Patent Publication Number: US-7909097-B2

Title: Well liner segments for in situ petroleum upgrading and recovery, and method of in situ upgrading and recovery

Description:
FIELD OF THE INVENTION 
     This invention relates to horizontal well liners, and more particularly to well liner segments which permit in situ upgrading of hydrocarbons during recovery from an underground reservoir, a method of manufacture of same, and to a process of in situ upgrading and recovery using such horizontal well segments. 
     BACKGROUND OF THE INVENTION AND DESCRIPTION OF THE PRIOR ART 
     Oil upgrader catalyst, such as a standard hydrotreating/HDS catalyst manufactured by Akzo Chemie Nederaland by Amsterdam, and identified as Ketjenfine 1 ™ 742-1, 3AQ, has been used in prior art oilfield in situ hydrocarbon upgrading processes of the type described in U.S. Pat. No. 6,412,557.  1  Trademark of Akzo Chemie Nederaland by Amsterdam for hydrotreating catalyst 
     Specifically, U.S. Pat. No. 6,412,557 describes a process for upgrading hydrocarbons within a petroleum reservoir by placing such a known hydrotreating catalyst around an exterior periphery of a centrally located perforated pipe situated in the horizontal leg of a horizontal well bore for upgrading and producing oil from a heavy oil (bitumen) formation. 
     Specifically, as may be understood from the in situ upgrading process of U.S. Pat. No. 6,412,557 and the methodology of the prior art in relation to in situ oil upgrading, a hole is drilled from the surface down to the target reservoir oil zone of the petroleum formation. The hole is curved so that it becomes horizontal when it arrives at the target reservoir oil zone. The horizontal section is typically created near the lowermost base portion of the target reservoir zone, and is extended laterally along the lowermost base portion to create a horizontal well, typically extending for hundreds of meters to the intended toe of the horizontal well. The vertical section of such well is cased. If the reservoir rock is consolidated, the horizontal section may be left open and un-cased, but sometimes a perforated liner is emplaced in the horizontal section to mitigate against the production of sand fines. If the rock is un-consolidated it is imperative to emplace a perforated liner to prevent complete collapse of the hole. Once drilling of the hole is completed a metal pipe is pushed into the hole, typically all the way to the intended toe of the horizontal well. In the horizontal section, this pipe is referred-to as the ‘liner’. The liner will have openings that are sized to allow reservoir fluids to enter the interior of the liner for flowing to the surface, but exclude the entry of sand that could plug the liner or cause operational difficulty with oil treating facilities at the surface. The openings in the liner can be narrow slits, in which case the pipe is called a ‘slotted liner’, or they may be narrow apertures between rows of wire that is wrapped around a pipe having relatively large holes, which are called ‘wire-wrapped screens’. Both slotted liners and wire-wrapped screens are commonplace in the design of horizontal wells. The separation of the liner from the undisturbed reservoir is small, typically in the range of 1-2 inches based on a centralized liner. While the bore hole may be drilled larger by reaming operations to leave more space between the liner and the reservoir, this is an additional expense. 
     As taught in the prior art and for example U.S. Pat. No. 6,412,557, the 1-2 inch annular interstitial space which exists between an un-reamed hole (typically approximately 12.25 inches in diameter) and the outside diameter of the centralized liner (typically of in the range of about 9.6 inches) is filled with catalyst of the type described above or a similar catalyst, by pumping such catalyst downhole into such interstitial space. The catalyst permits upgrading of the oil immediately prior to entering the perforated well liner so as to increase flowability of the produced oil within the horizontal well to more easily produce such oil to surface. 
     Disadvantageously, however, with this prior art method, since the resulting vertical path of draining fluids (oil) into the perforated liner is very short, the residence time of the oil in the interstitial space which contains such catalyst is very short, and the Gas and Liquid Hourly Space Velocity (“LHSV”) will be very high. By way of example, for a well of the above dimensions producing 100 m 3 /day of produced oil having a well 1-inch annular catalyst zone, the LHSV is approximately 2670 hr −1  and the residence time is only approximately 11 seconds. While this short residence time may provide some upgrading, it would be much more desirable to have a catalyst placement design that provides much longer residence times for the oil being exposed to such upgrading catalyst. 
     Accordingly, a real need exists for a liner design and an improved oilfield in situ hydrocarbon upgrading process which allows increased time of exposure of the produced oil to upgrader catalyst, to thereby improve flowability and increase effective recovery from underground petroleum formations, particularly from bitumen and tar sands formations. 
     SUMMARY OF THE INVENTION 
     The present invention relates to horizontal well liner designs which allow increased time or extent of exposure in which produced oil is exposed to upgrader catalyst during in situ hydrocarbon production, as well as improved methods for producing hydrocarbons using in situ hydrocarbon production methods, contemplating use of well liner segments containing catalyst to upgrade oil during production. 
