Patent Publication Number: US-7905282-B2

Title: Latchable carrier assembly for pipe conveyed well logging

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority under 35 U.S.C. §119(e) to U.S. Provisional Application Ser. Nos. 61/065,666; 61/065,718; and 61/065,719, each filed on Feb. 14, 2008, and each of which is incorporated herein by reference. In addition, this application is a continuation-in-part of U.S. patent application Ser. No. 11/753,192, filed on May 24, 2007; now U.S. Pat. No. 7,661,475 which in turn is entitled to the benefit of, and claims priority to U.S. Provisional Patent Application Ser. No. 60/891,775, filed on Feb. 27, 2007, the entire disclosures of each of which are incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to well logging, and more particularly to pipe conveyed memory based well logging. 
     BACKGROUND 
     Logging tools are commonly used in subterranean hydrocarbon wellbores to obtain geological information related to the wellbore. Such logging tools are most often conveyed into these wellbores via a wireline cable using gravity to guide the tools into the wellbore. The wireline cable provides a means to control tool descent and position, to transfer data from a downhole position to the wellbore surface, and to retrieve the tools from the wellbore. Wellbore conditions, such as wellbore inclinations greater than approximately 60 degrees from the vertical, and/or severe washouts or ledges are commonly referred to as tough logging conditions (TLCs) and are generally not suitable for gravity tool deployment by conventional wireline cable means. Such conditions typically require other conveyance means such as a drill pipe, to reach a position in a TLC wellbore where logging is desired. Additionally, or in the alternative, a tractor may be used to assist in the conveyance. 
     Drill pipe conveyed logging tools often include wireless or memory based logging tools. Such tools are typically either powered by downhole batteries, and equipped with memory devices for storing collected data. Currently, these wireless tools must be retrieved to the surface of the wellbore in order to recover the collected data. Such retrieval is time consuming, often requiring 15 hours or more to complete. Thus, imposing a considerable risk to the logging operation, since it cannot be known if the log was properly performed or the data was properly collected until retrieval is complete. 
     In spite of the potential risks, there is an increasing desire for drill pipe conveyed logging, driven by increased horizontal well applications and the potential cost savings of logging integrated with hole conditioning runs. Accordingly, a need exists for improved pipe conveyed logging tools and/or techniques. 
     SUMMARY OF THE INVENTION 
     One embodiment of the present invention includes a pipe conveyed well logging assembly and a method of performing a wellbore logging operation using a logging tool operated in memory mode. 
     In another embodiment the present invention includes a mechanical means to convey and deploy a memory logging tool with pipe assisted conveyance while retaining pump through and well control functionality. 
     In still another embodiment the present invention includes means to remotely recover data obtained downhole by a memory logging tool. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The exemplary embodiments of the present invention will be better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings wherein: 
         FIG. 1  is a schematic view of a pipe conveyed well logging assembly according to one embodiment of the present invention disposed in a subterranean hydrocarbon wellbore; 
         FIG. 2  is a memory logging tool, which forms a portion of the pipe conveyed well logging assembly of  FIG. 1 , showing the memory logging tool removed from the remainder of the assembly for clarity; 
         FIG. 3  is an enlargement of a portion of  FIG. 2  taken from detail  3  of  FIG. 2 ; 
         FIG. 4  is a schematic view of a carrier assembly, which forms a portion of the pipe conveyed well logging assembly of  FIG. 1 ; 
         FIG. 5  shows the memory logging tool of  FIG. 2  retracted within a carrier assembly, which forms a portion of the pipe conveyed well logging assembly of  FIG. 1 ; 
         FIGS. 6A-6B  each show an enlargement of a portion of  FIG. 5  taken from detail  6  of  FIG. 5 , with  FIG. 6A  showing a valve assembly in an open position and  FIG. 6B  showing the valve assembly in a closed position; 
         FIG. 6C  is an enlargement of the valve assembly of  FIG. 6A , showing the valve assembly in the open position; 
         FIG. 7  is a top view of an outer surface of the valve assembly of  FIGS. 6A-6C ; 
         FIG. 8  is a top view of an outer surface of a piston which interacts with the valve assembly of  FIGS. 6A-6C ; 
         FIG. 9  shows the memory logging tool of  FIG. 2  protruding from a carrier assembly, which forms a portion of the pipe conveyed well logging assembly of  FIG. 1 ; 
         FIG. 10  is an enlargement of a portion of  FIG. 9  taken from detail  10  of  FIG. 9 ; 
         FIG. 11  shows a fishing tool for remotely retrieving logging data from the pipe conveyed well logging assembly; 
         FIG. 12  shows a memory logging tool according to an alternative embodiment of the invention; and 
         FIG. 13  shows a pumpable dart for remotely retrieving logging data from the pipe conveyed well logging assembly. 
