Apparatus, method and system for measuring formation pressure and mobility

A method for characterizing an earth formation surrounding a borehole having a borehole wall, the method comprising:

• a) providing a tool including an elongated body adapted for downhole operation in the borehole and a probe body that is moveable out of and back into the elongated body,
• wherein the probe body defines a flow line,
• wherein the probe body includes a barrel, a piston moveable in the barrel whereby volume of said barrel vacated by movement of the piston is part of the flow line, a pressure sensor for measuring fluid pressure in the flow line, a housing, and a shoe supporting at least one sealing member that surrounds the barrel,
• wherein the barrel is rigidly coupled to the housing and the shoe is coupled to housing in a manner that allows for movement of the housing and barrel relative to the shoe, and
• wherein the housing encloses and supports an electrical motor actuator that is adapted to move the piston in the barrel in order to vary volume of the flow line;
• b) with the sealing member and the barrel of the probe body in a configuration wherein a distal end portion of the barrel extends away from the elongated body beyond the sealing member, moving the probe body away from the elongated body such that the distal end portion of the barrel is at or near contact with the borehole wall;
• c) subsequent to b), moving the shoe of the probe body toward the borehole wall to compress the sealing member to form a seal between the sealing member and the borehole wall, wherein, during the operation of c), the distal end portion of the barrel is fixed in positioned at or near contact with the borehole wall;
• d) subsequent to c), moving the piston to expand the volume of the flow line to allow for formation fluid to enter into the flow line;
• and
• e) subsequent to d), measuring pressure in the flow line with the pressure sensor in order to characterize the formation.