Optimised centrifuge performance for fluid cleaning during CT drilling

MinEx CRC researchers have identified centrifuge operating parameters (most importantly bowl rotation speeds) required to optimise separation of solids and drilling fluids at flow rates and fluid viscosities typical of coiled tubing (CT) drilling.

Centrifuges, for the separation of solid phases from drilling fluids, are critical components of the Hydraulic Processing System (HPS) which delivers clean drilling fluid vital for CT drilling. To date, the centrifuges used for solid separation in the drilling industry have been optimised for fluid parameters typical of diamond drilling. There has been little understanding of centrifuge performance over the range of fluid parameters encountered during CT drilling, including higher fluid viscosity, higher flow rates and coarser solid load than diamond drilling.

MinEx CRC established a stand-alone project to address the issue of centrifuge performance in the context of CT drilling. The project relies on extensive experimental study, characterising the performance of centrifuge decanter under different CT drilling conditions. We have set up a field-scale centrifuge decanter in our dynamic loop experimental facility at Curtin University. Our first experiments have shown a sensitive relationship between centrifuge performance and bowl rotation speed – which in some circumstances requires adjustment of the centrifuge outside the typical operating range. Preliminary findings suggest that the optimised operating parameters are achievable (and safe!) and can be accommodated in the HPS design.

Our findings pave the way for an efficient CT drilling platform and will be used to tune and optimise the control system of the centrifuge component of the HPS – to match and constantly adjust to fluid characteristics and drilling conditions. We look forward to deploying a prototype version of the optimised centrifuge and control system in CT drilling operations during 2021.

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