A method for optimizing rotary wellbore coring instrument

Abstract

The present invention discloses a method for optimizing a rotary sidewall coring instrument, comprising collecting statistics on sidewall coring operation records of operated wells, establishing a sidewall coring database, collecting statistics on rotary sidewall coring instrument operation records of operated wells, establishing a rotary sidewall coring instrument database, wherein the sidewall coring database includes physical property data of coring points at different horizons, can obtain physical property parameter ranges of different horizons, and establishes a rotary sidewall coring instrument selection chart based on the types of rotary sidewall coring instruments used at the coring points at different horizons. Based on data of the horizon to be cored and sidewall coring data required for experimental analysis, the rotary sidewall coring instrument database, the sidewall coring database, and the rotary sidewall coring instrument selection chart are combined to select the rotary sidewall coring instrument most suitable for operating in the horizon to be cored. The present invention aims to effectively improve operation efficiency and reduce exploration costs while ensuring the quality of core data and meeting the needs of geological research.

Description

Technical Field

[0001] The invention belongs to the technical field of offshore oil exploration and development, and in particular relates to an optimization method for a rotary well wall coring instrument. Background Art

[0002] In the process of oil exploration and development, core data is widely used to determine reservoir lithology, physical properties and other parameters. Currently, there are three ways to obtain core data: drilling coring, percussive sidewall coring, and rotary sidewall coring. The cores obtained by drilling coring are regular and highly representative of the formation information. They can be directly used for experimental analysis to obtain reservoir lithology and physical properties, and to conduct oil and gas content analysis. However, drilling coring operations are difficult to access the target layer and the operation cost is high. The wall cores obtained by percussive sidewall coring are relatively irregular, and the coring process will destroy the wall core pore structure, making the cores basically unusable for porosity and permeability analysis. Rotary sidewall coring, on the other hand, can accurately obtain the required cores, which can be used for experimental analysis to obtain formation parameters such as porosity, permeability, and saturation. In addition, sidewall coring is simple to operate, can obtain a large number of cores per trip, has a high success rate, and is relatively low in cost. Since its promotion and use, it has been widely used.

[0003] Currently, there are three main types of rotary sidewall coring instruments in common use: 1. Oilfield Services' large-diameter rotary sidewall coring; 2. Baker Hughes' large- and small-diameter rotary sidewall coring; and 3. Schlumberger's large- and small-diameter rotary sidewall coring. Each company's coring instruments have varying adaptability to different formations, resulting in varying coring quality. Currently, the most common method for selecting coring instruments is empirical, selecting the appropriate instrument based on the performance of the coring instruments in recent wells, the actual conditions of the wells to be operated, and the availability of each company's coring instruments. However, offshore operations are often demanding and costly. If a coring instrument malfunctions, it can be difficult to coordinate resources from land in a timely manner. Furthermore, with the large number of coring instruments currently available and the rapid pace of instrument upgrades, the varying adaptability of each instrument to different formations makes selection difficult. Summary of the Invention

[0004] The problem to be solved by the present invention is to provide a method for optimizing a rotary wellbore coring instrument, aiming to effectively improve operating efficiency and reduce exploration costs while ensuring the quality of core data and meeting the needs of geological research.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: a method for optimizing a rotary well wall coring instrument, characterized in that it includes the following steps:

[0006] S1: collecting records of sidewall coring operations of operated wells and establishing a sidewall coring database, wherein the sidewall coring database includes physical property data of coring points at different layers;

[0007] S2: obtaining the range of physical property parameters of different layers according to the physical property data of the coring points of different layers in the wellbore coring database;

[0008] S3: Collect the operation records of the rotary sidewall coring instrument in the operated wells and establish a rotary sidewall coring instrument database;

[0009] S4: obtaining the type of rotary sidewall coring instrument used for coring points at different layers, and establishing a rotary sidewall coring instrument selection chart based on the range of physical property parameters of different layers;

[0010] S5: Screening rotary sidewall coring instruments based on the data of the to-be-cored layer and the sidewall coring data required for experimental analysis and in combination with the rotary sidewall coring instrument database;

[0011] S6: Based on the data of the layer to be cored, the wellbore coring data required for experimental analysis and the screened operation data of the rotary wellbore coring instrument, combined with the wellbore coring database and the rotary wellbore coring instrument selection chart, a rotary wellbore coring instrument for the layer to be cored is selected.

[0012] Furthermore, in S1, the wellbore coring operation record includes the well name, block, type of the rotary wellbore coring instrument, size of the wall cores taken out by the rotary wellbore coring instrument and the number of wall cores harvested, number of operations of the rotary wellbore coring instrument, and number of drilling attempts by the rotary wellbore coring instrument.

