Pressure-maintaining rock core ground temperature control device and under-pressure testing method

Abstract

The invention discloses a pressure-maintaining rock core ground temperature control device and an under-pressure testing method. In the device, a heat preservation and insulation bin is provided with an upper opening; the plurality of heating units are transversely laid at the lower part of the heat preservation and insulation bin; the circulating manifold surrounds the lower part of the heat insulation bin and is in heat conduction connection with the heating unit; the pipeline pump is communicated with the circulating manifold so as to pump the heat-conducting liquid in the circulating manifold for circulating flow; the injection valve is communicated with the circulating manifold in an openable and closable manner; the discharge valve is arranged at one end of the heat preservation and insulation bin and can be communicated with the circulating manifold in an openable and closable manner; the temperature control system is arranged at the other end of the heat preservation and insulation bin and connected with and controls the heating unit and the pipeline pump. A plurality of base brackets are distributed in the heat preservation and insulation bin to support a pressure-maintaining coring inner cylinder for accommodating a rock core; the heat preservation heating cover plate detachably covers the upper opening in a sealing mode, and the heat preservation heating cover plate comprises an injection port used for leading in liquid nitrogen and a discharge port used for discharging nitrogen. The device meets two different test requirements of oil reservoir core ultralow temperature freezing and gas reservoir core heating and gas collection.

Description

Technical Field

[0001] The present invention relates to the technical field of core detection, and in particular to a surface temperature control device for a pressure-maintaining core and a pressure testing method. Background Art

[0002] The pressure-maintaining coring technology can minimize the loss of components such as oil and gas in the core, and can accurately obtain important formation parameters such as reservoir fluid saturation under bottom hole conditions. It reflects the significant advantages of "maintaining oil and gas" in the actual application of natural gas hydrate and shale gas exploration. However, after obtaining the pressure-maintaining core, it is more important to use the core to test formation parameters such as oil and gas content and reservoir properties. Since the pressure-maintaining core is always sealed in the inner tube, its testing process has the particularity of carrying high pressure. At present, the ground processing method of the pressure-maintaining core mainly adopts the method of pressure analysis to directly collect gas for analysis and gas content determination. However, for oil reservoirs, this method is not effective, the gas content is low, and the release rate is slow. It is more suitable to freeze the core to quickly solidify the oil, gas and water components in the core in the core and then process it. However, there is currently no technology and equipment suitable for ground processing of pressure-maintaining coring in oil reservoirs. The above information disclosed in the background technology section is only used to enhance the understanding of the background of the present invention, and therefore may contain information that does not constitute the prior art known to ordinary technicians in the field. Summary of the invention

[0003] The purpose of the present invention is to provide a pressure-maintaining core ground temperature control device, that is, a pressure testing method, which can meet two different testing requirements of ultra-low temperature freezing of oil reservoir cores and heating and gas collection of gas reservoir cores, solve the problems of imperfect existing pressure-maintaining core ground processing equipment, high risk, and low gas analysis efficiency, and improve operational safety and operating efficiency.

[0004] In order to achieve the above object, the present invention provides the following technical solutions:

[0005] A surface temperature control device for a pressure-maintaining core of the present invention comprises:

[0006] A heat-insulating bin having an upper opening;

[0007] A plurality of heating units are horizontally laid at the lower part of the heat-insulating bin;

[0008] A circulation manifold, which surrounds the lower part of the thermal insulation bin and is thermally connected to the heating unit;

[0009] A pipeline pump connected to the circulation manifold to pump the heat transfer liquid in the circulation manifold for circulation;

[0010] An injection valve is provided at one end of the heat-insulating bin, and the injection valve can be opened and closed to connect to the circulation manifold;

[0011] A discharge valve is provided at one end of the heat-insulating bin, and the discharge valve can be opened and closed to be connected to the circulation manifold;

[0012] A temperature control system, which is arranged at the other end of the heat-insulating bin, and the temperature control system is connected to and controls the heating unit and the pipeline pump;

[0013] A plurality of base supports, which are distributed in the heat-insulating chamber to support a pressure-maintaining coring inner cylinder for accommodating the core;

[0014] The heat-insulating and heating cover plate is detachably sealed to cover the upper opening, and the heat-insulating and heating cover plate comprises an injection port for introducing liquid nitrogen and a discharge port for discharging nitrogen.

