Apparatus and method for enhanced oil recovery

Abstract

An impingement device in a side pocket mandrel or other downhole tools for injecting a predetermined quality of steam in one or more zones of a formation. The impingement device directs and mixes the laminae of hot fluid and vapor and a valve in a valve pocket controls the flow of steam to the zone from the side pocket mandrel or other downhole tools. Along with the impingement device, a centralizer to guide tools through the impingement device and to cause a pressure change and dispersion of the steam; and an agitation device to amalgamate the steam may be used if further blending is required.

We claim: 
     
       1. A side pocket mandrel with a first longitudinal flow passageway extending therethrough and a valve pocket offset therefrom for distribution of steam comprising: a. means for connecting one end of the side pocket mandrel to a source of pressurized steam;   b. means for connecting the other end of the side pocket mandrel to other downhole well equipment;   c. impingement means within the first longitudinal flow passageway to mix and direct the steam flow through the first longitudinal flow passageway;   d. fourth port means for communication of steam from the first longitudinal flow passageway to the valve pocket;   e. valve means in the valve pocket to control the flow of the steam from the fourth port means; and   f. first port means in the side pocket mandrel for communication of steam from the valve means to the exterior of the side pocket mandrel.   
     
     
       2. A side pocket mandrel with a first longitudinal flow passageway extending therethrough and a valve pocket communicating with and offset therefrom for distribution of steam comprising: a. means for connecting one end of the side pocket mandrel to a source of pressurized steam;   b. means for connecting the other end of the side pocket mandrel to other downhole well equipment;   c. centralizer means within the first longitudinal flow passageway to guide tools through the side pocket mandrel and to cause a pressure change and dispersion of the steam;   d. impingement means within the first longitudinal flow passageway to mix and direct the steam flow through the first longitudinal flow passageway;   e. fourth port means for communication of steam from the first longitudinal flow passageway to the valve pocket;   f. valve means in the valve pocket to control the flow of the steam from the fourth port means; and   g. first port means in the side pocket mandrel for communication of steam from the valve means to the exterior of the side pocket mandrel.   
     
     
       3. A side pocket mandrel with a first longitudinal flow passageway extending therethrough and a valve pocket offset therefrom for distribution of steam comprising: a. means for connecting one end of the side pocket mandrel to a source of pressurized steam;   b. means for connecting the other end of the side pocket mandrel to other downhole well equipment;   c. agitation means within the first longitudinal flow passageway to amalgamate the steam;   d. impingement means within the first longitudinal flow passageway to mix and direct the steam flow; through the first longitudinal flow passageway   e. fourth port means for communication of steam from the first longitudinal flow passageway to the valve pocket;   f. valve means in the valve pocket to control the flow of the steam from the fourth port means; and   g. first port means in the side pocket mandrel for communication of steam from the valve means to the exterior of the side pocket mandrel.   
     
     
       4. A side pocket mandrel as described in claims 1, 2 or 3 wherein the valve means further comprises: a. latch means;   b. choke means;   c. means for controlling direction of steam flow; and   d. sealing means.   
     
     
       5. A side pocket mandrel as described in claims 1, 2 or 3 wherein the impingement means further comprises: a. first mandrel means having a second longitudinal flow passageway therethrough;   b. helical directing means for mixing and directing the steam toward the valve means;   c. second port means to allow communication between the second longitudinal flow passageway and the first longitudinal flow passageway;   d. longitudinal directing means to divide the steam flow proportionately between the second longitudinal flow passageway and the first longitudinal flow passageway;   e. means for connecting one end of the first mandrel means to the side pocket mandrel; and   f. means for connecting the other end of the first mandrel means to other downhole well equipment.   
     
     
       6. A side pocket mandrel as described in claim 5 wherein the helical directing means further comprises: a. spirally cut lands and grooves formed on the outside diameter of the first mandrel means; and   b. chamber means formed between the outside diameter and the inside diameter of the first longitudinal flow passageway.   
     
