Zahiraniza Mustaffa

An application of K-Nearest Neighbor interpolation on calibrating corrosion measurements collected by two non-destructive techniques

Every measuring equipment or inspection tool is known to have its own accuracy, which may affect the reliability of its measurements. This affects Oil and Gas pipeline corrosion measurements, which may affect data reliability if not well interpreted. The inspection tolerance occurred in the measurements should be treated carefully for each equipment to prevented misinterpretation of the data which could lead to incorrect assessment. This paper presents a new application of K-Nearest Neighbor interpolation to calibrate corrosion measurements collected by Magnetic Flux Leakage intelligent pig (MFL-IP) with the readings of Ultrasonic Testing (UT) scan device. The final enhanced metrics will be used in the integrity assessment report of the pipeline to decide whether the pipeline is fit for service or needs certain maintenance.

Bending and Moment Stability in Reel Mechanisms

This paper is examining the instabilities of reeled pipelines during spooling of initially straight or laying of initially bent pipe and sifting parametrically number of reel lay mechanisms. A combination of composite materials is studied and number of bending stability cases (i.e., ovalization and bifurcation buckling) is discussed. It is demonstrated that composite pipeline exhibit more stability than Steel pipes. The bending stability of spooled pipeline is examined in detail and, in particular, the case on the diameter drum of the reel lay system. Moreover, results on the strain energy release in the reel lay system are presented, extending the findings of previous works on controlling the spooling or laying mechanism.

Wounding Composite Pipeline with Internally Pressurized Conditions

Although installing offshore pipelines by reel-laying method is eases and cost-effective, still conceal some of plastic deformation into the pipeline which may, in combination with ageing, affect strength and ductility of the pipe material. Therefore, reeling pipelines that internally pressurized is addressed in this study sifting parametrically pipelines stiffness to prevent the ovalization and bifurcation produces during spooling of (initially straight) or laying of (initially bent) pipe. A combination of composite materials is examined and number of bending cases at the limit of ovalization and bifurcation is investigated. It is demonstrated that composite pipeline exhibit more bending stability than Steel. Results on the strain energy release in the reel lay system are presented, extending the findings of previous works on the methods of spooling and laying mechanism.

Hydraulic characteristics of energy dissipation systems

Hydraulic structure design deals with the water flow and its effects on the built and natural environment. The construction of various water structures causes scour downstream due to the erosive action of water flowing over or through these hydraulic structures. Energy dissipating structures are the common engineering solutions applied to a water system to reduce environmental impact like local scours. The baffle blocks for instance, are normally provided at the downstream section of high velocity flow (supercritical) simply to convert it to low velocity flow (subcritical). This paper aims at studying the impact of scour depths caused by high velocity flows of an energy dissipation system. The system comprises several energy dissipation components such as the baffle blocks, chute blocks, steps and concrete apron. The hydraulic characteristics of flows surrounding the system were critically studied. The flow was studied under moderate flows (12 to 15 L/s). The effectiveness of the system was measured based on the percentage loss of energy captured by each energy dissipation component.

Sustainable and Eco-Friendly Vege Roofing Tiles: An Innovative Bio-Composite

This paper presents a research study conducted on the usage of vegetable oil for the production of eco-friendly Vege roofing tiles. Conventional roofing tiles which constitute of concrete and clay are considered as environmentally unfriendly because of the significant amount of greenhouse gas emission during their production. An entirely novel methodology of utilizing catalyzed vegetable oil is proposed which can totally replace the use of traditional binders like cement and clay. Limited trails conducted on prototypes samples revealed that when catalyzed vegetable oil mixed with aggregates, properly compacted and heat cured at 190oC for 24 hours, have shown flexural strength up to 9.5 MPa. The superior strength gain of these prototype samples was considered due to the use of the catalyst with vegetable oil, which resulted in the initiation of catalytic oxy-polymerization set of reactions during heat curing, converting vegetable oil to solid, hard polymer which is considered responsible for strength achievement factor for these novel Vege roofing tiles. All prototypes samples were tested for performance indicators like water absorption, permeability, and flexural strength according to ASTM standards. Moreover, the susceptibility of oil leachate from the tiles oil, when tested using electrical conductivity method showed a negligible amount of the electrical conductivity. Moreover, the estimated embodied energy requirements for these tiles were found quite less when compared to conventional tiles.

