An apparatus for actuating a pressure delivery system of a fluid sampler. The apparatus includes a housing ( 302 ) having a longitudinal passageway and defining first and second chambers ( 338, 348 ). A piston ( 346 ) is disposed within the longitudinal passageway between the first and second chambers ( 338, 348 ). A valving assembly ( 356 ) is disposed within the longitudinal passageway. The valving assembly ( 356 ) is operable to selectively prevent communication of pressure from a pressure source of the fluid sampler to the second chamber ( 348 ). The valving assembly ( 356 ) is actuated responsive to an increase in pressure in the first chamber ( 338 ) which longitudinally displaces the piston ( 346 ) toward the valving assembly ( 356 ) until at least a portion of the piston ( 346 ) contacts the valving assembly ( 356 ), thereby releasing pressure from the pressure source into the second chamber ( 348 ) and longitudinally displacing the piston ( 346 ) away from the valving assembly ( 356 ).

CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This is a divisional of co-pending application Ser. No. 12/139,100, filed on Jun. 13, 2008, which is a divisional of application Ser. No. 11/702,810, filed on Feb. 6, 2007, now U.S. Pat. No. 7,472,589 B1, issued Jan. 6, 2009, which is a continuation-in-part of application Ser. No. 11/438,764, filed on May 23, 2006, which is a continuation-in-part of application Ser. No. 11/268,311, filed on Nov. 7, 2005, now U.S. Pat. No. 7,197,923 B1, issued Apr. 3, 2007. 
     
    
     TECHNICAL FIELD OF THE INVENTION 
       [0002]    This invention relates, in general, to testing and evaluation of subterranean formation fluids and, in particular to, a single phase fluid sampling apparatus for obtaining multiple fluid samples and maintaining the samples near reservoir pressure via a common pressure source during retrieval from the wellbore and storage on the surface. 
       BACKGROUND OF THE INVENTION 
       [0003]    Without limiting the scope of the present invention, its background is described with reference to testing hydrocarbon formations, as an example. 
         [0004]    It is well known in the subterranean well drilling and completion art to perform tests on formations intersected by a wellbore. Such tests are typically performed in order to determine geological or other physical properties of the formation and fluids contained therein. For example, parameters such as permeability, porosity, fluid resistivity, temperature, pressure and bubble point may be determined. These and other characteristics of the formation and fluid contained therein may be determined by performing tests on the formation before the well is completed. 
         [0005]    One type of testing procedure that is commonly performed is to obtain a fluid sample from the formation to, among other things, determine the composition of the formation fluids. In this procedure, it is important to obtain a sample of the formation fluid that is representative of the fluids as they exist in the formation. In a typical sampling procedure, a sample of the formation fluids may be obtained by lowering a sampling tool having a sampling chamber into the wellbore on a conveyance such as a wireline, slick line, coiled tubing, jointed tubing or the like. When the sampling tool reaches the desired depth, one or more ports are opened to allow collection of the formation fluids. The ports may be actuated in variety of ways such as by electrical, hydraulic or mechanical methods. Once the ports are opened, formation fluids travel through the ports and a sample of the formation fluids is collected within the sampling chamber of the sampling tool. After the sample has been collected, the sampling tool may be withdrawn from the wellbore so that the formation fluid sample may be analyzed. 
         [0006]    It has been found, however, that as the fluid sample is retrieved to the surface, the temperature of the fluid sample decreases causing shrinkage of the fluid sample and a reduction in the pressure of the fluid sample. These changes can cause the fluid sample to approach or reach saturation pressure creating the possibility of asphaltene deposition and flashing of entrained gasses present in the fluid sample. Once such a process occurs, the resulting fluid sample is no longer representative of the fluids present in the formation. Therefore, a need has arisen for an apparatus and method for obtaining a fluid sample from a formation without degradation of the sample during retrieval of the sampling tool from the wellbore. A need has also arisen for such an apparatus and method that are capable of maintaining the integrity of the fluid sample during storage on the surface. 
       SUMMARY OF THE INVENTION 
       [0007]    The present invention disclosed herein provides a single phase fluid sampling apparatus and a method for obtaining fluid samples from a formation without the occurrence of phase change degradation of the fluid samples during the collection of the fluid samples or retrieval of the sampling apparatus from the wellbore. In addition, the sampling apparatus and method of the present invention are capable of maintaining the integrity of the fluid samples during storage on the surface. 
         [0008]    In one aspect, the present invention is directed to an apparatus for obtaining a plurality of fluid samples in a subterranean well that includes a carrier, a plurality of sampling chambers and a pressure source. In one embodiment, the pressure source is selectively in fluid communication with at least two sampling chambers thereby serving as a common pressure source to pressurize fluid samples obtained in the at least two sampling chambers. In another embodiment, the carrier has a longitudinally extending internal fluid passageway forming a smooth bore and a plurality of externally disposed chamber receiving slots. Each of the sampling chambers is positioned in one of the chamber receiving slots of the carrier. The pressure source is selectively in fluid communication with each of the sampling chambers such that the pressure source is operable to pressurize each of the sampling chambers after the fluid samples are obtained. 
         [0009]    In another aspect, the present invention is directed to a method for obtaining a plurality of fluid samples in a subterranean well. The method includes the steps of positioning a fluid sampler in the well, obtaining a fluid sample in each of a plurality of sampling chambers of the fluid sampler and pressurizing each of the fluid samples using a pressure source of the fluid sampler that is in fluid communication with each of the sampling chambers. 