     
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS 
     As shown in  FIGS. 1-13 , embodiments of the present invention are directed to a pipe conveyed well logging assembly  10 . This assembly  10  includes a pipe string  12 , such as coiled tubing or drill pipe, connected to a carrier assembly  20  which carries a memory logging tool  24 . The pipe string  12  may be driven from the surface  14  of a subterranean hydrocarbon wellbore  16  by appropriate surface equipment  18  to a position within a wellbore  16  where logging is desired. This driving of the pipe string  12  allows the assembly  10  to be used in wellbores having tough logging conditions (TLCs). 
     However, the driving forces necessary to convey the assembly  10  can easily crush the memory logging tool  24 , which is relatively delicate to outside forces. As such, as the assembly  10  is forcibly driven to an area where logging is desired, the memory logging tool  24  is protected within the walls of the carrier assembly  20 . This protected position of the memory logging tool  24  disposed within the carrier assembly  20  is referred to herein as the retracted position (see for example  FIG. 5 ). 
     As described below, when an area desired to be logged is reached, the memory logging tool  24  may be ejected from the carrier assembly  20 , such that the memory logging tool  24  protrudes from a bottom end of the carrier assembly  20 . This ejected position of the memory logging tool  24  is referred to herein as the extended position (see for example  FIG. 9 ). In the extended position, the memory logging tool  24  may begin its memory logging. 
     To highlight some of the internal features of the pipe conveyed well logging assembly  10 ,  FIG. 2  shows the memory logging tool  24  separated from the carrier assembly  20 . As shown, the memory logging tool  24  is connected to a deployment head  22 . In one embodiment, a rotatable mounting device, such as a low torque swivel  26  is used to connect the memory logging tool  24  to the deployment head  22 . With this connection, the deployment head  22  is allowed to rotate about a longitudinal axis with respect to the memory logging tool  24  as shown by arrow  28 . Thus, in situations where the deployment head  22 , the carrier assembly  20 , and the pipe string  12  rotate together, the memory logging tool  24  maintains the ability to remain stationary. That is, the swivel  26  allows the pipe string  12  and the carrier assembly  20  to be rotated without a torque being transferred to the memory logging tool  24 . 
     Also shown in  FIG. 2 , and in the enlargement of  FIG. 3 , and as described further below, the deployment head  22  includes a collet  30  having radially movable latch fingers  32 . These latch fingers  32  interact with portions of the carrier assembly  20  to securely latch the memory logging tool  24  in either the above described retracted position or the above described extended position. Also shown in  FIGS. 2-3 , and described further below, are seals  34  which extend from an outer surface of the deployment head  22 . In addition, in one embodiment a fishing neck  25  is attached to an upper end of the deployment head  22 , the significance of which is described below. 
     As is also shown in  FIG. 2 , the memory logging tool  24  includes a battery  21 . The battery  21  is operable to activate and power the memory logging tool  24  during a logging operation. The memory logging tool  24  may also include a memory module  23 , which collects and stores logging data obtained by the memory logging tool  24  during a logging operation. Methods for retrieving logging data collected by the memory module are described below. 
