SELECTİON OF BEST FİTTİNG RHEOLOGİCAL MODEL FOR DRİLLİNG FLUİDS

Abstract

The rheological parameters of drilling fluids play a vital role in cleaning the drilled rock particles and keeping the rock particles and weighting agent in suspension. If the correct rheological parameters are not selected, various complications may arise in the oil well drilling. In addition to the selection of the rheological parameters of the drilling fluid, the selection of the model for expressing the rheological parameters is also one of the important issues. Different models are used to determine rheological parameters during various calculations. Bingham plastic model for expressing rheological parameters during drilling, power law and modified power law model during hydraulic calculations, etc. To investigate which of these models determines the parameters of the drilling fluid accurately 2 different oil-based drilling fluid samples were prepared.

A 6-speed viscometer was used to measure the shear stress of the prepared drilling fluid samples. The obtained shear stresses were expressed in Pa, and calculations were made by building models. Mean absolute percentage error was used to determine which of the obtained results was more accurate. As a result of the calculations, it was determined that the most suitable model for expressing the rheological parameters of the drilling fluid is the Herschel-Bulkley model.