METHOD AND APPARATUS FOR THE ANALYSIS OF GAS FROM DRILLING FLUIDS

Abstract

A system for analyzing gas extracted from drilling fluid is provided. In one embodiment, the system includes a gas extractor having a gas extraction chamber inside a gas extractor housing and a gas outlet for separating the gas from the drilling fluid inside the gas extraction chamber. Furthermore, the system includes a gas analyzer, which comprises an optical analyzer and an optical source located outside the gas extractor. A gas analysis zone is in fluidic communication with the gas extraction chamber and is optically connected, via at least one fiber optic cable, to the optical source and the optical analyzer. Additional methods, systems, and devices are also described. Figure 1

Description

Description Title of the invention: METHOD AND APPARATUS FOR ANALYZING GAS FROM DRILLING FLUIDS

[0001] — Wells are generally drilled into underground rocks to access Fluids, such as hydrocarbons, stored in underground formations. Drilling fluids (e.g., drilling mud) are used inside wells for various reasons, such as the inhibition of the flow of formation fluids in wells, cleaning and cooling of drill bits and removal Drilling debris. Drilling mud can circulate through a well thanks to the pumping drilling mud from a mud tank located on the surface in a well through a drill string. Drilling mud can exit the drill string at bottom of the well and then ascend towards the top of the well through the annular space located between the drilling rig and the well walls.

[0002] = The returning drilling mud may include drilling cuttings, other debris and a formation fluid. Various equipment can be used for conditioning and evaluate the returned drilling mud, including the analysis of the formation fluid mixed with drilling mud to reconstruct the geological succession of formations penetrated during drilling and to assess the types of fluids encountered in the drilled formations. For example, a gaseous formation fluid (gaseous hydrocarbons, carbon dioxide and hydrogen sulfide, for example) can be transported to the top of the well by drilling mud, extracted from the mud at the surface, and analyzed using of a gas chromatograph or other device to determine the gas composition.

[0003] — Certain aspects of certain embodiments described herein are set out below. It should be understood that these aspects are presented simply to provide the reader with a brief summary of some implementation methods and that these aspects are not intended to limit the scope of this invention. Indeed, the embodiments according to this inventions can encompass a variety of aspects that are not necessarily detailed below.