         [0010]    In a further aspect, the present invention is directed to an apparatus for obtaining a fluid sample in a subterranean well. The apparatus includes a housing having a sample chamber defined therein. The sample chamber is selectively in fluid communication with the exterior of the housing and is operable to receive the fluid sample therefrom. A debris trap piston is slidably disposed within the housing. The debris trap piston includes a debris chamber and, responsive to the fluid sample entering the sample chamber, the debris trap piston receives a first portion of the fluid sample in the debris chamber then displaces relative to the housing to expand the sample chamber. 
         [0011]    In one embodiment, the debris trap piston includes a passageway having a cross sectional area that is smaller than the cross sectional area of the debris chamber. In this embodiment, the first portion of the fluid sample passes from the sample chamber through the passageway to enter the debris chamber. Also in this embodiment, the first portion of the fluid sample is retained in the debris chamber due to pressure from the sample chamber applied to the debris chamber through the passageway. Alternatively or additionally, a check valve may be disposed in an inlet portion of the debris trap piston to retain the first portion of the fluid sample in the debris chamber. 
         [0012]    In another embodiment, the debris trap piston may include a first piston section and a second piston section that is slidable relative to the first piston section such that the debris chamber is expandable responsive to the fluid sample entering the debris chamber. In this embodiment, as engagement device may be disposed between the first piston section and the second piston section to prevent additional movement of the first piston section relative to the second piston section after expanding the debris chamber to a preselected volume. 
         [0013]    In an additional aspect, the present invention is directed to a method for obtaining a fluid sample in a subterranean well. The method includes the steps of disposing a sampling chamber within the subterranean well, actuating the sampling chamber such that a sample chamber within the sampling chamber is in fluid communication with the exterior of the sampling chamber, receiving a first portion of the fluid sample in a debris chamber of a debris trap piston slidably disposed within the sampling chamber, displacing the debris trap piston within the sampling chamber to expand the sample chamber and receiving the remainder of the fluid sample in the sample chamber. 
         [0014]    The method may also include passing the first portion of the fluid sample through the sample chamber and through a passageway of the debris trap piston before entering the debris chamber and retaining the first portion of the fluid sample in the debris chamber by applying pressure from the sample chamber to the debris chamber through the passageway. Additionally or alternatively, a check valve disposed in an inlet portion of the debris trap piston may be used to retain the first portion of the fluid sample in the debris chamber. 
         [0015]    In certain embodiments, the method may include expanding the debris chamber responsive to the fluid sample entering the debris chamber by sliding a first piston section relative to a second piston section and preventing additional movement of the first piston section relative to the second piston section after expanding the debris chamber to a preselected volume. 
         [0016]    In yet another aspect, the present invention is directed to a downhole tool including a housing having a longitudinal passageway. A piston, including a piercing assembly, is disposed within the longitudinal passageway. A valving assembly is also disposed within the longitudinal passageway. The valving assembly includes a rupture disk that is initially operable to maintain a differential pressure thereacross. The valving assembly is actuated by longitudinally displacing the piston relative to the valving assembly such that at least a portion of the piercing assembly travels through the rupture disk, thereby allowing fluid flow therethrough. 
         [0017]    In one embodiment, the piercing assembly includes a piercing assembly body and a needle that is held within the piercing assembly body by compression. In this embodiment, the needle has a sharp point that travels through the rupture disk. In addition, the needle may have a smooth outer surface, a fluted outer surface, a channeled outer surface or a knurled outer surface. In certain embodiments, the valving assembly may include a check valve that allows fluid flow in a first direction and prevents fluid flow in a second direction through the valving assembly once the valving assembly is actuated by the piercing assembly. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]    For a more complete understanding of the present invention, including its features and advantages, reference is now made to the detailed description of the invention, taken in conjunction with the accompanying drawings in which like numerals identify like parts and in which: 
           [0019]      FIG. 1  is a schematic illustration of a fluid sampler system embodying principles of the present invention; 
           [0020]      FIGS. 2A-H  are cross-sectional views of successive axial portions of one embodiment of a sampling section of a sampler embodying principles of the present invention; 
           [0021]      FIGS. 3A-E  are cross-sectional views of successive axial portions of actuator, carrier and pressure source sections of a sampler embodying principles of the present invention; 
           [0022]      FIG. 4  is a cross-sectional view of the pressure source section of  FIG. 3C  taken along line  4 - 4 ; 
           [0023]      FIG. 5  is a cross-sectional view of the actuator section of  FIG. 3A  taken along line  5 - 5 ; 
           [0024]      FIG. 6  is a schematic view of an alternate actuating method for a sampler embodying principles of the present invention; 
           [0025]      FIG. 7  is a schematic illustration of an alternate embodiment of a fluid sampler embodying principles of the present invention; 
           [0026]      FIG. 8  is a cross-sectional view of the fluid sampler of  FIG. 7  taken along line  8 - 8 ; and 
           [0027]      FIGS. 9A-G  are cross-sectional views of successive axial portions of another embodiment of a sampling section of a sampler embodying principles of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0028]    While the making and using of various embodiments of the present invention are discussed in detail below, it should be appreciated that the present invention provides many applicable inventive concepts which can be embodied in a wide variety of specific contexts. The specific embodiments discussed herein are merely illustrative of specific ways to make and use the invention, and do not delimit the scope of the invention. 
