CN117803370A - Method for monitoring lateral closure of fault of underground gas storage - Google Patents

Abstract

This application discloses a method for monitoring the lateral sealing properties of underground gas storage faults, which includes the following steps: a monitoring well acquisition step; a monitoring well modification step; a pressure monitoring device setting step and a lateral sealing judgment step. The above-mentioned monitoring method for fault lateral sealing of underground gas storage can be used to screen, transform and utilize abandoned wells around the boundary faults of underground gas storage. It can not only monitor the lateral sealing of faults of underground gas storage through abandoned wells Monitoring is not only simple, but also improves the operability of the monitoring method. In addition, through the secondary use of abandoned wells around the boundary faults of underground gas storage, it avoids the need for greater capital investment in the construction of new monitoring wells. , which can greatly reduce the cost of monitoring the fault lateral sealing of underground gas storage.

Description

A monitoring method for fault lateral sealing of underground gas storage

Technical field

This application belongs to the field of natural gas underground gas storage monitoring technology, and particularly relates to a method for monitoring the lateral sealing of faults in underground gas storages.

Background technique

Underground gas storage is an artificial gas reservoir formed by re-injecting natural gas into underground space. It has the characteristics of large storage capacity, economic rationality and durability. The construction of underground gas storage has a history of hundreds of years. According to statistics, about 30% of underground gas storage accidents are caused by the failure of fault sealing. Therefore, it is very important to study the sealing of faults.

The construction of underground gas storage in my country is mostly aimed at depleted sandstone gas reservoirs located in the eastern structurally complex areas. Their sealing performance is greatly affected by fault structures, making demonstration difficult. For this type of underground gas storage, the traditional fault tightness evaluation method has poor operability.

It should be noted that the information disclosed in the above background section is only used to enhance understanding of the background of the present disclosure, and therefore may include information that does not constitute prior art known to those of ordinary skill in the art.

Contents of the invention

This application aims to solve, at least to a certain extent, the technical problem of poor operability of traditional fault tightness evaluation methods. To this end, this application provides a method for monitoring the lateral sealing properties of underground gas storage faults.

The embodiment of the present application provides a method for monitoring the lateral sealing property of a fault in an underground gas storage reservoir, and the method for monitoring the lateral sealing property of a fault in an underground gas storage reservoir comprises the following steps:

The monitoring well acquisition step is to acquire abandoned wells located outside the boundary fault of the underground gas storage and within a preset range, and select target monitoring wells from the abandoned wells according to the screening conditions;

Monitoring well modification step: modify the target monitoring well so that the target monitoring well includes a vertical monitoring well section and a horizontal monitoring well section, and the bottom end of the vertical monitoring well section is located in the underground gas storage In the formation of the library, the horizontal monitoring well section extends horizontally from the bottom end of the vertical monitoring well section to the boundary fault, and the end point of the horizontal monitoring well section has a first distance from the boundary fault; in A vertical monitoring pipe is provided in the vertical monitoring well section and a vertical annular channel is formed between the vertical monitoring pipe and the vertical monitoring well section. A vertical monitoring pipe is provided in the horizontal and vertical monitoring well section. A horizontal monitoring pipe is connected to the vertical monitoring pipe and forms a horizontal annular channel between the horizontal monitoring pipe and the horizontal monitoring well section. The end point of the horizontal monitoring pipe is connected to the end of the horizontal and vertical monitoring well section. There are packers between the well walls;

The pressure monitoring device setting step is to set a first pressure monitoring device at the end of the horizontal monitoring pipe, and the first monitoring line connected to the first pressure monitoring device extends through the horizontal monitoring pipe and the vertical monitoring pipe to The wellhead of the target monitoring well; a second pressure monitoring device is provided in the horizontal annular channel, and the well wall of the horizontal monitoring well section corresponding to the second pressure monitoring device is perforated, and the The second monitoring line connected to the second pressure monitoring device extends to the wellhead of the monitoring well through the horizontal annular channel and the vertical annular channel; and,

In the step of judging the lateral sealability of the fault, the pressure monitoring and control device determines whether the boundary fault is based on the first pressure monitoring value obtained in real time by the first pressure monitoring device and the second pressure monitoring value obtained in real time by the second pressure monitoring device. Has a closed nature.

