OTC-27180-MS Shear Rate Estimation: A Detailed Review A. Raj, D. K. Rajak, S. Gautam, C. Guria, and A. K. Pathak, Indian School of Mines Copyright 2016, Offshore Technology Conference This paper was prepared for presentation at the Offshore Technology Conference held in Houston, Texas, USA, 2–5 May 2016. This paper was selected for presentation by an OTC program committee following review of information contained in an abstract submitted by the author(s). Contents of the paper have not been reviewed by the Offshore Technology Conference and are subject to correction by the author(s). The material does not necessarily reflect any position of the Offshore Technology Conference, its officers, or members. Electronic reproduction, distribution, or storage of any part of this paper without the written consent of the Offshore Technology Conference is prohibited. Permission to reproduce in print is restricted to an abstract of not more than 300 words; illustrations may not be copied. The abstract must contain conspicuous acknowledgment of OTC copyright. Abstract The main objective of this paper is to review the work already done related to shear rate estimation for non-Newtonian fluids with or without yield point or yield stress with the help of basic integral equation of couette flow. Aqueous solution of drilling fluid additives is non-newtonian in nature and exact shear rate determination helps to predict rheological properties, i.e., apparent, plastic viscosity and yield point very accurately. This estimation helps to select appropriate drilling fluid for optimal penetration rate, which makes drilling economical by reducing rig days required to drill total depth. If the fluid additives are chosen correctly, we protect the well from sloughing shales, drill pipe sticking, fluid loss problem etc. and save time as well. Modern logging tools employ mud pulse telemetry to send data to surface which required suitable drilling fluid for proper data communication. It also affects productivity of well. Rising complexity of fluid has made it pertinent to improve acceptable estimation of shear rate determination of apparent viscosity, plastic viscosity and yield point. This paper examines the generalized difference equation for the coquette flow which is used in the evaluation of m (flow behavior parameter) and k (flow consistency parameter) for power law type fluid and Herschel-bulkley type fluid. The proposed shear rate equations which are considered are quite general and can be applied to any fluid. This review paper confines the equations which have been developed for the determination of shear rate along with the rheological properties for the non-Newtonian fluid with or without yield stress, which is essential for the prediction of suitable drilling fluid properties to achieve successful completion of an oil well. Introduction The rate of penetration in any drilling operation is a major component in determining the economics of the oil field, which in turn depends on the drilling fluid used. Rheology of drilling fluid greatly defines its nature. The rheological properties such as viscosity, gel strength and yield point of drilling fluid are needed to be calculated accurately with exact estimation of shear rate (Gatlin, 1960; Darley and Gray, 1986; Bourgoyne et al. 1991). Fann viscometer is used to determine the rheological properties of drilling fluid. It is a device having two concentric cylinders so that fluid can stay in the annulus. Rotor rotation and bob deflection are the two measurable quantities in the viscometer (Bourgoyne et al. 1991). They are Downloaded from http://onepetro.org/OTCONF/proceedings-pdf/16OTC/1-16OTC/D011S003R007/1352654/otc-27180-ms.pdf/1 by Indian Institute of Technology (ISM) Dhanbad user on 23 August 2022