Formation pressure sensing system

A method of monitoring a fluid pressure in a subterranean formation, comprising:

• forming a borehole in the subterranean formation at least to a depth where the fluid pressure is to be measured;
• lowering a conduit pipe into the borehole until an inlet of the conduit pipe is at a depth adjacent an uncased portion of the borehole where the formation pressure is to be measured;
• lowering a grout pipe down into the borehole, where said grout pipe is separate from said conduit pipe and movable with respect to said conduit pipe;
• forcing a cementitious material down the grout pipe to fill the borehole with the cementitious material to a level substantially above the inlet of the conduit pipe and preventing the cementitious material from flowing up the conduit pipe with a non-return valve, whereby the cementitious material surrounds the inlet of the conduit pipe so that the bottom of said conduit pipe is fully enveloped by the cementitious material and is fixed in the uncased portion of the borehole when the cementitious material sets;
• purging the inlet of the conduit pipe of cementitious material by pumping a liquid down the conduit pipe and through the non-return valve and out of the inlet of the conduit pipe;
• the pumping of the liquid down the conduit pipe forms a fluid connection to the formation before the cementitious material around the inlet of the conduit pipe is fully set, forming the fluid connection by forming a lateral fluid path between the inlet of the conduit pipe through the cementitious material and to the formation by displacing the cementitious material around the inlet of the conduit pipe when the pumped liquid exits the conduit pipe inlet, whereby the formation pressure forces the formation fluid to flow through the fluid path and through the inlet of the conduit pipe;
• and
• removing the non-return valve from the conduit pipe before connecting a pressure sensing device under a packer and placing the packer and attached pressure sensor in the conduit pipe to block the conduit pipe and allow the pressure sensor to sense fluid pressures of the formation via the inlet of the conduit pipe.