Integrated abandoned well plugging quality evaluation technology

Abstract

The present invention discloses an integrated abandoned well plugging quality evaluation process technology, which specifically relates to the field of industrial exploration. The specific evaluation process includes the following steps: before the plugging operation is implemented, a wireless pressure sensor is placed in the well to monitor the pressure change in the abandoned plugging well; the abandoned well plugging operation is implemented, and a preset amount of cement slurry is injected into the abandoned well. After the cement slurry solidifies in the abandoned well, a cement protective plug can be formed to achieve the plugging of the abandoned well; a database is constructed to obtain a relationship model between the pressure sensor value change and the sealing performance; the pressure sensor value is recorded, and the wireless pressure sensor transmits the pressure curve in the plugging well at regular intervals; the pressure sensor pressure curve is compared with the database model to evaluate the quality of the plugging abandoned well. The integrated abandoned well plugging quality evaluation process technology in the present invention facilitates the monitoring of the sealing performance of abandoned well plugging, saves the detection cost, and lays the foundation for optimizing abandoned well plugging technology and improving abandoned well reclamation.

Description

Technical Field

[0001] The present invention relates to the field of industrial exploration technology, and more specifically to an integrated abandoned well plugging quality evaluation process technology. Background Art

[0002] Abandoned wells refer to mines, drilling wells, and water wells that cannot be used for various reasons and are approved by relevant departments to be permanently abandoned. In the field of industrial exploration, abandoned wells are divided into the following categories: wells that are ineffective in the development of oil and gas fields and have no comprehensive utilization value; wells that have adverse effects on the development of oil and gas fields; wells with casing damage that cannot be repaired; and wells that need to be scrapped in other cases. After becoming abandoned wells, proper follow-up treatment is also required. Abandoned wells are not sealed or the sealing measures are not in place, which leads to safety hazards. The traditional plugging method is to inject a preset amount of cement slurry into the abandoned well to be plugged. After the cement slurry solidifies in the waste gas well, a cement protective plug can be formed to achieve the plugging of the abandoned well. However, it is difficult to conduct quality inspection on abandoned wells after plugging.

[0003] The quality of abandoned well plugging affects the subsequent reclamation work. Modern cities are developing in the direction of super-large and borderless with the expansion and high-rise development. By 2150, the global population is expected to reach 15 billion, and the existing arable land has reached its support limit. According to the national land reclamation regulations, by managing abandoned well sites, restoring ecological resources, accelerating the intensive utilization of oil and gas waste land, and promoting the green and healthy development of the oil and gas industry. The completion of the reclamation of abandoned oil and gas field drilling is inseparable from the evaluation method of abandoned well plugging quality. The quality of abandoned well plugging is related to the environment of soil and water sources and reclamation work. The sealing of cement plugs is a key parameter for the quality of abandoned well plugging.

[0004] Patent application publication number CN108331575A discloses a method and system for evaluating the quality of abandoned wells using well test curves. The perforation layer of the abandoned well is determined according to the perforation layer of the abandoned well; the pressure measurement depth is determined according to the perforation layer of the updated well to obtain the original pressure data, and then the double logarithm and derivative curves of the original pressure data are drawn, and then compared with the theoretical double logarithm and derivative curves to determine whether it is a dual-porosity medium reservoir model; if it is, the quality of the abandoned well is not good, otherwise the quality of the abandoned well is good. This method is theoretically reliable, but it is expensive, difficult to operate, low in accuracy, and takes a long time to test, which is not conducive to large-scale promotion and application. Summary of the invention

[0005] In order to overcome the above-mentioned defects of the prior art, an embodiment of the present invention provides an integrated abandoned well plugging quality evaluation process technology, which can comprehensively evaluate the plugging quality of different types of abandoned wells, thereby laying a foundation for optimizing abandoned well plugging technology and improving abandoned well reclamation.

[0006] To achieve the above-mentioned purpose, the present invention provides the following technical solution: comprising the following steps: S1. Placing a wireless pressure sensor in the well before the plugging operation is carried out to monitor the pressure changes in the abandoned plugged well; S2. Implementing the abandoned well plugging operation, injecting a preset amount of cement slurry into the abandoned well, and after the cement slurry solidifies in the abandoned well, a cement protective plug can be formed to achieve the plugging of the abandoned well; S3. Constructing a database to obtain a model of the relationship between the value change of the pressure sensor and the sealing performance; S4. Recording the value of the pressure sensor, and the wireless pressure sensor regularly transmits the pressure curve in the plugged well; S5. Comparing the pressure curve of the pressure sensor with the database model to evaluate the quality of plugging the abandoned well.

