Improving drilling hydraulics estimations-a case study

Abstract

Accurate pressure drop estimation is important for drill string and bit nozzles design and optimized fluid circulations as well as identifying the drilling problems such as bit nozzle(s) washout or plugging. In this study, the Bingham Plastic model has been modified by applying a coefficient to its turbulent pressure loss calculations. This coefficient encompasses the effects of the drill pipe tool joints and other effects in estimation of pressure losses. The range of the coefficient was determined in field applications for different hole sizes and mud types. The results showed that applying a correction coefficient of 1.08–1.12 to turbulent pressure loss equations (depending on borehole size and mud type) improves the pressure loss estimation. By applying this coefficient, the estimated pressure losses are increased to compensate the under-estimation of the Bingham Plastic model. This is considered a significant contribution to accurate calculation of borehole hydraulics and in-time detection and identification of borehole problems and reduction of invisible lost time. The findings also showed that this enhanced effect is independent of the mud type. The use of this coefficient removes the necessity of using rather complex mud rheological models such as the Herschel–Bulkley model.

Discrete fracture modeling by integrating image logs, seismic attributes, and production data: a case study from Ilam and Sarvak Formations, Danan Oilfield, southwest of Iran

“…Assessing and modeling fracture distribution requires inputs from field observations, core analysis, well-log interpretation, fluid production trends, fluid losses during drilling, and wellbore images (Tingay et al 2009, Lacombe et al 2011Nwabia and Leung 2020;Liu et al 2021;Khoshbakht et al 2012;Rajabi et al 2010, Ezati et al 2018Yarmohammadi et al 2020;Ashena et al 2021). Valuable information about fracture systems is also available from seismic data (Al-Dossary and Marfurt 2006;Chopra and Marfurt 2007), including amplitude variations and details of wave scattering and elasticity (Malehmir et al 2009;Tsvankin 2012) and seismic attribute analysis (Karimpouli et al 2013;Kosari et al 2015Kosari et al , 2017Hosseinzadeh et al 2019).…”

Stepwise mathematical derivation of the Herschel–Bulkley laminar fluid flow equations—in pipes

“…Effective diameter defined by Reed and Pilehvari (1993) for non-Newtonian flow, i.e., the diameter of a circular pipe that would have the identical pressure drop for flow of a Newtonian fluid with viscosity equal to the apparent viscosity and the same average velocity as the non-Newtonian flow [m] D hyd Hydraulic diameter used for transformation of pipe flow to annular flow equations [m] f YP A parameter defined by and However, some fluids especially drilling fluids, slurries or suspensions are not well approximated by these two models. Some modifications to these models may be applied to increase their prediction accuracy, and an example is a work done by Ashena et al (2021) by applying a correction coefficient; in another example, roles of different affecting parameters on accuracy were quantified (Ashena et al 2022). Alternatively, non-Newtonian fluids can be better represented by the HB model (Hanks 1979) and the RS model (Robertson and Stiff 1976).…”