Drill string rotary speed influence on equivalent circulating density value
Rafał Wiśniowski, Krzysztof Skrzypaszek, Piotr Kiebzak
Vol. 35, no. 1 (2018), pp. 283-293, [1]
Presented article displays a debate about very complex and still not fully understood issue of drill string rotary speed (DSRS) impact on pressure losses in wellbore annulus, thus Equivalent Circulating Density (ECD) value. With the aim of exploring the topic, series of numerical simulations were conducted and presented in following paper. Real, field data from two already accomplished wells was used to recreate actual wellbores conditions in Halliburton Landmark Drilling Software and to calculate ECD values. Dedicated to check and confirm the program’s results accuracy, the outcomes were compared with pressure while drilling (PWD) equipment measurement results, collected during drilling operations. Collaterally, numerical simulations were made in order to analyze how drill string rotary speed shifts may affect overall ECD value, especially in deviated and horizontal wellbore sections. Simultaneously, both rate of penetration and flowrate were modeled to imitate poor and good cleaning conditions. Additionally with the object of confronting received results, in the article are included outcomes of other researchers conducted by T. Hemphill and K. Ravi (2011), I. Kjøsens, G. Løklingholm et al. (2003). Similarly to above mentioned papers, analysis and interpretation of collected data gave contrary conclusions. In other words DSRS can positively impact optimization of ECD value but in the same time cause growth of ECD parameter, depending on current wellbore conditions.