Abstract:
The high temperature/high pressure (HTHP) reactor of the present invention includes a main cylinder, a reversible piston inside the cylinder that divides the main cylinder into a pressurization chamber and a reactor chamber, a thermal jacket, a lid and an end cap. The HTHP reactor of the present invention is configured to facilitate microbial growth in the reactor chamber that provides high temperature and high pressure conditions that simulate resource reservoir conditions, wherein the resource may be an oil reservoir. The HTHP chamber of the present invention is configured to receive a fluid sample from the underground oil reservoir that has been maintained at reservoir temperature and pressure throughout sampling, transfer to transport bottle, transport to the laboratory, and inoculation into the chamber. The HTHP chamber of the present invention is also configured to allow the use of a variety of instrumentation and valves that can be customized to allow a user to monitor desired physical properties within the reaction chamber and the microbial behavior and byproducts. This information is used to create an individual treatment plan for a reservoir to maximize the resource recovery, for example during Microbiobial Enhanced Oil Recovery (MEOR).

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Patent Application No. 61/243,472 having a filing date of Sep. 17, 2009 and is a continuation-in-part of U.S. Non-Provisional patent application Ser. No. 12/884,693 having a filing date of Sep. 17, 2010. The disclosures and teachings of both related applications identified above are hereby incorporated by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    Approximately sixty-five percent of all the oil discovered remains trapped underground in reservoirs following primary production (natural reservoir pressure) and secondary production (water or gas flood). Microbial enhanced oil recovery (“MEOR”) holds considerable promise for recovering a significant proportion of trapped global oil reserves. 
         [0003]    Conventional MEOR is an empirical process whereby inexpensive nutrients are pumped into an oil reservoir to stimulate growth of indigenous, dormant microorganisms. In theory, the rejuvenated microbial community produces environmentally friendly biometabolites such as gases, acids, solvents, and surfactants that release trapped oil and/or biomass and polymers that plug water channels thereby diverting subsequent water or gas floods into oil bearing zones. 
         [0004]    Conventional MEOR has been employed for decades and has been moderately successful but, frequently, the results have been disappointing. A typical MEOR approach is to pump molasses and/or agricultural fertilizer into a watered-out reservoir and hope for the best. This hit-or-miss approach is not based on scientific principles and any positive, negative, or damaging results remain unexplained. In some cases, undesirable bio-metabolites such as hydrogen sulfide have caused irreversible reservoir damage, equipment corrosion, and health threats. 
         [0005]    There are many applications of MEOR, but none of them include prior metabolic characterization of microbial communities that inhabit oil reservoirs. According to some culture-based and genetic evidence, microbial communities are markedly different among oil reservoirs depending on rock type, temperature, depth, and various other factors. Therefore, blindly injecting nutrients into an oil reservoir and hoping for beneficial results is an uncertain and potentially damaging process. Pumping the same nutrient into several reservoirs and expecting similar results is unscientific and unreasonable. There is no way currently to predict what bio-metabolic response, if any, can be expected in a given oil reservoir when nutrients are injected. Therefore, it would be beneficial to have a device for growing reservoir microorganisms in a controlled and scientific way to determine the optimal growth conditions and production of metabolic byproducts in a certain reservoir through laboratory experimentation that maintains and replicates the bottomhole temperatures and pressures. 
         [0006]    Targeted, scientifically-based MEOR treatments could be devised for individual oil reservoirs if one knew the likely metabolic response of the microbial community to an infusion of nutrients. Then one could stimulate the desirable microbes and suppress the undesirable ones, for example, suppressing the sulfate-reducing bacteria responsible for souring oil. It is important to ascertain what the reactions the microbial community in a given reservoir has to nutrient infusions, what bioproducts they are capable of producing, and exactly what nutrients and co-factors are needed to grow at optimum rates. However, most reservoir microbes die when brought to the surface in a sampler, due to being exposed to air, low temperature, low pressure, and a variety of other stressors. Few, if any, indigenous microbial species survive when hoisted to the surface. Therefore, conventional laboratory culture of oil-reservoir microorganisms in Petri dishes or in flasks of liquid growth media at room temperature is not feasible. Some high temperature high pressure growth chambers have been attempted. Several of these attempts have required the introduction of an inert gas along with the sample to provide the proper pressurization. These methods and growth chambers do not replicate bottomhole conditions. It is also very difficult to simultaneously maintain an elevated pressure and temperature during the entire process of transferring the sample and adding an inert gas which results in losing a substantial portion of the viable material due to changes in temperature or pressure. 
         [0007]    Therefore, it would be beneficial to have a microbial reactor that replicates and maintains the anaerobic, high temperature and pressure conditions of an underground reservoir in a laboratory setting without the addition of an inert gas. It is particularly desirable to substantially maintain the anaerobic, high temperature and pressure bottomhole conditions during the transfer of the down-hole fluid sample from the sampler or a transport vessel into a HTHP microbial reactor. It would further be beneficial to have a HTHP microbial reactor that facilitates growing the indigenous, dormant reservoir microorganisms of an underground reservoir under high temperature and pressure conditions while providing instrumentation to observe the results and bi-products of their growth when a variety of nutrients, stimulants or other conditions are present. 
