Delivery tracer capsule and use method thereof

Abstract

The invention discloses a delivery tracer capsule and a use method thereof, and belongs to the technical field of dynamic monitoring of oil field production. According to the delivery tracer capsule and the using method thereof, the solid tracer and the powerful magnet particles are gathered in the capsule body, the tracer can be put in a target layer on the premise that a shaft is not polluted, a tracer base of an operation well is accurately extracted, the phenomenon that in the injection process of a common tracer, base recording is inaccurate, and the accuracy of the tracer is improved is effectively avoided. And whether plugging succeeds cannot be judged. Whether the casing damage plugging well is successfully plugged or not can be accurately judged, and data support is provided for next measures of the oil producing well.

Description

Technical Field

[0001] The invention belongs to the technical field of oil field production dynamic monitoring, and in particular relates to a deferred tracer capsule and a use method thereof. Background Art

[0002] Tracer monitoring technology is widely used in the dynamic analysis of injection and production well groups, and can effectively determine the connectivity relationship. Generally speaking, the tracer inter-well monitoring technology is to inject one or more water-soluble tracers in the injection wells in general or in layers, take samples from the surrounding expected connected oil wells, analyze the concentration of tracers in the water samples, draw the tracer production curve according to the test results, and use the tracer interpretation software to fit and analyze the tracer production curve, interpret the reservoir parameters, and thus obtain the heterogeneity of the reservoir.

[0003] With the development of fracturing technology, tracers are used in fracturing wells to determine the degree of crack closure. In multi-stage fracturing operations, different tracers are usually injected into the fracturing fluid in steps to be injected into different fracturing layers. The tracers enter the cracks with the fracturing fluid for seepage. After the fracturing construction is completed, the tracer will be returned along with the fracturing fluid and the subsequent well production. The tracer concentration data is sampled regularly on the ground. By classifying and testing the tracer samples contained in the produced fluid and measuring the concentration, the relationship curve of the tracer return concentration over time can be obtained. The return concentration curve is often used to evaluate the return efficiency, cleaning efficiency and liquid production contribution rate of the fracturing fluid. At the same time, since different characteristic parameters of the post-fracturing fracture will lead to different tracer return concentration curves, the tracer return concentration curve also contains the parameter characteristics of the post-fracturing fracture to a certain extent. By analyzing the tracer flowback curve, the fracture morphology after fracturing can be obtained through corresponding theoretical research and practical field application, and the fracture-related parameters can be obtained and the production capacity can be calculated. It can be used to evaluate various fracturing parameters (physical parameters of the fracturing section, mechanical parameters of the fracturing section), guide reservoir evaluation, geological design, fracturing design and the design of a reasonable working system. As for the use of tracers, such as the patent CN202011005732.1, after the tracer is dissolved, it is injected into the formation, injected from the injection well, and produced from the production well to monitor the connectivity between wells. CN201910645239.7, its purpose is to prevent the entire process of transportation, packaging and use from being sealed and there is no secondary contamination.

[0004] However, for old oil fields that have been developed for many years, many wells have casing damage due to the long time the casing has been in the well. The occurrence of casing damage is the result of the combined effects of physical and chemical factors. It is manifested as the casing of oil and water wells being subjected to external forces or corrosion during the development process, resulting in plastic deformation, rupture or corrosion perforation. Water outflow from the casing damage point will cause violent flooding of the oil well, seriously restricting the normal production of the oil well. In order to ensure the normal production of the oil well, cement squeeze and packer are usually used to plug the casing damage point, but it is impossible to judge whether the plugging is successful. Summary of the invention

[0005] In order to overcome the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a deferred tracer capsule and a method of using the same, so as to solve the technical problem that it is impossible to accurately judge whether the plugging is successful during oil production.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] The present invention discloses a deferred tracer capsule, comprising a solid tracer 2, strong magnetic particles 3 and a capsule body 1. The solid tracer 2 and the strong magnetic particles 3 are mixed and gathered in the capsule body 1, and the volume ratio of the solid tracer 2 to the strong magnetic particles 3 is 2:1 to 3:1.

[0008] Furthermore, the capsule body 1 dissolves at the target layer temperature within 5 to 7 days to release the solid tracer 2 in the capsule body 1 .