         [0029]    Referring initially to  FIG. 1 , therein is representatively illustrated a fluid sampler system  10  and associated methods which embody principles of the present invention. A tubular string  12 , such as a drill stem test string, is positioned in a wellbore  14 . An internal flow passage  16  extends longitudinally through tubular string  12 . 
         [0030]    A fluid sampler  18  is interconnected in tubular string  12 . Also, preferably included in tubular string  12  are a circulating valve  20 , a tester valve  22  and a choke  24 . Circulating valve  20 , tester valve  22  and choke  24  may be of conventional design. It should be noted, however, by those skilled in the art that it is not necessary for tubular string  12  to include the specific combination or arrangement of equipment described herein. It is also not necessary for sampler  18  to be included in tubular string  12  since, for example, sampler  18  could instead be conveyed through flow passage  16  using a wireline, slickline, coiled tubing, downhole robot or the like. Although wellbore  14  is depicted as being cased and cemented, it could alternatively be uncased or open hole. 
         [0031]    In a formation testing operation, tester valve  22  is used to selectively permit and prevent flow through passage  16 . Circulating valve  20  is used to selectively permit and prevent flow between passage  16  and an annulus  26  formed radially between tubular string  12  and wellbore  14 . Choke  24  is used to selectively restrict flow through tubular string  12 . Each of valves  20 ,  22  and choke  24  may be operated by manipulating pressure in annulus  26  from the surface, or any of them could be operated by other methods if desired. 
         [0032]    Choke  24  may be actuated to restrict flow through passage  16  to minimize wellbore storage effects due to the large volume in tubular string  12  above sampler  18 . When choke  24  restricts flow through passage  16 , a pressure differential is created in passage  16 , thereby maintaining pressure in passage  16  at sampler  18  and reducing the drawdown effect of opening tester valve  22 . In this manner, by restricting flow through choke  24  at the time a fluid sample is taken in sampler  18 , the fluid sample may be prevented from going below its bubble point, i.e., the pressure below which a gas phase begins to form in a fluid phase. Circulating valve  20  permits hydrocarbons in tubular string  12  to be circulated out prior to retrieving tubular string  12 . As described more fully below, circulating valve  20  also allows increased weight fluid to be circulated into wellbore  14 . 
         [0033]    Even though  FIG. 1  depicts a vertical well, it should be noted by one skilled in the art that the fluid sampler of the present invention is equally well-suited for use in deviated wells, inclined wells or horizontal wells. As such, the use of directional terms such as above, below, upper, lower, upward, downward and the like are used in relation to the illustrative embodiments as they are depicted in the figures, the upward direction being toward the top of the corresponding figure and the downward direction being toward the bottom of the corresponding figure. 
         [0034]    Referring now to  FIGS. 2A-2H  and  3 A- 3 E, a fluid sampler including an exemplary fluid sampling chamber and an exemplary carrier having a pressure source coupled thereto for use in obtaining a plurality of fluid samples that embodies principles of the present invention is representatively illustrated and generally designated  100 . Fluid sampler  100  includes a plurality of the sampling chambers such sampling chamber  102  as depicted in  FIG. 2 . Each of the sampling chambers  102  is coupled to a carrier  104  that also includes an actuator  106  and a pressure source  108  as depicted in  FIG. 3 . 
         [0035]    As described more fully below, a passage  110  in an upper portion of sampling chamber  102  (see  FIG. 2A ) is placed in communication with a longitudinally extending internal fluid passageway  112  formed completely through fluid sampler  100  (see  FIG. 3 ) when the fluid sampling operation is initiated using actuator  106 . Passage  112  becomes a portion of passage  16  in tubular string  12  (see  FIG. 1 ) when fluid sampler  100  is interconnected in tubular string  12 . As such, internal fluid passageway  112  provides a smooth bore through fluid sampler  100 . Passage  110  in the upper portion of sampling chamber  102  is in communication with a sample chamber  114  via a check valve  116 . Check valve  116  permits fluid to flow from passage  110  into sample chamber  114 , but prevents fluid from escaping from sample chamber  114  to passage  110 . 
         [0036]    A debris trap piston  118  separates sample chamber  114  from a meter fluid chamber  120 . When a fluid sample is received in sample chamber  114 , piston  118  is displaced downwardly. Prior to such downward displacement of piston  118 , however, piston section  122  is displaced downwardly relative to piston section  124 . In the illustrated embodiment, as fluid flows into sample chamber  114 , an optional check valve  128  permits the fluid to flow into debris chamber  126 . The resulting pressure differential across piston section  122  causes piston section  122  to displace downward, thereby expanding debris chamber  126 . 
         [0037]    Eventually, piston section  122  will displace downward sufficiently far for a snap ring, C-ring, spring-loaded lugs, dogs or other type of engagement device  130  to engage a recess  132  formed on piston section  124 . Once engagement device  130  has engaged recess  132 , piston sections  122 ,  124  displace downwardly together to expand sample chamber  114 . The fluid received in debris chamber  126  is prevented from escaping back into sample chamber  114  by check valve  128  in embodiments that include check valve  128 . In this manner, the fluid initially received into sample chamber  114  is trapped in debris chamber  126 . This initially received fluid is typically laden with debris, or is a type of fluid (such as mud) which it is not desired to sample. Debris chamber  126  thus permits this initially received fluid to be isolated from the fluid sample later received in sample chamber  114 . 