     
       7. A side pocket mandrel as described in claim 5 wherein the longitudinal directing means further comprises: a. alternating fingers and slots on one end of the first mandrel means to divide steam flow between the first longitudinal flow passageway and the second longitudinal flow passageway; and   b. third port means for draining steam from the chamber formed between the wall of the first longitudinal flow passageway and the outer surface of the first mandrel means.   
     
     
       8. A side pocket mandrel as described in claim 5 wherein the second port means further comprises the first mandrel means having one or more holes allowing communication between the inside diameter and the outside diameter of the first mandrel means. 
     
     
       9. A side pocket mandrel as described in claim 2 wherein the centralizer means further comprises: a. second mandrel means having a third longitudinal flow passageway therethrough;   b. means for connecting one end of the second mandrel means to the side pocket mandrel;   c. venturi means for guidance of tools through the side pocket mandrel and to cause a pressure change and dispersion of the steam; and   d. means for connecting the other end of the second mandrel means to a source of pressurized steam.   
     
     
       10. A side pocket mandrel as described in claim 3 wherein the agitation means further comprises: a. third mandrel means with a fourth longitudinal passageway therethrough;   b. one or more sets of interior lands and grooves within the fourth longitudinal flow passageway;   c. means for connecting one end of the third mandrel means to the side pocket mandrel; and   d. means for connecting the other end of the third mandrel means to the source of pressurized steam.   
     
     
       11. A side pocket mandrel is described in claim 10 wherein the agitation means further comprises means for guidance of tools through the side pocket mandrel. 
     
     
       12. A side pocket mandrel as described in claim 3 wherein agitation means further comprises: one or more sets of interior lands and grooves within the first longitudinal flow passageway. 
     
     
       13. An impingement device for distribution of steam comprising: a. mandrel means having a longitudinal flow passageway therethrough;   b. helical directing means for mixing and directing the steam;   c. first port means to allow communication between the longitudinal flow passageway and an outside diameter of the mandrel means;   d. longitudinal directing means to divide the steam flow proportionately between the longitudinal flow passageway and outside diameter of the mandrel means; and   e. means for connecting the mandrel means to a downhole tool.   
     
     
       14. An impingement device as described in claim 13 wherein the helical directing means further comprises: a. spirally cut lands and grooves formed on the outside diameter of the mandrel means; and   b. second port means for draining steam from the outside diameter of the mandrel means into the longitudinal flow passageway.   
     
     
       15. An impingement device as described in claim 13 wherein the longitudinal directing means further comprises alternating fingers and slots on one end of the mandrel means to divide steam flow between the outside diameter of the mandrel means and the longitudinal flow passageway. 
     
     
       16. An impingement device as described in claim 13 wherein the first port means further comprises the mandrel means having one or more holes allowing communication between the inside diameter and the outside diameter of the mandrel means. 
     
     
       17. A side pocket mandrel with a first longitudinal flow passageway extending therethrough and a valve pocket offset therefrom for distribution of steam comprising: a. means for connecting one end of the side pocket mandrel to a source of pressurized steam;   b. means for connecting the other end of the side pocket mandrel to other downhole well equipment;   c. impingement means within the first longitudinal flow passageway to mix and direct the steam flow through the first longitudinal flow passageway comprising: first mandrel means having a second longitudinal flow passageway therethrough;   helical directing means for mixing and directing the steam toward the valve means;   second port means to allow communication between the second longitudinal flow passageway and the first longitudinal flow passageway;   longitudinal directing means to divide the steam flow proportionally between the second longitudinal flow passageway and the first longitudinal flow passageway;   means for connecting one end of the first mandrel means to the side pocket mandrel; and   means for connecting the other end of the first mandrel means to other downhole well equipment;     d. fourth port means for communication of steam from the first longitudinal flow passageway to the valve pocket;   e. valve means in the valve pocket to control the flow of the steam from the fourth port means; and   f. first port means in the side pocket mandrel for communication of steam from the valve means to the exterior of the side pocket mandrel.   
     