     Specifically, in a broad embodiment of the present invention, a well liner segment for upgrading hydrocarbons during collection is provided to better allow collection of hydrocarbons from an underground hydrocarbon reservoir. Such liner segment possesses first and second mutually opposite ends and is adapted to be coupled in a horizontal manner at both of said mutually opposite ends to other elongate well liner segments to form an elongate well liner. 
     Significantly, each well liner segment comprises:
         (i) an elongate substantially hollow outer liner member, having a longitudinal axis and possessing a plurality of apertures in at least an upper or lower portion of a periphery thereof, each of a size sufficient to allow flow therethrough of a flowable hydrocarbon;   (ii) an elongate substantially hollow inner liner member, concentrically disposed within an interior of said outer member along said longitudinal axis thereof so as to form an interstitial space between said inner member and said outer member, likewise having a plurality of apertures in an upper and/or lower portion of a periphery thereof to permit ingress of partially upgraded hydrocarbon from said interstitial space to within said inner member;
 
wherein the interstitial space is adapted to be filled with a catalyst to permit upgrading and improve flowability of said hydrocarbon when the hydrocarbon flows through said interstitial passage and thereafter into the inner liner member via said apertures therein.
       

     In a first embodiment, the well liner segment of the present invention is adapted to permit inward radial flow of the produced oil. Specifically, the apertures in the outer and inner members are located so as to permit the oil to travel radially inwardly through apertures in the outer liner member into the interstitial space where such oil contacts the catalyst, and continue directly radially inwardly or alternatively circumferentially about the inner liner and thereafter radially inwardly through radially-aligned apertures in the inner liner and be collected in the inner liner, where after such upgraded oil may then be pumped or transferred in an appropriate manner to the surface (hereinafter the so-called “radial flow” configuration). 
     The increase in exposure time to catalyst which results from such horizontal well liner design can be seen mathematically. For example, in the prior art, where as mentioned above, the diameter of an unreamed horizontal well bore outside diameter is typically 12.25 inches and the tubing diameter of prior art (single tube) well liner being in the range of 9.6 inches, accounting for a well liner thickness of ¼ inch, the effective length of travel of oil through catalyst in the outside space between the horizontal well bore and the well liner is only 1.075 inches (ie [12.25−2×(0.25)−9.6]/2} and the resulting cross-sectional area of such space [π×(11.75 2 −9.6 2 )/4]=36 sq. inches, assuming the well liner is concentrically located in the well bore. 
     By way of contrast, for a 9.6 inch diameter circular outer well liner segment of the present invention (ie outer liner member diameter equals 9.6 inches) and an inner member outside diameter of 5.0 inches, assuming a tubing thickness of ¼ inches, the effective radial length of travel of oil through catalyst in the resulting interstitial space between the outer member and the inner member centrally located within such outer member, when the thickness of the steel is accounted for, is increased to 2.0 inches (ie [9.6−2×(0.25)−5.0]/2=2.0) and the resulting cross-sectional area of the interstitial space in which catalyst is placed increases accordingly to: [π(9.6−0.25×2) 2 −5.0 2 )/4]=45.4 sq. inches. If catalyst is also placed in the interstitial space between the horizontal well bore and the outer liner member, the effective radial length of travel of oil is increased to 3.075 inches (ie 1.075+2.0 inches), thus nearly tripling the radial distance which the oil travels through catalyst and thus likewise similarly increasing the time the oil is exposed to catalyst. 
     In a second alternative embodiment of the well liner of the present invention which likewise serves to increase the amount and time or extent of exposure to catalyst, apertures are situated in the outer liner relative to the inner liner to allow oil at one end of the outer well liner to flow into the interstitial space and thereafter cause such oil to flow laterally along such interstitial space to apertures in the inner liner member located proximate the opposite end of the well liner segment, before permitting the oil to drain or flow into the inner liner member, so as to thereby increase the time and amount of exposure of such oil to catalyst which is packed in such interstitial space (hereinafter the so-called “lateral flow” configuration). The effect of the lateral flow is to greatly increase the residence time of the draining fluids over the catalyst. For example, if the lateral travel length of oil in the interstitial passage between unaligned apertures of the outer and inner liners is 15 inches, the residence time using a lateral flow design of the present invention will be more than ten times as for the radial flow case in the prior art for identical fluid volumetric flow rates having only a effective length of travel of oil through catalyst of only 1,075 inches. While it may seen desirable to make the slotted segments shorter, for longer residence times, this must be balanced with the expected reduction in volumetric fluid production rates since there are fewer slots open to the reservoir on the outer liner. 
     Accordingly, in such second alternative embodiment of the well liner of the present invention, the apertures in said outer member are situated proximate a first end of mutually opposite ends of the well liner segment, and the apertures in the inner member are situated proximate an opposite second end of the well liner segment. The particular arrangement of such apertures respectively in the inner and outer liner members, namely positioning the apertures in the outer member proximate said first end thereof, allows said hydrocarbon to enter the interstitial space and to thereafter travel longitudinally along the well liner segment and within said interstitial space towards said second end while simultaneously contacting said catalyst therein so as to be upgraded, and to thereafter pass into said inner member via apertures in said inner member proximate said second end so as to become collected in said inner member of said well liner segment. 
