Drilling machine on-site chromatographic column repair

Abstract

A method for repairing a gas chromatography apparatus at a drilling rig site includes providing a gas chromatography (GC) apparatus including at least a trap column, a main column, and a detector. The primary column is configured to separate at least methane, ethane, propane, butane, and pentane compounds in the gas stream. The trap column is configured to remove interfering olefin or alcohol compounds from the gas stream. Multiple GC measurements are taken at the drilling rig site by flowing the gas flow in a forward direction through the capture column and the main column to the detector. After completing the plurality of GC measurements, a repair gas is flowed through the trap column in an opposite direction on the drilling rig site while heating the trap column to a temperature of at least 120 DEG C to repair the trap column.

Description

Cross Reference to Related Applications

[0001] This application claims the benefit of EPO Application No. EP 23305456.8, filed March 30, 2023, entitled “RIG SITE CHROMATOGRAPHIC COLUMN RECONDITIONING,” the disclosure of which is hereby incorporated by reference herein. BACKGROUND

[0002] In drilling a subterranean wellbore, circulating drilling fluids typically bring formation fluids and dissolved formation gases to the surface. Such gases can be released through the drill bit as the drill bit cuts the formation and can include various alkane gases such as methane (Ci), ethane (C2), propane (C3), butane (C4), pentane (C5), etc., as well as olefins and alcohols. At the time of drilling, the released gases are typically evaluated at the surface. Such measurements can provide valuable information to mud loggers and can provide information about the maturity and nature of hydrocarbons in the reservoir, the compartmentalization and oiliness of the intervals in the reservoir being drilled, and information about production zones, lithology changes, reservoir-accumulation history, or effectiveness of the cap rock.

[0003] Gas chromatography is often used to separate and analyze the released gases. In some operations, continuous measurements are made at the time of drilling with the goal of quantifying light hydrocarbon compounds (e.g., alkane gases from Ci to C5 or from Ci to C8 for a rich and more complete analysis) while tolerating or neutralizing non-hydrocarbon compounds such as alcohols that can be generated from the degradation of oil-based drilling fluids under the high temperature and high pressure in the borehole. Such measurements can be difficult, especially in oil-based drilling fluids that include synthetic oils. These drilling fluids often contain or generate interfering compounds that elute at times between the elution times of the Ci and C5 alkane gases and can cause an overestimation of the alkane gases, particularly the C4 and C5 gases.

[0004] Commonly-assigned U.S. Patent 8,616,051 discloses the deployment of a polar column in or upstream of a gas chromatography column to capture interfering compounds. While the use of such a polar column has been found to be commercially viable, the column becomes saturated with continued use (saturation time depends on the quantity and nature of the interfering compounds in the gas stream). Moreover, the captured compounds are often too heavy to be removed via routine backflushing of the column. To replace the polar column, the gas chromatograph including the polar column is sent offsite for maintenance. The time and expense required to remove the gas chromatograph and maintain a spare device can be prohibitive. There is a need for a gas chromatograph configuration and method that enables timely on-site regeneration (repair) of the polar column. BRIEF DESCRIPTION OF DRAWINGS

[0005] To gain a more complete understanding of the disclosed subject matter and its advantages, reference is now made to the following description taken in conjunction with the accompanying drawings: Figure 1 An example drilling rig is described, including the disclosed gas chromatography apparatus for measuring the composition of formation gases.

[0006] Figure 2 An example gas chromatography apparatus including a pre-cut column and a main column is described.

[0007] Figure 3 An example column assembly is depicted, including a trap column, a pre-cut column, and a main column connected to a multi-port valve.

[0008] Figure 4 Depicting including Figure 3 The block diagram above shows an example GC device with column components.

[0009] Figure 5 Depicting Figure 4 The above is a schematic diagram of the GC device.

[0010] Figure 6A and Figure 6B (Figure 6) depicts Figure 4 and Figure 5 The example flow diagram of the gas chromatography apparatus shown illustrates the multi-port valve in... Figure 5 A is in the first position and Figure 5 B is in the second position.

[0011] Figure 7 A flowchart is depicted for a method used to perform gas chromatography measurements.