         [0038]    Meter fluid chamber  120  initially contains a metering fluid, such as a hydraulic fluid, silicone oil or the like. A flow restrictor  134  and a check valve  136  control flow between chamber  120  and an atmospheric chamber  138  that initially contains a gas at a relatively low pressure such as air at atmospheric pressure. A collapsible piston assembly  140  in chamber  138  includes a prong  142  which initially maintains another check valve  144  off seat, so that flow in both directions is permitted through check valve  144  between chambers  120 ,  138 . When elevated pressure is applied to chamber  138 , however, as described more fully below, piston assembly  140  collapses axially, and prong  142  will no longer maintain check valve  144  off seat, thereby preventing flow from chamber  120  to chamber  138 . 
         [0039]    A floating piston  146  separates chamber  138  from another atmospheric chamber  148  that initially contains a gas at a relatively low pressure such as air at atmospheric pressure. A spacer  150  is attached to piston  146  and limits downward displacement of piston  146 . Spacer  150  is also used to contact a stem  152  of a valve  154  to open valve  154 . Valve  154  initially prevents communication between chamber  148  and a passage  156  in a lower portion of sampling chamber  102 . In addition, a check valve  158  permits fluid flow from passage  156  to chamber  148 , but prevents fluid flow from chamber  148  to passage  156 . 
         [0040]    As mentioned above, one or more of the sampling chambers  102  and preferably nine of sampling chambers  102  are installed within exteriorly disposed chamber receiving slots  159  that circumscribe internal fluid passageway  112  of carrier  104 . A seal bore  160  (see  FIG. 3B ) is provided in carrier  104  for receiving the upper portion of sampling chamber  102  and another seal bore  162  (see  FIG. 3C ) is provided for receiving the lower portion of sampling chamber  102 . In this manner, passage  110  in the upper portion of sampling chamber  102  is placed in sealed communication with a passage  164  in carrier  104 , and passage  156  in the lower portion of sampling chamber  102  is placed in sealed communication with a passage  166  in carrier  104 . 
         [0041]    In addition to the nine sampling chambers  102  installed within carrier  104 , a pressure and temperature gauge/recorder (not shown) of the type known to those skilled in the art can also be received in carrier  104  in a similar manner. For example, seal bores  168 ,  170  in carrier  104  may be for providing communication between the gauge/recorder and internal fluid passageway  112 . Note that, although seal bore  170  depicted in  FIG. 3C  is in communication with passage  172 , preferably if seal bore  170  is used to accommodate a gauge/recorder, then a plug is used to isolate the gauge/recorder from passage  172 . Passage  172  is, however, in communication with passage  166  and the lower portion of each sampling chamber  102  installed in a seal bore  162  and thus servers as a manifold for fluid sampler  100 . If a sampling chamber  102  or gauge/recorder is not installed in one or more of the seal bores  160 ,  162 ,  168 ,  170  then a plug will be installed to prevent flow therethrough. 
         [0042]    Passage  172  is in communication with chamber  174  of pressure source  108 . Chamber  174  is in communication with chamber  176  of pressure source  108  via a passage  178 . Chambers  174 ,  176  initially contain a pressurized fluid, such as a compressed gas or liquid. Preferably, compressed nitrogen at between about 7,000 psi and 12,000 psi is used to precharge chambers  174 ,  176 , but other fluids or combinations of fluids and/or other pressures both higher and lower could be used, if desired. Even though  FIG. 3  depicts pressure source  108  as having two compressed fluid chambers  174 ,  176 , it should be understood by those skilled in the art that pressure source  108  could have any number of chambers both higher and lower than two that are in communication with one another to provide the required pressure source. As best seen in  FIG. 4 , a cross-sectional view of pressure source  108  is illustrated, showing a fill valve  180  and a passage  182  extending from fill valve  180  to chamber  174  for supplying the pressurized fluid to chambers  174 ,  176  at the surface prior to running fluid sampler  100  downhole. 
         [0043]    As best seen in  FIGS. 3A and 5 , actuator  106  includes multiple valves  184 ,  186 ,  188  and respective multiple rupture disks  190 ,  192 ,  194  to provide for separate actuation of multiple groups of sampling chambers  102 . In the illustrated embodiment, nine sampling chambers  102  may be used, and these are divided up into three groups of three sampling chambers each. Each group of sampling chambers can be referred to as a sampling chamber assembly. Thus, a valve  184 ,  186 ,  188  and a respective rupture disk  190 ,  192 ,  194  are used to actuate a group of three sampling chambers  102 . For clarity, operation of actuator  106  with respect to only one of the valves  184 ,  186 ,  188  and its respective one of the rupture disks  190 ,  192 ,  194  is described below. Operation of actuator  106  with respect to the other valves and rupture disks is similar to that described below. 
         [0044]    Valve  184  initially isolates passage  164 , which is in communication with passages  110  in three of the sampling chambers  102  via passage  196 , from internal fluid passage  112  of fluid sampler  100 . This isolates sample chamber  114  in each of the three sampling chambers  102  from passage  112 . When it is desired to receive a fluid sample into each of the sample chambers  114  of the three sampling chambers  102 , pressure in annulus  26  is increased a sufficient amount to rupture the disk  190 . This permits pressure in annulus  26  to shift valve  184  upward, thereby opening valve  184  and permitting communication between passage  112  and passages  196 ,  164 . 