[0015] The pressure-maintaining core surface temperature control device further includes a liquid nitrogen source containing liquid nitrogen, which is connected to the injection port via a liquid nitrogen freezing pipeline.

[0016] In the pressure-maintaining core surface temperature control device, the interiors of the thermal insulation bin and the thermal insulation cover plate are filled with thermal insulation materials.

[0017] In the pressure-maintaining core surface temperature control device, the circulation manifold is serpentinely wrapped around the lower part of the thermal insulation bin.

[0018] In the pressure-maintaining core surface temperature control device, the thermal insulation cover plate is provided with a handle.

[0019] In the pressure-maintaining core surface temperature control device, the heat-insulating chamber is a hollow rectangular parallelepiped structure.

[0020] The pressure-maintaining core surface temperature control device also includes a temperature sensor for measuring the temperature of the heat-insulating chamber, which is connected to the temperature control system.

[0021] In the pressure-maintaining core surface temperature control device, a plurality of heating units are evenly distributed on the lower part and side walls of the thermal insulation bin.

[0022] A temperature control method of a pressure-maintaining core surface temperature control device comprises the following steps:

[0023] When the core in the pressure-maintaining coring inner barrel is a gas reservoir core, place the pressure-maintaining coring inner barrel on the base bracket in the thermal insulation bin; close the discharge valve, inject water into the thermal insulation bin through the water injection port, close the injection valve after the water injection is completed, start the temperature control system to heat the pressure-maintaining coring inner barrel, start the pipeline pump to pump the water in the thermal insulation bin to circulate in the circulation manifold for uniform heating, and after heating to the required temperature, switch to the insulation state to collect the gas content. After the gas collection is completed, close the temperature control system to stop heating, open the discharge valve to discharge the water, and complete the heating test;

[0024] When the core in the pressure-maintaining coring inner barrel is a reservoir core, place the pressure-maintaining coring inner barrel on the base bracket in the thermal insulation bin; drain the water in the circulation manifold, close the injection valve and the discharge valve, and cover the thermal insulation cover plate; connect the liquid nitrogen freezing pipeline to the injection port on the cover plate; open the liquid nitrogen tank, inject liquid nitrogen into the thermal insulation bin, and discharge it from the discharge port on the thermal insulation cover plate to freeze the core barrel.

[0025] In the above technical scheme, the present invention provides a ground temperature control device for pressure-maintained cores and a pressure testing method, which have the following beneficial effects: the ground temperature control device for pressure-maintained cores can integrate two different core processing processes and equipment, namely, freezing of oil reservoir cores and heating of gas reservoir pressure-maintained cores, into one, and adopts a water bath heating method to heat and precisely control the temperature of the pressure-maintained cores, thereby improving the gas analysis rate of the cores and the accuracy of gas content determination. At the same time, ultra-low temperature liquid nitrogen freezing of the pressure-maintained cores can be achieved, effectively preventing the escape and loss of oil and gas components in the cores, and improving the accuracy of oil and water saturation determination. The processing process can be selected according to the actual needs of the site, reducing the investment and cost of the test equipment, ensuring safe operation, and improving the efficiency of the ground processing operation of the cores. The ground temperature control device for pressure-maintained cores puts the pressure-maintained coring inner tube and the core as a whole into the heating or freezing process, and there is no process of opening the inner tube to take the core, so the oil and gas components in the core will not be lost to the outside, and are always in the pressure-maintained inner tube. When heated, the core is always in the inner tube, and the gas analysis rate and gas content determination accuracy of the core in the pressure-maintained state are improved by heating. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0027] Figure 1 A schematic structural diagram of a surface temperature control device for a pressure-maintaining core provided in an embodiment of the present invention.

[0028] Figure 2 A partial structural schematic diagram of a pressure-maintaining core surface temperature control device provided in an embodiment of the present invention.