[0012] Figure 8 A flowchart is depicted for a method of repairing a trapping column in a gas chromatography apparatus. Detailed Implementation

[0013] A method for on-site repair of a gas chromatography (GC) apparatus is disclosed. The method includes providing a GC apparatus comprising at least a trapping column, a main column, and a detector. The main column is configured to separate at least methane, ethane, propane, butane, and pentane compounds from the gas stream, and the trapping column is configured to remove interfering olefins or alcohols from the gas stream. Multiple GC measurements are performed on-site by allowing the gas stream to flow forward through the trapping column and the main column to the detector. After completing the multiple GC measurements, a repair gas is flowed in the opposite direction through the trapping column on-site. The trapping column is heated to a temperature of at least 120°C while the repair gas is flowed in the opposite direction to repair the trapping column.

[0014] Figure 1An example drilling rig 20 is depicted, including a gas chromatography apparatus 100 for assessing the composition of formation gases. The drilling rig 10 may be positioned above a subsurface formation (not shown). The drilling rig may include, for example, a derrick and lifting equipment (also not shown) for raising and lowering a drill string 30, which extends into a wellbore 40 and includes, for example, a drill bit 32 and one or more downhole measurement tools 50 (e.g., logging-while-drilling tools or measurement-while-drilling tools). Suitable drilling systems, including, for example, drilling, steering, logging, and other downhole tools, are well known in the art. The drilling rig 20 also includes a surface system 80 for controlling the flow of drilling fluid used on the drilling rig (e.g., when drilling the wellbore 40). In the depicted example drilling rig, drilling fluid 35 is pumped downhole via a conventional mud pump 82 (as depicted at 92). Drilling fluid 35 may be pumped, for example, through a riser 83 and mud hose 84 en route to the drill string 30. Drilling fluid typically emerges from or near the drill string 30 at or near the drill bit 32, creating an upwelling flow 94 of mud through the annulus (the annular space between the drill string and the wellbore wall). The drilling fluid then flows to the mud pit 81 via return pipe 88. It should be understood that the terms drilling fluid and mud are used synonymously herein.

[0015] As known to those skilled in the art, formation gas can be released into the wellbore 40 via a drilling process (e.g., by mechanically crushing formation rock by the drill bit) and can also migrate into the wellbore 40, for example, via fractures in the formation rock. Once in the wellbore, the formation gas can be transported to the surface via drilling fluid (in an upwardly flowing fluid 94). The formation gas may be dissolved in the drilling fluid and / or in the form of bubbles, and can be sampled in the surface system, for example, via one or more drilling fluid degassers deployed in, for example, return pipe 88 or mud pit 91 and / or a topspace gas probe (not shown) deployed in, for example, return pipe 88. The disclosed embodiments do not explicitly limit how the gas is sampled.

[0016] Further reference Figure 1 The drilling rig 20 may also include a testing facility 60 (e.g., a laboratory trailer including one or more instruments suitable for various measurements of drill cuttings and formation gases in the drilling fluid). In the depicted embodiment, the testing facility 60 includes a gas chromatography apparatus 100 (described in more detail below) configured to receive formation gases and evaluate their composition. Of course, the testing facility 60 may include many other testing instruments known to those skilled in the art. It should be understood that the disclosed embodiments can utilize virtually any suitable gas chromatography (GC) apparatus, including, for example, gas chromatography (VPC) and gas-liquid partition chromatography (GLPC) apparatus connected to any suitable detector, such as, but not limited to, a flame ionization detector (FID), a thermal conductivity detector, a mass spectrometer, etc.

[0017] While GC is a powerful chemical analysis technique capable of separating many (most) chemicals at the detector, there is still room for improvement. In many gas samples (such as those containing light hydrocarbons), the elution times of certain substances may partially or completely overlap. This results in overlapping peaks in the chromatogram and complicates the quantitative determination of gas composition. For example, in gas samples containing light hydrocarbons (e.g., C1, C2, C3, C4, and C5), various gases such as alkenes and alcohols may overlap with peaks of saturated aliphatic hydrocarbons of interest. To overcome this difficulty, GC devices may also include polar columns that act as (and are referred to herein) trapping columns for alcohols that may interfere with the light hydrocarbons of interest in the gas sample, without affecting the retention times of the light hydrocarbons of interest.