         [0045]    Fluid from passage  112  then enters passage  110  in the upper portion of each of the three sampling chambers  102 . For clarity, the operation of only one of the sampling chambers  102  after receipt of a fluid sample therein is described below. The fluid flows from passage  110  through check valve  116  to sample chamber  114 . An initial volume of the fluid is trapped in debris chamber  126  of piston  118  as described above. Downward displacement of the piston section  122 , and then the combined piston sections  122 ,  124 , is slowed by the metering fluid in chamber  120  flowing through restrictor  134 . This prevents pressure in the fluid sample received in sample chamber  114  from dropping below its bubble point. 
         [0046]    As piston  118  displaces downward, the metering fluid in chamber  120  flows through restrictor  134  into chamber  138 . At this point, prong  142  maintains check valve  144  off seat. The metering fluid received in chamber  138  causes piston  146  to displace downward. Eventually, spacer  150  contacts stem  152  of valve  154  which opens valve  154 . Opening of valve  154  permits pressure in pressure source  108  to be applied to chamber  148 . Pressurization of chamber  148  also results in pressure being applied to chambers  138 ,  120  and thus to sample chamber  114 . This is due to the fact that passage  156  is in communication with passages  166 ,  172  (see  FIG. 3C ) and, thus, is in communication with the pressurized fluid from pressure source  108 . 
         [0047]    When the pressure from pressure source  108  is applied to chamber  138 , piston assembly  140  collapses and prong  142  no longer maintains check valve  144  off seat. Check valve  144  then prevents pressure from escaping from chamber  120  and sample chamber  114 . Check valve  116  also prevents escape of pressure from sample chamber  114 . In this manner, the fluid sample received in sample chamber  114  is pressurized. 
         [0048]    In the illustrated embodiment of fluid sampler  100 , multiple sampling chambers  102  are actuated by rupturing disk  190 , since valve  184  is used to provide selective communication between passage  112  and passages  110  in the upper portions of multiple sampling chambers  102 . Thus, multiple sampling chambers  102  simultaneously receive fluid samples therein from passage  112 . 
         [0049]    In a similar manner, when rupture disk  192  is ruptured, an additional group of multiple sampling chambers  102  will receive fluid samples therein, and when the rupture disk  194  is ruptured a further group of multiple sampling chambers  102  will receive fluid samples therein. Rupture disks  184 ,  186 ,  188  may be selected so that they are ruptured sequentially at different pressures in annulus  26  or they may be selected so that they are ruptured simultaneously, at the same pressure in annulus  26 . 
         [0050]    Another important feature of fluid sampler  100  is that the multiple sampling chambers  102 , nine in the illustrated example, share the same pressure source  108 . That is, pressure source  108  is in communication with each of the multiple sampling chambers  102 . This feature provides enhanced convenience, speed, economy and safety in the fluid sampling operation. In addition to sharing a common pressure source downhole, the multiple sampling chambers  102  of fluid sampler  100  can also share a common pressure source on the surface. Specifically, once all the samples are obtained and pressurized downhole, fluid sampler  100  is retrieved to the surface. Even though certain cooling of the samples will take place, the common pressure source maintains the samples at a suitable pressure to prevent any phase change degradation. Once on the surface, the sample may remain in the multiple sampling chambers  102  for a considerable time during which temperature conditions may fluctuate. Accordingly, a surface pressure source, such a compressor or a pump, may be used to supercharge the sampling chambers  102 . This supercharging process allows multiple sampling chambers  102  to be further pressurized at the same time with sampling chambers  102  remaining in carrier  104  or after sampling chambers  102  have been removed from carrier  104 . 
         [0051]    Note that, although actuator  106  is described above as being configured to permit separate actuation of three groups of sampling chambers  102 , with each group including three of the sampling chambers  102 , it will be appreciated that any number of sampling chambers  102  may be used, sampling chambers  102  may be included in any number of groups (including one), each group could include any number of sampling chambers  102  (including one), different groups can include different numbers of sampling chambers  102  and it is not necessary for sampling chambers  102  to be separately grouped at all. 
         [0052]    Referring now to  FIG. 6 , an alternate actuating method for fluid sampler  100  is representatively and schematically illustrated. Instead of using increased pressure in annulus  26  to actuate valves  184 ,  186 ,  188 , a control module  198  included in fluid sampler  100  may be used to actuate valves  184 ,  186 ,  188 . For example, a telemetry receiver  199  may be connected to control module  198 . Receiver  199  may be any type of telemetry receiver, such as a receiver capable of receiving acoustic signals, pressure pulse signals, electromagnetic signals, mechanical signals or the like. As such, any type of telemetry may be used to transmit signals to receiver  199 . 
         [0053]    When control module  198  determines that an appropriate signal has been received by receiver  199 , control module  198  causes a selected one or more of valves  184 ,  186 ,  188  to open, thereby causing a plurality of fluid samples to be taken in fluid sampler  100 . Valves  184 ,  186 ,  188  may be configured to open in response to application or release of electrical current, fluid pressure, biasing force, temperature or the like. 