[0029] Figure 3 A schematic structural diagram of a surface temperature control device for a pressure-maintaining core provided in an embodiment of the present invention.

[0030] Figure 4 A schematic structural diagram of a pressure-maintaining core surface temperature control device provided in an embodiment of the present invention is provided by inserting a pressure-maintaining coring inner barrel.

[0031] Figure 5A schematic diagram of the bottom structure of a pressure-maintaining core surface temperature control device provided in an embodiment of the present invention.

[0032] Figure 6 A schematic diagram of the structure of liquid nitrogen freezing of a pressure-maintaining core surface temperature control device provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0036] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0037] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0038] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0039] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0040] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0041] See also Figure 1-2 As shown, in one embodiment, a pressure-maintaining core surface temperature control device of the present invention includes:

[0042] A heat-insulating bin 2 having an upper opening;

[0043] A plurality of heating units 4 are horizontally laid at the lower part of the heat-insulating warehouse 2;

[0044] A circulation manifold 6, which surrounds the lower part of the heat-insulating bin 2 and is heat-conductingly connected to the heating unit 4;

[0045] A pipeline pump 5 connected to the circulation manifold 6 to pump the heat transfer liquid in the circulation manifold 6 for circulation;

[0046] An injection valve 7, which is disposed at one end of the heat-insulating bin 2, and the injection valve 7 can be opened and closed to connect to the circulation manifold 6;

[0047] A discharge valve 8, which is arranged at one end of the heat-insulating bin 2, and the discharge valve 8 can be opened and closed to connect to the circulation manifold 6;

[0048] A temperature control system 1 is provided at the other end of the heat-insulating bin 2, and the temperature control system 1 is connected to and controls the heating unit 4 and the pipeline pump 5;

[0049] A plurality of base supports 11, which are distributed in the heat-insulating bin 2 to support a pressure-maintaining coring inner barrel for accommodating the core;

[0050] The heat-insulating and heating cover plate is detachably sealed to cover the upper opening, and the heat-insulating and heating cover plate comprises an injection port 9 for introducing liquid nitrogen and a discharge port 10 for discharging nitrogen.

[0051] In a preferred embodiment of the pressure-maintaining core surface temperature control device, a liquid nitrogen source containing liquid nitrogen is further included, which is connected to the injection port 9 via a liquid nitrogen freezing pipeline.

[0052] In a preferred embodiment of the pressure-maintaining core surface temperature control device, the interiors of the thermal insulation bin 2 and the thermal insulation cover plate 3 are filled with thermal insulation materials.

[0053] In a preferred embodiment of the pressure-maintaining core surface temperature control device, the circulation manifold 6 is serpentinely wrapped around the lower part of the thermal insulation bin 2.

[0054] In a preferred embodiment of the pressure-maintaining core surface temperature control device, the circulation manifold 6 is serpentinely wrapped around the lower part of the thermal insulation bin 2 and serpentinely wrapped around the side wall of the thermal insulation bin 2 .

[0055] In a preferred embodiment of the pressure-maintaining core surface temperature control device, the thermal insulation cover plate 3 is provided with a handle.

[0056] In a preferred embodiment of the pressure-maintaining core surface temperature control device, the thermal insulation chamber 2 is a hollow rectangular parallelepiped structure.

[0057] In a preferred embodiment of the pressure-maintaining core surface temperature control device, it also includes a temperature sensor for measuring the temperature of the thermal insulation chamber 2, which is connected to the temperature control system 1.

[0058] In a preferred embodiment of the pressure-maintaining core surface temperature control device, a plurality of heating units 4 are evenly distributed on the lower part and side walls of the thermal insulation bin 2 .