       FIG. 4  shows a simplified schematic version of the carrier assembly  20 . As shown, the carrier assembly  20  includes an inner housing  36  and an outer housing  38 . In one embodiment, the inner and outer housings  36 ,  38  are each substantially cylindrical tubular structures which may be concentrically positioned. In one embodiment, an upper portion of the outer housing  38  includes a pipe adapter  55  for connection to the pipe string  12 ; and a lower portion of the outer housing  38  includes a guide shoe  65 . The guide shoe  65  may include an exterior fluted reamer profile. In one embodiment, the pipe adapter  55  includes an internal profile to accept a pump-down check valve, which may be preinstalled as a redundant blow-out prevention valve. Note that the leftmost dashed representation of the memory logging tool  24  in  FIG. 4  indicates the retracted position of the memory logging tool  24 , and the rightmost dashed representation of the memory logging tool  24  in  FIG. 4  indicates the extended position of the memory logging tool  24 . 
     As described in detail below, the inner housing  36  includes an ejector assembly  40 , a receiver assembly  44  and a transition area  42  disposed therebetween. Mentioned briefly here and in detail below, the ejector assembly  40  includes an upper latch for holding the memory logging tool  24  in the retracted position, and the receiver assembly  44  includes a lower latch for holding the memory logging tool  24  in the extracted position. 
     The ejector assembly  40  also includes a valve assembly (described in detail below in conjunction with  FIGS. 6A-8 ) for selectively directing a fluid flow either through an inner bore  48  of the inner housing  36 , or to an annulus  46  between the inner and outer housings  36 ,  38 . Such upper and lower latches, and such alternate flowpaths would not be possible if the carrier assembly  20  were a simple drill pipe. 
       FIG. 5  shows the memory logging tool  24  in the retracted position.  FIGS. 6A-6B  show an enlargement of a portion of  FIG. 5 . As shown in  FIGS. 6A-6B , the ejector assembly  40  forms a portion of the inner housing  36  of the carrier assembly  20 . An inner surface of the ejector assembly  40  includes a profile (described herein as the upper latch profile  50 ) which matches an outer profile of the latch fingers  32  of the deployment head  22 . As such, when the latch fingers  32  of the deployment head  22  are mated with the upper latch profile  50  of the carrier assembly  20 , the memory logging tool  24  is securely latched in the retracted position. 
       FIG. 9  shows the memory logging tool  24  in the extended position.  FIG. 10  shows an enlargement of a portion of  FIG. 9 . As shown in  FIG. 10 , the receiver assembly  44  forms a portion of the inner housing  36  of the carrier assembly  20 . An inner surface of the receiver assembly  44  includes a profile (described herein as the lower latch profile  52 ) which matches an outer profile of the latch fingers  32  of the deployment head  22 . As such, when the latch fingers  32  of the deployment head  22  are mated with the lower latch profile  52  of the carrier assembly  20 , the memory logging tool  24  is securely latched in the extended position. 
       FIGS. 6A-8  show how the memory logging tool  24  is moved from the retracted position to the extended position according to one embodiment of the present invention. As shown in  FIG. 6A , a piston  54  forms an upper portion of the ejector assembly  40 . Rotatably mounted about an outer surface of the piston  54  is a valve assembly  56 . However, the valve assembly  56  also includes an inwardly extending lug  58  which rides within a circumferentially extending groove  60  in the outer surface  62  of the piston  54 , such that the valve assembly  56  is longitudinally movable by the piston  54  (see also  FIGS. 6C and 8 ). 
     As is further shown in  FIG. 6A , an outer surface  66  of the valve assembly  56  includes a circumferentially extending “J-slot” groove  64  (see also  FIGS. 6C and 7 ). A stationary pin  68 , such as a set screw extending radially inwardly from the outer housing  38  of the carrier assembly  20 , rides within the J-slot groove  64 . Thus, as discussed in detail below, longitudinal movements of the piston  54  in combination with the outer housing pin  68  riding in the valve J-slot  64 , and the valve lug  58  riding in the piston groove  60 , cause the valve assembly  56  to move both rotationally and longitudinally with respect to piston  54 . These movements cause the valve assembly  56  to shift between an open position ( FIG. 6A ) and a closed position ( FIG. 6B ) as described further below. 
     As the pipe conveyed well logging assembly  10  is conveyed further and further downhole into the wellbore  16 , a wellbore hydrostatic pressure external to the pipe conveyed well logging assembly  10  gradually increases, thus creating a large pressure differential between the internal environment of the assembly  10  and the external environment of the assembly  10 . If this pressure differential is too large, then internal components within the assembly  10  can be undesirably displaced and/or damaged, and at extreme pressure differentials, the assembly  10  itself can even collapse or implode. 