         [0054]    Referring now to  FIGS. 7 and 8 , an alternate embodiment of a fluid sampler for use in obtaining a plurality of fluid samples that embodies principles of the present invention is representatively illustrated and generally designated  200 . Fluid sampler  200  includes an upper connector  202  for coupling fluid sampler  200  to other well tools in the sampler string. Fluid sampler  200  also includes an actuator  204  that operates in a manner similar to actuator  106  described above. Below actuator  204  is a carrier  206  that is of similar construction as carrier  104  described above. Fluid sampler  200  further includes a manifold  208  for distributing fluid pressure. Below manifold  208  is a lower connector  210  for coupling fluid sampler  200  to other well tools in the sampler string. 
         [0055]    Fluid sampler  200  has a longitudinally extending internal fluid passageway  212  formed completely through fluid sampler  200 . Passageway  212  becomes a portion of passage  16  in tubular string  12  (see  FIG. 1 ) when fluid sampler  200  is interconnected in tubular string  12 . In the illustrated embodiment, carrier  206  has ten exteriorly disposed chamber receiving slots that circumscribe internal fluid passageway  212 . As mentioned above, a pressure and temperature gauge/recorder (not shown) of the type known to those skilled in the art can be received in carrier  206  within one of the chamber receiving slots such as slot  214 . The remainder of the slots are used to receive sampling chambers and pressure source chambers. 
         [0056]    In the illustrated embodiment, sampling chambers  216 ,  218 ,  220 ,  222 ,  224 ,  226  are respectively received within slots  228 ,  230 ,  232 ,  234 ,  236 ,  238 . Sampling chambers  216 ,  218 ,  220 ,  222 ,  224 ,  226  are of a construction and operate in the manner described above with reference to sampling chamber  102 . Pressure source chambers  240 ,  242 ,  244  are respectively received within slots  246 ,  248 ,  250  in a manner similar to that described above with reference to sampling chamber  102 . Pressure source chambers  240 ,  242 ,  244  initially contain a pressurized fluid, such as a compressed gas or liquid. Preferably, compressed nitrogen at between about 10,000 psi and 20,000 psi is used to precharge chambers  240 ,  242 ,  244 , but other fluids or combinations of fluids and/or other pressures both higher and lower could be used, if desired. 
         [0057]    Actuator  204  includes three valves that operate in a manner similar to valves  184 ,  186 ,  188  of actuator  106 . Actuator  204  has three rupture disks, one associated with each valve in a manner similar to rupture disks  190 ,  192 ,  194  of actuator  106  and one of which is pictured and denoted as rupture disk  252 . As described above, each of the rupture disks provides for separate actuation of a group of sampling chambers. In the illustrated embodiment, six sampling chambers are used, and these are divided up into three groups of two sampling chambers each. Associated with each group of two sampling chambers is one pressure source chamber. Specifically, rupture disk  252  is associated with sampling chambers  216 ,  218  which are also associated with pressure source chamber  240  via manifold  208 . In a like manner, the second rupture disk is associated with sampling chambers  220 ,  222  which are also associated with pressure source chamber  242  via manifold  208 . In addition, the third rupture disk is associated with sampling chambers  224 ,  226  which are also associated with pressure source chamber  244  via manifold  208 . In the illustrated embodiment, each rupture disk, valve, pair of sampling chambers, pressure source chamber and manifold section can be referred to as a sampling chamber assembly. Each of the three sampling chamber assemblies operates independently of the other two sampling chamber assemblies. For clarity, the operation of one sampling chamber assembly is described below. Operation of the other two sampling chamber assemblies is similar to that described below. 
         [0058]    The valve associated with rupture disk  252  initially isolates the sample chambers of sampling chambers  216 ,  218  from internal fluid passageway  212  of fluid sampler  200 . When it is desired to receive a fluid sample into each of the sample chambers of sampling chambers  216 ,  218 , pressure in annulus  26  is increased a sufficient amount to rupture the disk  252 . This permits pressure in annulus  26  to shift the associated valve upward in a manner described above, thereby opening the valve and permitting communication between passageway  212  and the sample chambers of sampling chambers  216 ,  218 . 
         [0059]    As described above, fluid from passageway  212  enters a passage in the upper portion of each of the sampling chambers  216 ,  218  and passes through an optional check valve to the sample chambers. An initial volume of the fluid is trapped in a debris chamber as described above. Downward displacement of the debris piston is slowed by the metering fluid in another chamber flowing through a restrictor. This prevents pressure in the fluid sample received in the sample chambers from dropping below its bubble point. 
         [0060]    As the debris piston displaces downward, the metering fluid flows through the restrictor into a lower chamber causing a piston to displace downward. Eventually, a spacer contacts a stem of a lower valve which opens the valve and permits pressure from pressure source chamber  240  to be applied to the lower chamber via manifold  208 . Pressurization of the lower chamber also results in pressure being applied to the sample chambers of sampling chambers  216 ,  218 . 
         [0061]    As described above, when the pressure from pressure source chamber  240  is applied to the lower chamber, a piston assembly collapses and a prong no longer maintains a check valve off seat, which prevents pressure from escaping from the sample chambers. The upper check valve also prevents escape of pressure from the sample chamber. In this manner, the fluid samples received in the sample chambers are pressurized. 