The effect of different weight functions on calibrating corrosion measurements using KNN technique

Pipeline corrosion scan devices have different accuracies which may affect the reliability of corrosion measurements used to investigate the pipeline’s integrity assessment. In this paper K-Nearest Neighbor (KNN) interpolation technique was used to enhance the accuracy of corrosion measurements collected by two corrosion scan devices. Considering that KNN is a weighted interpolator, the use of the proper weight function will raise the chance of representing the original points correctly. The effect of using various weight functions within (KNN) were tested to determine the most appropriate interpolator for calibrating corrosion metrics. The comparison has relied on the effect of the weight function on the neighbor points, the position of the interpolator, and the error between the original and the enhanced metrics using the interpolation technique. (KNN) interpolation showed the potential to enhance corrosion measurements collected by several scan devices with different accuracies. This enhancement will b...

Reassessment of Remaining Strength of Subsea Corroded Pipeline using Bayesian Updating

System strength evaluation of subsea pipeline, which has already completed its design life, is an important issue to deal with especially when hydrocarbon is the material to be transported. The remaining strength of pipeline in terms of probability of failure can be determined using assessment of maximum operating pressure and its capacity by using burst test results. Monte Carlo simulation is used to find probability of failure and then with burst test results the existing probability of failure can be updated using Bayesian updating technique.

Finite Element Assessment of Difficult Pipelines at Bends

This paper presents numerical assessment of difficult pipelines at bends using the finite element method (FEM). Difficult pipelines are those that are unable to be inspected using a pig inspection tool. These unpiggable pipes, especially at the bend sections, exhibit difficulties to be piggable for several reasons, thus they are exposed to hazards that can neither be inspected nor controlled. The structural response of the bends is then required to be investigated. This paper aims at simulating the structural response of bends caused by internal corrosions using the ANSYS FEM software. Circular pitting corrosion at different depths and diameters were applied to simulate the stress distribution for three pipe models, namely standard 90° pipe bend, miter bend and unbarred full-bore tees pipe bend near dead end. The results of different corrosion equivalent stress distribution were compared and the most reliable type of bend was reported.

Top-of-Line Spatial Corrosion Prediction in Gas Pipelines

The top-of-line corrosion (TLC) is corrosion observed at the upper section of a pipeline, as measured from the circumference of the pipe. The magnitude of TLC is mostly determined using the mechanistic condensation models. The spatial prediction of TLC, however, has not been of the interest among researchers, so as to know at what o’clock orientations (with respect to pipeline cross section) corrosion may accumulate the most. TLC spatial prediction is directly related to the release of corrosion inhibitor (CI) in the pipeline. The probability of retaining CI at the upper part of the pipeline is always a challenge due to the inconsistency of the operational flow parameters coupled by acceleration due to gravity. Thus, there is the need to properly understand the development of TLC with regard to its space. This paper proposes the analysis on TLC spatial prediction to be carried out by means of statistical approaches called the Exploratory Data Analysis (EDA) due to the nature of corrosion that are random. EDA is a simple tool that is able to summarize the main characteristics of TLC data using visual methods. The TLC data was taken from a gas pipeline operating in Malaysian offshore region. A median polish model (of EDA) for the TLC was later generated. A prediction table was also developed to guide users on the estimate of TLC in gas pipelines with regards to the o’clock orientations of the pipe circumference.Copyright

A Review on Composite Materials for Offshore Structures

Research into advanced composite materials for offshore structures is growing due to factors such as new challenges in extreme environments, contaminated contexts (chemical, biological) and increasing awareness of earthquake risks. Advances in theory and practice of composites technology have modified the general perception of offshore structures. This paper provided an introduction to composite material and reviewed the application of composites in offshore structures. This survey focused on (1) composites, especially FRP, for repairing offshore structures and also (2) fire protection of composites in offshore structures. Various national and international research projects on uses of composites for marine structures either ongoing or completed during last decades summarized. Future environmental issues considered and eco-friendly sustainable composite suggested and forecasted for new generation of offshore structures.Copyright