     Thus, an internal pressure may be created within the assembly  10  to prevent too large of a pressure differential from developing between the internal and external environments of the assembly  10 . This internal pressure may be created by pumping a circulation fluid through the assembly  10 . The surface equipment  18  described above may include a pump for providing this circulating fluid to the assembly  10 . 
     As such, as the pipe conveyed well logging assembly  10  is conveyed downhole to a position where logging is desired, the valve assembly  56  is typically held in the open or run-in-hole position of  FIG. 6A  to allow a circulating fluid to be pumped therethrough. Note that in the open position of the valve assembly  56 , orifices  72  in the piston  54  fluidly connect the inner bore  48  of the inner housing  36  to the annulus  46  between the inner and outer housings  36 ,  38  of the carrier assembly  20 . Thus, with the valve assembly  56  in the open position, a circulation fluid is allowed to follow a flow path shown by arrows  70 . As shown in  FIG. 6A , as the circulating fluid is pumped through the assembly  10 , the fluid is directed through the piston orifices  72  rather than continuing down the inner bore  48  of the inner housing  36 . This is due to a fluid seal that is created between an inner surface  74  of the ejector assembly  40  and outer seals  34  on the deployment head  22 . 
     Thus, when the memory logging tool  24  is in the retracted position, protected within the inner housing  36  of the carrier assembly  20 , and the valve assembly  56  is in the open position, circulating fluid is not allowed to enter the inner bore  48  of the inner housing  36  (where the memory logging tool  24  is disposed) and instead is allowed to circulate through the assembly  10  in the annulus  46  between the inner and outer housings  36 ,  38 . Thus, as the circulating fluid is circulated through the assembly  10 , it is not allowed to contact the memory logging tool  24 . Consequently, any debris clogging or erosive effects that the circulating fluid might have on the memory logging tool  24  is avoided. 
     Also, note that when the valve assembly  56  is in the open position, circulation fluid is allowed to flow along flow path  70  in both the downhole and uphole directions. That is, both a regular circulation and a reverse circulation of the circulating fluid is allowed when the valve assembly  56  is in the open position. 
     Referring back to the interactions of the piston  54  with the valve assembly  56  (as shown in  FIGS. 6A-8 ), the piston  54  is spring biased in the uphole direction by a compression member  76  such as a spring. When a pressure differential between the inner bore  48  of the inner housing  36  and the annulus  46  between the inner and outer housings  36 ,  38  is small, then the spring  76  is uncompressed and the piston  54  is stationary. However, exceeding a predetermined pressure differential threshold P 1  between the inner bore  48  and the annulus  46  causes the spring  76  to compress, allowing the piston  54  to move longitudinally downwardly relative to the deployment head  22 . 
     This pressure differential threshold P 1  may be exceeded by operating a pump in the surface equipment  18  to either increase the flow rate of the circulating fluid when the valve assembly  56  is open, or to simply increase the pressure of the circulating fluid when the valve assembly  56  is closed and the circulating fluid is stationary. In a similar manner, the pump in the surface equipment  18  may be used to create other pressure differentials described below for effectuating other actions within the assembly  10 . 
     In one embodiment, the valve assembly  56  is moved between the open and closed positions as shown in  FIGS. 6A-8 . In this embodiment, the valve assembly  56  includes three open positions O 1 -O 3  and three closed positions C 1 -C 3 . However, as described below, in alternative embodiments the valve assembly  56  may include as few as one open position and one closed position. 
