Gas logging experimental device and method considering wellbore annular volume change

Abstract

This invention discloses a gas logging experimental apparatus and method that considers changes in wellbore annular volume. The apparatus includes a drilling fluid injection mechanism, a gas sample injection mechanism, a gas logging analysis mechanism, a wellbore, a drill bit, a drill string, and an annular assembly. The annular assembly includes at least two retractable annular structures connected sequentially. The at least two retractable annular structures are disposed on the sidewall of the drill string. Each retractable annular structure has a radial slide rail at one end. The retractable annular structures can slide radially along the radial slide rails at the side ends of adjacent retractable annular structures, allowing each retractable annular structure to be radially offset. Each retractable annular structure can expand and contract circumferentially around the drill string to change the annular volume between the drill string and the wellbore. This apparatus quantifies the impact of wellbore annular volume on gas logging data, contributing to improving the comprehensiveness and accuracy of oil and gas content evaluation in reservoirs under development.

Description

Technical Field

[0001] This invention relates to the field of oil and gas logging technology, and in particular to a gas logging experimental device and method that takes into account changes in wellbore annular volume. Background Technology

[0002] Gas logging technology plays an irreplaceable role in oil and gas development and is currently a crucial method for evaluating oil and gas reservoirs. This technology assesses the oil and gas content of reservoirs under development by analyzing the hydrocarbon gas content in the drilling fluid. However, the hydrocarbon gas content in the drilling fluid is affected by numerous factors, easily leading to inaccuracies in gas logging data. These factors include drilling fluid parameters (density, viscosity, temperature), wellbore annulus volume, bottom hole pressure fluctuations, and formation temperature variations. Among these factors, the impact of wellbore annulus volume on gas logging data is rarely discussed. Different wellbore annulus volumes affect the migration of hydrocarbon gases with the drilling fluid, causing fluctuations in gas logging data. Summary of the Invention

[0003] To enrich the product types of gas logging experimental devices and to introduce the influence of wellbore annular volume changes on gas logging results, this invention provides a gas logging experimental device and method that considers wellbore annular volume changes.

[0004] In a first aspect, embodiments of the present invention provide a gas logging experimental device that considers changes in the volume of the wellbore annulus, including a drilling fluid injection mechanism, a gas sample injection mechanism, a gas analysis mechanism, a wellbore, a drill bit, a drill string, and an annular assembly;

[0005] The drill string and the drill bit are axially connected vertically and are housed inside the wellbore.

[0006] The ring-shaped component includes at least two retractable ring-shaped structures that are sequentially and movably connected.

[0007] The at least two retractable annular structures are disposed on the sidewall of the drill string;

[0008] Each of the aforementioned retractable annular structures has a radial slide rail on one side.

[0009] The retractable ring structure can slide radially along the radial slide rails at the side ends of adjacent retractable ring structures, so that each of the retractable ring structures can be radially offset.

[0010] Each of the aforementioned retractable annular structures can expand and contract circumferentially around the drill string to change the annular volume between the drill string and the wellbore;

[0011] The drilling fluid injection mechanism is connected to the inlet of the drill string;

[0012] The gas injection mechanism is connected to the bottom of the wellbore;

[0013] The gas analysis unit is connected to the top of the wellbore.

[0014] In one or more alternative embodiments, the annular assembly further includes a fixed circumferential slide rail;

[0015] The fixed circumferential slide rail is sleeved on the drill string;

[0016] The at least two retractable ring structures are arranged sequentially along a preset direction;

[0017] The retractable ring structure at the head end can slide and unfold along the fixed circumferential slide rail.

[0018] In one or more alternative embodiments, each of the retractable annular structures is provided with a retractable circumferential slide rail at its radial end;

[0019] The retractable circumferential slide rail can expand and contract circumferentially with the retractable annular structure;

[0020] The rear retractable ring structure can slide and unfold along the retractable circumferential slide rail at the radial end of the front retractable ring structure.

[0021] In one or more alternative embodiments, the rear retractable annular structure is capable of sliding along a radial guide rail on the side end of the front retractable annular structure.

[0022] In one or more alternative embodiments, the radial slide rail is a magnet, and a magnetic element is provided on the other end of the retractable annular structure;

[0023] When the retractable annular structure is in its circumferentially unfolded state, the radial slide rail and the magnetic component are magnetically attracted and attached.