[0004] — In one embodiment of the present invention, a system includes an extractor of gas and a gas analyzer. The gas extractor includes an extraction chamber of gas inside a gas extractor housing and a gas outlet that allows the Gas separated from the drilling fluid exits the gas extraction chamber. The analyzer of gas includes an optical analyzer and optical source located outside of the gas extractor. A gas analysis zone is in fluidic communication with the gas extraction chamber and is optically connected by at least one fiber optic cable optics to the optical source and to the optical analyzer. In another embodiment, an apparatus includes a gas extractor comprising a gas extraction chamber within a gas extractor housing and a gas outlet that allows the gas separated from the drilling fluid to exit the gas extraction chamber. A gas analysis probe is attached to the gas extractor housing to receive and facilitate the analysis of the separated gas exiting the gas extraction chamber via the gas outlet. In another embodiment, a method includes receiving drilling fluid in a gas extractor and transporting the gas from the drilling fluid to a gas analysis zone. An optical signal is transmitted from an optical source via a fiber optic cable through the gas located within the gas analysis zone. The method also includes analyzing the gas, based on the optical signal, with an optical analyzer optically coupled to the gas analysis zone using a fiber optic cable. Various improvements to the features mentioned above may exist in relation to various aspects of these embodiments. Other features may also be incorporated into these various aspects. These improvements and additional features may exist individually or in combination. For example, various features discussed below in relation to the illustrated embodiments may be incorporated into any of the aspects of the present invention described above, alone or in any combination. Again, the brief summary presented above is simply intended to familiarize the reader with certain aspects and contexts of some embodiments without limitation to the subject matter claimed. These characteristics, aspects, and advantages of certain embodiments, as well as others, will be better understood after reading the following detailed description with reference to the attached drawings in which identical characters represent identical parts throughout the drawings, in which: [fig.1] generally represents a drilling system with equipment for circulating drilling fluid according to an embodiment of the present invention; [fig.2] generally represents a gas extractor with a gas extraction chamber for separating gas from drilling fluid and a gas analysis probe used to analyze the gas according to one embodiment; [fig.3] represents the gas extractor of figure 2 coupled to a remote spectrometer by a cable according to one embodiment; [fig.4] is a cross-section of a gas analysis probe according to one embodiment; [fig.5] represents the gas analysis probe of figure 4 screwed into an orifice of a gas extractor housing according to one embodiment; [fig.6] is an elevation view of opposite ends of the gas analysis probe of figures 4 and 5 according to one embodiment; [fig.7] is an elevational view of opposite ends of the gas analysis probe of figures 4 and 5 according to one embodiment; [fig.8] generally represents the removal of the gas analysis probe from Figures 4 and S from the gas extractor housing and the connection of a gas line in place of the gas analysis probe for use with a different gas analyzer according to one embodiment; [fig.9] represents a gas extractor such as that in figure 2, but in which the gas analysis probe is installed in a vertical orientation rather than in a horizontal orientation, according to an embodiment: [fig.10] represents a gas extractor designed to facilitate gas analysis without a gas analysis probe according to one embodiment; [fig.11] represents a gas extractor designed to facilitate gas analysis without a gas analysis probe according to one embodiment; [Fig. 12] represents a self-cleaning gas cell with orifices for injecting a cleaning fluid according to one embodiment; and [fig.13] is a cross-section of the gas cell of figure 12 and illustrates the routing of the cleaning fluid inside the gas cell through the orifices according to one embodiment. Specific embodiments of the present invention are described below. These described embodiments are examples of techniques actually described. In an effort to provide a concise description of these embodiments, some features of an actual implementation may not be described in the specification. It should be noted that, in developing such an actual implementation, as in any engineering or design project, many implementation-specific decisions may be made to achieve the designers' specific objectives, such as compliance with system and activity constraints, which may vary from one implementation to another. Furthermore, it should be understood that such a development effort may be complex and time-consuming, but would remain a routine design, manufacturing, and production undertaking for those skilled in the art who would benefit from this invention. When introducing elements of various embodiments, the articles "a," "an," "the," and "said" are intended to signify that one or more of these elements exist. The terms "comprising," "including," and "comprising" are meant to be inclusive and mean that there may be additional elements other than those listed. Furthermore, any use of "above," "below," "above," "below", other directional terms, and variants of these terms are made for convenience, but do not impose any particular orientation on the components. Some embodiments of the present invention generally relate to the analysis of gas extracted from drilling fluids. More particularly, some embodiments of the present invention relate to methods and apparatus for detecting and measuring gases, such as C1, C2, and C3 hydrocarbons (with isomers), i.e., alkanes containing 1 to 8 carbon atoms, from drilling fluids, using a gas analysis probe mounted on or inside a gas extractor. This can facilitate the direct measurement of the gas locally at the gas extractor, instead of transporting the gas from the extractor through a gas pipeline to a remote location for analysis. In some embodiments, the gas analysis probe is provided in the form of a fiber optic probe that is connected to a spectrometer via a fiber optic cable.The fiber optic probe may include a gas cell for receiving the extracted gas, and an optical signal (e.g., infrared radiation) may be