[0009] Furthermore, the temperature of the target layer is 100-120°C.

[0010] Furthermore, the temperature of the target layer is 60-70°C.

[0011] The present invention also discloses a method for using the above-mentioned delayed tracer capsule, comprising the following steps:

[0012] The deferred tracer capsule is placed between the double packers 4 so that the deferred tracer capsule 1 is adsorbed on the pipe string between the double packers 4 and then lowered into the well together to plug the casing damage layer.

[0013] Furthermore, there are multiple deferred tracer capsules placed between the double packers 4.

[0014] Furthermore, after the delayed tracer capsule dissolves in the well, if the water content of the plugged casing damaged oil production well increases, the tracer content is detected through the wellhead to determine whether the double seal plugging has failed.

[0015] Furthermore, the temperature of the damaged layer of the plugging sleeve is 110°C.

[0016] Furthermore, the double packer 4 is located between the oil pipe 5 and the casing 6 in the well.

[0017] Furthermore, the double packer 4 is located above the casing perforation 7 .

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The present invention discloses a deferred tracer capsule, which gathers solid tracer and strong magnet particles in the capsule body, and can put the tracer in the target layer without polluting the wellbore, accurately extract the tracer base of the working well, and effectively prevent the inaccurate base recording caused by the injection of ordinary tracers, and cannot judge whether the plugging is successful. The deferred tracer capsule is put into the double seal plugging casing damage position, and after a period of time, the capsule dissolves and gathers between the double seals. If the water content of the plugged casing damage oil production well suddenly increases, the tracer content can be detected by the wellhead to determine whether the double seal plugging fails.

[0020] The present invention also discloses a method for using the above-mentioned deferred tracer capsule, wherein strong magnetic particles are mixed into the capsule tracer, and the capsule tracer is strongly adsorbed on the pipe string between the double seals on the ground. When the pipe string is lowered into the well, the capsule tracer is lowered into the well together with the pipe string, and then accurately lowered into a determined position between the double seals. Whether the double seal plugging has failed can be determined by detecting the tracer content at the wellhead. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the structure of the delayed tracer capsule of the present invention;

[0022] Figure 2 It is a schematic diagram of the state of the delayed tracer capsule of the present invention when in use;

[0023] Figure 3 A flow chart of the use of the deferred tracer capsule of the present invention;

[0024] Among them: 1-capsule body; 2-solid tracer; 3-strong magnetic particles; 4-double packer; 5-oil pipe; 6-casing; 7-casing perforation. DETAILED DESCRIPTION

[0025] In order to enable those skilled in the art to understand the characteristics and effects of the present invention, the following is a general description and definition of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used in the text are the common meanings understood by those skilled in the art for the present invention. In the event of a conflict, the definition in this specification shall prevail.

[0026] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0027] Herein, all features such as values, quantities, contents and concentrations defined in the form of numerical ranges or percentage ranges are for simplicity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered to have included and specifically disclosed all possible secondary ranges and individual values ​​within the range (including integers and fractions).

[0028] In this document, in order to make the description concise, not all possible combinations of various technical features in various embodiments or examples are described. Therefore, as long as there is no contradiction in the combination of these technical features, the various technical features in various embodiments or examples can be combined arbitrarily, and all possible combinations should be considered to be within the scope of this specification.

[0029] like Figure 1 As shown, the present invention provides a delayed tracer capsule, comprising a solid tracer 2, strong magnetic particles 3 and a capsule body 1, wherein the solid tracer 2 and the strong magnetic particles 3 are mixed and aggregated inside.

[0030] When in use, the capsule body 1 can be dissolved in 5-7 days at the target layer temperature according to the temperature of the oil and gas reservoir, and the solid tracer 2 in the capsule body 1 can be released.

[0031] At the same time, the strong magnetic particles 3 in the capsule body 1 can be adsorbed on the pipe string between the double packers 4 before being put into use, and then lowered into the well together with the pipe string, and then accurately lowered into the determined position between the double packers.

[0032] When in use, the deferred tracer capsule of the present invention does not enter the formation, but is always between the double packers 4, and its main purpose is to monitor whether the packers are invalid. It can accurately judge whether the casing damage plugging well is successfully plugged, and provide data support for the next step of the oil production well.