[0024] In one or more alternative embodiments, the gas injection mechanism includes a gas storage tank, a gas delivery pipe, a first control valve, a first booster pump, and a gas injection tank;

[0025] The gas injection groove is connected to the bottom of the wellbore;

[0026] The gas pipeline is connected to the gas injection tank and the gas storage tank respectively;

[0027] The first control valve is located at the outlet of the gas storage tank and is connected to the gas transmission pipe;

[0028] The first booster pump is installed in the gas pipeline.

[0029] In one or more alternative embodiments, the gas injection tank includes an air inlet, an annular simulated rock layer, and a gas distributor;

[0030] The annular simulated rock layer is disposed within the air intake groove, and an annular air injection cavity is formed between the annular simulated rock layer and the air intake groove;

[0031] The gas distributor is disposed inside the annular gas injection chamber and is in close contact with the annular simulated rock layer;

[0032] An air inlet is provided on the side wall of the air inlet slot, and the air inlet is connected to the air supply pipe.

[0033] In one or more alternative embodiments, the gas distributor is a ring-shaped mesh structure;

[0034] A baffle plate is provided at the position opposite to the air inlet of the gas distributor.

[0035] In one or more alternative embodiments, the drilling fluid injection mechanism includes a storage tank, a delivery pipe, a second control valve, and a second booster pump;

[0036] The infusion tubing is connected to the outlet of the storage tank and the inlet of the drill string, respectively.

[0037] The second control valve is located at the outlet of the storage tank and connected to the infusion pipe;

[0038] The second booster pump is installed in the infusion pipe.

[0039] In one or more alternative embodiments, the gas analysis apparatus includes a degassing tank, a degasser, a chromatograph, an analysis display, and a recovery tank;

[0040] The degasser is disposed within the degassing tank;

[0041] The degassing troughs are connected to the top of the wellbore and the recovery box, respectively;

[0042] The chromatograph is connected to the degasser and the analysis display, respectively.

[0043] In a second aspect, embodiments of the present invention provide a gas logging experiment method considering wellbore annular volume changes, employing the gas logging experiment apparatus for considering wellbore annular volume changes described in the first aspect, including:

[0044] A retractable annular structure is unfolded circumferentially around the drill string to change the annular volume between the drill string and the wellbore.

[0045] Drilling fluid is injected into the drill string through a drilling fluid injection mechanism;

[0046] A gas sample is injected into the bottom of the wellbore using a gas sample injection mechanism;

[0047] The hydrocarbon gas content in the gas returning from the wellbore is collected and analyzed by a gas analysis unit.

[0048] Stop injecting gas samples and drilling fluid;

[0049] The next retractable annular structure is radially offset from the already circumferentially unfolded retractable annular structure and is circumferentially unfolded with the drill string as the center, so as to change the annular volume between the drill string and the wellbore again.

[0050] Re-inject gas samples and drilling fluid, and collect and analyze the hydrocarbon gas content in the gas returning from the wellbore;

[0051] The process of repeatedly unfolding the next stretchable annular structure and collecting and analyzing the hydrocarbon gas content in the returning drilling fluid is repeated.

[0052] The beneficial effects of the above-mentioned technical solutions provided in the embodiments of the present invention include at least the following:

[0053] The gas logging experimental device considering wellbore annular volume changes provided in this invention utilizes multiple expandable annular structures that can unfold circumferentially around the drill string to alter the annular volume between the drill string and the wellbore. A drilling fluid injection mechanism injects drilling fluid into the drill string, a gas sample injection mechanism simulates the process of formation gas entering the wellbore, and a gas logging analysis mechanism analyzes the hydrocarbon gas content in the drilling fluid returning to the wellbore. By altering the annular volume through the annular structures and combining the drilling fluid injection mechanism, gas sample injection mechanism, and gas logging analysis mechanism, gas logging experiments with different annular volumes can be conducted. This quantifies the impact of wellbore annular volume on gas logging data, contributing to improved comprehensiveness and accuracy in evaluating the oil and gas content of reservoirs to be developed.

[0054] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description and the accompanying drawings.

[0055] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0056] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0057] Figure 1 This is a schematic diagram of the gas logging experimental device considering wellbore annular volume changes provided in an embodiment of the present invention.

[0058] Figure 2 This is a schematic diagram of the retractable structure provided in an embodiment of the present invention;

[0059] Figure 3 This is a schematic diagram of the ring-shaped component in its undeployed state provided in an embodiment of the present invention;

[0060] Figure 4 This is a schematic diagram of the three retractable ring structures provided in the embodiments of the present invention;

[0061] Figure 5 This is a schematic diagram showing the unfolded structure of the three retractable ring structures provided in the embodiment of the present invention.