carried by the gas inside the gas cell and then detected to facilitate gas characterization. Referring now to the drawings, a drilling system 10 at a well site is described in Figure 1 according to one embodiment. Although some elements of the drilling system 10 are described in this figure and generally discussed below, it is evident that the drilling system 10 may include other components (such as a wellhead assembly) in addition to, or instead of, those illustrated and discussed herein. As shown, the system 10 includes a drilling rig 12 positioned above a well 14. Although described as an onshore drilling system 10, it should be noted that the drilling system could instead be an offshore drilling system. The drilling rig 12 supports a drill string 16 which includes a downhole assembly 18 with a drill bit 20. The drilling rig 12 can rotate the drill string 16 (and its drill bit 20) to drill the well 14. The drill string 16 is suspended inside the well 14 from a hook 22 of the drilling rig 12 via an injection head 24 and a drive rod 26. Although not shown in Figure 1, those skilled in the art will understand that the hook 22 can be connected to a lifting system used to raise and lower the drill string 16 inside the well 14. By way of example, such a lifting system could include a fixed pulley block and a drill winch that cooperate to raise and lower a moving pulley block (to which the hook 22 is connected) via a hoist line. The drive rod 26 is coupled to the drill string 16, and the injection head 24 allows the drive rod 26 and the drill string to drilling 16 to rotate relative to the hook 22. In the embodiment currently illustrated, a rotating table 28 on a drilling floor 30 of the drilling rig 12 is constructed to grasp and rotate the drive rod 26 to drive the rotation of the drill string 16 in order to drill the well 14. However, in other embodiments, a top drive system could instead be used to drive the rotation of the drill string 16. During operation, drilling cuttings or other debris may accumulate near the bottom of well 14. Drilling fluid 32, also called drilling mud, can circulate through well 14 to remove this debris. The drilling fluid 32 can also clean and cool the drill bit 20 and provide positive pressure inside well 14 to prevent formation fluids from entering the wellbore. In Figure 1, the drilling fluid 32 is circulated through well 14 by a pump 34 of a drilling fluid circulation system. The drilling fluid 32 is pumped from a mud pool (or other reservoir, such as a tank) into the drill string 16 via a feed line 36, the injection head 24, and the drive rod 26.The drilling fluid 32 exits near the bottom of the drill string 16 (for example, at the drill bit 20) and returns to the surface through the ring 38 between the wellbore and the drill string 16. A return conduit 40 (originating for example from a wellhead) carries the return drilling fluid 32 away from the wellbore 14. In some embodiments, and as described in more detail below, the return drilling fluid 32 passes through various pieces of equipment 58 of the drilling fluid circulation system for conditioning, analysis and reuse in the wellbore 14. In addition to the drill bit 20, the downhole assembly 18 also includes various instruments that measure information of interest within the well 14. For example, as illustrated in Figure 1, the downhole assembly 18 includes a drilling logging (LWD) module 44 and a drilling measurement (MWD) module 46. Both modules include sensors, housed in drill collars, that collect data and enable the creation of real-time measurement logs during a drilling operation. The modules could also include memory devices to store the measured data. The LWD module 44 includes sensors that measure various characteristics of the rock and formation fluid properties within the well 14.The data collected by the LWD 44 module could include measurements of gamma rays, resistivity, neutron porosity, formation density, sound waves, optical density, etc. The MWD 46 module includes sensors that measure various characteristics of the downhole assembly 18 and the borehole, such as the orientation (azimuth and inclination) of the drill bit 20, torque, shocks and vibrations, weight on the. Drill bit 20 and downhole temperature and pressure. Data collected by the MWD module 46 can be used to control drilling operations. The downhole assembly 18 can also include one or more additional modules, such as modules 48, 50, 52, and 54 shown in Figure 1. Examples of these additional modules include power modules, control modules, communication modules, and other LWD or MWD modules. It should be noted that the downhole assembly 18 is modular, and the positions and presence of specific modules within the assembly can be changed as needed. The drilling system 10 also includes a monitoring and control system 56. The monitoring and control system 56 may include one or more computer systems for monitoring and controlling various components of the drilling system 10. The monitoring and control system 56 may also receive data from the downhole assembly 18 (for example, data from the LWD module 44, the MWD module 46, and the supplementary modules 48, 50, 52, and 54) or from surface equipment 58 for processing and communication with an operator, to name just two examples. Although it is shown on the drill floor 30 in Figure 1, it should be noted that the monitoring and control system 56 could be located elsewhere, and that the system 56 could be a distributed system with components supplied to different locations near or at a distance from the well 14. As noted above, drilling fluid 32 can be circulated through well 14, and drilling fluid 32 returning from well 14 can be conveyed through equipment 58 to the surface. Equipment 58 may include a variety of devices for cleaning or analyzing the returning drilling fluid 32. For example, equipment 58 may include solids control equipment, such as vibrating screens, grit chambers, silt chambers, etc., to remove drill cuttings and other particles from the returning drilling fluid 32. The equipment 58 may also include a degasser (also called a gas extractor) for removing gas from the returning drilling fluid 32, and gas analysis equipment (for example, a spectrometer or gas chromatograph) for analyzing the gas. An example of a gas extractor 60 used as a component of the equipment 58 is typically shown in Figure 2 according to one embodiment. In this illustrated embodiment, the gas extractor 60 includes a housing 62 having a gas extraction chamber 64. The returning drilling fluid 32 from the well 14 can enter the gas extraction