     Alternatively, a configuration of apertures may be used which combines both a “lateral flow” configuration and a “radial flow” configuration. 
     In a preferred embodiment, at one end of the well liner segment the outer liner is affixed to the inner liner, and at another end the outer liner is in a slidable relationship to the inner liner (as more fully described below in various contemplated configurations) so as to allow some longitudinal movement of the inner liner member relative to the outer liner member in order to prevent buckling or overstressing of either the outer or inner liner members due to differential thermal expansion of the inner liner relative to the outer liner, which may otherwise arise in in situ production methods where well liner segments of the present invention are used. 
     Thus in one preferred embodiment, the inner well liner is centrally located in the outer well liner by means of an annular ring at one end, welded to the exterior of the inner well liner and to the interior of the outer well liner. At an opposite end the inner liner is concentrically located within the outer liner by two concentric rings, a first ring welded to the interior of the outer liner, and a second ring mounted to the exterior of the inner liner, which concentric ring arrangement permits thermal growth expansion of the inner liner relative to the outer liner, should uneven heating of the inner and outer liner members occur during use. The annular ring, and the concentric rings both also serve to maintain catalyst within the interstitial area between the inner and outer liners. 
     In an alternative configuration, there is provided means for slidably coupling the inner liner member to the outer liner member at a corresponding end of each of the inner and outer liner member, to prevent the inner liner member from being displaced from within the outer liner member, but simultaneously allowing some slidabie longitudinal movement at one end of the inner liner relative to the outer liner. More particularly, means slidably coupling said inner liner member to said outer liner member at one end is provided, which comprises a first ring member fixedly attached to said outer liner member, which further contacts said inner liner member in slidable engagement therewith so as to permit longitudinal slidable movement of said inner liner member relative to the outer liner member. Alternatively, the means coupling said inner liner member to said outer liner member comprises a first ring member fixedly attached to said inner liner member, which contacts said outer liner member in slidable engagement therewith so as to permit longitudinal slidable movement of said inner liner member relative to the outer liner member. 
     Still further alternatively, in a preferred embodiment, the means coupling said inner liner member to said outer liner member comprises a first and second pair of ring members situated proximate one end of said well liner segment, said first ring member fixedly coupled to said inner liner member, said second ring member fixedly coupled to said outer liner member, wherein each of said first and second ring members co-operate in a mutual slidable engagement relationship so as to permit longitudinal movement of associated inner and outer liner members relative to each other. 
     In a further aspect of the present invention, the invention comprises an improved in situ process for upgrading hydrocarbons when collecting said hydrocarbons from an underground hydrocarbon reservoir. 
     Such improved in situ process of the present invention comprises the steps of:
         (i) providing at least one production well having a substantially horizontal leg and a substantially vertical production well connected thereto, wherein the substantially horizontal leg has a heel portion in the vicinity of its connection to the vertical production well and a toe portion at the opposite end of the horizontal leg, said horizontal leg of said production well being situated in a lower part of said hydrocarbon reservoir;   (ii) providing at least one injection well for injecting an oxidizing gas into said hydrocarbon reservoir;   (iii) coupling together a plurality of elongate well liner segments, each fluidly coupled together so as to form a horizontal well liner within said horizontal leg, each of said well liner members comprising:
           (a) an elongate substantially hollow outer member, having a longitudinal axis and possessing a plurality of apertures in an upper portion of a periphery thereof, each of a size sufficient to allow flow therethrough of a flowable hydrocarbon;   (b) an elongate substantially hollow inner member, concentrically disposed within an interior of said outer member along said longitudinal axis thereof so as to form an interstitial space between said inner member and said outer member, likewise having a plurality of apertures in an upper portion of a periphery thereof to permit ingress of partially upgraded hydrocarbon from said interstitial space to within said inner member;   (c) said interstitial space filled with a catalyst to upgrade and improve flowability of said hydrocarbon when said hydrocarbon flows through said interstitial passage and thereafter into said inner member via said apertures therein;   
           (iv) injecting an oxidizing gas through the injection well to conduct in situ combustion, so that combustion gases are produced so as to cause the combustion gases to progressively advance as a front, substantially perpendicular to the horizontal leg, in the direction from the toe portion to the heel portion of the horizontal leg, and fluids drain into the horizontal well liner within said horizontal leg and into said interstial space filled with catalyst and to contact said catalyst and thereby become upgraded; and   (v) recovering said partially upgraded hydrocarbon which flows into said inner liner member of each of said well liner segments within said horizontal well liner.       

     The catalyst which is provided in the interstitial space is contemplated as comprising a hydrocarbon upgrading catalyst selected from the group of hydrocarbon upgrading catalysts comprising:
         (i) pelletized catalysts; and/or   (ii) granularized catalysts
 
wherein such catalyst is of a size sufficient to be substantially be prevented from escaping through any of said apertures in said outer or inner members so as to substantially prevent loss of said catalyst once said catalyst is situated in said interstitial space.
