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Drill string rotary speed influence on equivalent circulating density value

Wiśniowski R., Skrzypaszek K., Kiebzak P.

AGH Drilling, Oil, Gas

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2018

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Vol. 35, no. 1

283--294

EN

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.

2

Wellbore trajectory impact on equivalent circulating density

Wiśniowski R., Skrzypaszek K., Kiebzak P., Kański M.

AGH Drilling, Oil, Gas

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2017

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Vol. 34, no. 1

181--202

EN

Undermentioned article presents how wellbore trajectory changes may impact mud flow pressure losses in wellbore annulus and overall Equivalent Circulating Density (ECD) value. In order to investigate this topic, there were conducted two series of tests. In the first round actual, field data from six previously drilled wells was used to recreate real wellbores conditions in Halliburton Landmark Drilling Software and to calculate ECD values. In order to check and confirm the results accuracy, the outcomes were compared with pressure while drilling (PWD) equipment surveys’ results made during drilling operations. Next it was analyzed how ECD parameter's values change in particular sections of vertical and horizontal wellbores, due to trajectory angle modifications. With aim of expanding scope of the work, the second group of tests was made in Drilling Fluids Laboratory at Faculty of Drilling, Oil and Gas. Using Grace Sagging Tester M8500 Ultra HPHT it was examined how in wellbore conditions (high pressure and temperature) wellbore trajectory angle modifications may impact solids sedimentation process and fluid density changes in the annulus thus ECD value as well. The results indicate that there is a relationship between wellbore trajectory angle changes and ECD value shifts. In addition there are included field tests outcomes prepared by K&M Technology Group which confirm presented assumption.

3

ECD optimization with specially designed low rheology drilling fluids

Wiśniowski R., Skrzypaszek K., Kiebzak P.

AGH Drilling, Oil, Gas

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2017

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Vol. 34, no. 1

169--179

EN

This article presents a method in which low rheology drilling muds are used as a solution for demanding wellbore pressure management and high Equivalent Circulating Density (ECD) values. In order to investigate this problem series of numerical simulations were conducted. 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. In order to check and confirm the program’s results accuracy, the outcomes were compared with pressure while drilling (PWD) equipment surveys results made during drilling operations. Next, simulations were made in order to check how low rheology parameters of drilling muds will impact overall ECD values. Additionally in the article are included field tests results from Hibernia Platform, prepared by Bolivar, Joung et al. in 2007 where specially treated (TMSB) low rheology drilling fluids was used to mitigate lost circulation issues and extensive ECD values. Both researches’ results indicate that low rheology drilling muds may solve ECD optimization problems while still maintaining required properties and executing tasks of drilling fluids.