chamber 64 through a drilling fluid inlet 66. As noted above, drilling fluid 32 returning from well 14 may include a gas, such as gaseous hydrocarbons from a formation penetrated by the well. The gas can be separated from the drilling fluid 32 inside the gas extraction chamber 64; separated gas can exit chamber 64 through a gas outlet 70, while the remaining degassed drilling fluid 32 can flow from chamber 64 through a liquid outlet 68. Although reference is made to degassed drilling fluid and a liquid outlet 68, it will be understood that the degassed drilling fluid 32 exiting through the liquid outlet 68 may include some entrained gas that has not separated from the fluid 32 inside the gas extraction chamber 64. In at least some embodiments, including that described in Figure 2, the gas extractor 60 also includes a drilling fluid agitator facilitating the separation of the gas from the drilling fluid 32. For example, the gas extractor 60 is shown in Figure 2 as comprising an agitator in the form of a paddle wheel 72 that can be driven in rotation by a motor 74 (such as a pneumatic or electric motor) and a shaft 76 to agitate the drilling fluid 32 and facilitate gas separation within the gas extraction chamber 64. One or more plates, such as discs 80 and 82, can be positioned inside the gas extraction chamber 64 to prevent the upward movement of drilling mud or any other liquid (such as a splash) while allowing the separated gas to flow to the gas outlet 70.As shown in Figure 2, disc 80 is a solid plate that allows gas to flow around its outer circumference (i.e., between disc 80 and the inner wall of the gas extraction chamber 64), while disc 82 is a grid plate that allows gas to flow through the plate while inhibiting liquids. In other embodiments, however, one or both discs 80 and 82 could be omitted, replaced by another disc, or supplemented by one or more additional discs. The agitator can also have any other suitable configuration.In addition, in at least some embodiments, the gas extractor 60 can be equipped with an automatic positioning system, which can be based on pressure variation detection, fluid level detection (for example, by means of ultrasound, radar, proximity detectors, paddles or lasers), or mechanical actuation (for example, a float), although the position of the gas extractor 60 can, instead, be static. The gas extractor 60 shown in Figure 2 includes a gas analysis probe 90 positioned inside an extension 86 of the housing 62. The architecture of the gas extractor may also differ from that shown, and the gas analysis probe 90 may be located elsewhere within the gas extractor than in the extension 86. The gas analysis probe 90 is shown as having a gas cell 92, and consequently, the gas analysis probe 90 may also be called a gas cell assembly 90. The gas analysis probe 90 also includes a linking device 94 (for example, a sub-miniature assembly linking device (SMA)) and a cable 96 facilitating communication between the probe 90 and other devices, such as gas analyzers. In at least some embodiments, such as that described in Figure 2, the gas analysis probe 90 is a fiber optic probe that is operationally coupled to a gas analyzer via a fiber optic cable 96. As discussed in more detail below, the gas analysis probe 90 can be used to analyze, within a gas analysis zone 100, the gas extracted from the drilling fluid 32 (for example, to determine the hydrocarbon content). As used here, "gas analysis zone" means a region for passing a measurement signal (for example, an optical signal) through a gas to be analyzed. A carrier gas, such as air or helium, can be injected into the gas extraction chamber 64 via a pneumatic link or inlet 98 to push the separated gas toward the gas analysis probe 90 and the gas outlet 70.Although shown positioned between discs 80 and 82 in Figure 2, the pneumatic inlet 98 could be omitted or positioned elsewhere, for example above disc 82 or below disc 80. In addition to the gas analysis probe 90, one or more sensors 102 can be used with the gas extractor 60, as generally shown in Figure 3, to measure the characteristics of a fluid or other operating parameters. Each sensor 102 can be installed in series or parallel with the gas analysis probe 90. The accuracy of the measurements acquired with the gas analysis probe 90 can depend on the pressure, temperature, and humidity within the gas analysis zone 100. Consequently, in at least some embodiments, the sensors 102 include sensors to measure some or all of these parameters within the gas analysis zone 100.The measured pressure, temperature, and humidity can be used to refine measurements acquired via the gas analysis probe 90 (for example, via mathematical error correction) or for quality control. In some cases, the sensors 102 can be used with a control device 104 to regulate one or more operating parameters, such as temperature or pressure. For example, the control device 104 can be a temperature control device that transmits an electrical signal to a resistive heating element of the gas analysis probe 90 in response to the input (for example, temperature or pressure) from one or more sensors 102. Additional sensors 102 can also, or instead, be used with the gas analysis probe 90. As will be understood, the area (for example, on a well site) in which the gas extractor 60 is installed can be classified as a hazardous area (by (e.g., explosive zone). In some embodiments, for example, the gas extractor 60 is installed with other equipment in an area classified as a hazardous zone of zone 0, zone 1, or zone 2 in accordance with IEC standard 60079-10-1:2015 or ATEX Directive 99 / 92 / EC. As used here, a hazardous zone is an area that would be classified as a hazardous zone of zone 0, zone 1, or zone 2 in accordance with IEC standard 60079-10-1:2015 or ATEX Directive 99 / 92 / EC, while a non-hazardous zone is an area that would not be classified as such a hazardous zone of zone 0, zone 1, or zone 2 in accordance with IEC standard 60079-10-1:2015 or ATEX Directive 99 / 92 / EC. In at least some embodiments, the gas analysis probe 90 is located at the gas extractor 60 to facilitate the analysis of the gas separating from the drilling fluid 32 inside the gas extraction chamber 64. In other words, rather than installing a long gas pipeline from the gas extractor 60 to a remote location (e.g., a mud logging cabin), and then transporting the gas through this gas pipeline to a gas chromatograph or other device enabling gas analysis at the remote location, the gas analysis probe 90 of some embodiments can be used at the gas extractor 60 itself for the