Petroleum Engineering

Kinetic hydrate inhibitors (KHIs) are employed to mitigate gas hydrate formation in pipelines at low concentrations. Ionic liquids and conventional available KHIs (polymers) perform poorly at high subcooling and extended shut-in conditions. Thus, it's necessary to understand the inhibition mechanism and performance of mix kinetic inhibitors for gas hydrate mitigation in oil and gas transmission lines. In this work, the synergic kinetic inhibition effect of 1-Ethyl-3-methy-limidazolium chloride (EMIM-Cl) + Polyvinylpyrrolidone (PVP) on the induction time and gas uptake during carbon dioxide (CO2) gas hydrate formation is reported. The study was performed in a high pressure sapphire cell at a pressure and temperature of 36 Bar and 1 o C respectively using an isochoric constant cooling method. Result suggests that, the induction time of deionized water + carbon dioxide hydrate increased over 100% in the presence of pure EMIM-Cl and PVP, with PVP slightly higher than EMIM-Cl comparatively. Surprisingly, a significant reductions in CO2 hydrate inhibition performance is observed in the presence of EMIM-Cl + PVP studied synergic systems compared to their inhibition in pure state.

The effect of salinity towards methane hydrate formation and induction time was modelled using CMG STARS. Salinity greatly influenced gas hydrate formation and dissociation due to its ability to act as an inhibitor by delaying the nucleation of methane hydrate. However, most of the developed kinetics model did not take into consideration of salts in porous media during the simulation. In this research, the objectives are to simulate and investigate the induction time of methane hydrate formation using Clarke and Bishnoi kinetic model in the presence of saline water. The simulation is conducted using different salinity concentration of 0 ppm, 5000 ppm, 15000 ppm, 25000 ppm,35000 ppm, and 40000 ppm. The presence of salts in porous media increases the induction time from 464 minutes to 515 minutes.

In an offshore system, hydrocarbon fluids are produced at deeper depths in the oceans, and extended pipelines delivering fluids over long distances are common. Subsequently, these practices increase the tendency of unprocessed water-containing hydrocarbon fluid to be exposed to lower temperatures and higher pressures conditions where hydrate formation is favourable. One of the solutions to resolve this problem is by introducing hydrate inhibitors preferably low dosage hydrate inhibitors (LDHIs). The more versatile LDHIs; Kinetic Hydrate Inhibitors (KHIs) could further be optimised in cost and its biodegradation properties. The current study used an ionic, neutral, hydrophilic, mucoadhesive and highly branched Tamarindus indica L. polysaccharide (TSP). TSP as a new natural kinetic hydrate inhibitor due to its high methoxyl content. In this study, the polysaccharides were extracted using water-based extraction method which resulted in 61.3% yield. The performance of TSP in delaying th...

The influence of water to cement ratio and degree of hydration to the dispersion characteristic of oilwell cement slurries during 24 hrs of hydration is evaluated and expressed in the form of magnitude and frequency effect at above cutoff frequency. It is observed that the magnitude of conductivity dispersion increases with the reduction in water content and pore volume. At initial hydration, the dispersion characteristic appears in the minimum value and raises as hydration continue. The frequency effect is growth as the hydration and saline concentration increases. It is shown that the single frequency measurement for evaluating the cement slurries properties may not be reliable. An implicit correlation to the interface conductivity is indicated from dispersion respond throughout hydration process.

The influence of water to cement ratio and degree of hydration to the dispersion characteristic of oilwell cement slurries during 24 hrs of hydration is evaluated and expressed in the form of magnitude and frequency effect at above cutoff frequency. It is observed that the magnitude of conductivity dispersion increases with the reduction in water content and pore volume. At initial hydration, the dispersion characteristic appears in the minimum value and raises as hydration continue. The frequency effect is growth as the hydration and saline concentration increases. It is shown that the single frequency measurement for evaluating the cement slurries properties may not be reliable. An implicit correlation to the interface conductivity is indicated from dispersion respond throughout hydration process.