[0062] Figure 6 This is a schematic diagram of the gas injection mechanism provided in an embodiment of the present invention.

[0063] Figure label:

[0064] 1. Storage tank; 2. Second control valve; 3. Infusion pipe; 4. Second booster pump; 5. Drill string; 6. Drill bit; 7. Wellbore; 8. Gas storage tank; 9. First control valve; 10. Gas infusion pipe; 11. First booster pump; 12. Injection tank; 121. Inlet tank; 122. Gas distributor; 123. Annular simulated rock strata; 124. Annular injection chamber; 13. Degassing tank; 14. Degasser; 15. Chromatograph; 16. Analytical display; 17. Recovery tank; 18. Ring assembly; 181. Telescopic ring 1811. First retractable annular structure; 1812. First radial slide rail; 1813. First retractable circumferential slide rail; 1814. Telescopic surface; 182. Fixing element; 183. Fixed circumferential slide rail; 184. First retractable annular structure; 1841. First radial slide rail; 1842. First retractable circumferential slide rail; 185. Second retractable annular structure; 1851. Second radial slide rail; 1852. Second retractable circumferential slide rail; 186. Third retractable annular structure; 1861. Third radial slide rail. Detailed Implementation

[0065] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0066] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," "outer," "far," "near," "front," and "rear," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0067] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0068] The inventors have discovered that several gas logging experimental devices have been developed to study the impact of different factors on gas logging data, such as a downhole gas logging test device (CN201720060698.5), a gas logging data detection device simulating the wellbore environment (CN202011123186.1), and a Fourier transform infrared gas logging method and apparatus (CN201910717334.3). However, none of these devices can simulate different wellbore annulus volumes, thus making it impossible to discuss the impact of wellbore annulus volume on gas logging data.

[0069] Example 1

[0070] Based on this, embodiments of the present invention provide a gas logging experimental device and method that considers changes in wellbore annulus volume, which will be described in detail below through specific embodiments.

[0071] This invention provides a gas logging experimental device that considers changes in wellbore annular volume, referring to... Figures 1-3 As shown, it includes:

[0072] It includes a drilling fluid injection mechanism, a gas sample injection mechanism, a gas testing and analysis mechanism, a wellbore 7, a drill bit 6, a drill string 5, and an annular assembly 18;

[0073] The drill string 5 and the drill bit 6 are axially connected vertically and are housed inside the wellbore 7;

[0074] The ring-shaped component 18 includes at least two retractable ring structures 181 that are sequentially and movably connected;

[0075] The at least two retractable annular structures 181 are disposed on the side wall of the drill string 5;

[0076] Each of the retractable annular structures 181 is provided with a radial slide rail 1811 on one side end;

[0077] The retractable ring structure 181 can slide radially along the radial slide rail 1811 at the side end of the adjacent retractable ring structure 181, so that each of the retractable ring structures 181 can be offset radially.

[0078] Each of the aforementioned retractable annular structures 181 can expand and contract circumferentially around the drill string 5 to change the annular volume between the drill string 5 and the wellbore 7;

[0079] The drilling fluid injection mechanism is connected to the inlet of the drill string 5;

[0080] The gas injection mechanism is connected to the bottom of the wellbore 7;

[0081] The gas analysis unit is connected to the top of the wellbore 7.

[0082] In this embodiment of the invention, reference is made to Figures 2-5 As shown, the retractable annular structure 181 can slide radially along the radial slide rail 1811 on the side end of adjacent retractable annular structures 181, so that each retractable annular structure 181 can be radially offset. Specifically, at least two retractable annular structures 181 are arranged sequentially along a preset direction (clockwise or counterclockwise) in an undeployed state. The radial slide rail 1811 on the side end of the first retractable annular structure 181 is movably connected to the adjacent retractable annular structure 181, so that the adjacent retractable annular structure 181 can slide radially along the radial slide rail 1811, thereby being radially offset from the first retractable annular structure 181. Correspondingly, the retractable annular structures 181 arranged later can all slide radially along the adjacent retractable annular structures 181 arranged in front, so that all retractable annular structures 181 can be radially offset, realizing the change of the annular volume of the wellbore 7 by deploying different numbers of retractable annular structures 181.