       SUMMARY OF THE INVENTION 
       [0008]    The present invention is directed toward a high temperature/high pressure (HTHP) reactor that provides a growth chamber for microorganisms collected from or intended for introduction into HTHP (alternatively, HT or HP) environments. The present invention provides pressure and temperature continuity for bottomhole-sampled reservoir microbes that are transported to the laboratory, transferred to the HTHP growth chamber, and then grow and metabolize under conditions of high temperature and high pressure as if they never left the reservoir. This temperature and pressure continuity maintained in obtaining, transporting, inoculating, and studying reservoir microbial consortia in the laboratory is the key discriminator that separates this novel HTHP technology from all other current studies and applications of MEOR. The present invention is configured to be able to simulate reservoir and other HTHP environments in the laboratory, thus facilitating research, development, engineering, and other activities. The primary use of the HTHP reactor is to study growth, metabolism, and product formation of microbes under HTHP conditions, usually in a liquid environment. Other uses include studying biological, chemical, and/or physical interactions of microbes and substrates in HTHP environments, and studying, assessing, and/or evaluating other biological, physical, and/or chemical reactions and phenomena under HTHP conditions. 
         [0009]    Potential uses of the HTHP reactor include but are not limited to culturing the following: a) oil and brine reservoir microorganisms ex situ (i.e. in the laboratory) in a variety of growth media under high-temperature high-pressure (HTHP) conditions that mimic reservoir conditions; b) microorganisms collected from other hydrocarbon formations including but not limited to heavy oil formations, oil sands (tar sands), tight oil and tight gas formations, coal seams, natural gas formations, oil shales (kerogen) and other intermediate stages of hydrocarbon formation, and deep-ocean gas hydrates (methyl clathrates); c) any and all extremophiles or facultative microorganisms from other HTHP environments including but not limited to those that colonize uranium, precious metals, and other subterranean ore deposits, deep ocean environments especially hydrothermal vents, salt domes and deposits, aquifers, and nuclear and other deep geological waste-disposal or waste-injection sites; and d) natural and engineered microbes destined for introduction into HTHP environments. 
         [0010]    Environmental or experimental samples suitable for inoculation into the reactor chamber include not only fluid samples from subterranean reservoirs, ore bodies and other formations and sources, but also gases, slurries, emulsions, semi-solids, and/or solids especially if in a liquid milieu or if a suitable liquid milieu is added. 
         [0011]    In addition, other items can be placed in the reaction chamber to study the various phenomena including (1) small sections of tubing, (2) wire, Teflon® or other mesh, (3) sandstone, carbonate, or other core or rock samples, and (4) other materials and substances that would provide substrates for attachment or otherwise elucidate formation of biofilms, metabolic activity, byproduct production and other phenomena. 
         [0012]    The HTHP reactor of the present invention will have direct applications to studying the following: growth and metabolism of microorganisms and the formation of bioproducts involved in Microbial Enhanced Oil Recovery (MEOR); Carbon Capture and Sequestration (CCS) including biomineralization of injected CO 2 ; methanogenesis of hydrocarbons and other substrates; introduction of genetically engineered microbes into subterranean reservoirs for alkane and other hydrocarbon production; bioleaching of uranium, precious metals, and other ores; subterranean upgrading of oil sands, heavy oils, and other hydrocarbons by microbial, chemical, and/or physical means; effects of nutrient infusions into subterranean reservoirs; effects of chemical and physical treatments in HTHP environments, e.g., heat and energy treatments of subterranean and mined kerogen deposits; waste disposal in HTHP environments; various methods for bioreclamation and bioremediation under HTHP conditions; basic and applied studies on microbes from or to be introduced into HTHP environments; and other physical and chemical reactions, effects, and consequences under HTHP conditions. 
         [0013]    In general, the HTHP reactor of the present invention includes a main cylinder, and a reversible piston within the main cylinder. The piston separates the interior of the cylinder into two distinct chambers, a pressurization chamber and a reaction chamber. The pressurization chamber is configured to receive the mechanism or method of adjusting the position of the piston Within the cylinder to increase or decrease the pressure within the reaction chamber. The reaction chamber is where the experiments on the growth metabolism and formation of byproducts by microorganisms take place. The HTHP reactor of the present invention is configured such that the piston maintains the bottomhole pressure on the reaction chamber such that no introduction of a foreign inert gas into the reaction chamber is necessary to pressurize the sample. The HTHP reactor of the present invention further includes a thermal jacket that is positioned over at least a portion of the main cylinder corresponding to the reaction chamber. The thermal jacket is configured to regulate and vary the temperature of the chamber to replicate the sample&#39;s in situ conditions. One embodiment includes a thermal jacket  16  that allows the passage of a heating or cooling fluid around the outside of the main cylinder. Alternatively, the thermal jacket may include electric heating elements to adjust and maintain the temperature of the reaction chamber. 
         [0014]    The HTHP reactor includes a lid that is generally coupled to an end of the main cylinder. The HTHP lid also is configured to be coupled to the vessel jacket and may be in fluid communication with the vessel jacket allowing heating and/or cooling fluid to pass through the lid. The lid is generally configured such that a plurality of instruments can be mounted thereon. The instruments are generally configured to be in communication with the reaction chamber and measure various physical and chemical properties within the reaction chamber. The instruments assist the technicians in monitoring the growth and metabolism of the microorganisms, observe the byproducts made by the microorganisms, and/or provide a means to stimulate the contents in the reaction chamber. One embodiment of the present invention may include one or more of the following instruments: a pH indicator, a thermowell, a thermometer, a pressure gauge, a stirrer, and inlet or outlet valves to introduce or remove agents or samples. It is important to note that the present invention is configured to include active pH monitoring of the reaction chamber during the high temperature high pressure testing that, until now, was not possible in the current state of the art. Any instrumentation known or hereafter developed that would be useful in the experimentation may be mounted to the lid or reactor of the present invention and is within the scope of the present invention. 