[0018] Figure 2 An example GC apparatus 100 is depicted, comprising a gas sample injection port 142 configured to deliver a gas sample into a column assembly 120, which includes a trapping column 122, a pre-cutting column 124, and a GC main column 126. The GC apparatus 100 also includes a carrier gas supply 175, such as compressed nitrogen, argon, helium, or air. The injected gas sample is mixed with the carrier gas and delivered through the column assembly 120. The trapping column 122 is designed to remove interfering compounds, such as alcohols, from the gas stream. The pre-cutting column 124 may be configured to remove heavy hydrocarbon compounds with a carbon number above a threshold, such as C6, C8, or C10 and above. The main column 126 includes a stationary phase and is designed to separate various gaseous compounds in the gas sample such that they arrive at detector 160 at different elution times, for example, such that C1 arrives before C2, which arrives before C3, and so on. The detector may include virtually any suitable GC detector, such as an FID detector, a TC detector, or a mass spectrometer. Furthermore, although the example device 100 includes pre-cut columns 124, it should be understood that the disclosed implementation is not limited in this respect.

[0019] Figure 3 An example column assembly 120 is depicted, comprising a trap column, a pre-cut column, and a main column (not depicted separately in this figure) deployed around a mandrel 121. These columns are in fluid communication with a multi-port (e.g., 10-port) valve 128. As described in more detail below, the multi-port valve 128 allows a gas sample to be guided through the trap column, pre-cut column, and main column to a detector 160. Figure 2 The depicted column assembly 120 also includes one or more heating elements (also not shown) deployed on the mandrel 121. The heating elements enable the temperature of the mandrel and column to be controlled and / or maintained at any temperature, for example, up to about 200°C.

[0020] Figure 4 Depicting includingFigure 3 The block diagram above shows an example GC device 100 with column assembly 120. As depicted, the column assembly is deployed within a GC housing 102. The device also includes a flow manifold 130 in fluid communication with a multi-port valve 128. Flow manifold 130 may include, for example, multiple controllable valves, pressure regulators, and flow regulators (not shown). In the depicted embodiment, the flow manifold is in fluid communication with the multi-port valve 128 via multiple flow passages at 132, with an external exhaust port at 134, multiple gas inlet ports at 140, and a GC detector 160 at 136. Inlet ports may include, for example, a gas sample injection port 142, a carrier gas injection port 145, and a backflow injection port 148.

[0021] Continue to refer to Figure 4 The GC device 100 also includes an electronic controller 150 configured to control the positions of the detector 160, flow manifold 130, multi-port valve 128, and heating elements in the column assembly 120. In doing so, the controller can be configured to cause the GC device to perform GC measurements and / or repair trap columns in the column assembly, for example, as described below regarding... Figure 7 and Figure 8 More detailed description. It should be understood that the controller may include computer hardware and software configured to cause the GC device to perform the functions described above. The hardware may include one or more processors (e.g., microprocessors) that can be connected to one or more data storage devices (e.g., hard disk drives or solid-state drives) and a user interface. It should also be understood that the disclosed embodiments may include processor-executable instructions stored in the data storage device. Of course, the disclosed embodiments are not limited to the use or configuration of any particular computer hardware and / or software.

[0022] Figure 5 Depicting Figure 4 The above diagram illustrates a GC device. As depicted, in this example embodiment, the trap column 122, pre-cut column 124, and main column 126 are in fluid communication with a multi-port valve 128. Specifically, the trap column 122 and pre-cut column 124 are connected in series and in fluid communication with ports 1 and 8 of the multi-port valve 128. The main column 126 is in fluid communication with port 7 and detector 160. In this particular embodiment, the carrier gas supply 175 is in fluid communication with ports 6 and 9. In an alternative embodiment, the carrier gas supply may be in fluid communication with port 6, and a separate gas supply may be in fluid communication with port 9. The gas sample injection port 142 is in fluid communication with port 4. The sample collection loop 170 is in fluid communication with ports 2 and 5. Ports 3 and 10 are exhaust ports. The depicted example GC device 100 also includes multiple pressure regulators 137 and flow regulators 138, as well as an exhaust line 134.

[0023] Figure 6A and Figure 6B (collectively referred to as Figure 6) depicts Figure 5 The example flow diagram of the gas chromatography apparatus shown shows the multi-port valve 128 in... Figure 6A In the first position and in Figure 6B The valve is in the second position. When the valve is in the first position, port 2 and port 3 are in fluid communication, port 4 and port 5 are in fluid communication, and so on. When the valve is in the second position, port 1 and port 2 are in fluid communication, port 3 and port 4 are in fluid communication, and so on.