     
       18. A side pocket mandrel with a first longitudinal flow passageway extending therethrough and a valve pocket offset therefrom for distribution of steam comprising: a. means for connecting one end of the side pocket mandrel to a source of pressurized steam;   b. means for connecting the other end of the side pocket mandrel to other downhole well equipment;   c. agitation means within the first longitudinal flow passageway to amalgamate the steam comprising: third mandrel means with a fourth longitudinal flow passage therethrough;   one or more sets of interior lands and grooves within the fourth longitudinal flow passageway;   means for connecting one end of the third mandrel means to the side pocket mandrel; and   means for connecting the other end of the third mandrel means to the source of pressurized steam;     d. impingement means within the first longitudinal flow passageway to mix and direct the steam flow through the first longitudinal flow passageway;   e. fourth port means for communication of steam from the first longitudinal flow passageway to the valve pocket;   f. valve means in the valve pocket to control the flow of the steam from the fourth port means; and   g. first port means in the side pocket mandrel for communication of steam from the valve means to the exterior of the side pocket mandrel.   
     
     
       19. An impingement device for distribution of steam comprising: a. mandrel means having a longitudinal flow passageway therethrough;   b. helical directing means for mixing and directing the steam comprising: spirally cut lands and grooves formed on the outside diameter of the mandrel means; and   second port means for draining steam from the outside diameter of the mandrel means into the longitudinal flow passageway;     c. first port means to allow communication between the longitudinal flow passageway and an outer diameter of the mandrel means;   d. longitudinal directing means to divide the steam flow proportionally between the longitudinal flow passageway and outside diameter of the mandrel means; and   e. means for connecting the mandrel means to a downhole tool.   
     
     
       20. A side pocket mandrel with a first longitudinal flow passageway extending therethrough and a valve pocket communicating with an off set therefrom for a distribution of steam comprising: a. means for connecting one end of the side pocket mandrel to a source of pressurized steam;   b. means for connecting the other end of the side pocket mandrel to other downhole well equipment;   c. centralizer means within the first longitudinal flow passageway to guide tools through the side pocket mandrel and to cause a pressure change and dispersion of the steam;   d. impingement means within the first longitudinal flow passageway to mix and direct the steam flow through the first longitudinal flow passageway comprising: first mandrel means having a second longitudinal flow passageway therethrough;   helical directing means for mixing and directing the steam toward the valve means;   second port means to allow communication between the second longitudinal flow passageway and the first longitudinal flow passageway;   longitudinal directing means to divide the steam flow proportionally between the second longitudinal flow passageway and the first longitudinal flow passageway;   means for connecting one end of the first mandrel means to the side pocket mandrel; and   means for connecting the other end of the first mandrel means to other downhole well equipment;     e. fourth port means for communication of steam from the first longitudinal flow passageway to the valve pocket;   f. valve means in the valve pocket to control the flow of the steam from the fourth port means; and   g. first port means in the side pocket mandrel for communication of steam from the valve means to the exterior of the side pocket mandrel.   
     
     
       21. A side pocket mandrel with a first longitudinal flow passageway extending therethrough and a valve pocket offset therethrough for distribution of steam comprising: a. means for connecting one end of the side pocket mandrel to a source of pressurized steam;   b. means for connecting the other end of the side pocket mandrel to other downhole well equipment;   c. agitation means within the first longitudinal flow passageway to amalgamate to steam;   d. impingement means within the first longitudinal flow Passageway to mix and direct the steam flow through the first longitudinal flow passageway comprising: first mandrel means having a second longitudinal flow passageway therethrough;   helical directing means for mixing and directing the steam toward the value means;   second port means to allow communication between the second longitudinal flow passageway and the first longitudinal flow passageway;   longitudinal directing means to divide the steam flow proportionally between the second longitudinal flow passageway and the first longitudinal flow passageway;   means for connecting one end of the first mandrel means to the side pocket mandrel; and   means for connecting the other end of the first mandrel means to other downhole well equipment;     e. fourth port means for communication of steam from the first longitudinal flow passageway to the valve pocket;   f. valve means in the valve pocket to control the flow of the steam from the fourth port means; and   g. first port means in the side pocket mandrel for communication of steam from the valve means to the exterior of the side pocket mandrel. .Iadd.   
     