     Starting with the open position O 1 , movement of the valve assembly  56  is now described. That is, at position O 1 , the valve assembly  56  is open; the outer housing pin  68  is in position O 1  within the J-slot groove  64  in the outer surface  66  of the valve assembly  56 ; and the valve lug  58  is in position O 1  within the circumferential groove  60  in the outer surface  62  of the piston  54 . By exceeding the pressure differential threshold P 1 , the piston  54  is moved longitudinally downward relative to the deployment head  22  as described above. The downward movement of the piston  54  causes the valve assembly  56  to move downwardly due to the valve lug  58  being held within the piston groove  60 . The downward movement of the valve assembly  56  causes the outer housing pin  68  to follow a path as indicated by arrow  78  from position O 1  to position T 1 . Note however, that although the J-slot groove  64  allows for a further longitudinally downward movement of the piston  54  than that of the position of T 1 , the downward movement of the piston  54  is limited by a shear pin  84  extending radially inwardly from the outer housing  38 , the significance of which is described below. 
     Since the valve assembly  56  is free to rotate with respect to the piston  54 , the outer housing pin  68  moving from position O 1  to position T 1  causes the valve assembly  56  to rotate, creating a relative lateral movement (½L) between the valve assembly  56  and the piston  54 . The outer housing pin  68  will then stay in position T 1  until the predetermined pressure differential threshold P 1  between the inner bore  48  and the annulus  46  is no longer exceed. At that point, the spring  76  decompresses, forcing the piston  54  to move longitudinally upward, which in turn causes the outer housing pin  68  to follow a path as indicated by arrow  80  from position T 1  to position O 2 . As the outer housing pin  68  moves from position T 1  to position O 2 , the valve assembly  56  rotates, creating another relative lateral movement (½L) between the valve assembly  56  and the piston  54 . Thus, during one “cycle” of the valve assembly  56 , (such as the cycle from position O 1  to position O 2 ) the valve assembly  56  moves by a lateral distance of L. 
     Each time the valve assembly  56  moves laterally, the valve lug  58  correspondingly moves laterally within the piston groove  60 , such that during one full “cycle” movement of the valve assembly  56 , the valve lug  58  moves by a lateral distance of L relative to the piston  54 . By alternately exceeding and falling below the predetermined pressure differential threshold P 1  between the inner bore  48  and the annulus  46 , the valve assembly  56  may be cycled to each of the valve positions O 1  to O 3  and C 1  to C 3  as shown in  FIGS. 7-8 . 
     For example, when the valve assembly  56  is cycled from position O 2  to O 3 , the valve assembly  56  rotates relative to the piston  54 , causing the valve lug  58  to laterally move by a distance of L relative to the piston  54  just as it does in moving from position O 1  to O 2 . Similarly, when the valve assembly  56  is cycled from position O 3  to C 1 , the valve assembly  56  rotates relative to the piston  54 , causing the valve lug  58  to laterally move by a distance of L relative to the piston  54  just as it does in the previous two described cycles. However, due to the shape of the piston groove  60 , when the valve assembly  56  is cycled from position O 3  to C 1 , and the valve lug  58  is laterally moved by the distance L relative to the piston  54 , the valve assembly  56  moves longitudinally forward relative to the piston  54 . This relative longitudinal movement causes the valve assembly  56  to occlude or close off the orifices  72  in the piston  54  (as shown by the X labeled  45  in  FIG. 6B ). As a result, the flow path  70  between the inner bore  48  and the annulus  46  is closed off, and the valve assembly  56  is said to be in the closed position. 
     In the closed position of the valve assembly  56 , the circulating fluid is blocked from entering the annulus  46  between the inner and outer housings  36 ,  38 , and instead is directed to another flow path  82 . Following this flow path  82 , the motion of the circulating fluid is stopped by the fluid seals  34  disposed on the outer surface of the deployment head  22 , which create a fluid tight seal between the deployment head  22  an the inner surface  74  of the ejector assembly  40 . 
     With the valve assembly  56  in the closed position C 1 , the shear pin  84  (introduced above) may be sheared by cycling the valve assembly  56  from position C 1  to C 2 . That is, the shear pin  84  is sheared by an end  81  of the piston  54  when a predetermined pressure differential threshold P 2  between the inner bore  48  and the annulus  46  is exceeded causing the piston  54  to compress the piston spring  78  and move longitudinally downwardly with a force sufficient to shear shear pin  84  (note, that the pressure differential threshold P 2  required to shear the shear pin  84  is greater than the pressure differential threshold P 1  required to compress the piston spring  78 .) 