         [0015]    Further, the HTHP reactor of the present invention includes a closed end opposite the lid. Another embodiment includes an end cap that is coupled to the main cylinder at the end opposite the lid. The end cap may be configured to receive the connection for a pressurization system which may include a hydraulic or air hose, controls for a solenoid motor or other motor or other pressurization system or method known or hereafter developed. An alternative embodiment may include a vessel bottom member configured to be held in place against the end of the cylinder and to receive the pressurization input described above. In this embodiment, the end cap secures the vessel bottom to the main cylinder to seal off the end of the main cylinder. Yet another embodiment includes a closed end opposite the lid wherein the closed end results from welding a plate or cap over the end or machining the entire cylinder from a single piece of solid bar stock. 
         [0016]    Other and further objects of the invention, together with the features of novelty appurtenant thereto, will appear in the course of the following description. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
         [0017]    In the accompanying drawings, which form a part of the specification and are to be read in conjunction therewith in which like reference numerals are used to indicate like or similar parts in the various views: 
           [0018]      FIG. 1  is a cut-away perspective view of one embodiment of the HTHP reactor in fluid communication with a transport vessel in accordance with the teachings of one embodiment of the present invention; 
           [0019]      FIG. 2  is a perspective view of one embodiment of the HTHP reactor in accordance with the teachings of one embodiment of the present invention; 
           [0020]      FIG. 3  is a cross-sectional view cut along the line  3 - 3  of the embodiment of the HTHP reactor in accordance with the teachings of the embodiment of the present invention shown in  FIG. 2 ; 
           [0021]      FIG. 4  is a perspective view of one embodiment of the main cylinder of the HTHP reactor in accordance with the teachings of the present invention; 
           [0022]      FIG. 5  is a cross-sectional view of one embodiment of the thermal jacket of the HTHP reactor cut along line  3 - 3  in accordance with the teachings of the embodiment of the present invention shown in  FIG. 2 ; 
           [0023]      FIG. 6A  is a cross-sectional view of one embodiment of the lid of the HTHP reactor cut along line  3 - 3  in accordance with the teachings of the embodiment of the present invention shown in  FIG. 2 ; 
           [0024]      FIG. 6B  is a cross-sectional view of another embodiment of the lid of the HTHP reactor in accordance with the teachings of the present invention; 
           [0025]      FIG. 7A  is a top view of the lid of one embodiment of the HTHP reactor in accordance with the teachings of one embodiment of the present invention; 
           [0026]      FIG. 7B  is a side view of one embodiment of the HTHP reactor in accordance with the teachings of one embodiment of the present invention; and 
           [0027]      FIG. 8  is a cross-sectional view of one embodiment of the end cap of the HTHP reactor cut along line  3 - 3  in accordance with the teachings of the embodiment of the present invention shown in  FIG. 3 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0028]    The following detailed description of the present invention references the accompanying drawing figures that illustrate specific embodiments in which the invention can be practiced. The embodiments are intended to describe aspects of the invention in sufficient detail to enable those skilled in the art to practice the invention. Other embodiments can be utilized and changes can be made without departing from the scope of the present invention. The present invention is defined by the appended claims and the description is, therefore, not to be taken in a limiting sense and shall not limit the scope of equivalents to which such claims are entitled. 
         [0029]    One novel aspect of the HTHP reactor of the present invention is best understood in view of the circumstances surrounding its use. Therefore, a description how the HTHP reactor of the present invention is used is provided with the detailed description of the HTHP reactor. Once a bottomhole reservoir sample is collected and moved to the HTHP reactor, the HTHP reactor of the present invention substantially replicates the bottomhole temperatures and pressures allowing technicians to experiment with nutrient media formulations and concentrations that will provide for optimum microbial growth, maximum production of desirable byproducts, and suppression of undesirable microbes and byproducts. The sampling, transport, inoculation, and incubation phases are performed such that the HTHP chain is not broken. It is important that these conditions are not broken because a substantial amount of the native microbes will be killed. Based on these results and a review of the geology of the reservoir, a precise nutrient-medium formulation will be devised and injected into the reservoir in optimum quantities and will be allowed to remain for an optimum time to (a) plug watered-out channels, (b) to induce maximum production of other desirable biometabolites, and/or (c) to suppress growth and metabolism of undesirable microbes, especially those that produce H 2 S and sour oil. The result is enhanced recovery of oil. The objective of this MEOR technology is to increase the amount of oil ultimately produced over what would have been recovered using other treatments. 
         [0030]    Using HTHP reactor  10  includes assembling HTHP reactor  10  as described below. An assembled HTHP reactor  10  is illustrated in  FIG. 1 .  FIG. 1  further shows a transfer vessel  500  being in fluid communication with one embodiment of HTHP reactor  10  via tube  502 . 