In some embodiments, the screening conditions include at least the integrity of the abandoned well and the renovation budget of the abandoned well.

In some embodiments, the screening conditions also include ground monitoring conditions of the abandoned well.

In some embodiments, the first distance is 40m˜60m.

In some embodiments, there is a second distance between the end point of the horizontal monitoring pipeline and the end point of the horizontal monitoring well section, and the second distance is 1 m to 10 m.

In some embodiments, there is a third distance between the second pressure monitoring device and the first pressure monitoring device, and the third distance is 8 m to 12 m.

In some embodiments, the step of determining the lateral sealing property of the fault includes the following sub-steps:

A monitoring pressure difference value obtaining step, obtaining a monitoring pressure difference value between the first pressure monitoring value and the second pressure monitoring value;

The pressure difference change rate acquisition step is to obtain the pressure difference change rate according to the monitored pressure difference value;

The sealing judgment step is to judge whether the pressure difference change rate is greater than the preset change rate. When the judgment result is "yes", then the boundary fault does not have sealing properties; when the judgment result is "no", then the Boundary faults are closed.

In some embodiments, a pressure monitoring and control device is provided at the wellhead of the target monitoring well. The pressure monitoring and control device is connected to the first monitoring line and the second monitoring line respectively. The pressure monitoring and control device has Display function.

In some embodiments, the pressure monitoring control device has an alarm function.

In some embodiments, a second packer is provided in the annular channel on a side of the second pressure monitoring device away from the first pressure monitoring device.

The embodiments of the present application have at least the following beneficial effects:

The above-mentioned method for monitoring the lateral closure of underground gas storage faults can monitor the lateral closure of underground gas storage faults through the abandoned wells by screening, transforming and utilizing the abandoned wells around the boundary faults of the underground gas storage. Not only is the monitoring method simple, but it can also improve the operability of the monitoring method. In addition, through the secondary utilization of the abandoned wells around the boundary faults of the underground gas storage, it is possible to avoid the need for greater capital investment in the construction of new monitoring wells, which can greatly reduce the cost of monitoring the lateral closure of underground gas storage faults.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, a brief introduction will be made below to the drawings needed to be used in the description of the embodiments. Obviously, the drawings in the following description are some embodiments of the present application. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings without exerting creative efforts.

Figure 1 shows a flow chart of the monitoring method for fault lateral sealing of an underground gas storage in an embodiment of the present application;

Figure 2 shows the boundary fault structure and abandoned well distribution map of the underground gas storage in Figure 1;

Figure 3 shows the boundary fault structure and abandoned well distribution map of the underground gas storage after the monitoring wells in Figure 2 have been modified;

Figure 4 shows a schematic diagram of the installation positions of the packer, the first pressure monitoring device and the second pressure monitoring device in the horizontal monitoring well section in Figure 3;

Figure 5 shows a schematic cross-sectional view of the mid-level monitoring well section in Figure 3;

Reference signs:

100, boundary fault; 200, first abandoned well; 210, vertical monitoring well section; 211, bottom of vertical monitoring well section; 220, horizontal monitoring well section; 221, end point of horizontal monitoring well section; 230, horizontal monitoring pipeline; 231, end point of horizontal monitoring pipeline; 232, perforation; 240, packer; 250, first pressure monitoring point; 260, second pressure monitoring point; 270, second packer; 280, well wall; 290, rock; 300, second abandoned well; 400, cap rock; 500, gas reservoir; 600, formation.

Detailed ways

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of this application.

Furthermore, this application may repeat reference numbers and/or reference letters in different examples, such repetition being for the purposes of simplicity and clarity and does not by itself indicate a relationship between the various embodiments and/or arrangements discussed. In addition, this application provides examples of various specific processes and materials, but one of ordinary skill in the art will recognize the application of other processes and/or the use of other materials.