         [0062]    In the illustrated embodiment of fluid sampler  200 , two sampling chambers  216 ,  218  are actuated by rupturing disk  252 , since the valve associated therewith is used to provide selective communication between passageway  212  the sample chambers of sampling chambers  216 ,  218 . Thus, both sampling chambers  216 ,  218  simultaneously receive fluid samples therein from passageway  212 . 
         [0063]    In a similar manner, when the other rupture disks are ruptured, additional groups of two sampling chambers (sampling chambers  220 ,  222  and sampling chambers  224 ,  226 ) will receive fluid samples therein and the fluid samples obtained therein will be pressurize by pressure sources  242 ,  244 , respectively. The rupture disks may be selected so that they are ruptured sequentially at different pressures in annulus  26  or they may be selected so that they are ruptured simultaneously, at the same pressure in annulus  26 . 
         [0064]    One of the important features of fluid sampler  200  is that the multiple sampling chambers, two in the illustrated example, share a common pressure source. That is, each pressure source is in communication with multiple sampling chambers. This feature provides enhanced convenience, speed, economy and safety in the fluid sampling operation. In addition to sharing a common pressure source downhole, multiple sampling chambers of fluid sampler  200  can also share a common pressure source on the surface. Specifically, once all the samples are obtained and pressurized downhole, fluid sampler  200  is retrieved to the surface. Even though certain cooling of the samples will take place, the common pressure source maintains the samples at a suitable pressure to prevent any phase change degradation. Once on the surface, the samples may remain in the multiple sampling chambers for a considerable time during which temperature conditions may fluctuate. Accordingly, a surface pressure source, such a compressor or a pump, may be used to supercharge the sampling chambers. This supercharging process allows multiple sampling chambers to be further pressurized at the same time with the sampling chambers remaining in carrier  206  or after sampling chambers have been removed from carrier  206 . 
         [0065]    It should be understood by those skilled in the art that even though fluid sampler  200  has been described as having one pressure source chamber in communication with two sampling chambers via manifold  208 , other numbers of pressure source chambers may be in communication with other numbers of sampling chambers with departing from the principles of the present invention. For example, in certain embodiments, one pressure source chamber could communicate pressure to three, four or more sampling chambers. Likewise, two or more pressure source chambers could act as a common pressure source to a single sampling chamber or to a plurality of sampling chambers. Each of these embodiments may be enabled by making the appropriate adjustments to manifold  208  such that the desired pressure source chambers and the desired sampling chambers are properly communicated to one another. 
         [0066]    Referring now to  FIGS. 9A-9G  and with reference to  FIGS. 3A-3E , an alternate fluid sampling chamber for use in a fluid sampler including an exemplary carrier having a pressure source coupled thereto for use in obtaining a plurality of fluid samples that embodies principles of the present invention is representatively illustrated and generally designated  300 . Each of the sampling chambers  300  is coupled to a carrier  104  that also includes an actuator  106  and a pressure source  108  as depicted in  FIG. 3 . 
         [0067]    As described more fully below, a passage  310  in an upper portion of sampling chamber  300  (see  FIG. 9A ) is placed in communication with a longitudinally extending internal fluid passageway  112  formed completely through the fluid sampler (see  FIG. 3 ) when the fluid sampling operation is initiated using actuator  106 . Passage  112  becomes a portion of passage  16  in tubular string  12  (see  FIG. 1 ) when the fluid sampler is interconnected in tubular string  12 . As such, internal fluid passageway  112  provides a smooth bore through the fluid sampler. Passage  310  in the upper portion of sampling chamber  300  is in communication with a sample chamber  314  via a check valve  316 . Check valve  316  permits fluid to flow from passage  310  into sample chamber  314 , but prevents fluid from escaping from sample chamber  314  to passage  310 . 
         [0068]    A debris trap piston  318  is disposed within housing  302  and separates sample chamber  314  from a meter fluid chamber  320 . When a fluid sample is received in sample chamber  314 , debris trap piston  318  is displaced downwardly relative to housing  302  to expand sample chamber  314 . Prior to such downward displacement of debris trap piston  318 , however, fluid flows through sample chamber  314  and passageway  322  of piston  318  into debris chamber  326  of debris trap piston  318 . The fluid received in debris chamber  326  is prevented from escaping back into sample chamber  314  due to the relative cross sectional areas of passageway  322  and debris chamber  326  as well as the pressure maintained on debris chamber  326  from sample chamber  314  via passageway  322 . An optional check valve (not pictured) may be disposed within passageway  322  if desired. Such a check valve would operate in the manner described above with reference to check valve  128  in  FIG. 2B . In this manner, the fluid initially received into sample chamber  314  is trapped in debris chamber  326 . Debris chamber  326  thus permits this initially received fluid to be isolated from the fluid sample later received in sample chamber  314 . Debris trap piston  318  includes a magnetic locator  324  used as a reference to determine the level of displacement of debris trap piston  318  and thus the volume within sample chamber  314  after a sample has been obtained. 
         [0069]    Meter fluid chamber  320  initially contains a metering fluid, such as a hydraulic fluid, silicone oil or the like. A flow restrictor  334  and a check valve  336  control flow between chamber  320  and an atmospheric chamber  338  that initially contains a gas at a relatively low pressure such as air at atmospheric pressure. A collapsible piston assembly  340  includes a prong  342  which initially maintains check valve  344  off seat, so that flow in both directions is permitted through check valve  344  between chambers  320 ,  338 . When elevated pressure is applied to chamber  338 , however, as described more fully below, piston assembly  340  collapses axially, and prong  342  will no longer maintain check valve  344  off seat, thereby preventing flow from chamber  320  to chamber  338 . 