[0033] like Figure 2 As shown, the deferred tracer capsule is located between the double packers 4 when in use. The double packers 4 are located between the oil pipe 5 and the casing 6 in the well and are located in the casing damage plugging layer. At the same time, the double packers 4 are located above the casing perforations 7.

[0034] like Figure 3 As shown, the present invention also discloses a method for using the above-mentioned delayed tracer capsule. The delayed tracer capsule disclosed in the present invention is proposed for determining whether the double seal plugging fails, and includes the following steps:

[0035] S1: firstly, placing the deferred tracer capsule 1 between the double packers 4;

[0036] S2: Subsequently, due to the action of the strong magnetic particles 3, the tracer capsule 1 is adsorbed on the pipe string between the double packers 4;

[0037] S3: Then it is lowered into the well to plug the damaged casing layer;

[0038] S4: Due to the dissolution effect of the capsule body 1, if the water content of the plugged casing damaged oil production well increases, the tracer content is detected through the wellhead to determine whether the double seal plugging fails.

[0039] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0040] The present invention discloses a deferred tracer capsule, comprising a solid tracer 2, strong magnetic particles 3 and a capsule body 1. The solid tracer 2 and the strong magnetic particles 3 are mixed and gathered in the capsule body 1, and the volume ratio of the solid tracer 2 to the strong magnetic particles 3 is 2:1 to 3:1.

[0041] Preferably, the capsule body 1 dissolves at the target layer temperature within 5 to 7 days to release the solid tracer 2 in the capsule body 1 .

[0042] Preferably, the capsule body 1 dissolves the target layer at a temperature of 100-120°C.

[0043] Preferably, the capsule body 1 dissolves in the target layer at a temperature of 60-70°C.

[0044] A method for using a deferred tracer capsule comprises the following steps:

[0045] The solid tracer 2 and the strong magnet particles 3 are mixed in a mass ratio of 2:1 and then aggregated in the capsule body 1 to obtain a deferred tracer capsule.

[0046] Then, the obtained multiple deferred tracer capsules are placed between the double packers 4, so that the deferred tracer capsules 1 are adsorbed on the pipe string between the double packers 4, and then they are lowered into the well together to plug the casing damage layer;

[0047] After the deferred tracer capsule 1 is dissolved in the well, if the water content of the plugged casing damaged oil production well increases, the tracer content is detected through the wellhead to determine whether the double seal plugging fails.

[0048] Example 1

[0049] A method for using a deferred tracer capsule comprises the following steps:

[0050] The deferred tracer capsule 1 is placed between the double packers 4 so that the deferred tracer capsule 1 is adsorbed on the pipe string between the double packers 4 and then lowered into the well together to plug the casing damage layer.

[0051] Example 2

[0052] A method for using a deferred tracer capsule comprises the following steps:

[0053] As a preferred embodiment, the deferred tracer capsule 1 is placed between the double packers 4 so that the deferred tracer capsule 1 is adsorbed on the tubing between the double packers 4 and then lowered into the well together to plug the damaged casing layer. In this embodiment, a plurality of deferred tracer capsules 1 are placed between the double packers 4.

[0054] Example 3

[0055] A method for using a deferred tracer capsule comprises the following steps:

[0056] As a preferred embodiment, the deferred tracer capsule 1 is placed between the double packers 4 so that the deferred tracer capsule 1 is adsorbed on the pipe string between the double packers 4 and then lowered into the well together to plug the damaged casing layer. In this embodiment, eight deferred tracer capsules 1 are placed between the double packers 4.

[0057] Example 4

[0058] A method for using a deferred tracer capsule comprises the following steps:

[0059] As a preferred embodiment, in this embodiment, the deferred tracer capsule 1 is placed between the double packers 4, so that the deferred tracer capsule 1 is adsorbed on the pipe string between the double packers 4, and then lowered into the plugging casing damage layer in the well. The temperature of the plugging casing damage layer is 100°C; after 5 days, the capsule body 1 dissolves.