     
       22.  A side pocket mandrel with a first longitudinal flow passageway extending therethrough and a valve pocket offset therefrom for distribution of steam comprising: a. means for connecting one end of the side pocket mandrel to a source of pressurized steam;   b. means for connecting the other end of the side pocket mandrel to other downhole well equipment;   c. means to divide the steam flow between the valve pocket and the first longitudinal flow passageway;   d. fourth port means for communication of steam from the first longitudinal flow passageway to the valve pocket; and   e. valve means in the valve pocket to control the flow of the steam from the fourth port means and for communication of steam from the valve means to the exterior of the side pocket mandrel. .Iaddend. .Iadd.23. The side pocket mandrel of claim 22 wherein the valve means includes a venturi means. .Iaddend. .Iadd.24. The side pocket mandrel of claim 22 wherein the valve means includes a venturi means and steam emits from the side pocket after having been accelerated to its critical flow rate. .Iaddend. .Iadd.25. A side pocket mandrel with a first longitudinal flow passageway extending therethrough and a valve pocket communicating with and offset therefrom for distribution of steam comprising:   a. means for connecting one end of the side pocket mandrel to a source of pressurized steam;   b. means for connecting the other end of the side pocket mandrel to other downhole well equipment;   c. venturi means between said valve pocket and source of pressurized steam to cause a pressure change and dispersion of the steam;   d. fourth port means for communication of steam from the first longitudinal flow passageway to the valve pocket; and   e. valve means in the valve pocket to control the flow of the steam from the fourth port means and for communication of steam from the valve means to the exterior of the side pocket mandrel. .Iaddend. .Iadd.26. The side pocket mandrel of claim 25 wherein the valve means includes a venturi means. .Iaddend. .Iadd.27. A method of injecting steam at a selected mass flow rate into a production formation of a subterranean well having a tubing string traversing the production formation comprising the steps of:   supplying a steam flow to the surface end of the tubing string;   diverting the downwardly flowing steam into the radially separated flow components above and adjacent to the production formation;   directing one of said flow components into the inlet end of a Venturi passage, the outlet end of the Venturi passage being in communication with the production formation; and accelerating the flow rate of said one flow component by said Venturi passage to its critical mass flow rate.   
     