First of all, I would like to thank GOD for His Blessing and giving me the strength to successfully complete my Final Year Project with ease for this whole semester at Universiti Teknologi PETRONAS (UTP). There were many individuals and parties in which without hesitation I can say that my project could not be completed successfully without their generous assistance. Special thanks to my supervisor, Associate Professor Dr. Cecilia Devi Wilfred. The supervision, support, encouragement and advises that she gave truly help the progression and smoothness of the project. This report could not also been completed without generous assistance from many sources. Over the months, the department of PETRONAS Ionic Liquid Center (PILC) has supplied necessary research facilities and technical guidance to me, and. I wish to thank all the (PILC) staff and graduate assistants and also the technicians of UTP Petroleum Engineering Department who directly or indirectly helped me in completing this project. in sincere, if inadequate, recognition of her long-standing support. Last but not least, I would like to thank my family and friends for their moral support throughout the project as well as giving valuable tips and ideas which have guided me into completing this report successfully project.

This project investigates characteristics of vibration of a drillstring under the action of weight on bit and drillstring rotation. The dominant cause of drillstring and bottom hole assembly's failures, shocks and severe damages to borehole wall is recognized to be the lateral vibration. Thus, lateral vibration is chosen to be the only factor of interest and focused in this project. Lateral vibration manifests itself from the increased speed of rotary drilling. This study presents a finite element model using ANSYS software to investigate the lateral vibration of drillstring in a vertical well. The analysis proceeds in two stages. Firstly, modal analysis is performed to determine the natural frequencies of the drillstring and the second stage is to carry out harmonic analysis to obtain the frequency response at a varying length of drill pipe. Simulation is first carried out by simulating benchmark problem before proceeding to deal with the actual case studies by carrying out parametric study (drillstring length, weight on bit, rotational speed) and the results obtained are satisfying.

This project investigates lateral vibration of a drillstring under the action of weight on bit and drillstring rotation. The dominant cause of drillstring and bottom hole assembly’s failures, shocks and severe damages to borehole wall is recognized to be the lateral vibration. Thus, lateral vibration is chosen to be the only factor of interest and focused in this project. Lateral vibration manifests itself from the increased speed of rotary drilling. This study presents a finite element model using ANSYS software to investigate the lateral vibration of drillstring in a vertical well. The analysis proceeds in two stages. Firstly, modal analysis is performed to determine the natural frequencies of the drillstring and the second stage is to carry out harmonic analysis to obtain the frequency response at a varying length of drill pipe. Simulation is first carried out by simulating benchmark problem before proceeding to deal with the actual case studies by carrying out parametric study (...

In this work, two different artificial neural network (ANN) models — back-propagation neural network (BPN) and radial basis function neural network (RBFN) — are presented for the prediction of surface roughness in die sinking electrical discharge machining (EDM). The pulse current (Ip), the pulse duration (Ton), and duty cycle (τ) are chosen as input variables with a constant voltage of 50 volt, and surface roughness is the output parameters of the model. A widespread series of EDM experiments was conducted on AISI D2 steel to acquire the data for training and testing and it was found that the neural models could predict the process performance with reasonable accuracy, under varying machining conditions. However, RBFN is faster than the BPNs and the BPN is reasonably more accurate. Moreover, they can be considered as valuable tools for EDM, by giving reliable predictions and provide a possible way to avoid time-and money-consuming experiments.

Abstract: In this analysis, the optimisation of multiple responses of Electric discharge machining (EDM) using Fuzzy logic coupled with Taguchi method is attempted. The work piece material was AISI P20 tool steel and a cylindrical copper electrode was used with side impulse flushing. The influence of machining parameters, ie, pulse current (Ip), pulse duration (Ton), work time (Tw), lift time (Tup) and Inter Electrode Gap (IEG) on the Material Removal Rate (MRR) and Surface Roughness (SR) in EDM are examined. L27 ...

Electric discharge machining (EDM) has verified to be an alternate approach for machining complex and critical shapes on workpiece. In this work described EDM of AISI P20 tool steel in which best process environment (optimal) has been determined to satisfy efficiency of graphite electrode material. Multi objective optimization of various EDM parameters for obtaining favorable preference measures in surface integrity (surface crack density, white layer thickness and surface roughness) using PCA based grey relational analysis has been selected.