[0013] Furthermore, in S1, the physical property data includes layer data, depth data, acoustic wave data and density data.

[0014] Furthermore, in S3, the rotary wellbore coring instrument operation record includes the weight, outer diameter, maximum temperature resistance, length, fault record and maintenance record of the coring instrument, and the fault record includes the number of faults, fault location and fault cause of the rotary wellbore coring instrument.

[0015] Furthermore, in S5, the data of the layer to be cored include layer position, acoustic wave, density, temperature, and borehole diameter.

[0016] Furthermore, in S5, the wellbore coring data required for the experimental analysis include coring size, recovery rate and integrity rate.

[0017] Furthermore, the yield calculation formula is:

[0018] The harvest rate = the number of harvested wall cores / the number of drilling attempts × 100%.

[0019] Furthermore, the number of harvested wall cores includes the number of broken wall cores and the number of intact wall cores, and the integrity rate calculation formula is:

[0020] The completeness rate=1-the number of the broken wall cores / the number of the harvested wall cores×100%.

[0021] Furthermore, in S6, the operation data of the rotary sidewall coring instrument includes a failure rate of the rotary sidewall coring instrument.

[0022] Furthermore, the failure rate calculation formula of the rotary wellbore coring instrument is:

[0023] The failure rate = 1 - the number of failures / the number of instrument operations × 100%.

[0024] The advantages and positive effects of the present invention are:

[0025] The present invention establishes a wellbore coring database based on wellbore coring operation records of operated wells. Based on the physical property data in the wellbore coring database, the physical property parameter ranges of different layers are obtained, and the operation records of rotary wellbore coring instruments in operated wells are counted to establish a rotary wellbore coring instrument database. The types of rotary wellbore coring instruments used for coring points at different layers are obtained, and the coring points with different physical property parameters are matched with the types of rotary wellbore coring instruments in combination with the physical property parameter ranges to obtain a rotary wellbore coring instrument selection chart. The instrument is optimized based on the data of the layer to be cored, the wellbore coring data required for experimental analysis, and the rotary wellbore coring instrument selection chart and the rotary wellbore coring instrument database. By collecting the wellbore coring operation records and rotary wellbore coring instrument operation records of operated wells, a wellbore coring database and a rotary wellbore coring instrument database are established, and a rotary wellbore coring instrument selection plate is generated by data matching between the two databases. Then, a rotary wellbore coring instrument is selected based on the wellbore coring database, the rotary wellbore coring instrument database and the rotary wellbore coring instrument selection plate. The rotary wellbore coring instrument selected by this method is the most suitable for the operating well environment among existing instruments. This method is accurate and fast and can effectively reduce exploration costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is an overall flow chart of an embodiment of the present invention.

[0027] Figure 2 1. It is a schematic diagram of a Schlumberger large diameter tool in a rotary sidewall coring tool selection diagram in a specific embodiment of the present invention;

[0028] Figure 3 1. It is a schematic diagram of a Schlumberger small diameter tool in a rotary sidewall coring tool selection diagram in a specific embodiment of the present invention;

[0029] Figure 4 Schematic diagram of a Baker Hughes large diameter tool in a rotary sidewall coring tool selection diagram in a specific embodiment of the present invention;

[0030] Figure 5 Schematic diagram of a Baker Hughes small diameter tool in a rotary sidewall coring tool selection diagram in a specific embodiment of the present invention;

[0031] Figure 6 It is a schematic diagram of a large-diameter oil and gas instrument in a selection diagram of a rotary wellbore coring instrument in a specific embodiment of the present invention. DETAILED DESCRIPTION

[0032] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0033] The embodiments of the present invention are further described below with reference to the accompanying drawings:

[0034] like Figure 1 As shown, a method for optimizing a rotary wellbore coring instrument comprises the following steps:

[0035] S1: Collect records of sidewall coring operations for operated wells and establish a sidewall coring database. Sidewall coring operation records include the well name, block, rotary sidewall coring instrument type, sidewall core size and number of cores retrieved by the rotary sidewall coring instrument, number of rotary sidewall coring instrument operations, and number of rotary sidewall coring instrument drilling attempts.