     
        .Iaddend. .Iadd.28.  The method of claim 27 wherein the radially outer steam flow component is directed to a Venturi flow passage disposed on the exterior of the tubing string. .Iaddend. .Iadd.29. The method of claim 27 wherein each radially outer steam flow component is directed to a respective Venturi flow passage disposed on the exterior of tubing string and each radially inner steam flow component continues down the tubing string to the next production formation. .Iaddend. .Iadd.30. A method of injecting steam at selected mass flow rates into a plurality of vertically spaced production formations traversed by a single steam carrying tubing string, comprising the steps of: supplying a steam flow to the surface end of the tubing string;   diverting the downwardly flowing steam into two radially separated flow components above and adjacent to each of the production formations;   directing one of each said two flow components into the inlet end of a Venturi passage, the outlet end of the Venturi passage being in communication with a respective production formation; and accelerating the flow rate of each said one flow component by said respective Venturi passage to its critical mass flow rate; and   directing the other of each said flow components downwardly through the tubing string to the next lower production formation. .Iaddend. .Iadd.31. Apparatus for injecting steam into a production formation of a subterranean well at a selected mass flow rate comprising a tubular housing connectable in series relationship to the tubing string adjacent the production formation; fluid diverting means in said tubular housing for dividing the steam flow into two radially separated components; and means including a Venturi passage for accelerating the flow rate of one said flow component to the critical mass flow rate and directing the accelerated component to the production formation. .Iaddend. .Iadd.32. Apparatus for injecting steam at selected mass flow rates into a plurality of vertically spaced production formations through a single tubing string traversing said formations comprising: a plurality of tubular housings connected in series relationship to the tubing string and respectively positioned adjacent said production formations; fluid diverting means in each said tubular housing adjacent each production formation for dividing the steam flow into two radially separated components; and means including a Venturi passage for accelerating the flow rate of one said flow component to its critical mass flow rate and directing the accelerated component to the respective production formation, whereby said other flow component flows downwardly to the next lower tubular housing. .Iaddend. .Iadd.33. The apparatus of claim 31 or 32 wherein said Venturi passage is disposed exteriorly of said tubular housing. .Iaddend. .Iadd.34. Apparatus for injecting steam at a selected mass flow rate into a production formation of a subterranean well from a tubing string extending to the surface comprising: a tubular housing connectable in series relationship to the tubing string adjacent the production formation means in said tubular housing for diverting a portion of the steam flow down the tubing string to the outer peripheral wall of said tubular housing; said outer peripheral wall having a port opening therethrough; a secondary housing secured to the said exterior of tubular housing adjacent said port opening, said secondary housing defining an inlet chamber communicating with said port openings; and a downwardly directed Venturi passageway to discharge a portion of the high-velocity steam flow into an adjacent production formation. .Iaddend. .Iadd.35. The apparatus of claims 31, 32, or 34 wherein each said Venturi passage is proportioned to accelerate the steam to critical mass flow rate to deliver steam to the adjacent production formation at a selected mass flow rate. .Iaddend. .Iadd.36. The apparatus of claims 31, 32, or 34 further comprising stationary fluid mixing means disposed in the upper portion of said tubular housing above said fluid diverting means for producing a homogeneous mixture of steam vapor and liquid. .Iaddend. .Iadd.37. A method of injecting steam at a selected mass flow rate into a production formation of a subterranean well having a tubing string traversing the production formation comprising the steps of:   supplying a steam flow to the surface end of the tubing string;   diverting the downwardly flowing steam into two radially separated flow components adjacent to the production formation;   directing one of said flow components into the inlet end of a Venturi passage, the outlet end of the Venturi passage being in communication with the production formation; and accelerating the flow rate of said one flow component by said Venturi passage. .Iaddend. .Iadd.38. The method of claim 37 wherein the radially outer steam flow component is directed to a Venturi flow passage disposed on the exterior of the tubing string. .Iaddend. .Iadd.39. The method of claim 37 wherein each radially outer steam flow component is directed to a respective Venturi flow passage disposed on the exterior of tubing string and each radially inner steam flow component continues down the tubing string to the next production formation. .Iaddend. .Iadd.40. A method of injecting steam at selected mass flow rates into a plurality of vertically spaced production formations traversed by a single steam carrying tubing string, comprising the steps of:   supplying a steam flow to the surface end of the tubing string;   diverting the downwardly flowing steam into two radially separated flow components adjacent to each of the production formations;   directing one of each said two flow components into the inlet end of a Venturi passage, the outlet end of the Venturi passage being in communication with a respective production formation; and accelerating the flow rate of each said one flow component by said respective Venturi passage; and   directing the other of each said flow components downwardly through the tubing string to the next lower production formation. .Iaddend. .Iadd.41. Apparatus for injecting steam into a production formation of a subterranean well at a selected mass flow rate comprising a tubular housing connectable in series relationship to the tubing string adjacent the production formation; fluid diverting means in said