Explain how you can identify the best fit rheological model (Newtonian, Binghanm Plastic or Power Law)...

 

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Explain how you can identify the best fit rheological model (Newtonian, Binghanm Plastic or Power Law) for drilling fluid using viscometer measurements. Following readings were obtained from a rotational viscometer for a water based drilling mud; Rotor speed (rpm) Dial Readings (degrees) 600 63 300 43 200 35 100 24 4.5 3 3.5 a) Determine if the fluid behavior is Newtonian or non-Newtonian. Explain why? b) If the fluid behavior is non-Newtonian, explain how to determine whether it is Bingham Plastic or Power Law. c) Calculate parameters of rheological model selected in part b and determine the rheological model equation as the best fit curve. d) Using the power law model, compute the frictional pressure gradient if the mud is circulated in a 2.9 in ID drillpipe with a 50 gal/min flow rate. Assume the flow patern is laminar. e) Compute the shear rate at the wall of the drillpipe. What two rotational readings would you expect to give the best n and K factors for the pressure gradient computation. f) Calculate flow velocity and shear stress at 0.5-in away from the center of the pipe. 6. Explain how you can identify the best fit rheological model (Newtonian, Binghanm Plastic or Power Law) for drilling fluid using viscometer measurements. Following readings were obtained from a rotational viscometer for a water based drilling mud; Rotor speed (rpm) Dial Readings (degrees) 600 63 300 43 200 35 100 24 4.5 3 3.5 a) Determine if the fluid behavior is Newtonian or non-Newtonian. Explain why? b) If the fluid behavior is non-Newtonian, explain how to determine whether it is Bingham Plastic or Power Law. c) Calculate parameters of rheological model selected in part b and determine the rheological model equation as the best fit curve. d) Using the power law model, compute the frictional pressure gradient if the mud is circulated in a 2.9 in ID drillpipe with a 50 gal/min flow rate. Assume the flow patern is laminar. e) Compute the shear rate at the wall of the drillpipe. What two rotational readings would you expect to give the best n and K factors for the pressure gradient computation. f) Calculate flow velocity and shear stress at 0.5-in away from the center of the pipe. 6.

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For Non Newtonian model there 19 Usually a rgion at both low and hgh shear ... View the full answer