Research into creative Flow Rate Modelling for improved bitumen extractionLondon South Bank University PhD candidate turned away from existing injected steam and chemical techniques to refine a better approach
Instead, PhD student Marsha Maraj wanted to develop a three-pronged approach to maximise flow rates in an environmentally friendly way for improved bitumen extraction.
Research into creative Flow Rate Modelling
Current recovery rates are low and methods time consuming for extracting bitumen, the high carbon content heavy viscous oil trapped in reservoirs frequently associated with shale formations. LSBU's PhD candidate, Marsha Maraj, has turned away from existing injected steam and chemical techniques to develop a three-pronged approach to maximise flow rates in an environmentally friendly way. The method is planned to be able to be used with any material and in any location.
To date, the two principal ways to extract bitumen are mining to a depth of up to 70 metres or by injecting hot water, with or without chemicals, into reservoirs to increase in situ surface flow rates.
Marsha Maraj explains currently used techniques:
Two horizontal parallel wells are drilled. Through the uppermost we input steam and hot water to heat up and interact with the bitumen to lower its viscosity. It's freed up by emulsification to flow through the second well to the surface.Marsha Maraj, PhD student
The current recovery rate for bitumen in shale formations using this Steam Assisted Gravity Drainage (SAGD) is only about 20%. Conventional techniques are time consuming and expensive, with four barrels of heated water used to extract one barrel of oil. Marsha feels confident her research indicates that improved, less resource heavy, results are possible. She uses property prediction modelling to assess flow rates, as well as costs and energy sources utilised to prepare the steam for injection.
Maraj explains that they want to maximise the potential and do it in an environmentally friendly way.
A new approach to extraction
The project has two components: fabric characterisation to understand the oil sands themselves and then using the oil sands as a medium to create a methodology applicable to any material. The methodology which is the strength of the project can be employed anywhere - used for sandstone, carbonates and for unconsolidated and consolidated shale gas.
Pore Network Modelling
The method developed by Marsha Maraj combines and compares complementary technologies including Micro Computer Tomography (MICRO-CT). This is similar to taking X-rays of underground material in two dimensional (2D) slices that are then reassembled using computer software to obtain a 3D model, in a process known as pore network modelling. This reveals what the internal structure of the materials looks like.
The pore networks we produce are a really realistic representation if what is there, and this can be used to simulate the flow. I will be one of the first researchers to apply these three methods, Micro-CT pore network modelling, NMR and conventional pore testing for oil sands.Marsha Maraj, PhD student
MICRO-CT is complemented with conventional pore testing as well as Nuclear Magnetic Resonance (NMR), a technique that involves applying a magnetic field to a piece of material or sample. By examining the results from these three different methods, Martha is able to test for reliability in the use of unconsolidated and other materials to identify the error margins between them.
The originality of Marsha Maraj's PhD research combines these complementary technologies that have been in the public domain for a long time, using them to test specifically for oil sands rather than for a variety of materials.
LSBU Quality of Research Impressed
Marsha hails from Trinidad and Tobago (TT) in the Eastern Caribbean where she trained first as a mechanical engineer, taught for eight years at the university in TT, did an MSc in Petroleum Technology and then decided to go for a PhD.
Impressed by the quality of research at LSBU she applied and was awarded a studentship. Marsha found that LSBU was a good fit for her because everything she needed for her research was there. She also like the multicultural atmosphere and the area.