       

     In a preferred embodiment, the oil upgrader catalyst is a hydrodesulphurization catalyst, and in a further preferred embodiment is hydrotreating/HDS catalyst manufactured by Akzo Chemie Nederaland by Amsterdam, and identified as Ketjenfine 2 ™ 742-1, 3AQ.  2  Trademark of Akzo Chemie Nederaland by Amsterdam for hydrotreating catalyst 
     In a further aspect of the present invention, a method of manufacture of a well liner segment having an outer liner and an inner liner located within said outer liner is provided, comprising the steps of:
         (i) welding at least one seal ring to at least one of said inner and outer liner member, proximate one end thereof;   (ii) inserting said inner liner within said outer liner; and   (iii) inserting catalyst pellets in an interstitial space created between said inner liner and said outer liner.       

     In a preferred embodiment, such method comprises the further additional step of:
         (iv) inserting an annular member between said inner and outer liners at an end of each opposite said seal ring, so as to thereby encapsulate said catalyst pellets within said interstitial space between said seal ring and said annular member.       

    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further advantages and permutations will appear from the following detailed description of various non-limiting embodiments of the invention, taken together with the accompanying drawings, in which: 
         FIG. 1  is a schematic view of a catalytic petroleum upgrading system utilizing the well liner segments of the present invention employed in an in situ petroleum extraction application; 
         FIG. 2  is a perspective view of the exterior of a well liner segment of the present invention; 
         FIG. 3  is a cross-sectional view well taken along plane ‘A’-‘A’ of  FIG. 2 , showing a first embodiment of the well liner of the present invention, namely a well liner segment of the so-called “radial flow” configuration; 
         FIG. 4   a  is a cross-sectional view of the well liner segment shown in  FIG. 2 , taken along plane ‘A’-‘A’ of  FIG. 2 ; 
         FIG. 4   b  is a cross-section of a well liner segment of the present similar view to that shown in  FIG. 4   b , showing a modification to the alignment of apertures in each of the outer well liner and inner well liner, so as to provide more radial flow and exposure to catalyst in the interstitial area between the outer and inner well liner; 
         FIG. 5  is a cross-sectional view of a pair of fluidly coupled well liner segments as shown in  FIG. 3 , showing the manner of interconnection of such pair of well liner segments together and showing the manner by which oil is directed through catalyst contained in an interstitial space for the so-called radial-flow configuration; 
         FIG. 6  is a cross-sectional view of an alternative embodiment of the well liner of the present invention, namely a well liner segment of the so-called “lateral flow” configuration; 
         FIG. 7  is a cross-sectional view of a pair of fluidly coupled well liner segment of shown in  FIG. 6 , showing the manner of interconnection of such pair of well liner segments together and showing the manner by which oil is directed through catalyst contained in an interstitial space for the so-called lateral flow configuration; 
         FIG. 8  is a cross-sectional view of a well liner segment of the so-called “radial-flow” configuration, wherein in the embodiment shown a particular means is provided at opposite ends of the interior well liner to allow direct fluid coupling of one interior well liner to another; 
         FIG. 9  is a cross-sectional view of a pair of fluidly coupled well liner segments as shown in  FIG. 8 , showing the manner of interconnection of such pair of well liner segments together and showing the manner by which oil is directed through catalyst contained in an interstitial space for the so-called radial-flow configuration; 
         FIG. 10  is a cross-sectional view of a well liner segment of the so-called “lateral-flow” configuration, wherein in the embodiment shown another means is provided at opposite ends of the interior well liner to allow direct fluid coupling of one interior well liner to another; 
         FIG. 11  is a cross-sectional view of a pair of fluidly coupled well liner segments as shown in  FIG. 10 , showing the manner of interconnection of such pair of well liner segments together and showing the manner by which oil is directed through catalyst contained in an interstitial space for the so-called lateral-flow configuration; 
         FIG. 12  is a cross-sectional view of a so-called “lateral-flow” well liner, but in comparison to the embodiment shown in  FIG. 10  shows a variation in the manner by which the inner well liner may be concentrically located within the outer liner member by use of a seal ring, and 
         FIG. 13  is a cross-sectional view of a so-called “lateral-flow” well liner, but in comparison to the embodiment shown in  FIGS. 10 and 12  shows another variation in the manner by which the inner well liner may be concentrically located within the outer liner member by use of a seal ring. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       FIG. 1  shows a schematic diagram of an in situ hydrocarbon recovery system  2 , for improved recovery of hydrocarbons from a hydrocarbon-bearing formation  1 , utilizing a plurality of elongate well liner segments  10  of the present invention within the horizontal well bore  3  thereof. 