         [0031]    Once a target reservoir is selected, bottomhole samples are obtained and the samples are maintained at reservoir temperatures and pressures during sampling, during transport to the laboratory and, using the HTHP reactor of the present invention, during culture in a laboratory. A conventional industry PVT-type sampler may be used to obtain bottomhole samples, usually bringing two each 600-ml fluid samples to the surface. The reservoir samples are usually obtained from the oil/water interface (residual oil zone), but can be harvested from any location within the reservoir. Additional samples can be obtained if required. Bottomhole temperature and pressure are measured by the sampler itself or by a separate probe and recorded while the sample is harvested. Pressure in the sampler&#39;s canisters is maintained at bottomhole pressure by hydraulics or nitrogen injection as canisters are retrieved to the surface. In some instances, the samples may be transferred into a transport vessel  500  by the sampling technician or contractor. The high temperature and pressure of the bottomhole environment is maintained through this transfer process such that the sample will continuously be subject to substantially the same temperature and pressure from the instant the sample has been taken though testing the sample in a laboratory using the HTHP reactor of the present invention. Prior to transfer to one or more HTHP reactors  10  of the present invention, reservoir samples contained in the sampler or transfer vessel  500  may be stored in an oven to maintain reservoir temperature. Reservoir bottomhole temperature and pressure are maintained inside the sampler and, if applicable, transfer vessels  500  throughout the entire sampling and transport processes. The chamber of the sampler or transfer vessel that contains the samples are not opened prior to fluid transfer because exposure to oxygen, low temperatures, and low pressures kills virtually all of the microbes. 
         [0032]    In one embodiment, a reaction chamber  48  (as described below) of HTHP reactor  10  is loaded with selected sterilized nutrient media at ambient temperature and pressure. Growth and metabolic byproduct studies are often conducted of bottomhole microbial consortia in various liquid growth media including molasses, nitrogen/phosphate fertilizers, and various treatment grades of industrial wastes such as paper/pulp, sugar beet, brewery, feedlot, and municipal sewage that has undergone primary treatment. Further, many types of growth media are suitable for use including those typically used in empirical MEOR applications in the field. Some conventional MEOR solutions include but are not limited to: molasses (an inexpensive carbon source with micronutrients that is commonly used in MEOR), 0.5% aqueous solution (vol/vol) more or less; augmented molasses: 0.5% molasses, 0.15% KNO 3  (w/v), and 0.05% Na 3 PO 4  (wlv), or variations thereof; or an aqueous solution of fertilizer: 0.25% KNO 3  (w/v), and 0.05% NaH 2 PO 4  (w/v), or variations thereof. 
         [0033]    One method of using the present invention (shown in  FIG. 1 ) includes introducing about ninety (90) milliliters of sterile MEOR nutrient solution and/or industrial waste stream into reaction chamber  48  of one or more HTHP reactors  10  under ambient pressure through inlet valve  118 . The pressurization system including fluid and/or gas introduced into pressurization chamber  46  (as described below) of HTHP reactor  10  such that piston  14  (as described below) compresses the nutrient solution or waste material to a pressure that substantially matches the measured bottomhole pressure of the sample. After reaction chamber  48  is loaded with nutrient media, reaction chamber  48  is pressurized using the pressurization system to the measured bottomhole pressure and the temperature of reaction chamber  48  is brought up to substantially match the recorded bottomhole conditions by heating reaction chamber  48  with thermal jacket  16  (as described below). The temperature and pressure can be regulated manually or using any control system now known or hereafter developed. 
         [0034]    Only after the nutrient solution or industrial waste stream are brought to the bottomhole temperature and pressure, are about ten ( 10 ) milliliters of reservoir fluids from a single well added to reaction chamber  48  from transport vessel  500  at the bottomhole reservoir temperature and pressure, i.e. about a ten percent (10%) inoculum through tube  502 . Larger or smaller volume HTHP reaction chambers can be used and inoculum ratios can be modified depending on requirements and growth responses. In addition, volumes of the above components may be increased or decreased from those disclosed herein. Any variations in the volume and percentage of nutrient media or industrial waste streams and inoculum are within the scope of the present invention. 
         [0035]    A tubular connection  502  with a pressure gauge enables transfer of a portion of reservoir fluid (inoculum) from the sampler or transport vessel  500  to the loaded reaction chamber  48  of the present invention through inlet valve  118 . In one embodiment, inlet valve  118  is opened to pressurize tube  502  and allow the nutrient in the reaction chamber that is at the bottomhole temperature and pressure to fill tube  502 . Thus, when the sample is introduced into tube  502 , it is already full of nutrient substantially at the bottomhole temperature and pressure. Thus, there is no discontinuity in temperature or pressure when transferring the sample from the sampler or transport vessel  500 . The floating piston  14  allows for the nutrient to be introduced into the tube  502  and allows the sample to be pulled into reaction chamber  48  using differential pressures, but while preventing sudden pressure losses that result in killing the microbes in the reservoir fluid. During transfer of the sample of the reservoir fluid, the pressure in reaction chamber  48  is maintained at a pressure that is slightly less than the reservoir sample transport vessel  500  to provide for metered fluid flow into reaction chamber  48 . The slightly less pressure is close enough to the actual bottomhole conditions that it does not have an adverse effect upon the sample. The position of the floating piston in main cylinder  12  may be gradually adjusted manually or through a control system to allow for a uniform pressure to be maintained in reaction chamber  48  even though the volume of liquid is increasing. 