[0036] Among them, the well name and block are used to record the geographical location information of the operated well for easy future search. Recording the type of rotary wall coring instrument used is convenient for matching the rotary wall coring instrument with the coring point of accurate layer and physical parameters when establishing the rotary wall coring instrument selection chart. Recording the size of the wall core drilled and the number of wall cores harvested is used to query the coring capacity of the rotary wall coring instrument. Recording the number of times the rotary wall coring instrument is operated and the number of times the rotary wall coring instrument has attempted to drill is used to show the performance of the rotary wall coring instrument. In another embodiment, the wall coring operation record may also not include the number of times the rotary wall coring instrument is operated and the number of times the rotary wall coring instrument has attempted to drill. The performance of the rotary wall coring instrument is reflected by recording the drill bit wear data and drill bit replacement data of the rotary wall coring instrument.

[0037] The wellbore coring database includes the physical property data of coring points in different layers, and the physical property data includes layer data, depth data, acoustic wave data and density data.

[0038] The horizon and depth can reflect the location of the core sampling point. Acoustic wave and density data best reflect rock drillability. Scatter plots of density and acoustic wave data from core sampling points at different horizons can be used to obtain the ranges of physical property parameters for different horizons. For example, for the Neogene, acoustic wave 85-120µs / ft, density 2.15-2.35g / cm³; for the Paleogene, acoustic wave 65-85µs / ft, density 2.35-2.45g / cm³; and for the pre-Paleogene, acoustic wave 50-65µs / ft, density 2.45-2.7g / cm³. In another embodiment, the physical property data can also include resistivity or gamma ray data.

[0039] S2: According to the physical property data of the coring points at different layers in the wellbore coring database, the range of physical property parameters of different layers is obtained.

[0040] S3: Collect the operation records of rotary sidewall coring instruments in operated wells and establish a rotary sidewall coring instrument database. Rotary sidewall coring instrument operation records include the weight, outer diameter, maximum temperature resistance, length, fault records, and maintenance records of the coring instruments. Fault records include the number of rotary sidewall coring instrument failures, the location of the failure, and the cause of the failure.

[0041] Basic data of the rotary sidewall coring instrument, such as weight, outer diameter, length, and maximum temperature resistance, is recorded to serve as a reference for selecting a rotary sidewall coring instrument based on the actual well conditions. Failure and maintenance records of the rotary sidewall coring instrument are also recorded to highlight operational risks associated with the selected rotary sidewall coring instrument. In another embodiment, the rotary sidewall coring instrument operation record also includes drill bit data for the rotary sidewall coring instrument.

[0042] S4: Obtain the types of rotary sidewall coring instruments used at coring points in different layers, and establish a rotary sidewall coring instrument selection chart based on the range of physical property parameters of different layers.

[0043] S5: Rotary sidewall coring instruments are selected based on the data of the horizon to be cored and the sidewall coring data required for experimental analysis, in conjunction with the rotary sidewall coring instrument database. The data of the horizon to be cored includes horizon position, acoustic wave, density, temperature, and wellbore diameter. The reference physical property parameter range for selecting a rotary sidewall coring instrument for the horizon to be operated in the well to be operated is consistent with at least some data types in the sidewall coring database, facilitating matching and querying data information. In another embodiment, the data of the horizon to be cored includes resistivity, gamma, neutron density, and lithologic data of the horizon to be cored.

[0044] The wellbore coring data required for experimental analysis include coring size, recovery rate and completeness rate. A larger wall core size can better measure the real data of the cored formation. At the same time, when coring in an operating well, the more wall cores drilled and the more complete the wall cores, the more conducive it is to the experimental analysis of the real data of the cored formation. In addition, when coring in an operating well, coring points at different positions will be opened in the same layer. Due to the different lithology of the wellbore rock types in the layer to be cored, such as the rock is too hard or too soft, and the performance of the rotary wellbore coring instrument cannot match the lithology of the wellbore rock in the layer to be cored, there is a situation where the rotary wellbore coring instrument cannot remove the wall core when drilling at the coring point. In another embodiment, the wellbore coring data required for experimental analysis may not include recovery rate and completeness rate.

[0045] Specifically, the formula for calculating the yield rate is:

[0046] Harvest rate = number of harvested wall cores / number of drilling attempts × 100%.

[0047] The core recovery rates of different rotary sidewall coring instruments at different layers are calculated using the sidewall coring database data. The higher the sidewall coring recovery rate, the better the adaptability of the coring instrument to the formation. The instrument with a high sidewall coring recovery rate is preferred.

[0048] The number of harvested wall cores includes the number of broken wall cores and the number of intact wall cores. The calculation formula for the integrity rate is:

[0049] Completeness rate = 1-number of broken wall cores / number of harvested wall cores × 100%.