     With the shear pin  84  sheared by the cycling of the valve assembly  56  from position C 1  to C 2 , the full longitudinal movement of the piston  54  is no longer blocked; and when the valve assembly  56  is cycled from position C 2  to C 3 , the extra longitudinal movement of the piston  54  allows a shoulder  86  on a downhole portion of the piston  54  to contact and radially inwardly compress the latch fingers  32  on the collet  30  of the deployment head  22 . This radially inward compression of the latch fingers  32  disengages the latch fingers  32  from the upper latch profile  50  of the carrier assembly  20 . 
     With the latch fingers  32  disengaged, frictional drag from the circulating fluid flowing through inner bore  48  past the deployment head  22  carries the deployment head  22  (and hence the memory logging tool  24 ) downwardly relative to the carrier assembly  20 . This downward movement continues until the latch fingers  32  of the deployment head  22  reach and engage the lower latch profile  52  in the lower portion or receiver assembly  44  of the carrier assembly  20  as shown in  FIG. 10 . 
     In an alternative embodiment, the memory logging tool  24  may be released from the latched retracted position by an electronic trigger, such as any of the embodiments of the electronic trigger described in U.S. Pat. No. 7,337,850, filed on Mar. 4, 2008, the entire disclosures of which is incorporated herein by reference. 
     Note, that when the memory logging tool  24  is in the retracted position, the seals  34  of the deployment head  22  contact a small diameter portion  86  of the inner surface  74  of the ejector assembly  40 . Just as the deployment head  22  begins to move downwardly in its movement from the retracted position to the extended position, the inner surface  74  of the ejector assembly  40  opens up to a larger diameter  88  such that the seals  34  no longer contact the inner surface  74  of the ejector assembly  40 . Similarly, in the transition area  42  of the inner housing  36  of the carrier assembly  20  (i.e., the portion of the inner housing  36  between the ejector assembly  40  and the receiver assembly  44 ), the seals  34  do not contact the inner surface of the transition area  42 . Also similar to the ejector assembly  40 , the inner surface  89  of the receiver assembly  44  includes an enlarged diameter  90  which does not contact the seals  34  and a smaller diameter  92  which engages the seals  34  just as the latch fingers  32  engage the lower latch profile  52 . 
     Consequently, as the memory logging tool  24  is moved from the retracted position to the extended position, the seals  34  become quickly disengaged from the ejector assembly  40  upon a de-latching of the latch fingers  32  from the upper latch profile  50 ; remain disengaged as the deployment head  22  transverses the transition area  42 ; and become engaged with the smaller diameter  92  of the receiver assembly  44  upon the latching of the latch fingers  32  with the lower latch profile  52 . Thus, the amount of dynamic friction that the seals  34  experience in moving from the retracted position to the extended position, and the wear and tear on the seals  34  which results from such dynamic frictional forces, is minimized. 
     As shown in  FIG. 10 , orifices  94  in the receiver assembly  44  fluidly connect the inner bore  48  of the receiver assembly  44  to the annulus  46 . Thus, with the memory logging tool  24  latched in the extended position, the circulating fluid may be circulated through the assembly  10  by flowing flow path  96  through the inner bore  48  to the annulus  46  and out a lower end of the assembly  10 . 
     Note that with the memory logging tool  24  latched in the extended position (as shown in  FIG. 10 ), the valve assembly  56  may remain in the closed position or it may be cycled from position C 3  to O 1  to open the valve assembly  56 . In the closed position reverse circulation is allowed only up to the valve assembly  56 , as the valve assembly  10  prevents further reverse circulation as shown by the X labeled  98  in  FIG. 6B . Thus, if reverse circulation through the entire assembly  10  is desired, then the valve assembly  56  may be cycled from position C 3  to O 1  to open the valve assembly  56 . With the valve assembly  56  open, a reverse circulation of circulating fluid is allowed to follow flow path  70  through the assembly  10  as shown by  FIG. 6A . 
     However, regardless of whether the valve assembly  56  is in the open position or the closed position, reverse circulation of a circulation fluid through the assembly  10  cannot disengage latch fingers  32  from the lower latch profile  52 . That is, when the memory logging tool  24  is in the extended position, a reverse circulation of a circulation fluid through the assembly  10  cannot retract the memory logging tool  24  back into the carrier assembly  20 . 
