Hydrocarbon recovery

Abstract

A thermal hydrocarbon recovery apparatus comprises: a plurality of steam injector tubes each provided with a plurality of injector autonomous inflow control devices, AICDs, spaced apart from each other along the length of each steam injector tube; a plurality of production tubes each provided with a plurality of production autonomous inflow control devices, AICDs, spaced apart from each other along the length of each production tube; wherein said injector AICDs are arranged to inject steam into a geological formation so as to reduce the viscosity of hydrocarbons in the formation; and wherein said production AICDs are arranged to permit the flow of heated hydrocarbons into said production tubes for movement to the surface.

1 .- 18 . (canceled) 
     
     
         19 . A thermal hydrocarbon recovery apparatus comprising:
 a plurality of steam injector tubes each provided with a plurality of injector autonomous inflow control devices, AICDs, spaced apart from each other along the length of each steam injector tube;   a plurality of production tubes each provided with a plurality of production autonomous inflow control devices, AICDs, spaced apart from each other along the length of each production tube;   wherein said injector AICDs are arranged to inject steam into a geological formation so as to reduce the viscosity of hydrocarbons in the formation;   and wherein said production AICDs are arranged to permit the flow of heated hydrocarbons into said production tubes for movement to the surface.   
     
     
         20 . Apparatus as claimed in  claim 19 , wherein at least one injector AICD is configured to permit the flow of steam through the injector AICD at a substantially constant flow rate, once a pressure differential across the injector AICD exceeds a threshold value. 
     
     
         21 . Apparatus as claimed in  claim 20 , wherein said substantially constant flow rate varies over time by less than 10% of a mean value. 
     
     
         22 . Apparatus as claimed in  claim 20 , wherein for steam in the temperature range between 150 and 160 degrees centigrade, said substantially constant flow rate has a mean value of between 0.3 and 10 m 3 /hr. 
     
     
         23 . Apparatus as claimed in  claim 20 , wherein for steam in the temperature range between 150 and 160 degrees centigrade, said threshold value is a value between 8 kPa and 12 kPa. 
     
     
         24 . Apparatus as claimed in  claim 19 , wherein at least one production AICD is configured to permit flow of heated hydrocarbons and condensed water into a production tube but to restrict the flow of steam into the production tube. 
     
     
         25 . Apparatus as claimed in  claim 24 , wherein said at least one production AICD is configured so that in the event of steam from said steam injector tubes reaching the production AICD, the production AICD autonomously closes so that any steam entering the production tube via the production AICD is less than 5% by weight of the total fluid entering the production tube via the production AICD. 
     
     
         26 . An apparatus as claimed in  claim 19 , wherein at least some of said injector AICDs comprise a body defining a flow path through the AICD and defining a recess containing a movable valve body, arranged so that movement of fluid along said flow path causes the valve body to move by exploiting the Bernoulli effect thus controlling the flow of fluid along said flow path. 
     
     
         27 . An apparatus as claimed in  claim 19 , wherein at least some of said production AICDs comprise a body defining a flow path through the AICD and defining a recess containing a movable valve body, arranged so that movement of fluid along said flow path causes the valve body to move by exploiting the Bernoulli effect thus controlling the flow of fluid along said flow path. 
     
     
         28 . An apparatus as claimed in  claim 26 , wherein said valve body is a freely movable valve body. 
     
     
         29 . An apparatus as claimed in  claim 19 , wherein the injector AICDs of at least one of the steam injector tubes are configured to inject steam into said formation at substantially the same steam flow rate. 
     
     
         30 . An apparatus as claimed in  claim 19 , wherein the injector AICDs of at least one of the steam injector tubes are configured to inject steam into said formation at different steam flow rates so that appropriate flow rates can be used for different parts of said formation. 
     
     
         31 . An apparatus as claimed in  claim 19 , wherein said steam injector tubes are arranged to extend substantially horizontally. 
     
     
         32 . An apparatus as claimed in  claim 19 , wherein said production tubes are arranged to extend substantially horizontally. 
     
     
         33 . An apparatus as claimed in  claim 19 , wherein said geological formation is an oil sand. 
     
     
         34 . An apparatus as claimed in  claim 19 , wherein said hydrocarbons to be recovered are bitumen or heavy oil. 
     
     
         35 . An apparatus as claimed in  claim 19 , taking the form of a steam assisted gravity drainage, SAGD, system. 
     
     
         36 . A method for thermal recovery of hydrocarbons from a geological formation, the method comprising the steps of:
 a) providing a thermal hydrocarbon recovery apparatus as claimed in any preceding claim;   b) injecting steam into said geological formation via said injector AICDs;   c) collecting heated hydrocarbons in said production tubes via said production AICDs; and   d) moving said hydrocarbons to the surface via said production tubes.