[0050] The data from the wellbore coring database is used to calculate the coring integrity rates of different instruments in different layers. The higher the wellbore coring integrity rate, the better the coring quality. Instruments with high wellbore coring integrity rates are preferred.

[0051] S6: Based on the data of the desired coring zone, the sidewall coring data required for experimental analysis, and the selected rotary sidewall coring instrument operation data, combined with the sidewall coring database and the rotary sidewall coring instrument selection chart, a rotary sidewall coring instrument is selected for the desired coring zone. The rotary sidewall coring instrument operation data includes its failure rate. The failure probability of different instruments at different zones is calculated using data from the rotary sidewall coring instrument database. The lower the failure rate of the rotary sidewall coring instrument, the higher the coring efficiency. Therefore, a rotary sidewall coring instrument with a low failure rate is selected for operation.

[0052] Specifically, the failure rate calculation formula of the rotary wellbore coring instrument is:

[0053] Failure rate = 1 - number of failures / number of times the instrument has been operated × 100%. In another embodiment, the operating data of the rotary sidewall coring instrument includes the damage level of the rotary sidewall coring instrument, parts maintenance, and parts replacement records.

[0054] In the present invention, the type of rotary sidewall coring instrument is preliminarily selected based on the borehole diameter and temperature of the layer to be cored, and the laboratory's requirements for wall core size. Then, the failure records, wall core recovery rates, and integrity rates of the rotary sidewall coring instrument in each layer are checked in the rotary sidewall coring instrument database, and the rotary sidewall coring instrument is further optimized. Finally, according to the rotary sidewall coring instrument selection chart, the coring points are matched with the rotary sidewall coring instrument types to find the optimal coring instrument.

[0055] The technical solution of the present invention is further described below with reference to specific embodiments. Figure 2-Figure 6 As shown, the horizontal axis is the sound wave, the unit is µs / ft, and the vertical axis is the density, the unit is g / cm³. Figure 2 The △ in the figure represents the Schlumberger large diameter coring tool. Figure 3 The △ in the figure represents Schlumberger small diameter coring tool. Figure 4 The □ in the figure indicates Baker Hughes large diameter coring tool. Figure 5 The × in the figure indicates Baker Hughes small diameter coring tool. Figure 6 The ○ in the middle represents the large-diameter coring instrument produced by CNPC.

[0056] This method is applied in an exploration well A in an oil field:

[0057] The specific implementation steps are as follows:

[0058] S1: Collect records of sidewall coring operations in operated wells and establish a sidewall coring database. Specifically, based on the principle of big data, an innovative sidewall coring database is established to unify scattered single-well coring data into the database and update it in real time to facilitate subsequent statistical searches and provide important data for other project research.

[0059] S2: Based on the physical property data of coring points in different layers in the sidewall coring database, the physical property parameter ranges for different layers are obtained. Specifically, based on the matching of the established reservoir physical property parameter ranges with the types of rotary sidewall coring instruments, an innovative principle for selecting rotary sidewall coring instruments is established: for coring Neogene formations, large-diameter sidewall coring instruments from Oil Service and Technology are preferred; for coring Paleogene formations, small-diameter sidewall coring instruments from Schlumberger are preferred.

[0060] S3: Collect the operation records of rotary sidewall coring instruments in operated wells and establish a rotary sidewall coring instrument database; innovatively establish a rotary sidewall coring instrument database based on big data principles, and collect the parameters, fault records, maintenance records and other data of each service provider's rotary sidewall coring instruments in the database and update them in real time, which is conducive to real-time tracking of the instrument's operating performance, current dynamics and preparation status, and provides convenience for coring instrument optimization and operation record query.

[0061] S4: Obtain the type of rotary sidewall coring instrument used for coring points at different layers, and establish a rotary sidewall coring instrument selection chart based on the range of physical property parameters of different layers;

[0062] S5: Screening rotary sidewall coring instruments based on the data of the to-be-cored layer and the sidewall coring data required for experimental analysis and in combination with the rotary sidewall coring instrument database;

[0063] Specifically, the core layer of Well A is the Paleogene, with a core depth of 4200-4450m. The core layer data is: acoustic wave 75-88µs / ft, density 2.39-2.45g / cm³, core section hole size 8.5in, temperature 130℃;

[0064] According to the experimental analysis requirements, large-diameter wall cores are required. According to the preliminary selection results, the large-diameter rotary wall coring instruments that meet the requirements include Oilfield Services Oil Technology coring instruments, Baker Hughes coring instruments, and Schlumberger coring instruments. The Baker Hughes coring instruments have a core recovery rate of 75%, an integrity rate of 81.82%, and a failure rate of 22.22% in Paleogene formations; the Oilfield Services Oil Technology coring instruments have a core recovery rate of 80%, an integrity rate of 78.3%, and a failure rate of 25.5% in Paleogene formations; and the Schlumberger coring instruments have a core recovery rate of 45%, an integrity rate of 75%, and a failure rate of 33.33% in Paleogene formations. Based on the screening results, the large-diameter coring instruments from Oilfield Services Oil Technology and Baker Hughes are preferred.