The present application is described below in conjunction with the accompanying drawings and with reference to specific embodiments:

The embodiment of the present application proposes a method for monitoring the lateral sealing of faults in an underground gas storage. As shown in Figures 1 to 5, the method for monitoring the lateral sealing of faults in an underground gas storage includes the following steps:

The monitoring well acquisition step S100 is to acquire abandoned wells located outside the boundary fault 100 of the underground gas storage and within a preset range, and select target monitoring wells from the abandoned wells according to the screening conditions;

The monitoring well modification step S200 is to modify the target monitoring well so that the target monitoring well includes a vertical monitoring well section 210 and a horizontal monitoring well section 220, and the bottom end 211 of the vertical monitoring well section is located in the stratum 600 of the underground gas storage. , the horizontal monitoring well section 220 extends horizontally from the bottom end 211 of the vertical monitoring well section to the boundary fault 100, and the end point 221 of the horizontal monitoring well section has a first distance from the boundary fault 100; in the vertical monitoring well section 210, There is a vertical monitoring pipeline and a vertical annular channel is formed between the vertical monitoring pipeline and the vertical monitoring well section 210. A horizontal monitoring pipeline 230 connected to the vertical monitoring pipeline is provided in the horizontal vertical monitoring well section 210 and is in A horizontal annular channel is formed between the horizontal monitoring pipeline 230 and the horizontal monitoring well section 220, and a packer 240 is provided between the end point 231 of the horizontal monitoring pipeline and the well wall 280 of the horizontal and vertical monitoring well section 210;

In the pressure monitoring device setting step S300, a first pressure monitoring device is set at the end point 231 of the horizontal monitoring pipe. The first monitoring line connected to the first pressure monitoring device extends to the wellhead of the target monitoring well through the horizontal monitoring pipe 230 and the vertical monitoring pipe. ; Set up a second pressure monitoring device in the horizontal annular channel, and perform perforation 232 on the well wall 280 of the horizontal monitoring well section 220 corresponding to the second pressure monitoring device, and the second monitoring line connected to the second pressure monitoring device passes through The horizontal annular channel and the vertical annular channel extend to the wellhead of the monitoring well; and,

In the fault lateral sealing determination step S400, the pressure monitoring and control device determines whether the boundary fault 100 has sealing properties based on the first pressure monitoring value obtained in real time by the first pressure monitoring device and the second pressure monitoring value obtained in real time by the second pressure monitoring device.

Underground gas storage is an artificial gas reservoir formed by reinjecting natural gas into underground space. It has the characteristics of large reserve capacity, reasonable economy and durability. The construction of foreign gas storages has a history of hundreds of years. For example, there are more than 400 underground gas storages in operation in the United States, and the operating gas volume accounts for 18% of its gas consumption. As the proportion of natural gas in my country's energy consumption gradually increases, In recent years, underground gas storage has become a key link in ensuring the safe supply of natural gas in my country, and my country is in the rapid development stage of underground gas storage construction. The construction of underground gas storage can help revitalize the value of old oil and gas fields. According to statistics, about 30% of gas storage accidents abroad are caused by fault sealing failure. It can be seen that the sealing of underground gas storage is an important factor. For the safety and use of underground gas storage, it is crucial to study the sealing properties of faults. At home and abroad, great importance is attached to the sealing evaluation of underground gas storages, and the sealing evaluation before the construction of gas storages is getting more and more in-depth. There are many methods for evaluating fault sealing in gas reservoirs in China. For example, Lu Yanfang et al. proposed using fault reservoir displacement pressure difference to judge fault sealing, Lindsay proposed the mudstone smear factor method, Yielding proposed fault mud ratio and other methods. Evaluate fault sealability. However, most of the gas storage construction in my country is aimed at depleted sandstone gas reservoirs located in the eastern structurally complex areas. Their sealing performance is greatly affected by fault structures and is difficult to demonstrate. The traditional fault sealing evaluation method is aimed at this type of underground gas storage difficulties. The operability is poor. To this end, this application proposes a method for monitoring the lateral sealing of faults in an underground gas storage. In the method for monitoring the lateral sealing of faults in an underground gas storage in this embodiment, by monitoring the boundary faults of the underground gas storage 100 Abandoned wells around the area can be screened, renovated and utilized. The abandoned wells can monitor the fault lateral sealing properties of underground gas storages. Not only is the monitoring method simple, but it can also effectively reduce the risk of sealing failure of gas reservoirs. It can also improve the operability of monitoring methods. In addition, by reusing abandoned wells around the boundary fault 100 of the underground gas storage, it avoids the need for greater capital investment in the construction of new monitoring wells, and can greatly reduce the lateral sealing of the underground gas storage fault. Cost of monitoring.