     Such hydrocarbon recovery system  2  is adapted to direct hydrocarbons, particularly viscous oil  15  which, during the method of such hydrocarbon recovery system  2 , drains out of hydrocarbon formation  1 , through a catalyst-packed interstitial space  12  within each well liner segment  10 , for subsequent recovery to surface  13 . 
     A plurality of well liner segments  10  of the present invention are shown, each threadably coupled to an adjoining other well liner segments  10  so as to form a well liner  6  as shown in  FIG. 1  for use in in situ hydrocarbon recovery methods. 
     In operation, oil  15  which is heated by means of in situ combustion methods or alternatively steam assisted gravity drainage (SAGD) and which flows from such hydrocarbon-bearing formation  1  is upgraded during passage into the well liner segments  10  of the present invention, and is thereafter more easily flowed within the well liner  6  and thereafter produced to the surface  13  of the well. 
     With reference to  FIGS. 1-13  herein, the well liner segments  10  each comprise a slotted or wire-wrapped outer liner member  20 , typically of approximately 9.6 inches outer diameter. Such outer liner member  20  is in contact (particularly along the bottom portion of the exterior periphery thereof) with the inner diameter of an un-reamed horizontal well bore  3  as shown in  FIG. 1 , the latter being typically of approximately 12.2 inches in diameter, so that an interstitial space  24  may be formed between outer well liner  20  and the horizontal well bore  3 . 
     A slotted or wire-wrapped inner liner member  22  is provided, concentrically located within outer liner member  20  to form the interstitial space  12 , such inner liner member  22  having an inner volume/area  80  for collecting upgraded hydrocarbon and allowing it to be transferred to surface  13  by pumping or other transfer method. 
     In a preferred embodiment, each of outer liner member  20  and inner liner member  22  of the well liner segment  10  are cylindrical elongate members, adapted to be inserted in a cylindrical horizontal well bore  3  as shown in  FIG. 1 . Interstitial space  12  formed between the inner diameter of the outer liner  20  and the outer diameter of the inner well liner member  22  is accordingly an annular interstitial space  12 , as best shown in  FIGS. 4   a  and  4   b.    
       FIG. 2  shows a perspective view of a preferred embodiment of a well liner segment  10  of the present invention, having at a first end  60   a  thereof having a male threaded portion  61  thereon (preferably a standard NPT pipe thread) for threaded coupling to an opposite end  60   b  of an adjoining well liner segment  10 , such opposite end  60   b  having an internal female threaded portion  62  thereon as shown in  FIGS. 5 ,  7 , &amp;  9  herein. 
     In a preferred embodiment, as best shown in  FIG. 2 , outer member  20  is a rolled steel of approximately ¼ inch in thickness, and approximately 10 inches in outside diameter. Apertures  31  in outer member  20  comprise a plurality of slots, each having a width less than the width of the granules of catalyst  40  to prevent egress of such catalyst  40  from the interstitial space  12 , and sufficiently narrow in width to substantially prevent ingress of sand and other debris such as drill tailings into outer member  20  but of sufficient width to allow ingress of flowable hydrocarbons. Accordingly, the width of such apertures/slots  31  is in the range of 0.005 to 0.025 inches (0.128 to 0.625 mm), and length is typically 6 to 8 inches with approximately 50 of such apertures/slots  31  evenly spaced about a periphery of outer member  20 . Of course other spacing and slot lengths may be used, all with a view of maximizing ingress of hydrocarbons and preventing, within reasonable limits, ingress of sand and other debris into outer member  20 . 
     In a first embodiment and as shown in  FIGS. 2 &amp; 4   a , apertures/slots  31  are evenly spaced about a periphery of outer member  22 . Similarly, apertures/slots  41  in interior member  22  are likewise equally spaced about an entire periphery thereof. Apertures/slots  41  are typically larger in width than apertures  31 , as there is no remaining need to attempt to “screen” sand from the viscous oil  15  entering interior member  22 . Viscous oil  15  consequently flows directly radially inwardly through catalyst  40  in interstitial space  12  into interior area  80  in internal member  22 , as seen in  FIG. 4   a.    
     Alternatively, as seen in  FIG. 4   b , apertures/slots  31  in outer member  20  may be situated only on an upper portion of outer member  20 , and apertures/slot  41  in inner member  22  situated on a lower portion thereof. A vice versa arrangement is also contemplated. Under either of the two alternative configurations, viscous oil  15 , as shown in  FIG. 4   b , will necessarily be required to travel a circumferential distance within interstitial space  12 , thereby providing greater exposure time to catalyst  40  within interstitial space  12 , thereby improving upgrading of such viscous oil  15 . 