         [0036]    Once the inoculum has been introduced into reaction chamber  48 , the pressure and temperature are monitored using thermowell  112  and pressure gauge  114  (both shown in  FIG. 7A ) and the pressure and temperature are kept at substantially identical conditions to the recorded bottomhole pressure and temperature using any control system now known or hereafter developed. 
         [0037]    The growth of microbial consortia of various types may be assessed in the various dilutions of growth media by measuring (1) change in turbidity of growth medium, (2) numbers of microbes per ml (i.e., biomass), (3) volume of headspace gases produced, and (4) other measures of growth now known or hereafter developed. Other assessments may be performed and are within the scope of the present invention. Samples of headspace gases and liquid culture medium may be obtained out of outlet valve  120  for (1) chemical and volumetric analyses of headspace gases and (2) chemical nature of metabolic byproducts in the growth medium from microbial growth such as pH change, surfactants produced, polymers produced, and solvents produced. 
         [0038]    By measuring biomass and by chemically analyzing bio-metabolites produced in the laboratory, one obtains accurate data to guide nutrient selection for a targeted reservoir, thereby insuring maximum release of trapped oil and mitigating risk of reservoir damage. Under HTHP culture in the HTHP reactor  10  of the present invention, the byproducts of microbes from a specific oil reservoir could be identified and predictions of growth and metabolism of the microbial consortium in the presence of a given nutrient mix could be obtained. By culturing the consortium in a number of nutrient growth media and chemically and physically measuring acids, gases, solvents, surfactants, biomass, and polymers produced, predictions could be made about specific metabolic byproducts to be expected in a given oil reservoir when injected with a specific nutrient medium at a given optimum formulation and concentration, and for a given optimum time for the injected well system to be shut in for the maximum MEOR effect. The optimum time can be determined by analyzing the metabolism rates for the concentration of nutrient medium or other method as now known or hereafter developed. 
         [0039]    Measurements of acid, gas, and biomass production may be obtained in real-time using the instrumentation described below. Typical incubations are expected to take approximately two to six weeks each, and the end point is generally determined by cessation of acid and gas production. The volume and composition of metabolic off gases and pH of the nutrient medium may be analyzed in real-time or periodically in samples removed from the growth chamber to obtain gas-generation (via gas chromatograph) and acid-generation (via pH meter) curves for each reservoir-nutrient combination. Instrumentation is generally incorporated into the HTHP reactor of the present invention to monitor one or more of pH, pressure, temperature, gases, and other parameters and constituents remotely and in real time. Biomass is calculated during and at the end of incubation by cell count, turbidity, filtering and weighing, and/or other measurements to obtain microbial growth curves. 
         [0040]    Following incubation, liquid samples are transferred to a chemical laboratory for analysis. HTHP reactor  10  may be cleaned and sterilized using acceptable methods. HTHP reactor  10  may also be disassembled, cleaned with a solvent to remove hydrocarbon residues, and then autoclave-sterilized at 121° C. or equivalent to prepare for re-use. 
         [0041]    Now turning to  FIGS. 2 and 3 , the high temperature high pressure (HTHP) reactor  10  of the present invention generally comprises a main cylinder  12 , a piston  14  inside main cylinder  12 , a thermal jacket  16 , a lid  18 , and an end cap  20 . The components of HTHP reactor  10  are generally configured to provide a ex situ testing chamber which replicates the temperature and pressure of in situ underground environments including, but not limited to, subterranean stores of natural resources such as oil, natural gas, and precious metals, or other commercially valuable ores or metals. The testing chamber will generally be used to grow and observe the products of microorganisms collected from or intended to be introduced into the underground environments using a variety of stimuli, food sources, and other environmental conditions. 
         [0042]    As shown in  FIG. 4 , main cylinder  12  includes a first end  22 , a second end  24 , an inner face  26 , an outer face  28 , a length defined by the distance between first end  22  and second end  24 , and a wall thickness bounded by inner face  26  and outer face  28 . Embodiments of main cylinder  12  may have any cross-section now known or hereafter developed including: rectangular, oval, circular, polygonal, triangular, or any other cross-section. One embodiment includes a circular cross-section. A circular cross-section lends itself to a high pressure chamber as the forces applied on the cylinder due to the differential pressure are evenly distributed throughout the entire material. Cross-sections that include planar faces intersecting at a corner generally have stress concentrations at the corners thereby resulting in locations that are prone to material failure. However, triangular, rectangular or other polygonal shapes may be used if the cylinder and joints (if any) are designed to resist the desired maximum pressure. Further, the HTHP reactor of the present invention may include a plurality of main cylinders  12  of a variety of lengths that can be used interchangeably depending on the volume of samples tested, the pressure required, or any other variable. 
         [0043]    As further shown in  FIGS. 3 and 4 , first end  22  and second end  24  of main cylinder  12  are generally configured to be removably coupled to at least lid  18  and end cap  20 . This embodiment further includes a portion of first end  22  and second end  24  having threads  32  wherein the ends  22 ,  24  are configured to threadably couple with lid  18  and end cap  20 . Alternatively, one or more of first end  22 , second end  24 , lid  18 , and end cap  20  may be flanged to facilitate a compression coupling using clamps, tie-down bolts, or other compression fitting now known or hereafter developed to couple the members together and providing pressure resistance. 