analysis of the separated gas (e.g., to detect and measure C, Cs, and isomers in the gas) without transferring the gas for analysis to a remote location. A gas analyzer comprising an optical analyzer and an optical source can be used in certain embodiments to analyze gas that has separated from drilling fluid 32. For example, the gas analysis probe 90 can be operationally coupled to an optical analyzer, such as a spectrometer 108, by means of the optical fiber cable 96. As will be seen in more detail below, an optical signal can pass through the gas within the gas analysis zone 100 (for example, within the gas analysis probe 90) and then be transmitted to the spectrometer 108. The optical signal is modified by interaction with the gas in the gas analysis zone 100. By way of example, a beam of light can be transmitted through the gas within the probe 90 and then carried by the optical fiber cable 96 to the spectrometer 108.A light source 106 generating the optical signal can be located at a distance from the probe 90 and transmitted via a fiber optic cable 96. The extent of light attenuation by the gas inside the gas analysis probe 90 depends on the gas composition, which allows the spectrometer 108 to analyze the gas via the optical signal received from the gas analysis probe 90 via the fiber optic cable 96. Any suitable light, such as light in the visible, near-infrared, mid-infrared, or in-. Far-infrared wavelengths of the electromagnetic spectrum could be used for gas analysis according to current techniques. One or more optical fiber cables 96 can be connected to the cell 92 to allow simultaneous optical transmission of the signal from the light source 106 and the signal transmitted to the spectrometer 108. The construction of the optical fiber cable 96 can vary from one embodiment to another to suit the wavelength of the light used. Furthermore, gas analysis via the spectrometer 108 can be performed by various spectroscopic techniques, such as tunable diode laser absorption spectroscopy (TDLAS), Fourier transform infrared (FTIR) spectroscopy, photoacoustic FTIR spectroscopy, quantum cascade laser (QCL) spectroscopy, or Raman spectroscopy, to name several examples. The spectrometer 108 can be positioned at any suitable location. In some embodiments, the gas analysis probe 90 is positioned closer to the gas extractor 60 than to the spectrometer 108. More specifically, the gas analysis probe 90 is located within a hazardous area (for example, at the gas extractor 60), while the spectrometer 108 is located in a non-hazardous area in some embodiments. The dashed line 112 in Figure 3 generally represents a demarcation between a hazardous area containing the gas extractor 60 and a non-hazardous area containing the spectrometer 108.The spectrometer 108 can be located inside a cabin 110 (for example, a mud logging cabin at a well site), which can be placed within a non-hazardous area or can be pressurized so that, when the cabin 110 is used in a hazardous area, the interior of the cabin 110 is itself a non-hazardous area. In some examples, the spectrometer 108 can be placed 50–100 meters or even further from the gas extractor 60. A fiber optic cable is capable of transmitting an optical signal without loss and is therefore suitable for obtaining an accurate measurement with a remote analyzer. This presents fewer problems than when the gas is routed through a gas pipeline to the remote analyzer. Although the spectrometer 108 can be positioned in a non-hazardous area near the gas analysis probe 90, in other embodiments, the spectrometer 108 is positioned within a hazardous area along with the gas analysis probe 90. For example, the spectrometer 108 and the gas analysis probe 90 could be installed in an ATEX Zone 1 or Zone 2 hazardous area. As a further example, in some embodiments, the spectrometer 108 could be installed less than five meters from the probe 90, or even less than one meter from the probe 90, in an ATEX Zone 1 or Zone 2 hazardous area. The spectrometer 108 could, for example, be installed in an explosion-proof enclosure for facilitate deployment within a dangerous area. Additional analytical equipment 114 can be used (for example, with the spectrometer 108) to analyze the gas and deduce one or more properties of the gas in the gas analysis zone 100, such as the amount of at least one chemical element in the gas or the composition of the gas in the gas analysis zone. In some embodiments, the analytical equipment 114 includes a processor-based analysis unit (for example, a programmed computer) which derives, from an optical analyzer (for example, the spectrometer 108), one or more properties of the gas in the gas analysis zone as a function of the temperature, pressure, or humidity in the gas analysis zone (which can be measured by various sensors 102, as described above).The analytical equipment 114, which could be located in cabin 110, elsewhere on a well site, or at a location remote from the well site, may include a processor-based system or analytical unit that executes stored instructions to compare the light intensity received by the spectrometer 108 (from the gas analyzer probe 90 via the fiber optic cable 96) to the light intensity emitted in the gas inside the gas analyzer probe 90, for example. The spectrometer 108 can communicate with the analytical equipment 114 via a wired or wireless connection. In some cases, the analytical equipment 114 includes one or more other gas analyzers, such as a gas chromatograph, which can be used in addition to or instead of the spectrometer 108. In at least one embodiment, the analytical equipment 114 includes a gas chromatograph installed in series with the gas probe assembly 90. As shown in Figure 3, for example, the extracted gas can pass through the gas probe assembly 90 and then through a gas line 118 to a gas chromatograph or another gas analyzer of the analytical equipment 114 inside the cabin 110. In other embodiments, a gas chromatograph, an additional spectrometer 108, or another gas analyzer could also, or instead, be installed in parallel with the gas probe assembly 90 via a different gas outlet from the gas extractor 60.However, it should be noted that, while gas conveyed through a gas line to a gas chromatograph results in a delayed measurement (due to the travel time of the gas from the gas extractor 60 to the gas chromatograph), the optical signal from a fiber optic gas analysis probe 90 travels through the fiber optic cable 96 at a much higher speed, which allows for virtually instantaneous communication of the signal for analysis by the spectrometer 108, even