tubular housing for dividing the steam flow into two radially separated components; and means including a Venturi passage for accelerating the flow rate of one said flow component and directing the accelerated component to the production formation. .Iaddend. .Iadd.42. Apparatus for injecting steam at selected mass flow rates into a plurality of vertically spaced production formations through a single tubing string traversing said formations comprising: a plurality of tubular housings connected in series relationship to the tubing string and respectively positioned adjacent said production formations; fluid diverting means in each said tubular housing adjacent each production formation for dividing the steam flow into two radially separated components; and means including a Venturi passage for accelerating the flow rate of one said flow component and directing the accelerated component to the respective production formation, whereby said other flow component flows downwardly to the next lower tubular housing. .Iaddend. .Iadd.43. The apparatus of claim 41 or 42 wherein said Venturi passage is disposed exteriorly of said tubular housing. .Iaddend. .Iadd.44. The apparatus of claims 41 or 42 further comprising stationary fluid mixing means disposed in the upper portion of said tubular housing above said fluid diverting means for producing a homogeneous mixture of steam vapor and liquid. .Iaddend. .Iadd.45. The method of claims 27, 30, 37, or 40 further comprising the step of delivering steam at a selected mass flow rate by passing the steam through a Venturi passage prior to diverting the downwardly flowing steam into two radially separated flow components. .Iaddend. .Iadd.46. The method of claims 27, 30, 37, or 40 further comprising the step of passing the steam through a Venturi passage prior to diverting the downwardly flowing steam into two radially separated flow components. .Iaddend. .Iadd.47. Apparatus for injecting steam at a selected mass flow rate into a production formation of a subterranean well comprising a tubing string extending into the well to a production formation, a source of high pressure steam, a tubular housing connectable in series relationship to the tubing string adjacent the production formation, fluid diverting means in said tubular housing for dividing the steam flow into two radially separated components, means including a Venturi passage for accelerating the flow rate of one of said flow components and directing the accelerated flow component to the production formation, and means between said source of steam and said tubular housing defining a Venturi passage for the steam to accelerate same to its critical mass flow rate. .Iaddend. .Iadd.48. Apparatus for injecting steam at a selected mass flow rate into a production formation of a subterranean well comprising a tubing string extending into the well to a production formation, a source of high pressure steam, a tubular housing connectable in series relationship to the tubing string adjacent the production formation, fluid diverting means in said tubular housing for dividing the steam flow into two radially separated components, means including a Venturi passage for accelerating the flow rate of one of said flow components and directing the accelerated flow component to the production formation, and means between said source of steam and said tubular housing defining a Venturi passage for the steam to accelerate same. .Iaddend. .Iadd.49. Apparatus for injecting steam at selected mass flow rates into a plurality of vertically spaced production formations of a subterranean well comprising, a tubing string extending into the well to said production formations, a source of high pressure steam connecting said source to said tubing, a plurality of tubular housings connected in series relationship to the tubing string and respectively positioned adjacent said production formations, fluid diverting means in each said tubular housing for dividing the steam flow into two radially separated components, means including a Venturi passage for accelerating the flow rate of one of said flow components and directing the accelerated component to the respective production formation, whereby said other flow component flows downwardly to the next lower tubular housing, and means between said source of steam and the upper of said plurality of tubular housings defining a Venturi passage for the steam to accelerate same to its critical mass flow rate. .Iaddend. .Iadd.50. Apparatus for injecting steam at selected mass flow rates into a plurality of vertically spaced production formations of a subterranean well comprising, a tubing string extending into the well to said production formations, a source of high pressure steam connecting said source to said tubing, a plurality of tubular housings connected in series relationship to the tubing string and respectively positioned adjacent said production formations, fluid diverting means in each said tubular housing for dividing the steam flow into two radially separated components, means including a Venturi passage for accelerating the flow rate of one of said flow components and directing the accelerated component to the respective production formation, whereby said other flow component flows downwardly to the next lower tubular housing, and means between said source of steam and the upper of said plurality of tubular housing defining a Venturi passage for the steam to accelerate same. .Iaddend. .Iadd.51. Apparatus for injecting steam selected mass flow rate into a projection formation of a subterranean well comprising, a tubing string extending into the well to a production formation, a source of high pressure steam, a tubular housing connectable in series relationship to the tubing string, means in said tubular housing for diverting a portion of the steam flow down the tubing string to the outer peripheral wall of said tubular housing, said outer peripheral wall having a port opening therethrough, a second housing secured to the exterior of said tubular housing adjacent said port opening, said secondary housing defining an inlet chamber communicating with said port opening and a downwardly directed Venturi passageway to discharge a portion of the steam flow into an adjacent production formation, and means between said source of steam and said tubular housing defining a Venturi passage for the steam to   
     