[0024] exist Figure 6A In the first position, sample collection loop 170 is filled, pre-cut column 124 and trap column 122 are flushed counter-currently with carrier gas (e.g., to remove heavy hydrocarbons and interfering gases from the columns), and main column 126 is flushed with carrier gas. Specifically, as depicted, sample injection port 142 is in fluid communication with sample collection loop 170 via ports 4 and 5. Trapping column 122 and pre-cut column 124 are in fluid communication with gas supply 177 via ports 9 and 8. Carrier gas flows in the opposite direction through pre-cut column 124 and trap column 122 (to flush the columns) and is vented through ports 1 and 10. Carrier gas supply 175 is connected to main column 126 via ports 6 and 7 and is vented through detector ( Figure 5 (Not shown in A) Exhaust.

[0025] exist Figure 6B In the second position, when the multi-port valve 120 is in the sample loop 170, the gas sample is conveyed forward through the trapping column 122, the pre-cutting column 124, and the main column 126 to the detector. Specifically, as depicted, the carrier gas supply 175 is in fluid communication with the sample loop 170 via ports 6 and 5. The gas sample is conveyed sequentially to the trapping column and the pre-cutting column via ports 2 and 1, and then to the main column via ports 8 and 7. The sample injection port 142 exhausts gas through ports 4 and 3.

[0026] Turn now Figure 7 A flowchart of a method 200 for performing gas chromatography measurements is depicted. Method 200 includes providing a GC device at 202, such as those described above. Figure 3The GC device is described in Figure 6. The GC device includes a column assembly comprising a trap column, a pre-cut column, and a main column deployed around a mandrel and in fluid communication with a multi-port valve. The method further includes: setting the valve to a first position at 204; opening a sample injection port at 206 to fill the sample loop with a gas sample while the valve is in the first position; and opening a counter-current injection port at 208 to flush the sample loop with carrier gas in the opposite direction through the trap column and the pre-cut column while the valve is in the first position. The multi-port valve is then set to a second position at 210. The carrier gas port is opened at 212 to allow the gas sample in the sample loop to pass forward through the trap column and the pre-cut column, and then through the main column to the detector. The gas sample is then evaluated at the detector at 214 to estimate its composition.

[0027] Continue to refer to Figure 7 It should be understood that method 200 may also include heating the mandrel (to heat the trapping column, pre-cutting column, and main column) during GC measurements, for example, to a temperature in the range of about 40°C to about 100°C. Generally, depending on the characteristics of the analytical column, GC measurements can be performed at virtually any suitable temperature in the range of about ambient temperature (25°C) to about 350°C. For mud logging hydrocarbon analysis, since only light alkanes (typically C1 to C5 or C1 to C8) are quantified, the temperature range can be about ambient temperature to about 100°C. Method 200 may further include opening the carrier gas port when the valve is in a first position (e.g., at 206 and / or 208) to flush the main column in the forward direction. In addition, method 200 may also include, for example, repeating 204, 206, 208, 210, 212, and 214 substantially any number of times during drilling to perform multiple ordered GC measurements. Repetitions can be performed at substantially any suitable time interval. For example, the valve can be in the first position for about 40 to 50 seconds and in the second position for about 10 to 20 seconds, thus performing GC measurements at intervals of about 1 minute.

[0028] Turn now Figure 8 The diagram depicts a flowchart of method 250 for repairing (or regenerating) a trapping column in a gas chromatography apparatus. Method 250 includes providing a GC apparatus at 252, such as those described above. Figure 3The GC apparatus described in Figure 6. The GC apparatus includes a column assembly comprising a trap column, a pre-cut column, and a main column deployed around a mandrel and in fluid communication with a multi-port valve. The method aims to flush strongly absorbent compounds, such as alcohols, from the trap column. The method also includes setting the valve to a first position at 254 and heating the mandrel (and at least the trap column) at 256 to a temperature of at least 120°C (or at least 150°C) (e.g., heating to a temperature in the range of about 120°C to about 200°C or about 150°C to about 200°C, because hydrocarbons with boiling points above 150°C are generally not extracted from the drilling fluid in relevant quantities, nor are they delivered to the analyzer without significant condensation, nor can they be analyzed by mud logging gas chromatography). It should be understood that accurate column temperature measurements can be difficult and the measured temperature can vary depending on the location along the mandrel where the temperature measurement is performed. Therefore, a temperature of "about" 200°C can be understood as being in the range of 195°C to 205°C, and a temperature range of about 150°C to about 200°C can be understood as a temperature range of 145°C to 205°C.

