Radio Frequency Identification (RFID)-Enabled Circulation Sub Precisely Spots Loss Circulation Material in Critical Interval

Abstract

Pumping loss circulation material (LCM) to control drilling fluid losses to the formation is part of the overall solution when taking losses in a drilling operation. Precisely spotting the correct volume of LCM and protecting sensitive directional tools in the BHA has proven to be a considerable challenge. Recently in a critical offshore well in Norway, the 6.5? intermediate section was drilled to 10,446 feet through a soft porous limestone formation. In addition to the chalk formation's propensity for seepage, a pre-existing natural fault was also present. The drilling fluid utilized to drill this section was 8.7 pound per gallon (PPG) paraffin and mineral based mud. Factors key to controlling losses were LCM displacement in precise intervals of the section and timely delivery of the material into the well annulus through a diverter circulation sub. High flow rates and minimal differential pressure at the tool were key to the mud program. Because the RFID enabled diverter circulation sub was capable of being selectively opened and closed using specifically programmed transponders, it did not require a ball seat or mechanical indexing system. This feature coupled with the diverter circulation sub's extra-large total flow area (TFA) and integrated flapper system allowed precise and timely LCM pumping while completely protecting the measurement while drilling (MWD) and rotary steerable (RSS) systems from damaging debris. A total of twenty-nine pills were pumped in the fourteen-day period it took to drill the section. The intermediate section was drilled to 10,446 feet through a soft porous limestone formation. In addition to the chalk formation's propensity for seepage, a pre-existing natural fault was also present. The drilling fluid utilized to drill this section was 8.7 pound per gallon (PPG) paraffin and mineral based mud. Factors key to controlling losses were LCM displacement in precise intervals of the section and timely delivery of the material into the well annulus through a diverter circulation sub. High flow rates and minimal differential pressure at the tool were key to the mud program. Because the RFID enabled diverter circulation sub was capable of being selectively opened and closed using specifically programmed transponders, it did not require a ball seat or mechanical indexing system. This feature coupled with the diverter circulation sub's extra-large total flow area (TFA) and integrated flapper system allowed precise and timely LCM pumping while completely protecting the measurement while drilling (MWD) and rotary steerable (RSS) systems from damaging debris. A total of twenty-nine pills were pumped in the fourteen-day period it took to drill the section. The circulation sub was strategically opened and closed during this pill and LCM pumping program to control losses and allow the operator to drill ahead. By utilizing an RFID enabled circulation sub specifically designed to displace heavy pills and LCM, the operator was able to control losses, maintain proper hydrostatic pressure, and reach total depth (TD).