First LWD NMR Acquisition in 8.5-inch Extended Reach Well

Abstract

Abstract Logging-While-Drilling (LWD) nuclear magnetic resonance (NMR) data was acquired in an extended reach well targeting a carbonate formation to obtain rock quality and permeability data. The challenge was to minimize lateral motion that could affect the NMR data quality. Pre-job modeling was performed to evaluate the bottom-hole-assembly (BHA) stability and optimize the drilling parameters. A novel system using downhole drilling mechanics measurements while drilling was set up to evaluate the effect of drilling mechanics on the NMR sensor while drilling. Several intervals were relogged to compare the drill pass data and the reaming data, to confirm the absence of lateral motion affecting the data. The LWD NMR data was acquired while drilling over just under 4000 ft. The well experienced a build of inclination to optimize reservoir contact. The downhole drilling mechanics flag showed a medium risk of lateral motion, also highlighting the absence of stick and slip while drilling. The LWD NMR drill pass and ream pass data compared well, confirming the absence of significant lateral motion effect on the NMR sensor while drilling. The relog passes experienced more stick and slip than the drill passes, due to the low rotations per minute (RPM) used during ream passes acquisition. The NMR highlighted a good relationship between porosity and pore size distribution in both reservoir sections. For the first time in the region, LWD NMR data is acquired in the 8.5-inch section in an extended reach well with good quality NMR data.