         [0044]    An alternative embodiment not shown includes second end  24  of main cylinder being closed. The closed second end  24  may be machined through milling solid bar stock, or may include an end plate or cap seal welded to second end  24  of main cylinder  12 , or any other method known or hereafter developed for producing a pressure resistant closed cylinder end. This alternative embodiment may further include a portion of the closed second end  24  of the main cylinder  12  being configured to allow second end  24  to receive, or be removably coupled to, an element of the pressurization system, including an air hose, a hydraulic hose, or other known components that are used to connect the pressurization system to HTHP reactor  10  for pressurizing the contents of pressurization chamber  46  thereby compressing pistion  14  against the contents of reaction chamber  48 . 
         [0045]    Piston  14  generally is housed inside cylinder  12  as shown in  FIG. 3 . Piston  14  includes a top face  40 , a bottom face  42 , and an outer surface  46 . Piston  14  includes a depth defined between top face  40  and bottom face  42 . In the embodiment shown in  FIG. 3 , piston  14  is circular. However, piston  14  may be any shape known and will generally correspond with the cross-section of main cylinder  12 . As shown, piston  14  has an outer surface  44  corresponding to an outer diameter as shown in  FIG. 3 . The outer diameter of outer surface  44  of piston  14  is generally slightly less than the inner diameter of main cylinder  12  and piston  14  may travel linearly within main cylinder  12 . The depth of piston  14  is generally less than the length of main cylinder  12  and the dimensions are configured to create a pressurization chamber  46  and reaction chamber  48  within main cylinder  12 . In addition, top face  40  of piston  14  may be concave in profile as shown in  FIG. 3  to further define the extents of reaction chamber  48 . The volume of chambers  46  and  48  will vary depending upon the position of piston  14  within cylinder  12 . Piston  14  is reversible meaning its position within cylinder  12  may actively be controlled in two directions to either increase or decrease the pressure within reaction chamber  48  to actively maintain the desired pressure in reaction chamber  48 . 
         [0046]    As further shown in  FIG. 3 , outer surface  44  may also include at least one notched channel  50  around its entire perimeter wherein notched channel  50  is configured is receive a seal member  52  that prevents fluid and gas from migrating between pressurization chamber  46  and reaction chamber  48 . By preventing migration of fluid or gas between two chambers  46  and  48 , one or more seal members  52  thereby allows pressure to be increased or decreased in reaction chamber  48  using increasing the volume of air in pressurization chamber  46  to force the floating piston  14  to apply pressure to the contents of reaction chamber  48 . The pressure applied to reaction chamber  48  may be adjusted by increasing or decreasing the volume of gas in pressurization chamber  46  to increase or decrease the pressure of reaction chamber  48 . Generally, HTHP reactor  10  of the present invention is configured with a pressurization system, including the pressurization chamber  46 , which contains a combination of fluid and gas in pressurization chamber  46 , a gas or fluid pump or compressor (not shown) that can apply pressure the sample in reaction chamber  48  by compressing piston  14  against the sample. HTHP reactor  10  of the present invention is configured to operate under and maintain an applied pressure on a sample in a range from about one-half mean sea level pressure (8 psi) to about ten-thousand pounds per square inch (10,000 psi). Alternatively, the pressure of reaction chamber  48  may be maintained by using a hydraulic or electric cylinder (not shown) to control floating piston  14  or a screw mechanism (not shown) 
         [0047]    Thermal jacket  16  of HTHP reactor  10  generally facilitates adjusting the temperature of reaction chamber  48 . In one embodiment of the present invention, thermal jacket  16  is capable of reaching and maintaining a temperature in reaction chamber  48  in a range of about zero degrees Celsius (0° C.) to about one-hundred degrees Celsius (100° C.). As best seen in  FIG. 5 , one embodiment of thermal jacket  16  generally includes a first end  60  and a second end  62  defining a length therebetween. Thermal jacket  16  generally includes an inner face  66 , and an outer face  68  that defines a wall thickness between the two. Inner face  66  generally has a similar cross-section as outer surface  28  of main cylinder  12 . When inner face  66  has a circular shape, as shown in  FIG. 2 , inner face is defined by an inner radius. As seen in  FIG. 3 , the inner radius of inner face  66  is slightly larger or the same as the outer radius of outer face  28  of main cylinder  12  thereby allowing thermal jacket  16  to slide over main cylinder  12  as shown in  FIG. 3 . Further, thermal jacket  16  may also include flange  72  wherein an embodiment of flange  72  includes a step  74  around the perimeter of inner face  66  proximate cylinder  12  as shown in  FIG. 5 . In addition, another embodiment of thermal jacket  16  may include a continuous notch in flange  72  that houses flange seal  76 . 
         [0048]    The embodiment of thermal jacket  16  shown in  FIGS. 3 and 5  includes a liquid coolant flowing through thermal jacket  16 . Thermal jacket  16  includes a coolant inlet  78  proximate second end  62  and includes a continuous spiral coolant channel  80  in inner face  66  along at least a portion of the length of thermal jacket  16  as shown. Coolant channel  80  is configured to allow coolant to flow from inlet  78  to an outlet. One embodiment includes a coolant outlet proximate first end  60 . An alternative embodiment shown includes coolant outlet  82  on lid  18  as shown in  FIG. 7A . The embodiment shown includes the interface between thermal jacket  16  and lid  18  allowing fluid communication between the two members. Heated or cooled fluid can pass through channel  80  and contact outer face  28  thereby transferring heat to or away from reactor chamber such that the temperature of reaction chamber  48  may be set and maintained to substantially mimic the thermal conditions of the downhole reservoir. 