over long distances. Although the extracted gas can be pushed out of the gas extractor 60 with a carrier gas injected through the pneumatic inlet 98, in other embodiments, the gas The extracted gas can be removed from the gas extractor 60 by a downstream pump 120. The pump 120 can take various forms, including a peristaltic pump, another positive displacement pump, or a vacuum pump. The pump 120 can be installed in the gas line 118, as shown in Figure 3, to draw the extracted gas from the gas outlet 70 of the gas extractor 60 and convey the gas through the gas line 118 to additional equipment for analysis, storage, or disposal. In other cases, the extracted gas is released into the atmosphere (whether pushed by a carrier gas, drawn through the pump 120, or flowing freely) after passing through the gas analysis probe 90. In some embodiments, the gas analysis probe 90 is installed inside the gas extractor housing 62, such as inside the housing extension 86 as shown in Figures 2 and 3. In other embodiments, however, the gas analysis probe 90 is instead attached to the outside of the gas extractor housing 62. By way of example, the gas analysis probe 90 is shown again in Figures 4 and 5 in an embodiment in which the probe 90 includes a threaded end for screwing the probe 90 onto the gas extractor housing 62. More specifically, the gas analysis probe 90 in this embodiment differs from that in Figures 2 and 3 in that it includes a sleeve 124 having a threaded end 126. The sleeve 124 houses the gas cell 92, which is described as a reflective optical gas cell comprising a support 130 with a lens 132 and a mirror 134. In operation, light 136 can be emitted by an optical fiber linking device 94 into a gas inside the gas cell 92 and then reflected by the mirror 134 back to the linking device 94. In at least some embodiments, the gas analysis probe 90 includes an optical fiber for emitting the light 136 into the gas cell 92 and another optical fiber for receiving the light 136 after it has passed through the gas cell 92. The light 136 emitted into the gas cell 92 can be supplied from a suitable light source by the optical fiber cable 96, and the light 136 received after passing through the gas cell 92 can be carried as an optical signal by the optical fiber cable 96 to a suitable detector, such as the spectrometer 108.The housing components of the gas analysis probe 90, such as the sleeve 124 and the bracket 130, can be made of stainless steel or any other suitable material (e.g., a material resistant to abrasive and corrosive gases). In one embodiment, if the light source is an infrared light source, the lens 132 is a zinc selenide (ZnSe) lens with an antireflective coating and the mirror 134 is a copper mirror, but other suitable materials can also be used for these components. In some embodiments, an optical window can be used instead of a [missing word - likely "optical window"]. lens. The gas extracted from the drilling fluid 32 inside the gas extractor 60 can enter the gas cell 92 in any suitable manner, such as through slots or holes 138 in the body of the support 130. One or more filters 140 can be installed in line with and upstream of the gas cell 92 to remove particles and moisture from the extracted gas before analysis. Such filters may include, for example, a hydrophobic filter membrane, an anti-fog filter, or a coalescing filter. The gas to be analyzed can flow into the gas cell 92 through the filters 140 and then exit through one end 142 of the gas analysis probe 90. The gas cell 92 can be used, either continuously or intermittently in certain cases, to analyze gas exiting the gas extractor 60. Although an optical path of light 136 is shown in Figure 4 as an example, it will be understood that the optical path of light 136 will differ in other embodiments. For example, the length of the gas cell 92 may vary between embodiments, or the light 136 may be reflected several times within the gas cell 92 to increase its path length. In other embodiments, the gas cell 92 may be a non-reflective optical gas cell that omits the mirror 134, with the light 136 being emitted from an optical fiber at one end of the gas cell 92 and received by another optical fiber at the opposite end.In such cases, a pair of SMA or other 94 linking devices could be spaced and used to couple the transmitting and receiving optical fibers. As generally stated above, the gas measurement obtained with the gas analyzer probe 90 can be influenced by temperature. A measuring device using the gas analyzer probe 90 with an infrared spectrometer 108, for example, can be calibrated for a given temperature, such as 50 °C. Consequently, some embodiments include temperature control to facilitate measurement. By way of example, the gas analyzer probe 90 is shown in Figure 4 as having heating tape 144 wrapped around the outside of the sleeve 124. A temperature sensor 102 can be used to measure the temperature inside the gas analyzer probe 90, and during gas analysis, the control device 104 can regulate the temperature inside the gas analyzer probe 90 via the heating tape 144 in response to the measured temperature.A cover 146 could also be positioned around the heating ribbon 144, as illustrated in Figure 4. In some embodiments, the gas analysis probe 90 is mounted on the gas extractor housing 62. Although the gas analysis probe 90 can be mounted on the gas extractor housing 62 in various ways, in some In one embodiment, the gas analysis probe 90 includes a threaded end (for example, the threaded end 126) screwed into an opening in the gas extractor housing 62. An example of this is shown in Figure 5 according to one embodiment. More specifically, Figure 5 shows the gas analysis probe 90 of Figure 4 screwed into an opening 150 in the gas extractor housing 62 with corresponding threads. In this way, the gas analysis probe 90 can be mounted outside the housing 62 to receive the gas separated from the drilling fluid 32 for analysis. As noted above, additional sensors 102 can be connected to the gas analysis probe 90; an example of this is shown in Figure 5 as a sensor 148 (for example, a pressure sensor) connected to the probe 90. The end 142 of the gas analysis probe 90 may have one or more outlets to allow the gas to exit the probe 90. The configuration of these outlets may vary from one embodiment to another, but Figure 6 shows that the end 142 has outlet slots 152 allowing the gas to exit the probe 90 after passing through the gas cell 92. Figure 7 is an elevational view of the opposite end of the gas analysis probe (from inside the gas extractor housing 62) and shows the