Md. Khalilur Rahman (BSc, MEng, PhD, Grad.Dip, MIEB, SPE)

Summary of Research & Development Works

Drill string Design: I have developed a methodology to design drill strings with adequate reliability against static and dynamic loads combining two modules: static endurance limit analysis and cumulative fatigue analysis. The stress concentration due to die-marks on the pipe surface during making and breaking operations by grips is characterized and its effect is incorporated in the static and fatigue tolerant drill string design for the first time. The results of this work were presented in the International Association of Drilling Contractors and Society of Petroleum Engineers (IADC/SPE) Conference and published in two international journals.

Hydraulic Fracture Stimulation: I have been working in a number of projects in this area and carried out research to improve conventional hydraulic fracturing technology and to develop alternative fracturing technology. I have developed improved understandings of hydraulic fracture initiation and propagation based on analytical, numerical and experimental investigations. The major causes of conventional treatment failures in complex reservoir conditions are established by simulating mixed-mode fracture propagation by a boundary element based code, HYFRANC3D and potential remedies are recommended. Improvements in conventional hydraulic fracturing are also demonstrated by better treatment design for which a novel optimisation scheme is developed. The scheme optimises various treatment parameters integrating reservoir properties, production behaviour, investment-return cash flow behaviour, operational limitations, formation damage control requirements and various decision-making design objectives. The scheme uses the intelligent moving object algorithm (INTEMOB) and a combined objective function, which I developed combining features of genetic algorithm, polytope algorithm and evolutionary operation during my previous extensive research work in optimisation. I have also carried out research to develop an alternative fracturing stimulation technology (shear-dilation/water-frac) for naturally fractured reservoirs for which conventional fracturing treatments have been found ineffective. My major contribution in this work is developing an efficient analytical method for mixed-mode propagation of hydraulic fractures and integrating this with approximate shear-dilation theories. This development has made the response analysis of numerous natural fractures in hydraulically stimulated oil/gas and Hot Dry Rock reservoirs computationally feasible. I have published a significant number of papers in SPE conference proceedings, Journal of Petroleum Science and Engineering and other refereed journals from my work in hydraulic fracture stimulation.

Wellbore stability: I have developed a generic model to analyse various failures in generally oriented wellbores and to define the safe mud window based on the critical failure modes. The time-dependent penetration of drilling mud into shale formation due to the capillary phenomenon, and its effect on wellbore stability, is incorporated in the model based on experimental work and numerical multiphase fluid flow simulation. Chemical potential effects of different drilling fluids are also included. The model is currently improved to assess wellbore stability during High Pressure High Temperature (HPHT) drilling by including ballooning effects due to elastic deformation and fracture charging in naturally fractured formation. We have applied the model in a number of case studies and recommended appropriate drilling fluids to improve wellbore stability. I have published several papers in SPE Conference Proceedings and refereed journals to disseminate the knowledge of this work.

Other Research: Prior to joining the School of Petroleum Engineering in 1997, I conducted research on analytical and numerical analysis and optimum design of large structural systems for over 8 years. During this period, I developed:

I published a number of papers on these research works in refereed journals (please see the List of publications for my full publication records).