Optionally, in order to measure pressure changes, two pressure monitoring devices need to be installed in the horizontal direction downhole. Therefore, the target monitoring well needs to be sidetracked to form a horizontal monitoring well section 220, so that the pressure monitoring devices can be set at intervals in the horizontal monitoring well section. 220 to measure the pressure change of the underground gas storage, so as to determine the lateral tightness of the boundary fault 100 based on the pressure change.

As an optional implementation, in the monitoring well acquisition step in this embodiment, the preset range may be determined based on the construction budget of the new monitoring well. For example, firstly, the construction location and construction budget of the new monitoring well can be designed based on the location of the boundary fault 100 of the underground gas storage; and then the farthest distance between the abandoned well and the boundary fault 100 within the construction budget of the new monitoring well can be estimated, so that The renovation cost of the abandoned well is lower than the cost budget of the new monitoring well, that is, the farthest distance between the abandoned well and the boundary fault 100 is the preset range outside the boundary fault 100 of the underground gas storage. If the distance between the abandoned well and the boundary fault 100 exceeds the above-mentioned maximum distance, the cost of revamping the abandoned well will exceed the cost of a new monitoring well, resulting in a less economical monitoring method for fault lateral sealing of underground gas storage.

As an optional implementation, in the present application's monitoring method for fault lateral sealing of underground gas storage, the screening conditions at least include the integrity of the abandoned well and the reconstruction budget of the abandoned well. That is, when screening abandoned wells outside the boundary fault 100 of the underground gas storage and within the preset range, it is first necessary to confirm whether the integrity of the abandoned wells is good. If the integrity of the abandoned wells is poor, it cannot be used for underground storage. The monitoring method for the lateral sealing of gas reservoir faults needs to exclude abandoned wells with sealing failure. Secondly, the location of the abandoned well and the reconstruction budget need to be considered. For example, if the abandoned well is far away from the boundary fault of the underground gas storage 100 meters away, the sidetracking distance of the abandoned well needs to be longer, and the length of the monitoring pipeline needs to be set. It is longer and more expensive; if the abandoned well is close to the boundary fault 100 of the underground gas storage, the boundary fault 100 may be easily damaged or destroyed during the reconstruction of the abandoned well, or the horizontal monitoring well section 220 cannot be set up.

As an optional implementation, the screening conditions also include surface monitoring conditions of abandoned wells. In this embodiment, when monitoring the lateral sealing properties of underground gas storage faults, construction and/or related equipment need to be carried out on the ground near the wellhead of the abandoned well. Therefore, abandonment also needs to be considered when screening abandoned wells. The ground monitoring conditions of the well. If the ground monitoring conditions of the abandoned well cannot meet the construction conditions or the setting conditions of related equipment, the abandoned well needs to be excluded.

Optionally, in the monitoring method of fault lateral sealing of underground gas storage in this application, the screening conditions for abandoned wells need to comprehensively consider the structure, location, burial depth and economic factors of the abandoned wells, so that it can be based on The screening conditions select abandoned wells with matching structures, appropriate locations and the most economical properties as target monitoring wells to monitor the lateral sealing of underground gas storage faults.