       FIG. 3  shows a cross-section through the well liner segment  10  of the present invention, taken along plane A-A of  FIG. 2 , showing a first embodiment of the well liner segment  10 , namely a so-called “radial flow” configuration.  FIG. 5  shows a plurality of such well liner segments  10  of the “radial flow” configuration, wherein outer members  20  are each threadably coupled together at opposite ends  60   a ,  60   b  to form horizontal well liner  6 . As may be best seen from  FIGS. 4   a,    4   b , and  FIG. 5 , in the “radial flow” configuration viscous oil  15  within a hydrocarbon formation  1  flows radially inwardly through apertures/slots  31  in outer member  20 , radially inwardly through catalyst  40  packed into interstitial space  12  where such viscous oil  15  is at least partially upgraded, and further progresses radially inwardly though apertures  41  in interior member  22  into interior area  80 , whereafter such upgraded oil is transferred to surface  13 . 
     The well liner segment  10  of the “radial-flow” configuration shown in  FIGS. 3-5  is adapted to permit flow of oil  15  in a radial direction perpendicular to a longitudinal axis  30  of such well liner  10 , as shown from the direction of arrows in  FIGS. 3 ,  4   a ,  4   b , &amp;  5 . As seen from  FIGS. 3 ,  4   a , &amp;  5 , apertures  31  are provided in outer liner member  20 , to allow oil  15  to flow into interstitial space  12 . 
     Interstitial space  12  is typically packed during manufacture of such well liner segment  10  with a hydrocarbon upgrader catalyst  40 . One such hydrocarbon upgrader catalyst  40  which is suitable for use in the present invention is standard hydrotreating/HDS catalyst manufactured by Akzo Chemie Nederaland by Amsterdam, and identified as Ketjenfine 3 ™ 742-1, 3AQ.  3  Trademark of Akzo Chemie Nederaland by Amsterdam for hydrotreating catalyst consisting of a hydrodesulfurization catalyst containing 4.4 wt. % of CoO and 15 wt. % of MoO3 on γAl2O3 
     Preferably, hydrocarbon upgrader catalyst  40  when positioned in such interstitial space  12  during manufacture of such well liner segment  10  is of a pelletized or granularized form, of a size nominally greater than the size of apertures  31 , to prevent loss of catalyst from interstitial space  12  via apertures  31 . 
       FIG. 6  shows an alternative configuration of the well liner segment  10  of the present invention, adapted to permit lateral flow of oil  15  within interstitial space  12  so as to increase the extent and duration which oil  15  contacts upgrader catalyst  40 . Such alternative well liner segment configuration is hereinafter referred to as the “lateral flow” configuration.  FIG. 7  shows a plurality of well liner segments  10  of the “lateral flow” configuration threadably coupled together at mutually opposite ends  60   a ,  60   b , to form a well liner  6 . As best seen from arrows shown on  FIGS. 1 &amp; 7 , viscous oil  15  from formation  1 , during a hydrocarbon recovery method such as in situ combustion process as described in U.S. Pat. No. 6,412,557 or US publication No. 20080066907 published Mar. 20, 2008 and similarly assigned to a common owner, drains from formation  1  flows into apertures/slots  31  on outer members  20  proximate end  60   a  thereof, and into interstitial space  12 . Thereafter oil  15  flows laterally within such interstitial space  12  in the direction of the arrows shown, until, at an opposite end  60   b  of well liner segment  10 , apertures  41  in inner well liner  22  are reached, wherein oil  15  flows into the interior  80  of inner member  22 , and thereafter is transferred, generally by way of pumping, to surface  13 . This process is adapted to be repeated for in each well liner segment of the present invention when a plurality of well liner segments  10  are inserted in a horizontal well bore  3 . 
     In both the “radial flow” and “lateral flow” embodiments of the well liner  10  of the present invention, and as best shown in  FIGS. 3 &amp; 5 , and  FIGS. 6 &amp; 7  respectively, interior members  22  may be concentrically located within, and affixed to, outer members  20  at one end  60   b  thereof via a conical ring member  68 , which is affixed to each of outer and interior members  22 ,  22  via circumferential welds  72 . As further explained below, not only does conical ring member  68  serve to concentrically locate and affix interior member  22  to outer member  20  at one end thereof, such conical ring member  68  serves to retain catalyst  40  within interstitial space  12 . 
     Likewise, at an opposite end  60   a  of the well liner segment  10  of the present invention, in both the “radial flow” and “lateral flow” embodiments thereof, and as best seen for example in  FIGS. 3 &amp; 5 , and  FIGS. 6 &amp; 7  respectively, a sliding seal  52  is preferably provided at such opposite end  60   a . The purpose of the sliding seal  52  is to allow for differential thermal growth between the inner member  22  and the outer member  20 . This sliding seal  52  may be of a number of forms and configurations, as will necessarily now be apparent to a person of skill in the art. 
     In a first embodiment, as shown in FIGS.  3  &amp;  5 - 11 , such sliding seal  52  comprises a first (outer) ring member  50  fixedly secured via circumferential welds  72  to outer member  20 , and a second (inner) ring member  54  likewise secured via circumferential welds to inner member  22 , which ring members  50 ,  54  together act to concentrically locate inner liner member  22  within outer member  20 . 