[0029] When the valve is in the first position and the temperature is above 120°C (or about 150°C), the countercurrent injection port can be opened at 258 to flush the carrier gas in the opposite direction through the trapping column and the pre-cutting column. After a predetermined time (e.g., about 5 minutes to about 5 hours or about 1 hour to about 3 hours), the countercurrent injection port can be closed at 260 and the heating can be turned off (or the heating can be reduced).

[0030] Continue to refer to Figure 8 Method 250 may further include performing GC measurements using a GC apparatus with a remediated trap column. For example, method 250 may also include allowing the mandrel to cool to, for example, ambient temperature or a temperature in the range of about 40°C to about 100°C, and then opening the sample injection port to fill the sample loop. The multi-port valve can then be set to a second position and the carrier gas port opened to allow the gas sample in the sample loop to pass forward through the trap column and the pre-cut column, and then through the main column to the detector, where the gas sample can be evaluated. Furthermore, the GC measurement results can be evaluated to determine whether the remediation has completely removed the interfering compounds from the trap column.

[0031] It should be understood that the string repair in Method 250 can advantageously be performed on-site at the drilling rig without any need to remove or disconnect the GC equipment from the well gas line. Furthermore, the repair can be performed at virtually any time interval or whenever necessary. For example, a repair can be performed when GC measurements (e.g., performed using Method 200) indicate the presence of interfering compounds in the measurements. In other example applications, depending on the nature of the drilling operation and the amount of interfering compounds encountered, repairs can be performed at some predetermined time intervals (e.g., weekly, monthly, bi-monthly, quarterly, semi-annually, or annually). Furthermore, it should be understood that the repair can advantageously be performed during drilling rig downtime, such as when the drill string is run into or retrieved from the well.

[0032] In some example operations, it may be advantageous to perform tests to indicate whether column repair is required. For example, a test mixture containing one or more alcohols (such as alcohols comprising one to five carbon atoms) can be prepared. An example test mixture may include a nitrogen carrier containing methanol and / or isopropanol (e.g., 250 ppm methanol and 250 ppm isopropanol). The test mixture can be injected along with a gas sample, and the resulting chromatogram can be evaluated against alcohol peaks (e.g., methanol peaks close to the iC4 peak and / or isopropanol peaks close to the iC5 peak). The presence of alcohol peaks can be considered an indication that column repair is necessary (e.g., when such peaks are at least three times the background noise).

[0033] It should be understood that the determination of whether remediation is necessary can also be triggered by the analysis of field data (e.g., in near real-time during drilling). When the trapping column fails to retain alcohol contaminants, their peaks will appear on the chromatogram (e.g., near the C4 and C5 peaks). The presence of such peaks can alert the operator (via manual or automated detection) that column remediation is necessary.

[0034] Furthermore, it should be understood that the chromatogram can be evaluated for the presence of alcohol peaks after remediation. The absence of such alcohol peaks can be considered an indication of successful remediation. Again, this evaluation can be performed manually or automatically.

[0035] It should be understood that this disclosure includes many embodiments. These embodiments include, but are not limited to, the following embodiments.

[0036] In a first embodiment, a method for repairing a gas chromatography apparatus at a drilling rig site includes: providing a gas chromatography (GC) apparatus comprising at least a trapping column, a main column, and a detector, the main column being configured to separate at least methane, ethane, propane, butane, and pentane compounds from a gas stream, the trapping column being configured to remove interfering olefins or alcohols from the gas stream; using the GC apparatus at the drilling rig site to perform multiple GC measurements by allowing the gas stream to flow forward through the trapping column and the main column to the detector; after completing the multiple GC measurements, allowing a repair gas to flow in the opposite direction through the trapping column at the drilling rig site; and heating the trapping column to a temperature above 120°C while simultaneously allowing the repair gas to flow in the opposite direction to repair the trapping column.

[0037] The second implementation may include the first implementation, wherein the repair gas is a gas including argon, nitrogen, helium, air or a mixture thereof.

[0038] The third embodiment may include any one of the first to second embodiments, wherein the trapping column is heated to a temperature in the range of about 150°C to about 200°C.

[0039] The fourth implementation may include any one of the first to third implementations, wherein the remedy gas is flowed and the trapping column is heated for at least one hour.