As shown in Figures 2 and 3, in this embodiment, the underground gas storage includes a caprock 400, a gas storage layer 500 and a stratum 600 from top to bottom, which horizontally isolates natural gas through the boundary fault 100. (On the left side of the boundary fault 100 in the figure), outside the two underground gas storages (on the right side of the boundary end in the figure) there are several abandoned wells left behind by old oil and gas fields. Before the monitoring well acquisition step, the position of the boundary fault 100 of the underground gas storage can first be determined using geophysical methods. In the monitoring well acquisition step, the integrity of the abandoned wells is first tested, that is, the wellbore sealing properties of the abandoned wells are tested, and only abandoned wells with good wellbore sealing properties are retained for the next step of screening.

Based on the screening results based on wellbore sealing in the previous step, factors such as the distance between the abandoned well and the boundary fault 100 , sidetracking costs, and the formation 600 where the bottom of the abandoned well is located are then comprehensively considered. As shown in Figures 2 and 3, the integrity of the first abandoned well 200 and the second abandoned well 300 is good, that is, the wellbore sealing meets the requirements of the monitoring method for the fault lateral sealing of the underground gas storage. Among them, the first abandoned well 200 is close to the boundary fault 100 of the underground gas storage, but the bottom of the first abandoned well 200 is located above the gas storage stratum 600. The depth of the first abandoned well 200 needs to be adjusted, and the cost of sidetracking is relatively high. Low but the cost of deep drilling is higher. The second abandoned well 300 is far away from the boundary fault 100 of the underground gas storage, but the bottom of the second abandoned well 300 is close to the bottom layer of the underground gas storage. The sidetracking cost is high but the deep drilling cost is low. At this time, the comprehensive modification costs of sidetracking and deep drilling of the two wells can be combined, and factors such as the ground monitoring conditions of the abandoned wells can be further considered to select abandoned wells with lower modification costs as target monitoring wells, and further monitor the target The monitoring wells are modified to meet the needs of monitoring methods for fault lateral sealing of underground gas storages.

Further, in the monitoring well modification step, first adjust the depth of the target monitoring well so that the bottom of the vertical monitoring well section 210 of the target monitoring well is located in the formation 600 of the underground gas storage; secondly, from the vertical monitoring well section 210 The bottom of the well is sidetracked toward the boundary fault 100 to form a horizontal monitoring well section 220, which can be used to reflect the lateral migration of gas along the fault.

Furthermore, a horizontal monitoring pipe 230 and a vertical monitoring pipe are respectively provided in the vertical monitoring well section 210 and the horizontal monitoring well section 220 of the target monitoring well. Optionally, the horizontal monitoring pipe and the vertical monitoring pipe can be PVC pipes. As shown in FIG5 , the cross-section of the horizontal monitoring well section 220 is composed of the horizontal monitoring pipe 230, the annular channel, the cement well wall 280 and the underground rock 290 from the inside to the outside.

As an optional implementation, in the monitoring method of fault lateral sealing of underground gas storage in this application, as shown in Figure 3, the first spacing is 40m to 60m. That is, the distance between the end point 221 of the horizontal monitoring well section and the boundary fault 100 is 40 m to 60 m. More preferably, the distance between the end point 221 of the horizontal monitoring well section and the boundary fault 100 is 50 m.

In this embodiment, the horizontal monitoring well section 220 is used to set a pressure monitoring device to reflect whether leakage occurs in the boundary fault 100. Therefore, the first spacing between the horizontal monitoring well section 220 and the boundary fault 100 needs to have a suitable range. If the first distance is too large, the pressure monitoring device may not be able to obtain the pressure changes related to the boundary fault 100. If the first distance is too small, sidetracking to form the horizontal monitoring well section 220 will easily affect the structure of the boundary fault 100 and destroy the sealing of the fault. Sex leads to the abandonment of underground gas storage.

As an optional implementation, as shown in Figure 4, there is a second distance between the end point 231 of the horizontal monitoring pipeline and the end point 221 of the horizontal monitoring well section, and the second distance is 1 m to 10 m. Optionally, the second spacing can be 1m, 2m, 3m, 4m, 5m, 6m, 8m, 10m, etc.