     In a second embodiment, a first version of which is shown in  FIG. 12 , the sliding seal  52  comprises merely a single (outer) ring member  50  fixedly secured to said outer member  20 , as shown in  FIG. 12 , to allow not only longitudinal expansion of said inner liner member  22  to said outer liner member  20 , but also provide some clearance  55  to permit some radial growth due to thermal expansion in a radial direction. In a second version, shown in  FIG. 13 , the sliding seal  52  comprises merely a single (inner) ring member  54  fixedly secured to the inner liner member  22  via circumferential welds  72 , to allow not only longitudinal expansion/contraction of said inner liner member  22  relative to said outer liner member  20 , but also provide some radial clearance  55  to permit some radial growth. Importantly, in all configurations the sliding seal  52  not only concentrically locates inner liner member  22  within outer liner member  20 , but also simultaneously allows slidable longitudinal movement of inner liner  22  relative to outer liner member  20  to accommodate differential thermal expansion of outer liner  20  to inner liner member  22  which occurs during methods which employ heat in the collection of oil from hydrocarbon reservoirs of the type contemplated herein, including use in in situ hydrocarbon extraction recovery methods. 
     In the embodiments shown in FIGS.  3  &amp;  5 - 7 , and as noted above, a conical ring member  68  may be affixed to each of outer and interior members  20 ,  22  via circumferential welds  72 , to concentrically locate and affix interior member  22  to outer member  20  and to further retain catalyst  40  within interstitial space  12 . Alternatively, and as best seen in  FIGS. 8-11 , an annular retainer member  59  may instead be provided on inner liner member  22 , adapted to abut an annular shoulder  92  on outer liner member  20 . A lock ring  57  may be further provided so as to secure and retain retainer member  59  and associated inner liner  22  within outer liner member  20 . Lock ring  57  possesses external threads  69  to allow it to be threadably received on (internally threaded) end  60   b  of outer member  20 , as best seen in  FIG. 8 . Alternatively, lock ring  57  may be dispensed with, and inner liner member  22  secured within outer liner member  20  by one of the ends  60   b  thereof when another well liner segment  10  is threadably secured together, as shown in  FIG. 11 . However, in this embodiment, use of such externally threaded lock ring  57  is preferred, as such is useful to prevent inadvertent removal of such inner liner member  22  from said outer liner member  20  during shipping or transport of individual well liner segments  10 . 
     Preferably in all embodiments of the well liner segments  10  of the present invention, each of mutually opposite ends  60   a ,  60   b  of outer well liner  20  possess male external threaded end  61  and female (internal) threaded end  62  respectively, to permit threadable connection of respective ends  60   a  and  60   b  of separate well liner segments  10  together, as shown in  FIGS. 3 ,  5 ,  7 ,  9 , &amp;  11 , so as to form a continuous well liner  6  in which to produce oil  15  to surface  13 . 
     In another embodiment of the invention, provision may be made for the inner liner members  22  to be coupled together, as shown in  FIGS. 8-11 . In a first version of this alternative embodiment, as shown in  FIGS. 8 &amp; 9 , each of mutually opposite ends  70   a ,  70   b  on each of inner liner member  22  may possess male and female unthreaded ends  71   a ,  71   b , respectively, which may be insertable one within an other as shown in  FIG. 9 , to allow fluid coupling of inner liner members together at the time of threadable coupling together of mutually opposite ends  60   a  and  60   b  on each outer member  20 . 
     In a still further refinement, and as shown in  FIGS. 10 &amp; 11 , each of mutually opposite ends  70   a ,  70   b  on each inner liner member  22  may possess male  71   a  and female threaded ends  71   b  respectively, which permit threadable connection of mutually opposite ends  70   a ,  70   b  when mutually opposite ends  60   a ,  60  on each outer liner  20  are threadably connected. Such threaded opposite ends  60   a ,  60   b  and  70   a ,  70   b  are each typically a national pipe thread (NPT) configuration of the type commonly used for threaded pipe in the oil industry. 
     Other means of fluidly coupling well liner segments  10  together will now be clearly apparent to those of skill in the art, and are further contemplated within the scope of this invention as being other equally viable alternative means of fluidly coupling well liner segments  10  together. 
     For a horizontal well liner  10  of 414 meters, 69 connected well liner segments  10  each of 6-meter length are required. For an annular interstitial space of 1.5 inches, each well liner segment  10  will contain approximately 300 pounds of catalyst  40 . 
     The following is a description of how oil  15  is able to be collected and upgraded and thereafter pumped to surface  13  using the well liner segments  10  of the present invention in an in-situ hydrocarbon recovery system  2 . 
     Specifically, in an in situ hydrocarbon recovery process  2  as may be seen from  FIG. 1 , at least one production well  100  is drilled, having a substantially horizontal leg  101  and a substantially vertical production well  102  connected thereto, using horizontal and/or directional drilling techniques which are widely known and used in the art of horizontal drilling. The substantially horizontal leg  101  has a heel portion  103  in the vicinity of its connection to the vertical production well  102  and a toe portion  104  at the opposite end of the horizontal leg  101 , said horizontal leg  101  of said production well  100  being situated in a lower part  105  of a hydrocarbon reservoir  1 . An injection well  107  is provided, for injecting an oxidizing gas into an upper part of reservoir  1 . 
