Hydraulics optimization of foam drilling in drilling operations

Özer, Ceren
In drilling, drilling fluid affects every single step of operation. If rig system is thought as the human body, drilling mud can be defined as the blood system of it. Drilling fluid carries the cuttings, cools the bit, it conditions the hole and so on. Some special kinds of drilling fluids are used for special purposes such as underbalanced drilling. Underbalanced drilling is generally used to prevent formation damage, lost circulation and to increase the penetration rate.Since 1980’s foam is used as drilling fluid for underbalanced drilling purposes and there are some models for bit hydraulic optimizations. In this study, mathematical model has been derived considering not the volumetric flow rate but the mass flow rate of the foams. Maximum hydraulic horse power at the bit is determined as a function of mass flow rate. Using this concept, optimum volumetric flow rates for liquid and gas phases as well as optimum nozzle size are determined.Using this mathematical model, a computer program is developed for comparing the results with the existing data available in the literature. It accounts for the compressibility of foam and pressure losses inside the drill string, bit and annulus.Hole size, drill-string properties, formation temperature and pressure, maximum inlet pressure are used as input parameters. Program calculates static back pressure,pressure losses in the whole system, bottom hole foam properties such as quality and velocity and optimum liquid and gas flow rates which are the key parameters of foamdrilling optimization. Results show that liquid and gas rates should be increased with increasing hole sizeand formation pressure. Increasing temperature gradient causes a minimal decrease on foam rate properties. In addition, pressure losses due to friction increases with increasing hole size and formation pressure. Decrease in formation temperature also decreases the foam quality. Changes in temperature gradient causes minimal changes on foam rate properties. Comparisons of the proposed model with other models from the literature also gave good match. The optimization criteria and assumptions are differing from the existing models. As a result the comparison does not have to one to one match with the others. The results from this study may be used for optimization of flow rate of foam as drilling fluid based on mass flow.


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Gürbüz, Berkay; Mehmetoğlu, Mustafa Tanju; Department of Petroleum and Natural Gas Engineering (2012)
Properly preparing the drilling fluid is an essential part of any successful drilling operation, especially in complex operations like deviated and horizontal drilling. Understanding the flow behavior of the polymers used in the drilling fluids under different conditions takes a key part in this preparation. In this study, shear rheology of some traditionally used water soluble polymers in drilling and completion fluids; namely PAC (polyanionic cellulose) and xanthan gum, were investigated experimentally. I...
Pressure Loss at the Bit While Drilling with Foam
Ozbayoglu, E. M. (Informa UK Limited, 2009-01-01)
Foam is one of the most frequently used drilling fluids at underbalanced drilling operations. As foam flows, due to the pressure drop, a volumetric expansion is observed, which causes the foam quality to increase in the same direction with flow. Flow of foams through circular pipes and annular geometries are well studied. Interestingly, although one of the major sources of pressure drop is at the bit, there have been few studies of this subject for foams. Many drilling parameters including hole cleaning cap...
Rheological evaluation of polymers as drilling fluids
Kök, Mustafa Verşan (Informa UK Limited, 2003-01-01)
Polymers are recently found and still developing materials to overcome some drilling problems where conventional drilling fluids are not satisfactory enough. Simply, they are the best materials to use since they are non-toxic and do not cause serious environmental problems. In addition, polymeric drilling fluids may have properties such as better carrying capacity, less fluid loss, and thinner filtration cake depending on their composition and concentration. In this research, rheological parameters of two d...
Performance analysis of drilling fluid liquid lubricants
Sonmez, Ahmet; Kök, Mustafa Verşan; Ozel, Reha (Elsevier BV, 2013-08-01)
Excessive torque is one of the most important problems in oil/gas drilling industry. Friction between wellbore/casing and drill string causes excessive torque. This study discusses performance analysis of drilling fluid lubricants, which are used as friction reducers in well-bores. Three different types of chemical commercial lubricants, which are fatty acid and glyceride based, triglyceride and vegetable oil based and polypropylene glycol based, diesel oil, and crude oil, which consists of different API gr...
Computational Fluid Dynamics Modeling of Pipe Eccentricity Effect on Flow Characteristics of Newtonian and Non-Newtonian Fluids
SORGUN, MEHMET (Informa UK Limited, 2011-01-01)
The prediction of accurate drilling fluids behavior inside an annulus is especially important in drilling engineering during hydraulic program design. The flow characteristics of Newtonian and non-Newtonian fluids drastically change in the annuli when the inner pipe is eccentric. In this study, the fluid flow inside concentric, partially eccentric, and fully eccentric annuli are modeled using computational fluid dynamics. Computational fluid dynamics simulations are performed to investigate the effect of pi...
Citation Formats
C. Özer, “Hydraulics optimization of foam drilling in drilling operations,” M.S. - Master of Science, Middle East Technical University, 2009.