In-situ refraction apparatus and method

Abstract

An apparatus and method for estimating a fluid property downhole includes an electromagnetic energy emitter, a window having an input interface that receives electromagnetic energy emitted from the electromagnetic energy emitter and converges the electromagnetic energy entering the window, a fluid interface and an output interface. A detector detects electromagnetic energy exiting the window from the output interface.

1 . An apparatus for estimating a fluid property downhole comprising:
 an electromagnetic energy emitter;   a window having an input interface that receives electromagnetic energy emitted from the electromagnetic energy emitter and converges the electromagnetic energy entering the window, a fluid interface and an output interface; and   a detector that detects electromagnetic energy exiting the window from the output interface.   
   
   
       2 . An apparatus according to  claim 1 , wherein the electromagnetic energy emitter emits non-collimated electromagnetic energy. 
   
   
       3 . An apparatus according to  claim 1 , wherein the electromagnetic energy emitter includes one or more LED emitters. 
   
   
       4 . An apparatus according to  claim 1 , wherein the window comprises cone-shaped or conical frustum window. 
   
   
       5 . An apparatus according to  claim 1 , wherein the window and at least one of the input interface, fluid interface and the output interface comprise a monolithic structure. 
   
   
       6 . An apparatus according to  claim 1 , wherein the window and at least one of the input interface and the output interface comprise discrete members. 
   
   
       7 . An apparatus according to  claim 1 , wherein the window comprises a sapphire material. 
   
   
       8 . An apparatus according to  claim 1 , wherein the window provides a high-pressure barrier for evaluating a high pressure downhole fluid. 
   
   
       9 . An apparatus according to  claim 1 , wherein at least one of the input interface and the output interface includes a convex surface portion. 
   
   
       10 . An apparatus according to  claim 1 , further comprising a reflective material disposed on a surface of the window. 
   
   
       11 . An apparatus according to  claim 10 , wherein the reflective material includes aluminum, silver, gold, copper, chromium, or combinations thereof. 
   
   
       12 . An apparatus according to  claim 1 , wherein the detector comprises a detector array. 
   
   
       13 . An apparatus according to  claim 12 , wherein the detector array comprises a plurality of photodetectors. 
   
   
       14 . An apparatus according to  claim 12 , wherein the detector array comprises a CMOS. 
   
   
       15 . An apparatus according to  claim 1  further comprising a controller that receives one or more signals from the detector. 
   
   
       16 . An apparatus according to  claim 15 , wherein the controller includes a processor that processing the received signals according to programmed instructions to estimate the refractive index of a fluid. 
   
   
       17 . An apparatus according to  claim 16 , wherein the estimated refractive index is in a range of about 1.25 nD to about 1.65 nD. 
   
   
       18 . A method for estimating a fluid property downhole comprising:
 emitting electromagnetic from an electromagnetic energy emitter;   receiving the emitted electromagnetic energy at a window having an input interface that converges the electromagnetic energy entering the window, the electromagnetic energy being transmitted to a fluid interface, wherein at least a portion of the electromagnetic energy is transmitted to an output interface;   detecting electromagnetic energy exiting the window from the output interface using a detector; and   estimating the fluid property at least in part by using the detected electromagnetic energy.   
   
   
       19 . A method according to  claim 18 , wherein emitting electromagnetic from an electromagnetic energy emitter includes emitting non-collimated electromagnetic energy. 
   
   
       20 . A method according to  claim 18 , wherein detecting electromagnetic energy includes using a CMOS detector array. 
   
   
       21 . A method according to  claim 18 , wherein estimating the fluid property includes estimating a refractive index that is in a range of about 1.25 nD to about 1.65 nD. 
   
   
       22 . A method according to  claim 18  further comprising using the window at least in part as a pressure barrier for high pressure downhole fluids.