Figure F3. Borehole instrument assembly (BIA) installation schematic. The BIA hangs on a 4.5-in casing pipe, which in turn hangs on the riser hanger support just below the reentry cone. The cables from the sensors are strapped to the casing pipe with tie wraps and duct tape and protected by centralizers. Cement is pumped through the 4.5-in casing pipe and the BIA and out the bottom of the stinger. Cement is pumped to completely fill the bare hole and to extend into a lower part of the 10.75-in casing. The sensors are thus strongly coupled to the bare rock. PAT = power access terminal, MEG = multiple-access expandable gateway.