[0040] The fifth embodiment may include any one of the first to fourth embodiments, wherein causing the repair gas to flow in the opposite direction includes: setting a multi-port valve to a first position, the first position providing fluid communication between a countercurrent injection port and the trapping column; and opening the countercurrent injection port to allow the repair gas to flow through the trapping column in the opposite direction.

[0041] The sixth implementation may include the fifth implementation, and the method further includes: allowing the trapping column to cool to a temperature below about 100°C; and closing the backflow injection port.

[0042] The seventh embodiment may include the sixth embodiment, and the method further includes: opening the sample injection port to allow a gas sample from the gas flow to flow into the sample collection loop; setting the multi-port valve to a second position, the second position providing fluid communication between the sample collection loop and the trapping column; and opening the carrier gas injection port to allow the gas sample to flow in a forward direction through the trapping column and the main column to the detector for GC measurement.

[0043] The eighth embodiment may include the seventh embodiment, and the method further includes: evaluating the GC measurement for at least one alcohol peak.

[0044] The ninth embodiment may include any one of the sixth to eighth embodiments, and the method further includes performing a second GC measurement at the drilling site using the GC equipment after the repair gas has flowed through the trapping column in the opposite direction.

[0045] The tenth embodiment may include the ninth embodiment, wherein performing the second multiple GC measurement comprises: setting the multiport valve to the first position; opening the countercurrent injection port to allow the remedy gas to flow through the trapping column in the opposite direction; opening the sample injection port to allow the gas sample from the gas flow to flow into the sample collection loop; setting the multiport valve to the second position, the second position providing fluid communication between the sample collection loop and the trapping column; opening the carrier gas injection port to allow the gas sample to flow forward through the trapping column and the main column to the detector; and repeating setting the multiport valve to the first position, opening the countercurrent injection port, opening the sample injection port, setting the multiport valve to the second position, and opening the carrier gas injection port to perform the second multiple GC measurement.

[0046] In an eleventh embodiment, a gas chromatography (GC) apparatus includes: a housing; a column assembly comprising a main column and a trapping column in fluid communication with a multi-port valve, the main column being configured to separate at least methane, ethane, propane, butane, and pentane compounds from the gas stream, the trapping column being configured to remove interfering olefins or alcohols from the gas stream, the column assembly further including a heating element configured to heat the trapping column; a flow manifold in fluid communication with the column assembly, a carrier gas injection port, a countercurrent injection port, and a sample injection port; a GC detector in fluid communication with the flow manifold and the main column; and an electronic controller configured to: perform multiple GC measurements at the drilling site by allowing the GC apparatus to flow a gas stream in a forward direction through the trapping column and the main column to the detector; after completing the multiple GC measurements, allow a remedial gas to flow in the opposite direction through the trapping column; and heat the trapping column to a temperature above 120°C while allowing the remedial gas to flow in the opposite direction to remediate the trapping column.

[0047] The twelfth embodiment may include the eleventh embodiment, wherein the flow manifold includes a multi-port valve.

[0048] The thirteenth embodiment may include any one of the eleventh to twelfth embodiments, wherein the electronic controller is configured to allow the repair gas to flow through the trapping column in the opposite direction by: setting the multi-port valve to a first position, wherein the first position provides fluid communication between the backflow injection port and the trapping column; and opening the backflow injection port to allow the repair gas to flow through the trapping column in the opposite direction.

[0049] The fourteenth embodiment may include any one of the eleventh to thirteenth embodiments, wherein the controller is further configured to: allow the trapping column to cool to a temperature below about 100°C; close the backflow injection port; open the sample injection port, thereby allowing a gas sample from the gas flow to flow into the sample collection loop; set the multiport valve to a second position, the second position providing fluid communication between the sample collection loop and the trapping column; and open the carrier gas injection port to allow the gas sample to flow forward through the trapping column and the main column to the detector for another GC measurement.

[0050] The fifteenth embodiment may include any one of the eleventh to fourteenth embodiments, and the device further includes a pre-cutting column connected in series with the trapping column, the pre-cutting column being configured to remove hydrocarbon compounds with a carbon number higher than a threshold.