[0083] The gas logging experimental device considering wellbore annular volume changes provided in this invention alters the annular volume between the drill string 5 and the wellbore 7 by setting multiple retractable annular structures that can expand circumferentially around the drill string 5. A drilling fluid injection mechanism injects drilling fluid into the drill string 5, a gas sample injection mechanism simulates the process of formation gas entering the wellbore 7, and a gas logging analysis mechanism analyzes the hydrocarbon gas content in the drilling fluid returning to the wellbore 7. By changing the annular volume through the annular structures and combining the drilling fluid injection mechanism, gas sample injection mechanism, and gas logging analysis mechanism, gas logging experiments with different annular volumes can be conducted. This quantifies the impact of wellbore annular volume on gas logging data, contributing to improving the comprehensiveness and accuracy of oil and gas content evaluation in reservoirs to be developed.

[0084] In this embodiment of the invention, reference is made to Figures 2-5 As shown, the annular assembly 18 also includes a fixing member 182 and a fixed circumferential slide rail 183. The fixing member 182 is fixedly connected to the top of the drill string 5, and the fixed circumferential slide rail 183 is fixed to the fixing member 182 and sleeved on the drill string 5. The side end of the retractable annular structure 181 at the first end that does not have a radial slide rail 1811 is fixedly connected to the fixed circumferential slide rail 183, while the side end with the radial slide rail 1811 can slide circumferentially along the fixed circumferential slide rail 183, thereby ensuring that the retractable annular structure 181 at the first end can be smoothly extended and retracted.

[0085] In this embodiment of the invention, reference is made to Figures 2-5 As shown, each retractable annular structure 181 has a retractable circumferential slide rail 1813 at its radial end (the end radially away from the drill string 5) that allows it to expand and contract with the retractable annular structure 181. Since the retractable annular structures 181 arranged later can slide radially along their adjacent, preceding retractable annular structures 181, thus offsetting them, the retractable annular structures 181 arranged later, after being radially offset from their adjacent, preceding retractable annular structures 181, can slide circumferentially along the retractable circumferential slide rail 1813 at the radial end of the adjacent, preceding retractable annular structure 181. This ensures that all retractable annular structures 181 following the first retractable annular structure 181 can expand and retract smoothly. It should be noted that the retractable circumferential slide rail 1813 may not be provided at the radial end of the retractable annular structure 181 at the tail end.

[0086] In this embodiment of the invention, reference is made to Figure 2As shown, each retractable annular structure 181 has a radial slide rail 1811 on one side that is a magnet, and a corresponding magnetic element 1812 on the other side. The radial slide rail 1811 can attract the magnetic element 1812. Therefore, when any retractable annular structure 181 is circumferentially unfolded, the magnetic element 1812 on the retractable annular structure 181 can magnetically adhere to its own radial slide rail 1811 or the radial slide rails 1811 arranged at the tail end of the retractable annular structure 181, thereby ensuring that the retractable annular structure 181 can maintain its circumferentially unfolded state and ensuring the stability of the changed annular volume. The retractable portion between the magnetic element 1812 and the radial slide rail 1811 is the retractable surface 1814. Optionally, the magnet is a magnet, the magnetic element 1812 is a metal sheet, and the retractable surface 1814 is made of polypropylene.

[0087] In this embodiment of the invention, the number of retractable annular structures 181 can be reasonably set according to their own size and the size and specifications of the wellbore 7 and drill string 5, as long as it can reflect the influence of different wellbore annular volumes on the gas logging test results.

[0088] To provide a clearer explanation of the annular component 18 provided in the embodiments of the present invention, taking a total of three retractable annular structures 181 as an example, the following embodiments are provided to provide a clearer explanation of the annular component 18:

[0089] In this embodiment, refer to Figures 2-5 As shown, the annular assembly 18 includes a fixing member 182, a fixed circumferential slide rail 183, and a first retractable annular structure 184, a second retractable annular structure 185, and a third retractable annular structure 186 connected sequentially. The fixing member 182 is fixedly connected to the top of the drill string 5, and the fixed circumferential slide rail 183 is fixed to the fixing member 182 and sleeved on the drill string 5. The first retractable annular structure 183, the second retractable annular structure 184, and the third retractable annular structure 185 are arranged clockwise around the drill string 5. The first retractable annular structure 184 has a first radial slide rail 1841 and a first magnetic element (not shown in the figure) respectively at both ends, and a first retractable circumferential slide rail 1842 at its radial end; the second retractable annular structure 185 has a second radial slide rail 1851 and a second magnetic element (not shown in the figure) respectively at both ends, and a second retractable circumferential slide rail 1852 at its radial end; the third retractable annular structure 186 has a third radial slide rail 1861 and a third magnetic element (not shown in the figure) respectively at both ends. The first magnetic element is fixedly connected to the fixed circumferential slide rail 183, and the first radial slide rail 1841 is movably connected to the second magnetic element, so that the second retractable annular structure 185 can slide along the first radial slide rail radially 1841. Correspondingly, the second radial slide rail 1851 is also movably connected to the third magnetic element.

