Mechanism to allow low differential pressure measurement during fluid flow

A system for measuring permeability of a porous medium, comprising:

• an inlet line comprising an inlet pressure gauge, wherein a fluid is injected into the inlet line;
• a flow manifold, comprising,
• a first branch, comprising:
• a first inlet line comprising a first flow meter;
• a pressure control system, located downstream of the first flow meter, comprising a control coil and a flow control device located immediately downstream of the control coil;
• a first flow line, exiting the pressure control system,
• a first junction point, fluidly connected to the first flow line and a cross flow line, wherein the cross flow line comprises a second flow meter;
• a porous medium, located downstream of the first junction point;
• and
• a first outlet line,
• wherein the first flow line enters the porous medium and the first outlet line exits the porous medium, and
• a second branch, comprising:
• a second inlet line;
• a first coil, wherein the second inlet line is fluidly connected to an upstream side of the first coil;
• a second flow line, exiting the first coil;
• a second junction point, fluidly connected to the first flow line through the cross flow line;
• a second coil, wherein the second flow line enters the second coil;
• and
• a second outlet line exiting the second coil;
• wherein the cross flow line connects the first branch to the second branch;
• and
• an effluent line, wherein the first outlet line and the second outlet line combine to produce the effluent line.