In this embodiment, the first pressure monitoring device is set at the end point 231 of the horizontal monitoring pipeline, so that there is a second distance between the end point 231 of the horizontal monitoring pipeline and the end point 221 of the horizontal monitoring well section, so that the end point 231 of the horizontal monitoring pipeline is A certain monitoring space is formed between the terminal 221 of the horizontal monitoring well section, and a packer 240 is set at the end 231 of the horizontal monitoring pipeline to isolate the monitoring space from other spaces in the horizontal monitoring well section 220, so that the formation The natural gas in 600 diffuses into the monitoring space. As shown in Figure 4, a first pressure monitoring point 250 is provided in the monitoring space for setting a first pressure monitoring device to facilitate real-time monitoring of pressure changes in the monitoring space. In this embodiment, the length of the monitoring space formed between the end point 231 of the horizontal monitoring pipeline and the end point 221 of the horizontal monitoring well section is preferably 1 m to 10 m, thereby forming a monitoring space with a suitable volume to facilitate the diffusion and monitoring of natural gas. . The first pressure monitoring device transmits the monitoring signal to the outside through the first monitoring line. Preferably, the first monitoring line connected to the first pressure monitoring device passes through the horizontal monitoring pipe 230 and the vertical monitoring pipe in sequence and extends to the wellhead of the monitoring well. in order to transmit the first pressure monitoring signal of the first pressure monitoring device. Further preferably, in order to prevent the natural gas from diffusing into the monitoring space from diffusing out of the monitoring well through the horizontal monitoring pipe 230, a corresponding seal is provided between the end point of the horizontal monitoring pipe 230 and the first monitoring line to separate the monitoring space from the horizontal monitoring line. Pipe 230 is isolated.

As an optional implementation, there is a third distance between the second pressure monitoring device and the first pressure monitoring device, and the third distance is 8 m to 12 m.

In this embodiment, as shown in Figure 4, there is a horizontal annular channel between the horizontal monitoring well section 220 and the horizontal monitoring pipeline 230, and there is a vertical annular channel between the vertical monitoring well section 210 and the vertical monitoring pipeline. A second pressure monitoring point 260 is provided in the horizontal annular channel, and perforations 232 are performed at the well wall 280 of the horizontal monitoring well section 220 corresponding to the second pressure monitoring point 260, so that the perforations 232 connect the horizontal annular channel and the formation 600 , so that the natural gas in the formation 600 can diffuse into the horizontal annular channel, and then the pressure changes there are monitored in real time through the second pressure monitoring device. In this embodiment, it is preferable to make the third distance between the second pressure monitoring device and the first pressure monitoring device 8m～12m, that is, the horizontal annular channel forms a horizontal annular space receiving formation 600 with a length of 8m～12m. Real-time pressure monitoring of natural gas. The second pressure monitoring device transmits the monitoring signal to the outside through the second monitoring line. Preferably, the second pressure monitoring line connected to the second pressure monitoring device extends through the horizontal annular channel and the vertical annular channel to the wellhead of the monitoring well. in order to transmit the second pressure monitoring signal of the second pressure monitoring device.

As an optional implementation, a second packer 270 is provided in the annular channel on the side of the second pressure monitoring device away from the first pressure monitoring device. In this embodiment, as shown in Figure 4, in order to avoid diffusion outside the monitoring well through the perforations 232 into the horizontal annular channel, in the annular channel on the side of the second pressure monitoring device away from the first pressure monitoring device A second packer 270 is provided. The second packer 270 isolates a section of the horizontal annular channel corresponding to the perforation 232 from the rest of the horizontal annular pipeline. That is, through the packer 240 and the second packer 270, The split section of the horizontal annular pipeline forms a second pressure monitoring space, and a second pressure detection device is provided in the second pressure monitoring space to detect pressure changes there in real time.

As an optional implementation, a pressure monitoring and control device is provided at the wellhead of the target monitoring well. The pressure monitoring and control device is connected to the first monitoring line and the second monitoring line respectively, and the pressure monitoring and control device has a display function.