[0090] In this embodiment, refer to Figures 2-5 As shown, one end of the first retractable annular structure 184, which is provided with the first radial slide rail 1841, can slide circumferentially along the fixed circumferential slide rail 183, thereby unfolding the first retractable annular structure 184 circumferentially. When the first retractable annular structure 184 is unfolded circumferentially, the second retractable annular structure 185 and the third retractable annular structure 186 are still circumferentially parallel to the first retractable annular structure 184 (not yet radially extended). The second retractable annular structure 185 and the third retractable annular structure 186 slide circumferentially together with the first radial slide rail 1841. After the first retractable annular structure 184 is fully unfolded, the first magnetic element is attracted to and attached to the third radial slide rail magnet 1861.

[0091] In this embodiment, refer to Figures 2-5 As shown, after the first retractable annular structure 184 is fully extended, if the outer diameter of the drill string 5 is to be further changed, the second magnetic component slides out along the first radial slide rail 1841, and the second retractable annular structure 185 and the third retractable annular structure 186 slide out together. At this time, the second retractable annular structure 185 and the third retractable annular structure 186 are still in a circumferential parallel state. The first magnetic component and the first radial slide rail 1841 are attached together under magnetic attraction. The first retractable circumferential slide rail 1842 is extended into an annular shape. One end of the second retractable annular structure 185, which is provided with the second radial slide rail 1851, can slide circumferentially along the first retractable circumferential slide rail 1842, thereby extending the second retractable annular structure 185 circumferentially. After the second retractable annular structure 185 is fully extended, the second magnetic component and the third radial slide rail 1861 are magnetically attached to each other. Similarly, the third retractable annular structure 186 can slide out along the second radial slide rail 1851. One end of the third retractable annular structure 186 with the third radial slide rail 1861 can slide circumferentially along the second retractable circumferential slide rail 1852. After the third retractable annular structure 186 is fully unfolded, the third magnetic component magnetically adheres to the third radial slide rail 1861.

[0092] In an optional implementation, refer to Figure 1As shown, the gas injection mechanism, used to simulate the process of formation gas entering the wellbore 7, specifically includes a gas storage tank 8, a gas delivery pipe 10, a first control valve 9, a first booster pump 11, and an injection tank 12. The gas storage tank 8 stores a gas sample containing hydrocarbon gases. The injection tank 12 connects to the bottom of the wellbore 7 and is annularly sealed to the wellbore 7. The gas delivery pipe 10 connects to both the injection tank 12 and the gas storage tank 8, allowing the gas sample from the gas storage tank 8 to be injected into the injection tank 12, and then enter the wellbore 7 through the injection tank 12 and return with the drilling fluid. The first control valve 9 is located at the outlet of the gas storage tank 8 and connected to the gas delivery pipe 10, used to control the opening and closing of the outlet of the gas storage tank 8. The first booster pump 11 is located in the middle of the gas delivery pipe 10, used to pump the gas from the gas storage tank 8 into the injection tank 12.

[0093] In an optional implementation, refer to Figure 1 and Figure 6 As shown, the gas injection tank 12 includes an inlet tank 121, an annular simulated rock layer 123, and a gas distributor 122. The annular simulated rock layer 123 is disposed within the inlet tank 121, and an annular gas injection chamber 124 is formed between the annular simulated rock layer 123 and the inlet tank 121. An inlet is provided on the side wall of the inlet tank 121, which is connected to the gas supply pipe 10. Gas from the gas supply pipe 10 can enter the annular gas injection chamber 124 through the inlet. Under the action of injection pressure, the gas in the annular gas injection chamber 124 enters the wellbore 7 through the pores of the annular simulated rock layer 123, realizing the simulation of the process of formation gas entering the wellbore 7 during actual drilling. The gas distributor 122 is disposed within the annular gas injection chamber 124 and is in close contact with the annular simulated rock layer 123, and is used to evenly distribute the gas sample entering through the inlet of the inlet tank 121 into the annular gas injection chamber 124.