[0060] Example 5

[0061] As a preferred embodiment, the deferred tracer capsule 1 is placed between the double packers 4, so that the deferred tracer capsule 1 is adsorbed on the pipe string between the double packers 4, and then lowered into the well together to plug the casing damage layer. In this embodiment, the double packer 4 is located between the oil pipe 5 and the casing 6 in the well, and the double packer 4 is located above the casing perforation 7.

[0062] Example 6

[0063] As a preferred embodiment, the deferred tracer capsule 1 is placed between the double packers 4 so that the deferred tracer capsule 1 is adsorbed on the pipe string between the double packers 4 and then lowered into the plugging casing damage layer in the well. In this embodiment, the temperature of the plugging casing damage layer is 119°C.

[0064] Example 7

[0065] As a preferred embodiment, the deferred tracer capsule 1 is placed between the double packers 4 so that the deferred tracer capsule 1 is adsorbed on the pipe string between the double packers 4 and then lowered into the plugging casing damage layer in the well. In this embodiment, the temperature of the plugging casing damage layer is 109°C.

[0066] Example 8

[0067] As a preferred embodiment, the deferred tracer capsule 1 is placed between the double packers 4, so that the deferred tracer capsule 1 is adsorbed on the pipe string between the double packers 4, and then lowered into the plugging casing damage layer in the well together. In this embodiment, the volume ratio of the solid tracer 2 and the strong magnet particles 3 is 3:1.

[0068] Example 9

[0069] As a preferred embodiment, the deferred tracer capsule 1 is placed between the double packers 4, so that the deferred tracer capsule 1 is adsorbed on the pipe string between the double packers 4, and then lowered into the plugging casing damage layer in the well together. In this embodiment, the volume ratio of the solid tracer 2 and the strong magnet particles 3 is 1.5:1.

[0070] Example 10

[0071] As a preferred embodiment, the deferred tracer capsule 1 is placed between the double packers 4, so that the deferred tracer capsule 1 is adsorbed on the pipe string between the double packers 4, and then lowered into the plugging casing damaged layer in the well together. In this embodiment, the volume ratio of the solid tracer 2 and the strong magnet particles 3 is 1.8:1.

[0072] Embodiment 11

[0073] As a preferred embodiment, the deferred tracer capsule 1 is placed between the double packers 4, so that the deferred tracer capsule 1 is adsorbed on the pipe string between the double packers 4, and then lowered into the plugging casing damage layer in the well together. In this embodiment, the volume ratio of the solid tracer 2 and the strong magnet particles 3 is 1.9:1.

[0074] Example 12

[0075] As a preferred embodiment, the deferred tracer capsule 1 is placed between the double packers 4, so that the deferred tracer capsule 1 is adsorbed on the pipe string between the double packers 4, and then lowered into the plugging casing damage layer in the well together. In this embodiment, after the deferred tracer capsule is dissolved in the well, if the water content of the plugging casing damage oil well increases, the tracer content is detected by the wellhead to determine whether the double seal plugging has failed.

[0076] Embodiment 13

[0077] As a preferred embodiment, the deferred tracer capsule 1 is placed between the double packers 4 so that the deferred tracer capsule 1 is adsorbed on the pipe string between the double packers 4 and then lowered into the plugging casing damage layer in the well. In this embodiment, the temperature of the plugging casing damage layer is 50°C.

[0078] Embodiment 14

[0079] As a preferred embodiment, the deferred tracer capsule 1 is placed between the double packers 4 so that the deferred tracer capsule 1 is adsorbed on the pipe string between the double packers 4 and then lowered into the plugging casing damage layer in the well. In this embodiment, the temperature of the plugging casing damage layer is 55°C.

[0080] Embodiment 15

[0081] As a preferred embodiment, the deferred tracer capsule 1 is placed between the double packers 4 so that the deferred tracer capsule 1 is adsorbed on the pipe string between the double packers 4 and then lowered into the plugging casing damage layer in the well. In this embodiment, the temperature of the plugging casing damage layer is 58°C.

[0082] Example 16

[0083] As a preferred embodiment, the deferred tracer capsule 1 is placed between the double packers 4 so that the deferred tracer capsule 1 is adsorbed on the pipe string between the double packers 4 and then lowered into the plugging casing damage layer in the well. In this embodiment, the temperature of the plugging casing damage layer is 60°C.

