthotropic material behaviour. The main properties shaping the PAMs will be explained in terms of ...

Abu Dhabi International Petroleum Exhibition and Conference, 2014

Zakum Development Company (ZADCO) is operating Upper Zakum (UZ) Field offshore Abu Dhabi consisti... more Zakum Development Company (ZADCO) is operating Upper Zakum (UZ) Field offshore Abu Dhabi consisting several offshore wellhead platform towers (WHPT) which have been in service for over 30 years and evidence of severe corrosion has been found on majority of these well's conductors and casings. A major challenge faced by ZADCO is to repair corroded well's conductor casing to prevent well structural collapse and extend the life further to allow for safe and planned retirement. The challenges faced during the assessment includes the absence of design basis, well age, data accuracy and drilling quality for 30 years, the challenges takes another dimension when factoring the number of wells and possible different configurations. They way forward was to categorise the wells into several groups with close design configurations and then reverse engineer the design basis to a build a structural model for that fits the various wells configuration to establish the minimum thicknesses to ...