In this embodiment, by setting a pressure monitoring and control device at the wellhead of the target monitoring well, the pressure monitoring and control device can receive the first pressure detection signal of the first pressure detection device and the second pressure of the second pressure detection device. Detect the signal and perform corresponding data judgment and processing, so that the monitoring results of the fault lateral tightness can be output. Further preferably, the pressure monitoring and control device has a display function, which can display the first pressure detection signal of the first pressure detection device and the second pressure detection signal of the second pressure detection device, and can also display the monitoring of the lateral tightness of the output fault. result.

As an optional implementation, the pressure monitoring and control device has an alarm function. In this embodiment, by providing the pressure monitoring and control device with an alarm function, a corresponding alarm signal is issued when the monitoring result of the lateral tightness of the output fault acquired by the pressure detection and control device is abnormal. For example, if the judgment result in the fault lateral sealing judgment step is that the boundary fault 100 does not have sealing, an alarm signal such as an alarm sound or light can be sent out, or a reminder text message, email, etc. can be sent to a mobile terminal specified by the administrator to facilitate timely Carry out appropriate emergency response.

As an optional implementation, the fault lateral sealing judgment step includes the following sub-steps:

The monitoring pressure difference value acquisition step is to obtain the monitoring pressure difference value between the first pressure monitoring value and the second pressure monitoring value;

The pressure difference change rate acquisition step is to obtain the pressure difference change rate based on the monitored pressure difference value;

The sealing judgment step determines whether the pressure difference change rate is greater than the preset change rate. When the judgment result is "yes", the boundary fault 100 does not have sealing properties; when the judgment result is "no", the boundary fault 100 has sealing properties. sex.

In this embodiment, the pressures of two pressure monitoring points in the underground gas storage formation 600 can be automatically monitored for a long time by using the first pressure detection device, the second pressure detection device and the pressure monitoring and control device, and the pressures of the formation 600 corresponding to the two pressure monitoring points can be calculated using the formula of seepage mechanics. If it is found during the monitoring process that the pressure difference change rate changes sharply, that is, the pressure difference change rate is greater than the preset change rate, it means that the pressure of the formation 600 corresponding to the first pressure detection point has increased sharply, which means that gas leakage has occurred at the boundary fault 100.

In this embodiment, due to the complex structure of the underground gas storage, the bottom pressure corresponding to the two pressure monitoring points is not constant, so the pressure difference change rate is not fixed. Therefore, a preset change rate needs to be set to facilitate accurate judgment. Whether the lateral sealing property of the boundary fault 100 has failed. In this embodiment, the preset change rate can be preset based on the monitoring data accumulated by the pressure monitoring and control device for a certain period of time, thereby determining an appropriate preset change rate, and then judging the lateral sealing property of the fault based on the preset change rate.

In the present application, 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.

In the description of this application, it needs to be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", " The orientation or position indicated by "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" The relationship is based on the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore It cannot be construed as a limitation on this application.

It should be noted that all directional indications in the embodiments of this application are only used to explain the relative positional relationship, movement conditions, etc. between the components in a specific posture. If the specific posture changes, the directional indication will It also changes accordingly.

In this application, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

In addition, descriptions such as "first", "second", etc. in this application are for descriptive purposes only and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of indicated technical features. Therefore, features defined as "first" and "second" may explicitly or implicitly include one or more of the described features. In the description of this application, "plurality" means two or more than two, unless otherwise explicitly and specifically limited.

In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification.

In addition, the technical solutions in various embodiments can be combined with each other, but it must be based on the realization by those of ordinary skill in the art. When the combination of technical solutions is contradictory or cannot be realized, it should be considered that such a combination of technical solutions does not exist. , nor is it within the scope of protection required by this application.

Although the embodiments of the present application have been shown and described, those of ordinary skill in the art will understand that various changes, modifications, substitutions and modifications can be made to these embodiments without departing from the principles and purposes of the present application. The scope of the application is defined by the claims and their equivalents.