     Notwithstanding this, the latch fingers  32  and the lower latch profile  52  are designed such that a predetermined compressive force acting on the memory logging tool  24  will cause the latch fingers  32  to disengage from the lower latch profile  52  and allow the memory logging tool  24  to retreat at least partially back into the carrier assembly  20 . The value of the compressive force on the memory logging tool  24  required to disengage the latch fingers  32  from the lower latch profile  52  is pre-calculated and defined as a compressive force that would otherwise damage the memory logging tool  24  if the latch fingers  32  were to stay engaged with the lower latch profile  52  during the actuation of the compressive force on the memory logging tool  24 . Thus, concerns of damaging the memory logging tool  24  by unexpected compressive forces acting on the memory logging tool  24  when it is in the extended position are minimized. 
     As described above, in one embodiment the valve assembly  56  includes three open positions O 1 -O 3  and three closed positions C 1 -C 3 . In alternate embodiments, the valve assembly  56  may include as few as one open position and one closed position, or any combination of various numbers of open positions and closed positions. In embodiments were the valve assembly  56  includes multiple open positions, however, operators of the assembly  10  are allowed to adjust flow rates of circulating fluid through the assembly  10  without risk of inadvertently closing the valve assembly  56 . 
     For example, if the valve assembly  56  is in the above described position O 1 , an inadvertently large (or even intentionally large) increase in flow rate through the assembly  10  will not close the valve assembly  56 , but instead move it from position O 1  to O 2 . The same is true when the valve assembly  56  is in position O 2 . That is, when the valve assembly  56  is in the position O 2 , an inadvertently large (or even intentionally large) increase in flow rate through the assembly  10  will not close the valve assembly  56 , but instead move it from position O 2  to O 3 . 
     Referring back to  FIG. 1 , when the assembly  10  has been deployed to a area within the wellbore  16  where logging is desired, the assembly  10  is pulled upwardly toward the surface  14  of the wellbore  16  (or in some other manner positioned) such that at least a distance D exists between a lower end  15  of the wellbore  16  and a lower end  17  of the carrier assembly  20 , the distance D being equal in length to the amount of the memory logging tool  24  which protrudes from the lower end  17  of the carrier assembly  20  when the memory logging tool  24  is in the extended position. 
     With the distance D between the lower end  15  of the wellbore  16  and the lower end  17  of the carrier assembly  20  achieved, the memory logging tool  24  may be moved from the retracted position to the extended position, and the memory logging tool  24  may be activated to begin logging the wellbore  16 . In one embodiment, the memory logging tool  24  includes a battery  21  for activating the logging. As the wellbore  16  is logged, the assembly  10  may be simultaneously pulled toward the surface  14  of the wellbore  16 . This simultaneous pulling and logging may be continued until a desired length of the wellbore  16  has been logged. 
     After the wellbore  16  has been logged by the pipe conveyed well logging assembly  10 , logging data obtained during the logging operation may be retrieved in any one of several methods. For example, the entire pipe conveyed well logging assembly  10  may be withdrawn from the wellbore  16 . However, this is a time consuming process, and in some instances may be undesirable. One alternative is to withdraw the deployment head  22  and the memory logging tool  24  from the wellbore  16  without withdrawing the pipe string  12  and the carrier assembly  20 . This can be accomplished by attaching a fishing tool  100 , such as that shown in  FIG. 11 , to the fishing neck  25  of the deployment head  22 . That is, as the fishing tool  100  is lowered over the fishing neck  25  of the deployment head  22 , inwardly biased arms  102  latch onto a shoulder  104  of the fishing neck  25  to secure the fishing tool  100  to the fishing neck  25 . Thus secured, the fishing tool  100  and the fishing neck  25  (and therefore the deployment head  22  and the memory logging tool  24 ) may be withdrawn from the wellbore  16  separately from the pipe string  12  and the carrier assembly  20 . 
