Design and development of an X-ray sensor to measure the density and flow rate of drilling fluids in high pressure lines

There is a need for advanced technology that can accurately measure the density and mass flow rate of drilling fluids at the high pressure well inlet in real-time. Current reliance on antiquated metering technologies such as the pressurized mud balance and the pump stroke counter to make these measurements greatly impedes our ability to accurately predict the near well bore pressure profile and measure the delta flow rate, which is one of the primary indicators for trouble events such as kicks or lost circulation. In order to address this gap in technology an X-ray sensor was developed to make real-time measurements at greater than 99% percent accuracy and 1 Hz measurement frequency. The X-ray sensor can measure the density of drilling fluids in the 8 ppg to 20 ppg range and with flow rates of up to 1200 gpm. These measurements are made using 320 kV/1500W polychromatic X-ray source, which is well within the range of readily available industrial X-ray tubes. In the past such measurements would require X-ray voltages that could only be achieved with linear accelerators thereby making the cost and size of equipment non-conducive to the drilling environment. However, recent advances in pipe manufacturing, particularly using a class of low density and high pressure materials known as carbon fiber reinforced polymers (CRPs) and, are now making it viable to re-visit relatively low cost X-rays systems for density and mass flowrate measurements. Windows constructed from CRPs allow us to bypass the high density carbon steel standpipe and make measurements at voltages that do not require a linear accelerator. In this paper we discuss the design and implementation of a CRP based X-ray sensor that is used to measure drilling mud density and mass flowrate at the high pressure well inlet.