         [0049]    For the most efficient transfer of heat through the cooling channels, the interface between main cylinder  12  and thermal jacket  16  and thermal jacket  16  and lid  18  may be sealed by a plurality of o-rings or other sealing members. Thermal jacket  16  includes at least one seal  84  housed in a notch in inner face  66  proximate second end  62 . Thermal jacket  16  may be configured to be secured to lid  18  to create flange seal  76  as shown in  FIG. 3 . Flange seal  76  creates a fluid-tight seal between thermal jacket  16  and lid  18  proximate first end  60  of cylinder  12  when flange  72  is tightened against lid  18  as shown. Flange  72  of thermal jacket  16  includes a plurality of apertures  86  configured to facilitate securing thermal jacket  16  to lid  18 . Apertures  86  may be threaded to receive a bolt or set screw that secures flange  72  to lid  18  as shown in  FIG. 3 . Alternatively, apertures  86  may be smooth bored to allow a bolt or other fastener to pass through to secure flange  72  to lid  18 . 
         [0050]    Alternatively, in an embodiment not shown, thermal jacket  16  may include electric heating elements embedded in a thermal jacket or the electric heating elements being otherwise applied to a portion of main cylinder  12 . This embodiment necessarily includes a source of electricity including, but no limited to one or a combination of batteries, a generator, or a conventional plug into the public electricity grid. The thermal jacket of this embodiment may be fabric, plastic, carbon fiber, metal or any other configuration now known or hereafter developed that facilitates heat transfer from electric heating elements to main cylinder  12 . One embodiment includes thermal jacket being flexible such that thermal jacket can be wrapped around main cylinder  12 . The electric heat element is preferably radiant; however, any known electric heating method now known or hereafter developed is within the scope of the present invention. In any event, a thermostat (not shown) or other temperature control device or switch as now known or hereafter developed may be in communication with the thermal jacket of the present invention and activate the thermal jacket as necessary to maintain a temperature that substantially matches the actual bottomhole temperature for that sample. 
         [0051]    Lid  18  of HTHP reactor  10  is generally configured to be removably coupled to main cylinder  12  using any pressure resistant connection type known in the art or hereafter developed. Lid  18  is also generally disposed to allowing a technician to mount a plurality of various instruments in communication with reactor chamber  48  to observe the conditions and results of the tests. Lid  18  is generally a solid piece of material wherein the above features are milled or machined into the final piece. 
         [0052]    One embodiment of lid  18  shown in  FIG. 6A  includes a top face  90 , a bottom face  92 , a cylinder plug portion  94 , cylinder channel  96 , collar  98 , and flange  100 . When lid  18  is coupled to main cylinder  12 , main cylinder plug portion  94  extends a distance inside cylinder  12 . The cylinder plug portion  94  includes an outer diameter that is equal to or slightly less than inner diameter of main cylinder  12 . Seal  102  may be included in the interface between the outer surface of the cylinder plug portion and the inner surface  26  of main cylinder  12  to prevent migration of fluid or gas out of reaction chamber  48 . Cylinder channel  96  is configured to receive the walls of main cylinder  12  when lid  18  is coupled to cylinder  12  as shown in  FIG. 3 . In general, cylinder channel  96  may be defined by cylinder plug portion  94  on the inside and by collar  98  on the outside. A portion of collar  98  may be threaded and configured to engage a threaded first end  22  of main cylinder  12 . Cylinder channel  96  generally braces open first end  22  of main cylinder  12  when first end  22  of main cylinder  12  is received into channel  96  thereby reinforcing the open end of cylinder  12  at a known weak connection point. Lid  18  twists onto main cylinder  12  via the threads  32  to secure lid  18  to cylinder  12  to create a pressure resistant connection. 
         [0053]    An alternative embodiment shown in  FIG. 6B  includes lid  18 ′ having a top face  200 , a bottom face  202 , a collar  204 , a cylinder housing  206 , a flange  208  and a neck  210 . When lid  18 ′ is coupled to main cylinder  12 , cylinder  12  extends a distance inside cylinder housing  206 . Cylinder housing  206  is defined by an inside wall  212  of collar  204 . Inside wall  212  is defined by a diameter that is equal to or slightly greater than the outer diameter of main cylinder  12 . A seal  214  may be included in the interface between collar  204  and main cylinder  12  as shown in  FIG. 6B  to prevent migration of fluid or gas out of reaction chamber  48 . Seal  216  may otherwise be disposed on the interface between main cylinder  12  or, collar  204 . A portion of collar  204  may be threaded and configured to engage threaded first end  22  of main cylinder  12  (shown in  FIG.4 ). Lid  18 ′ generally twists onto main cylinder  12  via the threads  32  to secure lid  18 ′ to main cylinder  12  and compress seal  214  to create a pressure resistant connection. 