     In another alternative the memory module, may be fished separately from the remainder of the pipe conveyed well logging assembly  10 . An exemplary embodiment for achieving this is shown in  FIG. 12 .  FIG. 12  is substantially the same as the embodiment of  FIG. 2 . However, in the embodiment of  FIG. 12  the memory module  23 ′ has been moved to an upper end of the deployment head  22 ′. That is, the memory module  23 ′ is removeably connected to the fishing neck  25 ′ of the deployment head  22 ′, such as by one or more shear pins  104 . In addition, an outer surface of the memory module  23 ′ includes a typical fishing neck profile, with an upper shoulder  106 . Thus, the fishing tool  100  may be lowered over the shoulder  106  of the memory module  23 ′ to latch the fishing tool arms  102  to the memory module shoulder  106 . Thus latched, the fishing tool  100  may be pulled by a force sufficient to shear the shear pins  104  of the memory module  23 ′, allowing the fishing tool  100  and the memory module  23 ′ to be withdrawn from the wellbore  16  separately from the remainder of the assembly  10 . 
     In each of the retrieval operations described above involving the fishing tool  100 , although a specific fishing tool  100  is illustrated and described, any appropriate fishing tool  100  may be used. In addition, although the fishing tool  100  may be conveyed into and withdrawn from the wellbore  16  by any appropriate method, in one embodiment the fishing tool  100  is attached to a cable, such as a slickline or a wireline cable, for effectuating the deployment and withdrawal of the fishing tool  100  from the wellbore  16 . 
     In another alterative, a plug  108  (such as that shown in  FIG. 13 ) may be pumped down the wellbore  16  and lowered over the memory module  23 ′ of  FIG. 12  and secured thereto by latching arms  110  of the plug  108  to the memory module shoulder  106  in a similar manner to that described above with respect to the connection of the fishing tool  100  to the memory module  23 ′. However, when the plug  108  is connected to the memory module  23 ′, fins  112  form fluid tight seals with an inner surface of the inner housing  36  of the carrier assembly  20 . Thus, with the plug  108  secured to the memory module  23 ′; and the valve assembly  56  in the open position, a reverse circulation of the circulating fluid can be used to apply an upward force on inner surfaces of the fins  112  as shown by arrows  114 . These upward forces can be used to shear the shear pins  104  of the memory module  23 ′, allowing the reverse circulation of the circulating fluid to carry the plug  108  and the memory module  23 ′ to the surface  14  of the wellbore  16 . 
     In still another alternative, a wet connect assembly (also called a data transfer plug) may be pumped down and connected to the deployment head  22  such that logging data stored in the memory module  23  can be transferred from the memory module  23  to the wet connect; and from the wet connect to the surface  14  of the wellbore  16 . Using this method, the logging data can be retrieved to the surface without withdrawing any of the components of the deployment head  22  or the memory logging tool  24  from the wellbore  16 . 
     In another embodiment according to the present invention, the pipe conveyed well logging assembly  10  may be used to perform a first logging operation to obtain logging data related to a desired portion of the wellbore  16 ; and then the assembly  10  may be used to perform a second logging operation to obtain logging data related the same portion of the wellbore  16  as that of the first logging operation. This second logging operation can be referred to as a confirmation logging operation. In one embodiment, both the first logging operation and the confirmation logging operation are performed before the logging data is retrieved to the surface  14  of the wellbore  16 . 
     In the above description, although element  24  is described as being a memory logging tool, the entire assembly which includes element  24  can be called a memory logging tool. For example, the entire assembly of  FIG. 2  can be considered to be a memory logging tool. Using this nomenclature, what is described above as the deployment head  22  with respect to  FIG. 2  can be described as an upper portion (or deployment portion) of the memory logging tool; and what is described above as the memory logging tool  24  with respect to  FIG. 2  can be described as a lower portion (or logging portion) of the memory logging tool. 
     The preceding description has been presented with references to certain exemplary embodiments of the invention. Persons skilled in the art and technology to which this invention pertains will appreciate that alterations and changes in the described structures and methods of operation can be practiced without meaningfully departing from the principle, and scope of this invention. Accordingly, the foregoing description should not be read as pertaining only to the precise structures described and shown in the accompanying drawings. Instead, the scope of the application is to be defined by the appended claims, and equivalents thereof.