[0084] Embodiment 17

[0085] As a preferred embodiment, the deferred tracer capsule 1 is placed between the double packers 4 so that the deferred tracer capsule 1 is adsorbed on the pipe string between the double packers 4 and then lowered into the plugging casing damage layer in the well. In this embodiment, the temperature of the plugging casing damage layer is 110°C.

[0086] Embodiment 18

[0087] As a preferred embodiment, the deferred tracer capsule 1 is placed between the double packers 4, so that the deferred tracer capsule 1 is adsorbed on the pipe string between the double packers 4, and then lowered into the plugging casing damage layer in the well together. In this embodiment, the temperature of the plugging casing damage layer is 110°C, and the number of the deferred tracer capsules 1 is eight.

[0088] The present invention gathers the tracer in the capsule to form a deferred tracer, which can be placed in the target layer without polluting the wellbore, accurately extract the tracer base of the operating well, and effectively prevent the inaccurate base recording during the injection of ordinary tracers, and fail to judge whether the plugging is successful. 2. The deferred tracer is placed in the double seal plugging casing damage position. After a period of time, the capsule dissolves and gathers between the double seals. If the water content of the plugged casing damage oil production well suddenly increases, the tracer content can be detected at the wellhead to determine whether the double seal plugging has failed.

[0089] The capsule used in the present invention has the characteristic of slow dissolution. It can be dissolved in 5-7 days at the target layer temperature according to the oil and gas reservoir temperature, and release the solid tracer 2 in the capsule.

[0090] The present invention requires that the deferred tracer capsule be accurately placed between the double seals, so strong magnetic particles 3 are mixed into the solid tracer 2, and the deferred tracer capsule is strongly adsorbed on the pipe string between the double seals through the strong magnetic particles 3 on the ground. When the deferred tracer capsule is lowered into the well along with the pipe string, it is accurately lowered into the determined position between the double seals.

[0091] According to the temperature of the target layer under the oil well conditions in different regions, the capsule body of the deferred tracer capsule disclosed in the present invention can be selectively applied to meet the temperature of the target layer under the oil well conditions and can be dissolved at a specific time.

[0092] The deferred tracer capsule disclosed in the present invention does not enter the formation, but is always between the double seals, and its main purpose is to monitor whether the packer fails.

[0093] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A deferred tracer capsule, characterized in that: The invention comprises a solid tracer (2), strong magnetic particles (3) and a capsule body (1). The solid tracer (2) and the strong magnetic particles (3) are mixed and then gathered in the capsule body (1). The volume ratio of the solid tracer (2) and the strong magnetic particles (3) is 2:1 to 3:

1.

2. A delayed tracer capsule according to claim 1, characterized in that: The capsule body (1) dissolves at the target layer temperature within 5 to 7 days, releasing the solid tracer (2) in the capsule body (1).

3. A delayed tracer capsule according to claim 2, characterized in that: The temperature of the target layer is 100-120°C.

4. A delayed tracer capsule according to claim 3, characterized in that: The temperature of the target layer is 60-70°C.

5. The method for using the delayed tracer capsule according to any one of claims 1 to 4, characterized in that: The following steps are involved: The deferred tracer capsule is placed between the double packers (4), so that the deferred tracer capsule (1) is adsorbed on the pipe string between the double packers (4), and then lowered into the well together to plug the damaged casing layer.

6. The method for using a delayed tracer capsule according to claim 5, characterized in that: There are multiple deferred tracer capsules placed between the double packers (4).

7. The method for using a delayed tracer capsule according to claim 5, characterized in that: When the deferred tracer capsule dissolves in the well, if the water content of the plugged casing damaged oil production well increases, the tracer content is tested at the wellhead to determine whether the double seal plugging has failed.

8. The method for using a delayed tracer capsule according to claim 5, characterized in that: The temperature of the damaged layer of the plugging sleeve is 110°C.

9. The method for using a delayed tracer capsule according to claim 5, characterized in that: The double packer (4) is located between the oil pipe (5) and the casing (6) in the well.

10. The method for using a delayed tracer capsule according to claim 9, characterized in that: The double packer (4) is located above the casing perforation (7).

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