[0059] In one embodiment, Figure 1As shown, a pressure-maintaining core ground processing device includes a water bath heating temperature control system 1, a heat-insulating bin 2, a heat-insulating cover plate 3, a heating unit 4, a pipeline pump 5 and a circulation manifold 6. The water bath heating temperature control system 1 is installed at one end of the heat-insulating bin 2, and is used to control the start and stop of the heating unit 4 and the pipeline pump 5. A plurality of heating units 4 are laid horizontally at the lower part of the heat-insulating bin 2, and the clean water in the heat-insulating bin 2 can be heated. A plurality of base brackets 11 are distributed at the bottom of the heat-insulating bin 2. When the pressure-maintaining coring inner tube is heated or frozen, the coring inner tube is placed on the bracket and covered with the heat-insulating cover plate 3 to play a role in heat preservation and heat insulation. An injection valve 7 and a discharge valve 8 are provided at the other end of the heat-insulating bin 2. Clean water can be injected into the heat-insulating bin 2 through the injection valve 7. When the clean water is injected, the injection valve 7 is opened and the discharge valve 8 is closed. After the clean water is filled, the injection valve 7 is closed. The discharge valve 8 is connected to the circulation manifold 6. After the water bath heating is completed, the discharge valve 8 discharges the clean water. A circulation manifold 6 surrounds the lower part of the thermal insulation bin 2, and the clean water in the thermal insulation bin 2 can be continuously pumped and circulated by the pipeline pump 5 to achieve a uniform heating effect.

[0060] Liquid nitrogen injection ports 9 and discharge ports 10 are provided at both ends of the thermal insulation cover plate 3. When performing liquid nitrogen freezing, first drain the liquid in the thermal insulation bin 2 and the circulation manifold 6, and ensure that the injection valve 7 and the discharge valve 8 are closed. Connect the liquid nitrogen freezing pipeline to the injection port 9 on the cover plate, inject liquid nitrogen into the thermal insulation bin, and discharge it from the discharge port 10 on the cover plate to achieve freezing of the pressure-maintaining coring inner barrel. The thermal insulation bin 2 and the thermal insulation cover plate 3 are filled with thermal insulation materials to ensure that heat transfer and loss are reduced during heating or freezing.

[0061] A temperature control method of a pressure-maintaining core surface temperature control device comprises the following steps:

[0062] Identify whether the core in the pressure-maintaining coring inner barrel is an oil reservoir core or a gas reservoir core;

[0063] When it is identified that the core in the pressure-maintaining coring inner tube is a gas reservoir core, the pressure-maintaining coring inner tube is placed on the base bracket 11 in the thermal insulation bin 2; the discharge valve 8 is closed, and water is injected into the thermal insulation bin 2 through the water injection port. After the water injection is completed, the injection valve 7 is closed, and the temperature control system 1 is started to heat the pressure-maintaining coring inner tube, and the pipeline pump 5 is started to pump the water in the thermal insulation bin 2 to circulate in the circulation manifold 6 for uniform heating. After heating to the required temperature, it is switched to the heat preservation state to collect the gas content. After the gas collection is completed, the temperature control system 1 is closed to stop heating, and the discharge valve 8 is opened to discharge the water to complete the heating test;

[0064] When it is identified that the core in the pressure-maintaining coring inner barrel is a reservoir core, the pressure-maintaining coring inner barrel is placed on the base bracket 11 in the thermal insulation bin 2; the water in the circulation manifold 6 is drained, the injection valve 7 and the discharge valve 8 are closed, and the thermal insulation cover plate 3 is covered; the liquid nitrogen freezing pipeline is connected to the injection port 9 on the cover plate; the liquid nitrogen tank is opened, and liquid nitrogen is injected into the thermal insulation bin 2, and discharged from the discharge port 10 on the thermal insulation cover plate 3 to achieve freezing of the core barrel.

[0065] In one embodiment, the pressure-maintaining coring inner barrel is placed in the heat-insulating bin 2; the discharge valve 8 is closed, and clean water is injected into the heat-insulating bin 2 through the water injection port. After the water injection is completed, the injection valve 7 is closed. The temperature control system 1 is started to heat the pressure-maintaining coring inner barrel in a water bath; the pipeline pump 5 is started to heat the heat-insulating bin 2 evenly. After heating to the required temperature, it is switched to the heat-insulating state to collect the gas content. After the gas collection is completed, the control system is closed to stop heating, and the discharge valve 8 is opened to complete the heating test.