[0007] In a preferred embodiment, the wireless pressure sensor uses high-precision and high-stability diffused silicon as the pressure sensing chip, advanced technology, supports point-to-point, point-to-multipoint, and serial port to serial port applications, and transmits data through the GPRS wireless network. The measured medium can be liquid, fluid, or gas. The pressure measurement range is 0 to 60 MPa, and the ambient temperature is between -20 and 85°C. The placement depth of the wireless pressure sensor is greater than the depth of the cement plug. If the cement plugging depth of the abandoned well is 50 meters, the placement depth of the wireless pressure sensor is 80-100 meters. To ensure that the wireless pressure sensor is not damaged, it is surrounded by hollow metal material and suspended in the abandoned plugging well by high temperature resistant and wear-resistant materials.

[0008] In a preferred embodiment, the cement slurry in S2 can be any slurry with a sealing function, and the process of plugging the well can also be improved, such as using a segmented plugging method.

[0009] In a preferred embodiment, the database uses a modeling tool called PowerDesigner, and the specific steps are as follows: a1. Collect a certain number of plugged well downhole pressure sensor pressure values ​​as a pressure database. The well is an abandoned well in geological exploration. Steps S1 and S2 are performed to obtain a database of downhole pressure value curves over time; a2. Obtain the sealing results of the plugged wells in the above steps, and test the sealing tightness of the abandoned wells by negative pressure. After plugging with cement plugs, negative pressure methods such as pumping, gas lifting, and low replacement are used to reduce the liquid column pressure above the cement plug to at least Half of the reservoir pressure value isolated or blocked by cement plug or negative pressure of more than 10MPa, and the maximum value not exceeding the safety value of casing anti-external collapse strength, monitor the liquid level in the well for 4h to 6h, exclude other influencing factors, if the liquid level is not affected by the closed layer fluid and changes, the cement plug is qualified, so that the pressure data of the pressure sensor and the relationship between the airtightness are mapped; a3, construct a mapping relationship model between the pressure sensor pressure data and the airtightness relationship, the mapping model is based on Map-Reduce / mapping-reduction model, can draw on the signal processing process, and process large-scale data.

[0010] In a preferred embodiment, the data cleaning in a1 is divided into three cases: 1. Missing value processing. In the actual process of obtaining information and data, there will be various reasons that lead to data loss and vacancies. For these missing values, different methods will be used based on the distribution characteristics of the variables and the importance of the variables. If the missing rate of the variable is high, the coverage rate is low, and the importance is low, the variable can be deleted directly. This method is called deleting the variable; if the missing rate is low and the importance is low, it is filled with basic statistics according to the data distribution. This method is called missing value filling. For missing data, it is generally decided whether to "delete" or "fill" based on the missing rate. 2. Outlier processing Outliers are the norm of data distribution. Data outside a specific distribution area or range is usually defined as anomalies or noise. Our common method is to delete outliers. 3. Inconsistent data processing. In the actual data production process, due to some human factors or other reasons, the recorded data may be inconsistent, and these inconsistent data need to be cleaned before analysis. For example, errors in data input can be corrected by comparing with the original records, and knowledge engineering tools can also be used to detect data that violates the rules.

[0011] Technical effects and advantages of the present invention:

[0012] 1. The integrated abandoned well plugging quality evaluation process technology of the present invention facilitates the monitoring of the sealing tightness of the abandoned well by placing a wireless pressure sensor in the abandoned well, thus saving the detection cost;

[0013] 2. The integrated abandoned well plugging quality evaluation process technology of the present invention relies on big data analysis and Map-Reduce / mapping-reduction model, which can save manpower and facilitate supervision;

[0014] 3. The integrated abandoned well plugging quality evaluation process technology of the present invention can continuously improve its accuracy through continuous optimization, laying a foundation for optimizing abandoned well plugging technology and improving abandoned well reclamation. DETAILED DESCRIPTION

[0015] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. 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.