     
        accelerate same to its critical mass flow rate. .Iaddend. .Iadd.52. Apparatus for injecting steam at selected mass flow rate into a production formation of a subterranean well comprising, a tubing string extending into the well to a production formation, a source of high pressure steam, a tubular housing connectable in series relationship to the tubing string, means in said tubular housing for diverting a portion of the steam flow down the tubing string to the outer peripheral wall of said tubular housing, said outer peripheral wall having a port opening therethrough, a second housing secured to the exterior of said tubular housing adjacent said port opening, said secondary housing defining an inlet chamber communicating with said port opening and a downwardly directed Venturi passageway to discharge a portion of the steam flow into an adjacent production formation, and means between said source of steam and said tubular housing defining a Venturi passage for the steam to accelerate same. .Iaddend. .Iadd.53. The apparatus of claims 47, 48, 49, 50, 51, or 52 wherein each said Venturi passage is proportioned to deliver steam to the adjacent production formation at a selected mass flow rate. .Iaddend. .Iadd.54. The apparatus of claims 47, 48, 49, 50, 51, or 52 further comprising stationary fluid mixing means disposed in the upper portion of each said tubular housing above said fluid diverting means for producing a 
     
     
        homogeneous mixture of steam, vapor, and liquid. .Iaddend. .Iadd.55.  A method of injecting steam at a selected mass flow rate into a production formation of a subterranean well having a tubing string traversing the production formation comprising the steps of: supplying a steam flow to the surface end of the tubing string;   diverting the downwardly flowing steam into two radially separated flow components within the tubing;   directing one of said flow components into the inlet end of a choke passage, the outlet end of the choke passage being in communication with the production formation; and   accelerating the flow rate of said one flow component by said choke passage to a selected mass flow rate. .Iaddend. .Iadd.56. Apparatus for injecting steam into a production formation of a subterranean well at a selected mass flow rate comprising a tubular housing connectable in series relationship to the tubing string;   fluid diverting means in said tubular housing for dividing the steam flow into two radially separated components; and   means including a choke passage for accelerating the flow rate of one said flow component. .Iaddend. .Iadd.57. Apparatus for injecting steam at a selected mass flow rate into a production formation of a subterranean well from a tubing string extending to the surface comprising:   a tubular housing connectable in series relationship to the tubing string;   means in said tubular housing for diverting a portion of the steam flow down the tubing string to the outer peripheral wall of said tubular housing;   said outer peripheral wall having a port opening therethrough;   a secondary housing secured to the said exterior of tubular housing adjacent said port opening, said secondary housing defining an inlet chamber communicating with said port opening; and   a downwardly directed choke passageway to discharge a portion of the high-velocity steam flow. .Iaddend. .Iadd.58. Apparatus for injecting steam at a selected mass flow rate into a production formation of a subterranean well comprising:   a tubing string extending into the well to a production formation;   a source of high pressure steam connected to the tubing;   a tubular housing connectable in series relationship to the tubing string adjacent the production formation;   fluid diverting means in said tubular housing for dividing the steam flow into two radially separated components;   means including a choke passage for accelerating the flow rate of one said flow component and directing the accelerated component to the production formation; and   means defining a choke passage between the source of high pressure steam and said tubular housing to accelerate said steam. .Iaddend.