Application of drilling microchips for measurement of circulating pressure and temperature in vertical wells

Abstract

This study presents successful applications of drilling microchips to acquire distributed pressure and temperature data while drilling. It also presents the application of our developed method to track the drilling microchips in pipe and annulus. The measured data in the time domain are converted into a depth profile considering the slippage of drilling microchips. The method calibrates the predicted transit time with the actual transit time by varying a velocity profile parameter for both pipe and annulus sections. Over 100 drilling microchips were deployed in two batches in a vertical well. A total of 24 drilling microchips were retrieved at the surface, which showed a physical recovery rate of 25%. The field results indicate that none of the microchips were trapped for any time as sufficient pump rates were maintained throughout the job. A consistent pressure measurement in annular space is obtained from the results of drilling microchips. A unique circulating temperature profile for all the deployed microchips is obtained. It is realized that a short break in circulation may not significantly affect the circulating fluid temperature, but significant pressure changes can be detected from the pressure results. The measured pressure data provide new insights about the tracking of drilling microchips in flow conduits and allow obtaining distinct velocity profile parameters in both pipe and annulus. The method is useful for acquiring downhole data in critical zones where the application of logging tools is risky.

Keywords

• Drilling microchips
• Circulating temperature
• Circulating pressure
• Flow regime
• Tracer tracking