         [0070]    A piston  346  disposed within housing  302  separates chamber  338  from a longitudinally extending atmospheric chamber  348  that initially contains a gas at a relatively low pressure such as air at atmospheric pressure. Piston  346  includes a magnetic locator  347  used as a reference to determine the level of displacement of piston  346  and thus the volume within chamber  338  after a sample has been obtained. Piston  346  included a piercing assembly  350  at its lower end. In the illustrated embodiment, piercing assembly  350  is threadably coupled to piston  346  which creates a compression connection between a piercing assembly body  352  and a needle  354 . Alternatively, needle  354  may be coupled to piercing assembly body  352  via threading, welding, friction or other suitable technique. Needle  354  has a sharp point at its lower end and may have a smooth outer surface or may have an outer surface that is fluted, channeled, knurled or otherwise irregular. As discussed more fully below, needle  354  is used to actuate the pressure delivery subsystem of the fluid sampler when piston  346  is sufficiently displaced relative to housing  302 . 
         [0071]    Below atmospheric chamber  348  and disposed within the longitudinal passageway of housing  302  is a valving assembly  356 . Valving assembly  356  includes a pressure disk holder  358  that receives a pressure disk therein that is depicted as rupture disk  360 , however, other types of pressure disks that provide a seal, such as a metal-to-metal seal, with pressure disk holder  358  could also be used including a pressure membrane or other piercable member. Rupture disk  360  is held within pressure disk holder  358  by hold down ring  362  and gland  364  that is threadably coupled to pressure disk holder  358 . Valving assembly  356  also includes a check valve  366 . Valving assembly  356  initially prevents communication between chamber  348  and a passage  380  in a lower portion of sampling chamber  300 . After actuation the pressure delivery subsystem by needle  354 , check valve  366  permits fluid flow from passage  380  to chamber  348 , but prevents fluid flow from chamber  348  to passage  380 . 
         [0072]    As mentioned above, one or more of the sampling chambers  300  and preferably nine of sampling chambers  300  are installed within exteriorly disposed chamber receiving slots  159  that circumscribe internal fluid passageway  112  of carrier  104 . A seal bore  160  (see  FIG. 3B ) is provided in carrier  104  for receiving the upper portion of sampling chamber  300  and another seal bore  162  (see  FIG. 3C ) is provided for receiving the lower portion of sampling chamber  300 . In this manner, passage  310  in the upper portion of sampling chamber  300  is placed in sealed communication with a passage  164  in carrier  104 , and passage  380  in the lower portion of sampling chamber  300  is placed in sealed communication with a passage  166  in carrier  104 . 
         [0073]    As described above, once the fluid sampler is in its operable configuration and is located at the desired position within the wellbore, a fluid sample can be obtained into one or more of the sample chambers  314  by operating actuator  106 . Fluid from passage  112  then enters passage  310  in the upper portion of each of the desired sampling chambers  300 . For clarity, the operation of only one of the sampling chambers  300  after receipt of a fluid sample therein is described below. The fluid flows from passage  310  through check valve  316  to sample chamber  314 . It is noted that check valve  316  may include a restrictor pin  368  to prevent excessive travel of ball member  370  and over compression or recoil of spiral wound compression spring  372 . An initial volume of the fluid is trapped in debris chamber  326  of piston  318  as described above. Downward displacement of piston  318  is slowed by the metering fluid in chamber  320  flowing through restrictor  334 . This prevents pressure in the fluid sample received in sample chamber  314  from dropping below its bubble point. 
         [0074]    As piston  318  displaces downward, the metering fluid in chamber  320  flows through restrictor  334  into chamber  338 . At this point, prong  342  maintains check valve  344  off seat. The metering fluid received in chamber  338  causes piston  346  to displace downwardly. Eventually, needle  354  pierces rupture disk  360  which actuates valving assembly  356 . Actuation of valving assembly  356  permits pressure from pressure source  108  to be applied to chamber  348 . Specifically, once rupture disk  360  is pierced, the pressure from pressure source  108  passes through valving assembly  356  including moving check valve  366  off seat. In the illustrated embodiment, a restrictor pin  374  prevents excessive travel of check valve  366  and over compression or recoil of spiral wound compression spring  376 . Pressurization of chamber  348  also results in pressure being applied to chambers  338 ,  320  and thus to sample chamber  314 . 
         [0075]    When the pressure from pressure source  108  is applied to chamber  338 , pins  378  are sheared allowing piston assembly  340  to collapse such that prong  342  no longer maintains check valve  344  off seat. Check valve  344  then prevents pressure from escaping from chamber  320  and sample chamber  314 . Check valve  316  also prevents escape of pressure from sample chamber  314 . In this manner, the fluid sample received in sample chamber  314  is pressurized. 
         [0076]    While this invention has been described with a reference to illustrative embodiments, this description is not intended to be construed in a limiting sense. Various modifications and combinations of the illustrative embodiments as well as other embodiments of the invention, will be apparent to persons skilled in the art upon reference to the description. It is, therefore, intended that the appended claims encompass any such modifications or embodiments.