[0016] Example

[0017] The embodiment of the present invention provides an integrated abandoned well plugging quality evaluation process technology, and the specific evaluation process includes the following steps:

[0018] S1. Place a pressure sensor. Before the plugging operation is implemented, place a wireless pressure sensor in the well to monitor the pressure changes in the abandoned plugged well;

[0019] S2. Implementing the plugging operation of the abandoned well, injecting a preset amount of cement slurry into the abandoned well, and after the cement slurry solidifies in the abandoned well, a cement protective plug can be formed to plug the abandoned well;

[0020] S3. Build a database to obtain a mapping model of the relationship between the pressure sensor value change and the sealing performance;

[0021] S4. Record the pressure sensor value, and the wireless pressure sensor transmits the pressure curve in the plugged well at a fixed time;

[0022] S5. Compare the pressure curve of the pressure sensor with the database model to evaluate the quality of plugging and abandoning the well.

[0023] The wireless pressure sensor described in S1 uses high-precision and high-stability diffused silicon as the pressure-sensing chip, advanced technology, supports point-to-point, point-to-multipoint, and serial-to-serial applications, and transmits data through the GPRS wireless network. The measured medium can be liquid, fluid, or gas. The pressure measurement range is 0 to 60MPa, and the ambient temperature is between -20 and 85°C. The placement depth of the wireless pressure sensor is greater than the depth of the cement plug. If the cement plugging depth of the abandoned well is 50 meters, the placement depth of the wireless pressure sensor is 80-100 meters. To ensure that the wireless pressure sensor is not damaged, it is surrounded by hollow metal materials and suspended in the abandoned plugging well by high-temperature and wear-resistant materials.

[0024] The cement slurry in S2 can be any slurry with sealing function, and the process of plugging the well can also be improved, such as using a segmented plugging method.

[0025] The database modeling tool used in S3 is PowerDesigner. The specific steps are as follows:

[0026] a1. Collect a certain number of plugged downhole pressure sensor pressure values ​​as a pressure database. The well is an abandoned well in geological exploration. Steps S1 and S2 are performed to obtain a downhole pressure value versus time curve database. The database needs to be preprocessed. The data preprocessing method is data cleaning. The purpose of cleaning is achieved by filling missing values, smoothing or deleting outliers, and correcting data inconsistencies.

[0027] a2. Obtain the sealing results of the plugged wells in the above steps, and test the sealing of abandoned wells by negative pressure. After plugging with cement plugs, use negative pressure methods such as pumping, gas lifting, low displacement, etc. to reduce the liquid column pressure above the cement plug to at least half of the reservoir pressure value isolated or plugged by the cement plug or a negative pressure of more than 10MPa, and the maximum value shall not exceed the safety value of the casing anti-external collapse strength. Monitor the liquid level in the well for 4h to 6h, and exclude other influencing factors. If the liquid level does not change due to the influence of the sealing layer fluid, the cement plug is qualified, so that the relationship between the pressure data of the pressure sensor and the sealing is mapped;

[0028] a3. Construct a mapping relationship model between the pressure data of the pressure sensor and the airtightness. The mapping model is based on the Map-Reduce model and can refer to the signal processing process to process large-scale data.

[0029] The data cleaning in a1 is divided into three cases: (1) Missing value processing. In the actual process of obtaining information and data, there will be various reasons that lead to data loss and vacancies. For these missing values, different methods will be used based on the distribution characteristics of the variables and the importance of the variables. If the missing rate of the variable is high (greater than 80%), the coverage rate is low, and the importance is low, the variable can be deleted directly. This method is called deleting the variable; if the missing rate is low (less than 95%) and the importance is low, it is filled with basic statistics (maximum value, minimum value, mean, median, mode) according to the data distribution. This method is called missing value filling. For missing data, it is generally decided whether to "delete" or "fill" based on the missing rate. (2) Outlier processing Outliers (abnormal values) are the norm of data distribution. Data outside a specific distribution area or range is usually defined as abnormal or noise. Our common method is to delete outliers. (3) Inconsistent data processing. In the actual data production process, due to some human factors or other reasons, the recorded data may be inconsistent. These inconsistent data need to be cleaned before analysis. For example, errors in data entry can be corrected by comparing it with the original records, and knowledge engineering tools can also be used to detect data that violates rules.

[0030] The data processing in a3 includes three aspects: conversion of a data sequence, Map in Map-Reduce, obtaining another data sequence from one data sequence; conversion operations, including function mapping / map, filtering / filter and other operations, reducing the data sequence; Reduce in Map-Reduce is the consumption of the data sequence, which can count or accumulate the data sequence, and reduction operations include summing, finding the maximum value, finding the minimum value, finding the number, printing each element and other operations.