[0094] In an optional embodiment, the gas distributor 122 has an annular mesh structure, with its inner wall tightly attached to the outer wall of the annular simulated rock layer 123. The mesh diameter of the gas distributor 122 can be set very small to prevent gas samples from partially accumulating within the annular injection chamber 124. The specific mesh diameter can be reasonably set according to the specifications of the annular injection chamber 124 and the porosity of the annular simulated rock layer 123. Furthermore, to prevent a large amount of gas sample from directly passing through the annular simulated rock layer 123 into the wellbore 7 under injection pressure, which would result in uneven injection of the gas sample into the wellbore 7, a baffle plate (not shown in the figure) is provided on the gas distributor 122 at a position opposite to the inlet. The baffle plate has no mesh, which helps the incoming gas diffuse to the surroundings, ensuring that the gas sample passes evenly through the annular simulated rock layer 123 from the annular injection chamber 124 into the wellbore 7. This ensures that the gas injection process accurately simulates the process of injection of formation gas into the wellbore 7.

[0095] In an optional implementation, refer to Figure 1As shown, the drilling fluid injection mechanism is used to inject drilling fluid into the drill string 5, and includes a storage tank 1, a delivery pipe 3, a second control valve 2, and a second booster pump 4. The storage tank 1 is used to prepare and / or store drilling fluid. The delivery pipe 3 is connected to the outlet of the storage tank 1 and the top inlet of the drill string 5, respectively, for delivering the prepared drilling fluid from the storage tank 1 into the drill string 5. The second control valve 2 is located at the outlet of the storage tank 1 and connected to the delivery pipe 3, for controlling the opening or closing of the outlet of the storage tank 1. The second booster pump 4 is located in the middle of the delivery pipe 3, for pumping the drilling fluid from the storage tank 1 into the drill string 5.

[0096] In an optional implementation, refer to Figure 1 As shown, the gas analysis unit is used to collect and analyze the hydrocarbon gas content in the drilling fluid returning from the wellbore 7. Specifically, it includes a degassing tank 13, a degasser 14, and a recovery tank 17. The degassing tank 13 is connected to the top outlet of the wellbore 7 and the inlet of the recovery tank 17. The degasser 14 is installed inside the degassing tank 13. After the drilling fluid returning from the annulus of the wellbore 7 enters the degassing tank 13, the degasser 14 degasses the drilling fluid and collects the degassed gas. The degassed drilling fluid enters the recovery tank 17 from the degassing tank 13 for recovery. Specifically, the recovery box 17 is located below the degassing tank 13. The inlet of the degassing tank 13 is located on the upper side wall of the degassing tank 13, and the outlet of the degassing tank 13 is located on the lower side wall of the degassing tank 13. The outlet and the inlet of the degassing tank 13 are located on the side walls of the degassing tank 13 at different locations. The degasser 14 is located in the middle of the degassing tank 13 to ensure that the drilling fluid enters the degassing tank 13 from the inlet, is degassed by the degasser 14, flows to the outlet of the degassing tank 13, and enters the recovery box 17 from the outlet.

[0097] In an optional implementation, refer to Figure 1 As shown, the gas analysis apparatus also includes a chromatograph 15 and an analysis display 16. The chromatograph 15 is connected to the degasser 14 and can analyze and detect the hydrocarbon gas content in the gas collected by the degasser 14. The chromatograph 15 is connected to the analysis display 16, and the analysis results of the chromatograph 15 are transmitted to and displayed on the analysis display 16.

[0098] In this embodiment of the invention, taking the annular component 18 as an example where the total number of the above-mentioned retractable annular structures 181 is three annular components 18, the specific process of conducting a gas logging experiment considering the change in wellbore annular volume using a gas logging experimental device that considers the change in wellbore annular volume may include:

[0099] The first gas logging experiment was conducted without deploying any annular structure, and the results of the first gas logging experiment were recorded.

[0100] The first retractable annular structure is deployed circumferentially along the fixed circumferential slide rail 183 with the drill string 5 as the center, so as to change the annular volume between the drill string 5 and the wellbore 7. After the first retractable annular structure is fully deployed, the second gas logging experiment is carried out and the results of the second gas logging experiment are recorded.

[0101] The second and third retractable annular structures are slid out along the first radial slide rail, and the second retractable annular structure is circumferentially unfolded along the first retractable annular slide rail with the drill string 5 as the center, so as to change the annular volume between the drill string 5 and the wellbore 7 again. After the second retractable annular structure is fully unfolded, the third gas logging experiment is carried out and the results of the third gas logging experiment are recorded.

[0102] The third retractable annular structure is slid out along the second radial slide rail, and the third retractable annular structure is circumferentially unfolded along the second retractable annular slide rail with the drill string 5 as the center. The annular volume between the drill string 5 and the wellbore 7 is changed for the third time. After the third retractable annular structure is fully unfolded, the fourth gas logging experiment is carried out and the results of the fourth gas logging experiment are recorded.

