Method and system for producing hydrocarbon fluid through a well with a sensor assembly outside the well casing

Abstract

A method is disclosed for producing hydrocarbon fluids through a well having a well casing string with a casing section which is surrounded by an annular space which comprises a sensor assembly for measuring electromagnetic and/or other physical properties of solid and fluid materials within the annular space, in an underground formation surrounding the annular space and/or within the interior of the section of the casing string, wherein the sensor assembly is mounted on a body of swellable material, such as a swellable rubber or other elastomeric material, which is secured to the outer surface of said casing section and presses the sensor assembly against the inner surface of the surrounding underground formation after the casing string has been lowered into the wellbore.

1 . A method of producing hydrocarbon fluids through a well having a well casing string with a casing section which is surrounded by an annular space which comprises:
 a) providing in the well a sensor assembly for measuring electromagnetic and/or other physical properties of solid and fluid materials within the annular space, in an underground formation surrounding the annular space and/or within the interior of the casing section,
 wherein the sensor assembly is mounted on or in the vicinity of a body of swellable material, which body is secured to the outer surface of the casing section and is configured to swell against the inner surface of the underground formation surrounding the wellbore after the casing string has been lowered into the wellbore; 
 and the sensor assembly is configured to measure one or more of the following properties: 
 the pore pressure in pores of the formation adjacent to the annular space; 
 the chemical composition of fluid in the pores of the formation adjacent to the annular space; 
 the electrical resistivity and/or conductivity of the solid and fluid materials in the formation surrounding the annular space; 
 the streaming and spontaneous potentials of the solid and fluid materials in the formation surrounding the annular space; 
 the dielectric constant of the solid and fluid materials in the formation surrounding the annular space; 
 changes in a cement lining arranged in the annular space, including migration of any chemical contaminants through the cement lining; 
 properties of a fluid flowing through the interior of the non-magnetic section of the casing string; 
 deformation and/or tilting of the well casing string; 
 deformation, such as compaction and expansion, of the formation surrounding the annular space; 
 stress in any solid materials in the annular space and the formation surrounding the annular space; and 
 acoustic rock reflections; 
   b) producing hydrocarbons from the well; and   c) using the sensor assembly to sense one or more of the properties.   
     
     
         2 . The method of  claim 1 , wherein the sensor assembly is connected to an electrical and/or fiber optical data transmission conduit within the casing string by a wireless data and/or power transmission link, which transmits data and/or power through the wall of the non-magnetic section of the well casing string. 
     
     
         3 . The method of  claim 2 , wherein the wireless data and/or power transmission link comprises at least one pair of substantially coaxial inductive couplers which each comprise a coiled electrical cable. 
     
     
         4 . The method of  claim 1 , wherein the sensor assembly is mounted on a body of swellable elastomeric material. 
     
     
         5 . A system for producing hydrocarbon fluids through a well having a well casing string with a casing section which is surrounded by an annular space which comprises a sensor assembly for measuring electromagnetic and/or other physical properties of solid and fluid materials within the annular space, in an underground formation surrounding the annular space and/or within the interior of the casing section,
 wherein the sensor assembly is mounted on a body of swellable material, which body is secured to the outer surface of the casing section and presses the sensor against the inner surface of the underground formation surrounding the wellbore after the casing string has been lowered into the wellbore.   
     
     
         6 . The system of  claim 5 , wherein the sensor assembly is mounted on a body of swellable elastomeric material. 
     
     
         7 . The system of  claim 5 , wherein the casing section is made of a non-magnetic or weakly magnetic material. 
     
     
         8 . The system of  claim 7 , where the non-magnetic or weakly magnetic material is selected from the group of materials consisting of: non-metallic materials, Glassfiber Reinforced Plastic_(GRP); non-magnetic materials, aluminium, gold, titanium;_low curie temperature materials, inconel 718, monel K500; low magnetic permeability soft magnetic materials, and casing steel grades L80 and L80 13 Chrome, where the relative magnetic permeability μ r  is in the range from 50 to 200 and/or the bulk electrical resistivity is in the range from 30×10 −8   to 120×10 −8  Ωm.