Claims (10)

1. The method for monitoring the lateral closure of the fault of the underground gas storage is characterized by comprising the following steps of:

a monitoring well acquisition step of acquiring an abandoned well which is positioned outside a boundary fault of the underground gas storage and is in a preset range, and screening a target monitoring well from the abandoned well according to screening conditions;

a monitoring well reconstruction step of reconstructing the target monitoring well to enable the target monitoring well to comprise a vertical monitoring well section and a horizontal monitoring well section, wherein the bottom end of the vertical monitoring well section is positioned in a stratum of the underground gas storage, the horizontal monitoring well section horizontally extends from the bottom end of the vertical monitoring well section to the boundary fault, and the end point of the horizontal monitoring well section and the boundary fault have a first interval; a vertical monitoring pipeline is arranged in the vertical monitoring well section, a vertical annular channel is formed between the vertical monitoring pipeline and the vertical monitoring well section, a horizontal monitoring pipeline communicated with the vertical monitoring pipeline is arranged in the horizontal vertical monitoring well section, a horizontal annular channel is formed between the horizontal monitoring pipeline and the horizontal monitoring well section, and a packer is arranged between the end point of the horizontal monitoring pipeline and the well wall of the horizontal vertical monitoring well section;

a pressure monitoring device setting step, namely setting a first pressure monitoring device at the end point of the horizontal monitoring pipeline, wherein a first monitoring line connected with the first pressure monitoring device extends to a wellhead of the target monitoring well through the horizontal monitoring pipeline and the vertical monitoring pipeline; setting a second pressure monitoring device in the horizontal annular channel, perforating a well wall of the horizontal monitoring well section corresponding to the second pressure monitoring device, and extending a second monitoring line connected with the second pressure monitoring device to a wellhead of the monitoring well through the horizontal annular channel and the vertical annular channel; the method comprises the steps of,

and judging whether the boundary fault has closure or not according to the first pressure monitoring value obtained by the first pressure monitoring device in real time and the second pressure monitoring value obtained by the second pressure monitoring device in real time by the pressure monitoring control device.

2. The method for monitoring the lateral closure of a fault in an underground gas storage as claimed in claim 1 wherein said screening conditions include at least the integrity of said abandoned well and the retrofitting budget of said abandoned well.

3. The method for monitoring the lateral closure of a fault in an underground gas storage as claimed in claim 2 wherein said screening conditions further comprise surface monitoring conditions of said abandoned well.

4. The method for monitoring the lateral closure of a fault in an underground gas storage as claimed in claim 1 wherein said first spacing is 40m to 60m.

5. The method for monitoring the lateral closure of a fault in an underground gas storage as claimed in claim 1 wherein a second distance is provided between the end point of the horizontal monitoring conduit and the end point of the horizontal monitoring well section, said second distance being 1m to 10m.

6. The method for monitoring the lateral closure of a fault in an underground gas storage as claimed in claim 1, wherein a third distance is provided between the second pressure monitoring device and the first pressure monitoring device, and the third distance is 8 m-12 m.

7. The method for monitoring the lateral closure of a fault in an underground gas storage as claimed in claim 1, wherein in said step of determining the lateral closure of the fault, the method comprises the sub-steps of:

a step of acquiring a monitoring differential pressure value, wherein the monitoring differential pressure value of the first pressure monitoring value and the second pressure monitoring value is acquired;

a differential pressure change rate obtaining step, namely obtaining the differential pressure change rate according to the monitored differential pressure value;

judging whether the pressure difference change rate is larger than a preset change rate or not, and if yes, judging that the boundary fault does not have the closure; and when the judgment result is NO, the boundary fault has closure.

8. The method for monitoring the lateral closure of a fault in an underground gas storage according to any one of claims 1 to 7, wherein a pressure monitoring control device is arranged at a wellhead of the target monitoring well, the pressure monitoring control device is respectively connected with the first monitoring line and the second monitoring line, and the pressure monitoring control device has a display function.

9. The method for monitoring the lateral closure of a fault in an underground gas storage as claimed in claim 8, wherein the pressure monitoring control device has an alarm function.

10. The method for monitoring the lateral closure of a fault in an underground gas storage as claimed in claim 8, wherein a second packer is provided in the annular passage on the side of the second pressure monitoring device remote from the first pressure monitoring device.