[0066] In one embodiment, the pressure-maintaining inner barrel is placed in the thermal insulation bin 2; the liquid in the thermal insulation bin 2 and the circulation manifold 6 is drained, the injection valve 7 and the discharge valve 8 are closed, and the thermal insulation cover plate 3 is covered. The liquid nitrogen freezing pipeline is connected to the injection port 9 on the cover plate; the valve of the liquid nitrogen tank is opened, and liquid nitrogen is injected into the thermal insulation bin, and discharged from the discharge port 10 on the cover plate to achieve freezing of the core barrel.

[0067] Finally, it should be noted that the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making any creative work are within the scope of protection of the present application.

[0068] The above description is only by way of illustration of certain exemplary embodiments of the present invention. It is undoubted that those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A surface temperature control device for a pressure-maintaining core, characterized in that: These include, A heat-insulating bin having an upper opening; A plurality of heating units are horizontally laid at the lower part of the heat-insulating bin; A circulation manifold, which surrounds the lower part of the thermal insulation bin and is thermally connected to the heating unit; A pipeline pump connected to the circulation manifold to pump the heat transfer liquid in the circulation manifold for circulation; An injection valve is provided at one end of the heat-insulating bin, and the injection valve can be opened and closed to connect to the circulation manifold; A discharge valve is provided at one end of the heat-insulating bin, and the discharge valve can be opened and closed to be connected to the circulation manifold; A temperature control system, which is arranged at the other end of the heat-insulating bin, and the temperature control system is connected to and controls the heating unit and the pipeline pump; A plurality of base supports, which are distributed in the heat-insulating chamber to support a pressure-maintaining coring inner cylinder for accommodating the core; The heat-insulating and heating cover plate is detachably sealed to cover the upper opening, and the heat-insulating and heating cover plate comprises an injection port for introducing liquid nitrogen and a discharge port for discharging nitrogen.

2. A surface temperature control device for a pressure-maintaining core according to claim 1, characterized in that: Also included is a liquid nitrogen source containing liquid nitrogen, which is connected to the injection port via a liquid nitrogen freezing pipeline.

3. A surface temperature control device for a pressure-maintaining core according to claim 1, characterized in that: The interior of the thermal insulation bin and the thermal insulation cover plate are filled with thermal insulation materials.

4. A surface temperature control device for a pressure-maintaining core according to claim 1, characterized in that: The thermal insulation cover plate is provided with a handle.

5. A surface temperature control device for a pressure-maintaining core according to claim 1, characterized in that: The thermal insulation warehouse is a hollow rectangular structure.

6. A surface temperature control device for a pressure-maintaining core according to claim 1, characterized in that: It also includes a temperature sensor for measuring the temperature of the heat-insulating warehouse, which is connected to the temperature control system.

7. A surface temperature control device for a pressure-maintaining core according to claim 1, characterized in that: A plurality of heating units are evenly distributed on the lower part and side walls of the thermal insulation bin.

8. A temperature control method for a surface temperature control device for a pressure-maintaining core according to any one of claims 1 to 7, characterized in that: It includes the following steps, When the core in the pressure-maintaining coring inner barrel is a gas reservoir core, place the pressure-maintaining coring inner barrel on the base bracket in the thermal insulation bin; close the discharge valve, inject water into the thermal insulation bin through the water injection port, close the injection valve after the water injection is completed, start the temperature control system to heat the pressure-maintaining coring inner barrel, start the pipeline pump to pump the water in the thermal insulation bin to circulate in the circulation manifold for uniform heating, and after heating to the required temperature, switch to the insulation state to collect the gas content. After the gas collection is completed, close the temperature control system to stop heating, open the discharge valve to discharge the water, and complete the heating test; When the core in the pressure-maintaining coring inner barrel is a reservoir core, place the pressure-maintaining coring inner barrel on the base bracket in the thermal insulation bin; drain the water in the circulation manifold, close the injection valve and the discharge valve, and cover the thermal insulation cover plate; connect the liquid nitrogen freezing pipeline to the injection port on the cover plate; open the liquid nitrogen tank, inject liquid nitrogen into the thermal insulation bin, and discharge it from the discharge port on the thermal insulation cover plate to freeze the core barrel.

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