[0051] In a sixteenth embodiment, a method for on-site repair of a gas chromatography (GC) device at a drilling rig includes: providing a gas chromatography (GC) device comprising a trapping column, a pre-cutting column, a main column, a detector, and a multi-port valve, the multi-port valve being in fluid communication with the trapping column, the pre-cutting column, and the main column; the main column being configured to separate at least methane, ethane, propane, butane, and pentane compounds from the gas stream; the pre-cutting column being configured to remove hydrocarbon compounds with a carbon number exceeding a threshold from the gas stream; and the trapping column being configured to remove interfering olefins or alcohols from the gas stream; at the drilling rig... The GC device is used on-site to perform multiple GC measurements by causing the gas flow in the forward direction through the trap column and the main column to the detector; after completing the multiple GC measurements, the multi-port valve is set to a first position, which provides fluid communication between the countercurrent injection port and the trap column and the pre-cut column; the countercurrent injection port is opened to allow the repair gas to flow in the opposite direction through the pre-cut column and the trap column; and the column assembly is heated to a temperature above 120°C while the repair gas flows in the opposite direction to repair the trap column.

[0052] The seventeenth embodiment may include the sixteenth embodiment, wherein the trapping column is heated to a temperature in the range of about 150°C to about 200°C; and the remedy gas is circulated and the trapping column is heated for at least one hour.

[0053] The eighteenth embodiment may include any one of the sixteenth to seventeenth embodiments, and the method further includes: allowing the trapping column to cool to a temperature below about 100°C; closing the backflow injection port to stop the flow of the remedy gas; opening the sample injection port to allow a gas sample from the gas flow to flow into the sample collection loop; setting the multiport valve to a second position, the second position providing fluid communication between the sample collection loop and the trapping column; and opening the carrier gas injection port to allow the gas sample to flow forward through the trapping column and the main column to the detector for GC measurement.

[0054] The nineteenth embodiment may include the eighteenth embodiment, and the method further includes evaluating the GC measurement for at least one alcohol peak.

[0055] The twentieth implementation may include any one of the sixteenth to nineteenth implementations, and the method further includes performing a second GC measurement at the drilling site using the GC equipment after the repair gas has flowed through the trapping column in the opposite direction.

[0056] Although the on-site column repair at the drilling rig has been described in detail, it should be understood that various changes, substitutions and alterations may be made herein without departing from the spirit and scope of this disclosure as defined by the appended claims.

Claims

1. A method for repairing a gas chromatography equipment at a drilling rig site, the method comprising: A gas chromatography (GC) apparatus is provided, the GC apparatus comprising at least a trapping column, a main column, and a detector, the main column being configured to separate at least methane, ethane, propane, butane, and pentane compounds from the gas stream, and the trapping column being configured to remove interfering olefin or alcohol compounds from the gas stream; The GC device is used at the drilling site to perform multiple GC measurements by causing the airflow to flow in the forward direction through the trap column and the main column to the detector; After completing the multiple GC measurements, the repair gas is made to flow through the trapping column in the opposite direction at the drilling site. as well as The trapping column is heated to a temperature above 120°C while the repair gas flows in the opposite direction to repair the trapping column.

2. The method of claim 1, wherein the repair gas is a gas including argon, nitrogen, helium, air, or a mixture thereof.

3. The method of claim 1, wherein the trapping column is heated to a temperature in the range of about 150°C to about 200°C.

4. The method of claim 1, wherein the flow of the repair gas and the heating of the trapping column are continued for at least one hour.

5. The method of claim 1, wherein causing the repair gas to flow in the opposite direction comprises: Set the multi-port valve to a first position, the first position providing fluid communication between the backflow injection port and the trapping column; as well as Open the countercurrent injection port to allow the repair gas to flow through the trapping column in the opposite direction.

6. The method of claim 5, further comprising: The trapping column is allowed to cool to a temperature below approximately 100°C; as well as Close the reverse injection port.

7. The method of claim 6, further comprising: Open the sample injection port so that the gas sample from the gas flow can flow into the sample collection loop; The multi-port valve is set to a second position, which provides fluid communication between the sample collection loop and the trapping column; as well as The carrier gas injection port is opened to allow the gas sample to flow forward through the trapping column and the main column to the detector for GC measurement.

8. The method of claim 7, further comprising: The GC measurement was evaluated for at least one alcohol peak.

9. The method of claim 6, further comprising performing a second set of GC measurements at the drilling site using the GC equipment after the repair gas has flowed through the trapping column in the opposite direction.

