4 May 2018
Girvani Manoharan was awarded a Rideal Travel Bursary in October 2017 to travel to the NIST Centre for Neutron Research (NCNR) at Gaithersburg, Maryland, USA. Gurvani is a PhD student at the University of Aberdeen. Here, she describes how this research has broadened her scientific interests and the opportunity to present her research to the glass science community and receive valuable feedback.
‘I have always held a passion for academia, the pursuit of knowledge, and the practical application of science. I have diverse qualifications spanning physics (BSc), computing (BSc), biomedical engineering (MSc), and petroleum engineering (MSc). In addition to my academic qualifications, I have extensive knowledge of the oil and gas sector having worked as a reservoir engineer for three international operators. I worked as an Operations focused reservoir Engineer with Centrica and Maersk Oil Qatar, and before that as an Exploitation Engineer (Reservoir Engineer) with CNR International covering several assets across the North Sea.
‘I am currently a PhD student at the School of Engineering, University of Aberdeen. My PhD is on ‘In-situ visualisation of initiation and propagation of fractures in rocks’ and is supervised by Dr Yukie Tanino and Dr Amer Syed. I was awarded the SCI/RSC Rideal Travel Bursary October 2017 of £500 to travel to NIST Centre for Neutron Research (NCNR) at Gaithersburg, Maryland, USA. I have visited the NCNR in March 2018 with my supervisor Dr Amer Syed. At NIST I have worked with Dr David L Jacobson and Dr Jacob M LaManna to acquire neutron and X-ray images of Locharbriggs and Bearl sandstones under different loading conditions.
Background of the research
‘Fractures (naturally occurring as well as stimulated) in rocks facilitate effective flow of hydrocarbons from reservoir rocks. Hence an accurate prediction and characterization of fractures are necessary for increasing the rate of success and efficiency of recovery processes. Despite a large body of literature on fractures mechanics, fracture initiation in rocks is not very well understood and direct observations are limited.
‘The aim of this project is to acquire 3D neutron and X-ray images of fracture initiation and propagation under different states of triaxial stress. The two techniques offer complementary observations of the microstructure of the rock due to their different contrast generation mechanisms. The experiments are expected to inform the fracture parameters (fracture length and width) and details of crack tip stress field. The project intends to utilise combined X-ray and neutron imaging facility at the NIST Center for Neutron Research Gaithersburg, USA. The data sets obtained would significantly enhance the existing knowledge of fracture mechanics in rocks both through direct observations and by providing high-quality data for the development of numerical models. This information will be useful to the operators in designing well stimulation treatments as well to optimise reservoir management for improved oil recovery.
Research Outcomes
‘Locharbriggs and Bearl sandstones were chosen for the experiment due to their different grain size distribution and strength. Both rock samples were imaged under following axial stress conditions: 0 psi, 500 psi, and 900 psi. Acquired projections from X-rays and neutron tomograms are currently being processed and reconstructed. Reconstructed images will be analysed to identify the initiation of cracks and their propagation hence infer details of fracture length, fracture aperture and crack tip stress field. The data will be used to develop a percolation-based model to correlate numerically estimated fracture initiation and propagation with those observed from direct imaging. The results will be presented and published.
Impact of SCI/RSC travel bursary
‘This visit allowed me to benefit greatly from the scientific input of the Neutron Physics group at the NIST. They also provided access to a wider range of laboratory equipment and to benefit from the experience of people who worked for many years in this field. SCI/RSC bursary provided an opportunity to for researchers in the UK to collaborate with our colleagues in the US and to experience US research cultures and perspectives.’
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