filter 140 through which the gas can flow from the gas extraction chamber 64 to the gas cell 92. The gas extractor 60 can be designed for interchangeable use with different types of gas analyzers. As shown in Figure 8, for example, the gas analyzer probe 90 can be unscrewed from the threaded port 150, and a gas line 160 (e.g., a hose or tube) can be connected via a fitting 162 threaded into the port 150 in place of the gas analyzer probe 90. The gas line 160 can carry the separated gas from the gas extractor 60 to another gas analyzer 164, such as a gas chromatograph. Furthermore, this convertibility can provide operational flexibility and facilitate the use of the gas extractor 60 in a wider variety of applications.In some cases, for example, the gas extractor 60 could be used with a spectrometer 108 connected in communication with a gas analysis probe 90 installed on the gas extractor 60 (for example, installed in the port 150), while in others, a gas chromatograph could be connected to receive the gas from the gas extractor 60 via a gas line 160 attached to the port 150. That is to say, the gas analysis probe 90 can be disconnected from the gas extractor 60 and a gas chromatograph can be coupled to the gas extractor 60 with the gas line 160 in place of the disconnected gas analysis probe 90. Although the gas analysis probe 90 can be arranged horizontally, as shown in Figures 2, 3, and 5, in other embodiments the gas analysis probe 90 can be provided in a different orientation. In Figure 9, for example, the The gas analysis probe 90 is arranged vertically and offset from the gas extraction chamber 64 by a tube or other conduit 168 to reduce the path of particles and moisture to the probe 90. Regardless of its orientation, the distance of the gas analysis probe 90 from the gas extraction chamber 64 can vary between different embodiments. While the gas analysis probe 90 is installed directly on the gas extractor 60 in some embodiments, a gas line could carry gas to a gas analysis probe 90 located away from the gas extractor 60 in other embodiments. Furthermore, some embodiments may include several gas analysis probes 90 installed in parallel and connected to different gas analyzers to analyze the gas from the gas extractor 60. Furthermore, in some embodiments, the gas extracted from the drilling fluid 32 can be analyzed without a probe or gas cell. In one embodiment generally described in Figures 10 and 11, for example, the gas separated from the drilling fluid 32 inside the gas extraction chamber 64 can be analyzed with an optical signal (e.g., light 136) emitted through a gas analysis zone 100 inside the gas extraction chamber 64 itself. As shown, fiber optic cables 96 can be used to transmit the optical signal to and from the gas extractor 60 (e.g., to the gas extractor 60 from the light source 106 and from the gas extractor 60 to the spectrometer 108). In such an embodiment, the gas analysis zone 100 includes at least a portion of the gas extraction chamber 64.In other cases, however, the gas analysis zone 100 may be in fluidic communication with the gas extraction chamber 64 but supplied elsewhere inside the gas extractor 60, such as inside the extension 86 (with or without gas analysis probe 90). In still other embodiments, the gas analysis zone 100 may be positioned outside the gas extractor 60 and, in at least some of these embodiments, the gas analysis zone 100 may be positioned closer to the gas extractor 62 than to an optical analyzer for the analysis of an optical signal that has passed through the gas analysis zone 100. Finally, it should be understood that the gas extracted from the drilling fluid may not be clean. That is to say, the extracted gas may contain solid particles, moisture, oil, corrosive components, contaminants, etc., which can wear down or foul the optical elements of a gas cell. Gas cells can be disassembled to remove condensation and clean the optical elements. In some embodiments of the present technique, however, the gas cell 92 is a self-cleaning gas cell. An example of such a gas cell 92 is usually provided in Figures 12 and 13. In this described embodiment, the gas cell 92 includes cleaning nozzles or orifices 172 near the lens 132 and the mirror 134. A fluid, such as pressurized air, can be injected into the gas cell 92 through the orifices 172 to clean the lens 132 and the mirror 134. In some cases, one or more jets of air or another cleaning fluid can be supplied through the orifices 172 to remove dust, condensation, or other fouling agents from the optical surfaces. The cleaning fluid can also, or instead, be continuously injected through the orifices 172 onto or through the gas-facing surfaces of the lens 132 and the mirror 134 to reduce or avoid direct contact of the dirty gas with the optical surfaces.The analysis system can be calibrated to correctly account for the dilution of the gas to be analyzed with the cleaning fluid injected into the gas cell 92. Whether supplied continuously or in bursts, air or another cleaning fluid can be provided at a controlled flow rate. The rate at which the cleaning fluid is continuously supplied to prevent fouling of the optical surfaces can be lower than the flushing rate of the fouling agents on the optical surfaces. And in at least one embodiment, the flow rate is controlled using a sonic nozzle. In Figures 12 and 13, the supply pipes 174 provide the cleaning fluid to the distribution rings 176, which include channels 178 to direct the cleaning fluid to the orifices 172 so that the cleaning fluid is injected into the interior of the gas cell 92 (as generally represented by the arrows 180) to clean the optical surfaces. However, air or another cleaning fluid can be supplied to the gas cell 92 in any other suitable manner. Furthermore, these self-cleaning techniques could be used to clean the optical elements of other gas cells, such as lenses, mirrors, and optical windows, as well as gas cell filtration systems (e.g., the filter 140). The foregoing describes the features of several embodiments so that those skilled in the art can better understand aspects of the present invention. Those skilled in the art will understand that they can readily use the present invention as a basis for designing or modifying other processes and structures to achieve the same objectives or obtain the same advantages as the embodiments presented herein. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the present invention, and that they can make various changes, substitutions, and modifications without departing from the spirit and scope of the present invention.

