Experimental Study of Hole Cleaning Performance of Underbalanced Drilling at Downhole Conditions

Abstract

Underbalanced drilling is one of the most widely used drilling technologies while drilling poor permeability, low pressure and depleted reservoirs. Advantages inherent in application of this drilling technique which are major factors affecting cost, time and drilling quality can be significantly hindered due to poor hole cleaning performance. Experimental study of hole cleaning performance in underbalanced drilling at downhole temperatures26 0 C, 40 0 C and 60 0 C and water influx of 0.25m 3 /s in a simulated vertical well using gasified mud was carried out. Results showed that increasing down-hole temperature by 34 0 C above 26 0 C (ambient temperature) caused 42% and 21.6% increase in annular concentration at flow rates 0.3m 3 /s and 1.6m 3 /s respectively. Increasing mud flow rate by 1.3m 3 /s above 0.3m 3 /s at downhole temperatures:26 0 C and 60 0 C and water influx at 0.25m 3 /s caused 68% and 47.6% decrease in annular cutting concentration. Increase in downhole temperature at constant flow rate resulted in poor hole cleaning performance due to increased in annular cutting concentration. Also, increasing mud circulation rate at a given downhole temperature led to an improved hole cleaning performance due to decrease in annular cutting concentration. Sensitivity studies of effect of mud viscosity, gas/liquid ratio, cutting density and water influx at 40 0 C revealed that increasing mud viscosity and gas/liquid ratio significantly improved the hole cleaning performance while cutting density and water influx cause poor hole cleaning. However, effect of increasing water influx becomes problematic only when the volume is excessively high and miscible with the circulating mud.

Examination of drill pipe corrosion in water-based drilling fluids under wellbore conditions

“…These studies were limited to specific working conditions, and most of these studies were conducted under ambient and static conditions, which were considerably different from the actual corrosive conditions present during a drilling operation [5,7,8]. Dynamic tests were mainly performed in simple glass cells comprising rotating cylinder electrode, which could exhibit some basic corrosion characteristics but not the downhole conditions or large flow loops under high pressure and temperature that were used to mimic the complex and expensive downhole conditions [9][10][11].…”

Review of synthesis, characteristics and technical challenges of biodiesel based drilling fluids

“…r n a l P r e -p r o o fThe performance of drilling fluids can be determined by the capability to carry the cuttings out of the borehole(Lyons, Plisga, and Lorenz 2015;Adeboye and Oyekunle 2016;Husin et al 2015).Hole cleaning indicates the drilling fluids' capacity to transport and suspend the cuttings and the other solids. Hole cleaning relies on many parameters such as, drilling fluid properties (as rheology and density), annular velocity, well design, rotary speed, and cuttings characteristics (shape, density, size and aggregation)(Adeboye and Oyekunle 2016;Kenny and Hemphill 1996;Valluri et al 2006).…”

“…r n a l P r e -p r o o fThe performance of drilling fluids can be determined by the capability to carry the cuttings out of the borehole(Lyons, Plisga, and Lorenz 2015;Adeboye and Oyekunle 2016;Husin et al 2015).Hole cleaning indicates the drilling fluids' capacity to transport and suspend the cuttings and the other solids. Hole cleaning relies on many parameters such as, drilling fluid properties (as rheology and density), annular velocity, well design, rotary speed, and cuttings characteristics (shape, density, size and aggregation)(Adeboye and Oyekunle 2016;Kenny and Hemphill 1996;Valluri et al 2006). Hole-cleaning is especially important in horizontal and highly deviated drilling(Piroozian et al 2012;Caenn and Chillingar 1996).Generally, the ester-based drilling fluids showed superior ability to suspend and carry cuttings in comparison to the diesel oil-based drilling fluid (DODF) and low toxic oil-based drilling fluid (LTODF).…”