[0103] By comparing the results of four gas logging experiments, the influence of wellbore annular volume changes on hydrocarbon gas content was analyzed.

[0104] Furthermore, apart from the annular volume, the procedures and parameters of the four gas logging experiments were identical. The specific process of the gas logging experiment may include:

[0105] Drilling fluid is injected into the drill string 5 through the drilling fluid injection mechanism; specifically, the second control valve 2 is opened and the second booster pump 4 is started to deliver the drilling fluid prepared in the storage tank 1 into the drill string 5.

[0106] Gas samples are injected into the bottom of the wellbore 7 through a gas sample injection mechanism to simulate the process of formation gas passing through the wellbore 7. Specifically, the first control valve 9 is opened and the second booster pump 4 is started. The gas sample in the gas storage tank 8 is injected into the annular gas injection chamber 124 and then enters the wellbore 7 through the pores of the annular simulated rock layer 123 and returns with the drilling fluid.

[0107] The hydrocarbon gas content in the gas returning from the wellbore 7 is collected and analyzed by a gas analysis unit. Specifically, after the drilling fluid returning from the annulus of the wellbore 7 enters the degassing tank 13, the degasser 14 degasses the drilling fluid and collects the degassed gas. The degassed drilling fluid enters the recovery tank 17 from the degassing tank 13 for recovery. The chromatograph 15 analyzes and detects the hydrocarbon gas content in the gas collected by the degasser 14. The analysis and detection results are transmitted to the analysis display 16 and displayed on the analysis display 16.

[0108] Stop injecting gas samples and drilling fluid.

[0109] It should be noted that the results of the gas logging experiment are the hydrocarbon gas content in the drilling fluid returned to the wellbore 7.

[0110] Example 2

[0111] Based on the same inventive concept, this invention also provides a gas logging test method considering wellbore annular volume changes, using the gas logging test apparatus considering wellbore annular volume changes described in Embodiment 1, characterized in that it includes:

[0112] A retractable annular structure 181 is unfolded circumferentially around the drill string 5 to change the annular volume between the drill string 5 and the wellbore 7.

[0113] Drilling fluid is injected into the drill string 5 through the drilling fluid injection mechanism;

[0114] A gas sample is injected into the bottom of wellbore 7 using a gas sample injection mechanism;

[0115] The hydrocarbon gas content in the gas returning from the wellbore 7 is collected and analyzed by a gas analysis unit.

[0116] Stop injecting gas samples and drilling fluid;

[0117] The next retractable annular structure 181 is radially offset from the already circumferentially expanded retractable annular structure 181, and is circumferentially expanded with the drill string 5 as the center, so as to change the annular volume between the drill string 5 and the wellbore 7 again.

[0118] The gas sample and drilling fluid were re-injected, and the hydrocarbon gas content in the gas returned from the drilling fluid above the wellbore 7 was collected and analyzed.

[0119] The process of repeatedly unfolding the next stretchable annular structure 181 and collecting and analyzing the hydrocarbon gas content in the returning drilling fluid is repeated.

[0120] In this embodiment of the invention, the gas logging experiment method considering the change of wellbore annulus volume described above corresponds to the gas logging experiment device considering the change of wellbore annulus volume described in Embodiment 1. Its application process can refer to the process of carrying out the gas logging experiment considering the change of wellbore annulus volume using the gas logging experiment device considering the change of wellbore annulus volume described in Embodiment 1. Where it is repeated, it will not be described again.

[0121] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. This disclosure is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this disclosure is limited only by the appended claims. Thus, if these modifications and variations of the invention fall within the scope of the claims of the invention and their equivalents, the invention is also intended to include these modifications and variations.

Claims

1. A gas logging experimental apparatus considering changes in wellbore annulus volume, characterized in that, Includes drilling fluid injection mechanism, gas sample injection mechanism, gas testing and analysis mechanism, wellbore, drill bit, drill string and annular assembly; The drill string and the drill bit are axially connected vertically and are disposed inside the wellbore; The ring-shaped component includes at least two retractable ring-shaped structures that are sequentially and movably connected. The at least two retractable annular structures are disposed on the sidewall of the drill string; Each of the aforementioned retractable annular structures has a radial slide rail on one side. The retractable ring structure can slide radially along the radial slide rails at the side ends of adjacent retractable ring structures, so that each of the retractable ring structures can be radially offset. Each of the aforementioned retractable annular structures can expand and contract circumferentially around the drill string to change the annular volume between the drill string and the wellbore; The drilling fluid injection mechanism is connected to the inlet of the drill string; The gas injection mechanism is connected to the bottom of the wellbore; The gas analysis unit is connected to the top of the wellbore.