[0031] It can be seen from the above embodiments that: a high investment is required when starting to build a database to obtain a mapping curve between the pressure sensor curve and the airtightness. However, wireless pressure sensors can be placed in abandoned wells to facilitate the monitoring of the airtightness of abandoned well plugging, save detection costs, save manpower, facilitate supervision, and continuously improve accuracy through continuous optimization, laying the foundation for optimizing abandoned well plugging technology and improving abandoned well reclamation.

[0032] Finally: The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An integrated abandoned well plugging quality evaluation method, characterized in that: The following steps are involved: S1. Before the plugging operation is carried out, a wireless pressure sensor is placed in the abandoned well to monitor the pressure changes in the abandoned plugging well; S2. Implement abandoned well plugging operations, inject a preset amount of cement slurry into the abandoned well, and after the cement slurry solidifies in the abandoned well, form a cement protective plug to plug the abandoned well; S3. Build a database to obtain a model of the relationship between the value change of the pressure sensor and the sealing performance; S4. Record the value of the pressure sensor, and the wireless pressure sensor regularly transmits the pressure curve in the plugged well; S5. Compare the pressure curve of the pressure sensor with the database model to evaluate the quality of plugging the abandoned well; The wireless pressure sensor uses high-precision and high-stability diffused silicon as a pressure-sensitive chip, advanced technology, supports point-to-point, point-to-multipoint, and serial port-to-serial port applications, transmits data through a GPRS wireless network, and the measured medium is liquid or gas. The pressure measurement range is 0-60MPa, and the ambient temperature is between -20 and 85°C. The placement depth of the wireless pressure sensor is greater than the depth of the cement plug. If the cement plugging depth of the abandoned well is 50 meters, the placement depth of the wireless pressure sensor is 80-100 meters. In order to ensure that the wireless pressure sensor is not damaged, it is surrounded by a hollow metal material and suspended in the abandoned plugging well by a high-temperature resistant and wear-resistant material; The cement slurry described in S2 is any slurry with sealing function, and the process of plugging the well is improved by adopting a segmented plugging method; The modeling tool used in the database is PowerDesigner, and the specific steps are as follows: a1. Collect a certain number of pressure values ​​of plugged downhole pressure sensors as a pressure database. The abandoned well is a well drilled in geological exploration. According to steps S1 and S2, operations are performed to obtain a database of downhole pressure value curves over time; a2. Obtain the sealing results of the plugged wells in the above steps, and test the sealing tightness of the abandoned wells by negative pressure. After plugging with cement plugs, the liquid column pressure above the cement plugs is reduced to at least the pressure of the water by pumping, gas lifting the liquid level, and low replacement negative pressure methods. The mud plug is isolated or blocked by half of the reservoir pressure value or a negative pressure of more than 10MPa, and the maximum does not exceed the safe value of the casing's anti-external squeeze strength. The liquid level in the well is monitored for 4h to 6h, and other influencing factors are eliminated. If the liquid level is not affected by the closed layer fluid and changes, the cement plug is qualified. In this way, the relationship between the pressure data of the pressure sensor and the airtightness is mapped; a3. Construct a mapping model between the pressure data of the pressure sensor and the airtightness. The mapping model is based on the Map-Reduce model, draws on the signal processing process, and processes large-scale data.

2. The integrated abandoned well plugging quality evaluation method according to claim 1 is characterized in that: The data cleaning in a1 is divided into three cases: (1) missing value processing. In the actual process of obtaining information and data, there will be various reasons that lead to data loss and vacancies. For these missing values, different methods will be used based on the distribution characteristics of the variables and the importance of the variables. If the missing rate of the variable is high, the coverage rate is low, and the importance is low, the variable is directly deleted. This method is called deleting the variable; if the missing rate is low and the importance is low, it is filled with basic statistics according to the data distribution. This method is called missing value filling. For missing data, decide whether to "delete" or "fill" based on the missing rate; (2) outlier processing outliers are the norm of data distribution. Data outside a specific distribution area or range is defined as anomalies or noise, and outliers are deleted; (3) inconsistent data processing. In the actual data production process, due to some human factors or other reasons, the recorded data is inconsistent. These inconsistent data need to be cleaned before analysis.

3. The integrated abandoned well plugging quality evaluation method according to claim 1 is characterized in that: The data processing in a3 includes three aspects: conversion of a data sequence, Map in Map-Reduce, obtaining another data sequence from one data sequence; conversion operations, including function mapping map and filtering filter operations, reducing the data sequence; Reduce in Map-Reduce, consuming the data sequence, counting or accumulating the data sequence, and reduction operations including summing, finding the maximum value, finding the minimum value, finding the number, and printing each element.