Autonomous inflow restrictors for use in a subterranean well

Abstract

Autonomous flow restrictors for use in a subterranean well. An apparatus is disclosed for use in a well wherein both oil and gas are produced. The apparatus includes multiple flow blocking members having a density less than that of the oil. The members are positioned within a chamber with the members increasingly restricting a flow of the gas out of the chamber through multiple outlets. Another apparatus is disclosed for restricting production of at least one undesired fluid which has a density different from a density of a desired fluid. The apparatus includes at least one flow restrictor and at least one bypass flow restrictor. The bypass restrictor may have a greater restriction to flow therethrough as compared to the other flow restrictor. The apparatus further includes multiple flow blocking members operative to increasingly restrict flow of the undesired fluid through the flow restrictor in response to an increased proportion of the undesired fluid.

1 . An apparatus for use in a subterranean well wherein fluid is produced which includes both oil and gas, the apparatus comprising:
 multiple first flow blocking members, each of the first members having a density less than that of the oil, and the first members being positioned within a chamber so that the first members increasingly restrict a flow of the gas out of the chamber through multiple first outlets.   
   
   
       2 . The apparatus of  claim 1 , wherein passages between the chamber and the first outlets are vertically distributed. 
   
   
       3 . The apparatus of  claim 2 , wherein at least one of the passages is provided with an inlet which permits at least limited flow of the gas through the corresponding passage when one of the first members is engaged with the inlet. 
   
   
       4 . The apparatus of  claim 2 , wherein a first portion of the passages has greater flow restriction than a second portion of the passages. 
   
   
       5 . The apparatus of  claim 4 , wherein the first members do not increasingly restrict flow through the first portion of the passages in response to an increased proportion of gas in the chamber. 
   
   
       6 . The apparatus of  claim 4 , wherein the first members increasingly restrict, but do not prevent, flow through the first portion of the passages in response to an increased proportion of gas in the chamber. 
   
   
       7 . The apparatus of  claim 1 , wherein the first members increasingly restrict flow of the gas through an increased number of the first outlets in response to an increased proportion of the gas in the chamber. 
   
   
       8 . The apparatus of  claim 1 , wherein the produced fluid also includes water, and wherein the apparatus further comprises multiple second flow blocking members, each of the second members having a density greater than that of the oil, so that the second members increasingly restrict a flow of the water outward through multiple second outlets. 
   
   
       9 . The apparatus of  claim 8 , wherein the second members are positioned in the same chamber as the first members. 
   
   
       10 . The apparatus of  claim 8 , wherein the first and second members are not positioned in the same chamber. 
   
   
       11 . The apparatus of  claim 8 , wherein passages for flow to the second outlets are vertically distributed. 
   
   
       12 . The apparatus of  claim 11 , wherein at least one of the passages is provided with an inlet which permits at least limited flow of the water through the corresponding passage when one of the second members is engaged with the inlet. 
   
   
       13 . The apparatus of  claim 11 , wherein a first portion of the passages has greater flow restriction than a second portion of the passages. 
   
   
       14 . The apparatus of  claim 13 , wherein the second members do not increasingly restrict flow through the first portion of the passages in response to an increased proportion of water. 
   
   
       15 . The apparatus of  claim 13 , wherein the second members increasingly restrict, but do not prevent, flow through the first portion of the passages in response to an increased proportion of water. 
   
   
       16 . The apparatus of  claim 8 , wherein the second members increasingly restrict flow of the water through an increased number of the second outlets in response to an increased proportion of the water. 
   
   
       17 . An apparatus for restricting production of at least a first undesired fluid from a subterranean well, the first fluid having a first density different from a second density of a second desired fluid, the apparatus comprising:
 at least one first flow restrictor having a first flow restriction;   at least one second flow restrictor having a second flow restriction; and   multiple first flow blocking members, the first members being operative to increasingly restrict flow of the first fluid through the first restrictor in response to an increased proportion of the first fluid.   
   
   
       18 . The apparatus of  claim 17 , wherein the apparatus includes multiple first flow restrictors, and wherein passages of the first restrictors are vertically distributed. 
   
   
       19 . The apparatus of  claim 17 , wherein the second flow restriction is greater than the first flow restriction. 
   
   
       20 . The apparatus of  claim 17 , wherein the first members increasingly restrict, but do not prevent, flow of the first fluid through the second restrictors. 
   
   
       21 . The apparatus of  claim 17 , wherein the second restrictors have inlets which prevent complete flow blocking engagement between the first members and the inlets. 
   
   
       22 . The apparatus of  claim 17 , wherein the first members have a density less than the second density of the second fluid. 
   
   
       23 . The apparatus of  claim 17 , wherein the first members have a density less than the first density of the first fluid. 
   
   
       24 . The apparatus of  claim 17 , wherein the first members have a density approximately equal to the first density of the first fluid. 
   
   
       25 . The apparatus of  claim 17 , wherein a third undesired fluid has a third density different from the first and second densities, and wherein the apparatus further comprises multiple second flow blocking members, the second members being operative to increasingly restrict flow of the third fluid through the first restrictor in response to an increased proportion of the third fluid. 
   
   
       26 . The apparatus of  claim 25 , wherein the apparatus includes multiple first flow restrictors, and wherein passages of the first restrictors are vertically distributed. 
   
   
       27 . The apparatus of  claim 25 , wherein the second flow restriction is greater than the first flow restriction. 
   
   
       28 . The apparatus of  claim 25 , wherein the second members increasingly restrict, but do not prevent, flow of the third fluid through the second restrictors. 
   
   
       29 . The apparatus of  claim 25 , wherein the second restrictors have inlets which prevent complete flow blocking engagement between the second members and the inlets. 
   
   
       30 . The apparatus of  claim 25 , wherein the second members have a density less than the third density of the third fluid. 
   
   
       31 . The apparatus of  claim 25 , wherein the second members have a density greater than the second density of the second fluid. 
   
   
       32 . The apparatus of  claim 25 , wherein the second members have a density approximately equal to the third density of the third fluid.