         [0054]    Flange  100 ,  208  of lid  18 ,  18 ′ may also include coupling apertures  104 ,  218  that compliment the pattern of coupling apertures  86  through flange  72  of thermal jacket  16 . The coupling apertures  86  and  104 ,  218  are configured to facilitate the two members  16  and  18  being temporarily secured together. The temporary coupling of the two flanges  72  and  100 ,  208  may be achieved using any coupling method now known or hereafter developed including set screws, bolts, and clamps. 
         [0055]    As shown in  FIGS. 6A ,  6 B,  7 A and  7 B lids  18  and  18 ′ also generally include a plurality of instrument housings  106 ,  220  configured to allow a plurality of instruments to be mounted on lid  18 ,  18 ′ and in functional communication with reaction chamber  48 . Instrument housings  106 ,  220  are generally configured such that instruments may be mounted upon lid  18 ,  18 ′ such that the connection between lid  18 ,  18 ′ and the instruments resists the high pressures applied to reaction chamber  48 . The housings  106 ,  220  may be of a uniform size so that a technician can alter the configuration of instruments depending on which characteristics the testing is meant to measure or determine or, alternatively, may be configured for a particular instrument or tool. The embodiment shown in  FIG. 6A  generally includes raised housing that are machined or coupled to lid  18 . The embodiment shown in  FIG. 6B  generally includes top face  200  of lid  18 ′ being substantially planar wherein housings  220  are recessed in the body of lid  18 ′.  FIGS. 7A and 7B  illustrate an embodiment of the present invention that includes the following instruments: stirrer  110 , thermowell  112 , pressure gauge  114 , and pH-sensor  116 . However, any instruments known or hereafter developed are within the scope of the present invention, including a thermometer. Further, lid  18 ,  18 ′ may include an inlet valve  118 , an outlet valve  120 , and/or a pressure relief valve  119  to either add or remove contents from reaction chamber  48  as shown in  FIG. 7A . 
         [0056]    End cap  20  is generally coupled to second end  24  of main cylinder  12  providing a pressure resistant connection thereby allowing pressure to build up in pressurization chamber  46  and thereby applying pressure to reaction chamber  48  via piston  14 . Now turning to  FIG. 8 , end cap  20  generally includes a top face  129 , a bottom face  130 , an inner side face  132 , an outer side face  134 , a side thickness  136  and an end thickness  138 . The cross-sectional shape of end cap  20  generally corresponds and compliments the cross-sectional shape of main cylinder  12 . As shown in  FIG. 1 , an embodiment of the present invention includes main cylinder  12  and end cap  20  being circular. In this embodiment inner side face  132  is defined by an inner diameter wherein said inner diameter is equal to or slightly greater than outer diameter of main cylinder  12  as shown in  FIG. 3 . A portion of inner side face  132  may include threads  140  wherein threads  140  are configured to engage threads  32  of main cylinder  12 . End cap  20  may be removably coupled to main cylinder  12  by twisting it about threaded second end  24  of main cylinder  12  wherein the threaded connection secures end cap to main cylinder. End cap  20  may be configured to receive the connection to pressure regulation system, hydraulic, air, solenoid controls through any method now known or hereafter developed as shown in  FIG. 8 . 
         [0057]    Another embodiment, illustrated in  FIG. 3 , includes a cylinder bottom  142  having an inner face  144 , an outer face  146 , a protuberance  148  extending outwardly from outer face  146 , a cylinder plug section  150 , and a flange  152 . In this embodiment, cylinder plug section  150  is configured to extend a distance into main cylinder  12 . Cylinder plug section  150  may further include a seal member  156  on inner face that engages inner face  26  of main cylinder  12 . Flange  152  abuts second end  24  of main cylinder  12  and end cap  20  slides over cylinder bottom  142 . End cap  20  includes an aperture configured such that protuberance  148  of cylinder bottom  142  may pass through and extend outwardly from main cylinder  12  as shown. Protuberance  148  is configured to receive the connection to a pressure regulation system as described above. End cap  20  including threaded inner side face  132  is twisted upon second end  24  of main cylinder  12  thereby sandwiching cylinder bottom  142  against main cylinder  12 . The threaded connection allows cylinder bottom  142  to be tightened against main cylinder  12  by end cap  20  providing the necessary pressure resistant connection. 
         [0058]    To construct one embodiment of the HTHP reactor  10  of the present invention, piston  14  is placed within main cylinder  12 . Cylinder bottom  142  is placed adjacent to second end  24  of main cylinder  12 . End cap  20  is twisted over cylinder bottom  142  about main cylinder  12  and tightened to sandwich cylinder bottom  142  between end cap  20  and main cylinder  12  such that an air tight, pressure resistant connection results. Thermal jacket  16  is slid over first end  22  of main cylinder  12  and lid  18  is twisted upon the threaded first end  22  of main cylinder  12 . Thermal jacket  16  is coupled to lid  18 ,  18 ′ using fasteners through apertures  84  and  104 ,  218 . The instrumentation desired is selected and mounted in housings  106 ,  220  on lid  18 ,  18 ′. HTHP reactor  10  may be assembled in various different ways and is not restricted to an assembly in a certain order or configuration. 
         [0059]    From the foregoing it will be seen that this invention is one well adapted to attain all ends and objects hereinabove set forth together with the other advantages which are obvious and which are inherent to the structure. It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of the claims. Since many possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative, and not in a limiting sense.