Pressure measurement of a reservoir fluid in a microfluidic device

Abstract

Methods and related systems are described for measuring fluid pressure in a microchannel. A number of flexible membranes are positioned at locations along the microchannel such that pressure of the fluid in the microchannel causes a deformation of the membranes. An optical sensing system adapted and positioned to detect deformation of the membranes that thereby determine the pressure of the fluid flowing in the microchannel at a number of locations along the microchannel.

1 . A system for measuring fluid pressure in a microchannel comprising:
 a microchannel adapted to carry a fluid;   a first flexible member adapted and positioned such that pressure of the fluid in the microchannel causes a deformation of the first flexible member; and   an optical sensing system adapted and positioned to detect deformation of the first flexible member.   
     
     
         2 . A system according to  claim 1 , wherein the first flexible member is a first membrane. 
     
     
         3 . A system according to  claim 2 , further comprising a first cavity defined in part by the first membrane, wherein the first cavity is in fluid communication with the microchannel at a first location such that a fluid pressure within the first cavity corresponds to the fluid pressure in the microchannel at the first location, and the deformation of the first membrane is representative of the fluid pressure within the first cavity. 
     
     
         4 . A system according to  claim 3 , wherein the cavity and the microchannel are defined at least in part by a first substrate. 
     
     
         5 . A system according to  claim 4 , wherein the first substrate comprises silicon. 
     
     
         6 . A system according to  claim 3 , further comprising:
 a second cavity defined in part by a second membrane and positioned to be in fluid communication with the microchannel at a second location such that a fluid pressure in the second cavity corresponds to the fluid pressure in the microchannel at the second location, and a deformation of the second membrane is representative of the fluid pressure within the second cavity; and   a third cavity defined in part by a third membrane and positioned to be in fluid communication with the microchannel at a third location such that a fluid pressure in the third cavity corresponds to the fluid pressure in the microchannel at the third location and the deformation of the third membrane is representative of the fluid pressure within the third cavity.   
     
     
         7 . A system according to  claim 6 , wherein the optical sensing system includes first, second and third optical sensors that are adapted and positioned to detect deformation of the first, second and third membranes respectively. 
     
     
         8 . A system according to  claim 1 , wherein the microchannel exhibits a serpentine shape and a length of at least one meter. 
     
     
         9 . A system according to  claim 1 , wherein the microchannel exhibits a width within a range of tens of micrometers to hundreds of micrometers. 
     
     
         10 . A system according to  claim 1 , wherein the optical sensing system comprises an optical sensor, a spectrometer and a computer system. 
     
     
         11 . A system according to  claim 9 , wherein the optical sensor is a confocal chromatic sensor. 
     
     
         12 . A system according to  claim 1 , wherein the microchannel is part of a microfluidic apparatus for measuring thermo-physical properties of a fluid that is of a type selected from the group consisting of: reservoir fluid, biomedical fluid, and a fluid being monitored in connection with environmental monitoring. 
     
     
         13 . A system according to  claim 1 , further comprising an optical sensing system adapted and positioned to detect phase states of the fluid at a plurality of locations along the microchannel. 
     
     
         14 . A system according to  claim 1  wherein the first flexible member is formed from the same material that at least partially defines the microchannel. 
     
     
         15 . A system according to  claim 14  wherein the material is silicon. 
     
     
         16 . A method for measuring fluid pressure in a microchannel comprising:
 providing a microchannel adapted to carry a fluid, and a first flexible member adapted and positioned such that pressure of the fluid in the microchannel causes a deformation of the first flexible member;   introducing fluid under pressure into the microchannel, thereby causing a deformation of the first flexible member; and   optically detecting the deformation of the first flexible member.   
     
     
         17 . A method according to  claim 16 , further comprising determining a value representing the pressure at a location in the microchannel based at least in part on the optically detected deformation of the first flexible member. 
     
     
         18 . A method according to  claim 16 , wherein the first flexible member is a first membrane. 
     
     
         19 . A method according to  claim 17 , wherein a first cavity is defined in part by the first membrane, and the first cavity is in fluid communication with the microchannel at a first location such that fluid pressure within the first cavity corresponds to the fluid pressure in the microchannel at the first location, and wherein the optically detected deformation of the first membrane is representative of the fluid pressure in the microchannel at the first location. 
     
     
         20 . A method according to  claim 19 , further comprising optically detecting deformation of a second membrane and a third membrane both being adapted and positioned to deform according to fluid pressures in the microchannel at second and third locations on the microchannel respectively. 
     
     
         21 . A method according to  claim 16 , wherein the microchannel exhibits a width within a range of tens of micrometers to hundreds of micrometers. 
     
     
         22 . A method according to  claim 16 , wherein the deformation is detected using a confocal chromatic sensor. 
     
     
         23 . A method according to  claim 16 , wherein the introduced fluid is of a type selected from the group consisting of: reservoir fluid, biomedical fluid, and a fluid being monitored in connection with environmental monitoring, and the method further comprises determining one or more thermo physical properties of the introduced fluid flowing through the microchannel. 
     
     
         24 . A method according to  claim 23 , further comprising optically sensing phase states of the fluid at a plurality of locations along the microchannel.