     A plurality of elongate well liner segments  10  are coupled together via coupling means comprising exterior male  61  threaded portions and female threaded portions on respective ends  60   a ,  60   b  of outer well liners  20 , and inserted through horizontal well bore  3  so as to form a horizontal well liner  6  within said horizontal leg  101 , as shown in  FIGS. 3 ,  5 ,  7 , and  9 . Each of said well liner segments  10  comprise:
         (a) an elongate substantially hollow outer member  20 , having a longitudinal axis  30  and possessing a plurality of apertures  31  in at least an upper portion of a periphery thereof, each of a size sufficient to allow flow therethrough of a flowable hydrocarbon into an interior of said outer member;   (b) an elongate substantially hollow inner member  22 , concentrically disposed within an interior of said outer member  20  along said axis  30  thereof so as to form an interstitial space  12  between said inner member  22  and said outer member  20 , likewise having a plurality of apertures  41  on a portion of a periphery thereof to permit ingress of partially upgraded hydrocarbon  2  from said interstitial space  12  to within said inner member  22 ;   (c) said interstitial space  12  filled with a catalyst  40  to upgrade and improve flowability of said hydrocarbon when said hydrocarbon flows through said interstitial passage  12  and thereafter into said inner member  22  via said apertures  41  therein.       

     In the in situ extraction process as shown in  FIG. 1  utilizing the well liner segments of the present invention, oxidizing gas, such as air or oxygen, is injected through the injection well  107  and enters the formation through perforations  108  in well  107 . A source of ignition (not shown) is provided to cause in situ combustion. Alternatively, ignition may be spontaneous following heating of the oil near the injector well  107 . Upon ignition of the oil, combustion gases are produced which progressively advance as a combustion front  109 , substantially perpendicular to the horizontal leg  101 , in the direction from the toe portion  104  to the heel portion  105  of the horizontal leg  101 , and fluids drain into the horizontal well liner  6  within said horizontal leg  101  and into said interstitial space  12  filled with catalyst  40  and to contact said catalyst  40  and thereby become upgraded. The upgraded and heated petroleum drain by gravity and pressure differential into the horizontal leg  101 , namely the interstitial space  12  where such oil  15  is upgraded by coming into contact with catalyst  40 , and thereafter enters inner liner member  22 , and in particular inner volume area  80  thereof, where such oil is thereafter pumped to surface  13 . 
     A method for the manufacture of well liner segments  10  of the present invention is set out below. 
     For the embodiments of the well liner segments  10  shown in  FIGS. 3 ,  5 , and  6 - 7 , seal rings  50  and  54  are first circumferentially welded to outer and inner well liner members  20 ,  22  respectively. Inner well liner  22  is then inserted within outer well liner  20 , typically each being aligned in a vertical position, so that seal rings  50 ,  54  are positioned as shown in the  FIGS. 3 ,  5 , and  6 - 7 . Temporary spacers means (not shown) may be temporarily positioned about a periphery of inner member  22  at end  70   b  thereof so as to concentrically locate inner member  22  within outer member  20 . 
     Catalyst pellets  40  are then dropped into the interstitial space  12 , so as to fill such space  12  with catalyst  40 . Thereafter, the temporary spacers are removed, and conical ring member  68  is inserted and circumferentially welded at locations  72  so as to retain inner member  22  concentrically within outer member  20  and retain catalyst  40  within interstitial space  12 . 
     For manufacture of well liner segments  10  of the configuration shown in  FIGS. 12 and 13 , the procedure is similar, save that only one seal ring  50  and  54  is respectively welded to the inner  22  or outer liner  20 , as the case may be. 
     For the embodiments of the well liner segments  10  shown in  FIGS. 8-11 , seal rings  50  and  54  are first circumferentially welded to outer and inner well liner members  20 ,  22  respectively. Inner well liner  22  is then inserted within outer well liner  20 , typically each being aligned in a vertical position, so that seal rings  50 ,  54  are positioned as shown in the  FIGS. 8-11 . Locking ring  57  is then inserted as shown in  FIGS. 8-11  to secure inner member  22  to outer member  22  at such location. Catalyst pellets  40  are then dropped into the interstitial space  12  via aperture  99  in annular retainer ring  59 , so as to fill such space  12  with catalyst  40 . Aperture  99  may thereafter, if desired, be sealed by insertion of a plug (not shown) therein. 
     Although the disclosure describes and illustrates preferred embodiments of the invention, it is to be understood that the invention is not limited to these particular embodiments. Many variations and modifications will now occur to those skilled in the art. For a complete definition of the invention and its intended scope, reference is to be made to the summary of the invention and the appended claims read together with and considered with the disclosure and drawings herein.