2. The gas logging experimental apparatus considering wellbore annular volume changes according to claim 1, characterized in that, The annular assembly also includes a fixed circumferential slide rail; The fixed circumferential slide rail is sleeved on the drill string; The at least two retractable ring structures are arranged sequentially along a preset direction; The retractable ring structure at the head end can slide and unfold along the fixed circumferential slide rail.

3. The gas logging experimental apparatus considering wellbore annular volume changes according to claim 2, characterized in that, Each of the aforementioned retractable annular structures is provided with a retractable circumferential slide rail at its radial end; The retractable circumferential slide rail can expand and contract circumferentially with the retractable annular structure; The rear retractable ring structure can slide and unfold along the retractable circumferential slide rail at the radial end of the front retractable ring structure.

4. The gas logging experimental apparatus considering wellbore annular volume changes according to claim 2, characterized in that, The rear retractable ring structure can slide along the radial slide rail at the side end of the front retractable ring structure.

5. The gas logging experimental apparatus considering wellbore annular volume changes according to claim 1, characterized in that, The radial slide rail is a magnet, and a magnetic element is provided on the other end of the retractable annular structure. When the retractable annular structure is in its circumferentially unfolded state, the radial slide rail and the magnetic component are magnetically attracted and attached.

6. The gas logging experimental apparatus considering wellbore annular volume changes according to claim 1, characterized in that, The gas injection mechanism includes a gas storage tank, a gas transmission pipe, a first control valve, a first booster pump, and a gas injection tank; The gas injection groove is connected to the bottom of the wellbore; The gas pipeline is connected to the gas injection tank and the gas storage tank respectively; The first control valve is located at the outlet of the gas storage tank and is connected to the gas transmission pipe; The first booster pump is installed in the gas pipeline.

7. The gas logging experimental apparatus considering wellbore annular volume changes according to claim 6, characterized in that, The gas injection tank includes an air inlet tank, an annular simulated rock layer, and a gas distributor; The annular simulated rock layer is disposed within the air intake groove, and an annular air injection cavity is formed between the annular simulated rock layer and the air intake groove; The gas distributor is disposed inside the annular gas injection chamber and is in close contact with the annular simulated rock layer; An air inlet is provided on the side wall of the air inlet slot, and the air inlet is connected to the air supply pipe.

8. The gas logging experimental apparatus considering wellbore annular volume changes according to claim 7, characterized in that, The gas distributor has a ring-shaped mesh structure; A baffle plate is provided at the position opposite to the air inlet of the gas distributor.

9. The gas logging experimental apparatus considering wellbore annular volume changes according to claim 1, characterized in that, The drilling fluid injection mechanism includes a storage tank, a delivery pipe, a second control valve, and a second booster pump; The infusion tubing is connected to the outlet of the storage tank and the inlet of the drill string, respectively. The second control valve is located at the outlet of the storage tank and connected to the infusion pipe; The second booster pump is installed in the infusion pipe.

10. The gas logging experimental apparatus considering wellbore annular volume changes according to claim 1, characterized in that, The gas analysis unit includes a degassing tank, a degasser, a chromatograph, an analysis display, and a recovery box; The degasser is disposed within the degassing tank; The degassing troughs are connected to the top of the wellbore and the recovery box, respectively; The chromatograph is connected to the degasser and the analysis display, respectively.

11. A gas logging test method considering wellbore annular volume variation, using the gas logging test apparatus considering wellbore annular volume variation as described in any one of claims 1-9, characterized in that, include: A retractable annular structure is unfolded circumferentially around the drill string to change the annular volume between the drill string and the wellbore. Drilling fluid is injected into the drill string through a drilling fluid injection mechanism; A gas sample is injected into the bottom of the wellbore using a gas sample injection mechanism; The hydrocarbon gas content in the gas returning from the wellbore is collected and analyzed by a gas analysis unit. Stop injecting gas samples and drilling fluid; The next retractable annular structure is radially offset from the already circumferentially unfolded retractable annular structure and is circumferentially unfolded with the drill string as the center, so as to change the annular volume between the drill string and the wellbore again. Re-inject gas samples and drilling fluid, and collect and analyze the hydrocarbon gas content in the gas returning from the wellbore; The process of repeatedly unfolding the next stretchable annular structure and collecting and analyzing the hydrocarbon gas content in the returning drilling fluid is repeated.

Images