Browsing by Author "Rahman, Kazi Mahmudur"

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    Analysis of Drilling Fluid Rheology & Pressure Drop Modelling to Improve Drilling Efficiency
    (2018-12-21) Rahman, Kazi Mahmudur; Martinuzzi, Robert; Hassanzadeh, Hassan; Wood, David H.; Sudak, Leszek Jozef
    The major drilling problems such as fluid loss, wellbore strengthening, well control, carrying capacity, torque & drag, stuck pipe, etc. can result from the improper matching of drilling fluid properties. These problems occur due to variations in pressure, and temperature which has a great impact on the rheological properties. Drilling fluid properties can be modified for the successful drilling operation. Research continues the development of drilling fluid in shale inhibition, rheology modification, wellbore strengthening, high-temperature, high-pressure (HTHP) drilling fluids, etc. The main goal of this project is to develop a rheology-based pressure drop calculation incorporating the effects of temperature, pressure and gel strength of drilling fluid using experimental results for the better understanding of undesirable viscosity fluctuation and pressure losses. This study is based on the hypothesis that the rheology model for pressure loss prediction can be investigated to the desired level in an experimental laboratory facility, which can be applied to solve/reduce drilling problems in wells. This study presents a simplified procedure for selecting the rheological model which best fits the properties of a given hydraulic fluid to represent the shear-stress, shear-rate relationship for a given fluid. The project assumes that the model which gives the lowest absolute average percent error (EAAP) between the measured and calculated shear stresses is the best one for given drilling fluid. The results are of great importance for achieving the correct pressure drop and hydraulics calculations. It is found that the API rheological model provides, in general, the best prediction of rheological behaviour for the mud samples considered (EAAP= 5.84%). API hydraulics calculation gives a good approximation to measured pump pressure within 14% of measured field data.
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    Remote sensing-based determination of deciduous and understory phenology over boreal forest
    (2011) Rahman, Kazi Mahmudur; Hassan, Quazi K.; Haque, Anis S.
    Phenology of the deciduous trees and understory grasses are the vegetation developmental stages influenced by the climatic variables. The study of the deciduous and understory phenology is important in understanding plant growth, net ecosystem CO2 exchange, forest flammability, forest hydrology, risk of insect infestation, etc. The objective of the study was to determine the phenological stages of deciduous [i.e., deciduous leaf out (DLO), deciduous leaf fall (DLF)] and understory grass green-up [i.e., green grass stage (GGS)] over the boreal forested region in the Canadian province of Alberta. In this study, the MODIS-based 8-day: (i) surface temperature (Ts)-images to derive the equivalent air temperature (T O ; used to determine DLF), (ii) surface reflectances for calculation of normalized difference water index (NDWI: used to determine DLO and GGS) and (iii) accumulated growing degree days (AGDD: a favourable temperature regime for plant growth: used to determine DLO and GGS). The temporal dynamics of AGDD, T O and NDWI was analysed, in conjunction with in-situ DLO, DLF and GGS observations in determining the optimal thresholds for DLO in 2006 (i.e., 80 degree-days and NDWI 0.325), DLF in 2006-2007 (i.e., 4 °C) and GGS in 2006 (i.e., 90 degree-days and NDWI 0.45). The implementation of these thresholds revealed reasonable agreements [i.e. , on an average (91.9% of the DLO and 94.2% of the GGS for AGDD) and (65% of both DLO and GGS for NDWI) within ±2 periods or ±16 days of deviations during 2007-2008; and 77.4% of the DLF for Ta within same deviations during 2008)] with compare to the in-situ observed data.