10. The method of claim 9, wherein performing the second multiple GC measurements comprises: Set the multi-port valve to the first position; Open the countercurrent injection port to allow the repair gas to flow through the trapping column in the opposite direction; Open the sample injection port to allow gas samples from the gas flow to flow into the sample collection loop; The multi-port valve is set to the second position, which provides fluid communication between the sample collection loop and the trapping column; Open the carrier gas injection port to allow the gas sample to flow forward through the trapping column and the main column to the detector; as well as Repeatedly set the multi-port valve to the first position, open the countercurrent injection port, open the sample injection port, set the multi-port valve to the second position, and open the carrier gas injection port to perform the second multiple GC measurements.

11. A gas chromatography (GC) apparatus, said GC apparatus comprising: case; A column assembly comprising a main column and a trapping column in fluid communication with a multi-port valve, the main column being configured to separate at least methane, ethane, propane, butane, and pentane compounds from the gas stream, the trapping column being configured to remove interfering olefins or alcohols from the gas stream, and the column assembly further comprising a heating element configured to heat the trapping column. A flow manifold, which is in fluid communication with the column assembly, carrier gas injection port, countercurrent injection port and sample injection port; GC detector, wherein the GC detector is in fluid communication with the flow manifold and the main column; as well as An electronic controller is configured to: at the drilling site, cause the GC device to perform multiple GC measurements by causing airflow to flow in the forward direction through the trapping column and the main column to the detector; after completing the multiple GC measurements, cause the repair gas to flow in the opposite direction through the trapping column; The trapping column is heated to a temperature above 120°C while the repair gas flows in the opposite direction to repair the trapping column.

12. The GC device of claim 11, wherein the flow manifold includes a multi-port valve.

13. The GC device of claim 12, wherein the electronic controller is configured to allow the repair gas to flow through the trapping column in the opposite direction by: setting the multi-port valve to a first position, wherein the first position provides fluid communication between the backflow injection port and the trapping column; and opening the backflow injection port to allow the repair gas to flow through the trapping column in the opposite direction.

14. The GC apparatus of claim 13, wherein the controller is further configured to: allow the trapping column to cool to a temperature below about 100°C; close the backflow injection port; open the sample injection port, thereby allowing a gas sample from the gas flow to flow into the sample collection loop; set the multiport valve to a second position, the second position providing fluid communication between the sample collection loop and the trapping column; and open the carrier gas injection port to allow the gas sample to flow forward through the trapping column and the main column to the detector for another GC measurement.

15. The GC apparatus of claim 11, further comprising a pre-cutting column connected in series with the trapping column, the pre-cutting column being configured to remove hydrocarbon compounds having a carbon number above a threshold.

16. A method for repairing a gas chromatography equipment at a drilling rig site, the method comprising: A gas chromatography (GC) apparatus is provided, the GC apparatus comprising a trapping column, a pre-cutting column, a main column, a detector, and a multi-port valve, the multi-port valve being in fluid communication with the trapping column, the pre-cutting column, and the main column, the main column being configured to separate at least methane, ethane, propane, butane, and pentane compounds from the gas stream, the pre-cutting column being configured to remove hydrocarbon compounds with a carbon number higher than a threshold from the gas stream, and the trapping column being configured to remove interfering olefins or alcohols from the gas stream; The GC device is used at the drilling site to perform multiple GC measurements by causing the airflow to flow in the forward direction through the trap column and the main column to the detector; After completing the multiple GC measurements, the multi-port valve is set to a first position, which provides fluid communication between the backflow injection port and the trapping column and the pre-cutting column. Open the countercurrent injection port to allow the repair gas to flow in opposite directions through the pre-cut column and the trapping column; as well as The column assembly is heated to a temperature above 120°C, while the repair gas flows in the opposite direction to repair the trapping column.

17. The method of claim 16, wherein: The trapping column is heated to a temperature ranging from approximately 150°C to approximately 200°C; and The repair gas is allowed to flow and the trapping column is heated for at least one hour.

18. The method of claim 16, further comprising: The trapping column is allowed to cool to a temperature below approximately 100°C; Close the backflow injection port to stop the flow of repair gas; Open the sample injection port so that the gas sample from the gas flow can flow into the sample collection loop; The multi-port valve is set to a second position, which provides fluid communication between the sample collection loop and the trapping column; as well as The carrier gas injection port is opened to allow the gas sample to flow forward through the trapping column and the main column to the detector for GC measurement.

19. The method of claim 18, further comprising: The GC measurement was evaluated for at least one alcohol peak.

20. The method of claim 16, further comprising performing a second set of GC measurements at the drilling site using the GC equipment after the repair gas has flowed through the trapping column in the opposite direction.

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