Claims

Demands

1. System comprising: a gas extractor including: a gas extraction chamber inside a casing gas extractor; and a gas outlet in fluidic communication with the chamber gas extraction in such a way as to allow the gas separated from a drilling fluid inside the gas extraction chamber to exit the gas extraction chamber; and a gas analyzer including an optical analyzer and a optical sources located outside the gas extractor, in which is a gas analysis zone in fluidic communication The gas extraction chamber is optically connected by via at least one fiber optic cable at the source optics and optical analyzer.

2. System according to claim 1, wherein the gas analysis zone is positioned closer to the gas extractor than to the analyzer optical.

3. System according to claim 1, wherein the gas extractor includes the gas analysis area.

4. System according to claim 3, wherein the gas analysis zone includes at least a portion of the gas extraction chamber.

5. System according to claim 1, comprising an analysis cell gas attached to the gas extractor housing to receive and facilitate the analysis of the separated gas exiting the gas extraction chamber by the gas outlet intermediary.

6. System according to claim 5, comprising one or more po- filters positioned to filter the separated gas entering the gas analysis zone.

7. System according to claim 5, wherein the gas analysis cell includes a self-cleaning gas cell configured to clean at minus one element of the gas cell.

8. The system according to claim 1, wherein the gas extractor includes: a drilling fluid inlet in fluidic communication with the gas extraction chamber in order to allow the drilling fluid to enter the gas extraction chamber; a liquid outlet in fluidic communication with the gas extraction chamber so as to allow the liquid drilling fluid inside the extraction chamber gas exiting the gas extraction chamber.

9. System according to claim 1, wherein the system is configured so that the optical source transmits an optical signal by via at least one fiber optic cable to the area gas analysis, and that the optical signal modified by interaction with The gas separated in the gas analysis zone is transmitted to the analyzer. optical.

10. System according to claim 9, comprising a mirror for reflecting the optical signal transmitted by the optical source in the analysis area of gas.

11. System according to claim 1, comprising an analysis unit intended to derive, from the optical analyzer, one or more properties of the gas in the gas analysis zone.

12. System according to claim 11, wherein one or more properties include an amount of at least one chemical element in the gas or a gas composition in the gas analysis zone.

13. System according to claim 1, wherein the optical analyzer includes one or more of the following: a spectrometer tunable diode laser absorption (TDLAS), an in- spectrometer Fourier transform infrared (FTIR), a laser spectrometer Quantum cascade (QCL), or a Raman spectrometer.

14. | System according to claim 1, comprising at least one of a temperature sensor, pressure sensor, or sensor humidity in the gas analysis area.

15. System according to claim 14, comprising an analysis unit for to derive, from the optical analyzer, one or more properties of the gas in the gas analysis zone based on measurements obtained by the minus one of the temperature sensor, pressure sensor or the humidity sensor in the gas analysis area.

16. System according to claim 1, comprising a control unit of temperature in order to regulate the temperature in the analysis zone gas.

17. System according to claim 1, wherein the gas extractor is installed on a well site to receive drilling fluid extracted from a borehole.

18. | System according to claim 1, wherein the gas analysis zone is positioned inside a hazardous area and the analyzer The optics are positioned in a non-hazardous area.

19. Apparatus for analyzing gas extracted from drilling fluid, the apparatus including: a gas extractor including: a gas extraction chamber inside a casing gas extractor; a gas outlet in fluidic communication with the chamber gas extraction in such a way as to allow the gas to be separated from the drilling fluid inside the gas extraction chamber to exit the gas extraction chamber; a gas analysis probe attached to the gas extractor housing to receive and facilitate the analysis of the separated gas exiting the gas extraction chamber via the outlet of gas

20. A method comprising: the reception of drilling fluid in a gas extractor; the transport of gas from the received drilling fluid in the gas extractor towards a gas analysis area; the transmission of an optical signal from an optical source via a fiber optic cable and the gas located within the gas analysis area; and gas analysis, via optical signal, with a optical analyzer optically coupled to the analysis zone of gas via fiber optic cable or cable additional fiber optic.

21. A method according to claim 20, comprising: the disconnection of a fiber optic gas cell assembly the gas extractor; and the connection of a gas chromatograph to the extractor of gas via a gas pipeline connected to the gas extractor in place of the disconnected fiber optic gas cell assembly.

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