[0065] S6: Based on the data of the layer to be cored, the wellbore coring data required for experimental analysis and the screened operation data of the rotary wellbore coring instrument, combined with the wellbore coring database and the rotary wellbore coring instrument selection chart, a rotary wellbore coring instrument for the layer to be cored is selected.

[0066] Specifically, based on the matching results between the coring points and the types of rotary sidewall coring instruments in the rotary sidewall coring instrument selection chart, the coring instrument is further optimized. The rotary sidewall coring instrument selection chart shows that the Baker Hughes coring instrument is more suitable for operations in the Paleogene formation, and the Oil Service and Oil Technology coring instrument is more suitable for operations in the Neogene formation. Based on the above results, the Baker Hughes large-diameter coring instrument is preferred.

[0067] In summary, the present invention establishes a wellbore coring database based on the wellbore coring operation records of the operated wells. Based on the physical property data in the wellbore coring database, the physical property parameter ranges of different layers are obtained, and the operation records of the rotary wellbore coring instruments of the operated wells are counted to establish a rotary wellbore coring instrument database. The types of rotary wellbore coring instruments used for coring points in different layers are obtained, and the coring points with different physical property parameters are matched with the types of rotary wellbore coring instruments in combination with the ranges of physical property parameters to obtain a rotary wellbore coring instrument selection chart. The instrument is optimized by combining the data of the layer to be cored and the wellbore coring data required for experimental analysis with the rotary wellbore coring instrument selection chart and the rotary wellbore coring instrument database. By collecting the wellbore coring operation records and rotary wellbore coring instrument operation records of operated wells, a wellbore coring database and a rotary wellbore coring instrument database are established, and a rotary wellbore coring instrument selection plate is generated by data matching between the two databases. Then, a rotary wellbore coring instrument is selected based on the wellbore coring database, the rotary wellbore coring instrument database and the rotary wellbore coring instrument selection plate. The rotary wellbore coring instrument selected by this method is the most suitable for the operating well environment among existing instruments. This method is accurate and fast and can effectively reduce exploration costs.

[0068] The above is a detailed description of an embodiment of the present invention. However, the content described is only a preferred embodiment of the present invention and should not be considered to limit the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A method for optimizing a rotary wellbore coring instrument, characterized in that: The following steps are included: S1: collecting records of sidewall coring operations of operated wells and establishing a sidewall coring database, wherein the sidewall coring database includes physical property data of coring points at different layers; S2: obtaining the range of physical property parameters of different layers according to the physical property data of the coring points of different layers in the wellbore coring database; S3: Collect the operation records of the rotary sidewall coring instrument in the operated wells and establish a rotary sidewall coring instrument database; S4: obtaining the type of rotary sidewall coring instrument used for coring points at different layers, and establishing a rotary sidewall coring instrument selection chart based on the range of physical property parameters of different layers; S5: Screening rotary sidewall coring instruments based on the data of the to-be-cored layer and the sidewall coring data required for experimental analysis and in combination with the rotary sidewall coring instrument database; S6: Based on the data of the layer to be cored, the wellbore coring data required for experimental analysis and the screened operation data of the rotary wellbore coring instrument, combined with the wellbore coring database and the rotary wellbore coring instrument selection chart, a rotary wellbore coring instrument for the layer to be cored is selected.

2. The method for optimizing a rotary wellbore coring instrument according to claim 1, characterized in that: In S1, the wellbore coring operation record includes the well name, block, type of the rotary wellbore coring instrument, size of the wall cores taken out by the rotary wellbore coring instrument and the number of wall cores obtained, number of rotary wellbore coring instrument operations, and number of rotary wellbore coring instrument drilling attempts.

3. A method for optimizing a rotary wellbore coring instrument according to claim 1 or 2, characterized in that: In S1, the physical property data includes layer data, depth data, acoustic wave data and density data.

4. The method for optimizing a rotary wellbore coring instrument according to claim 2, characterized in that: In S3, the rotary wellbore coring instrument operation record includes the weight, outer diameter, maximum temperature resistance, length, fault record and maintenance record of the coring instrument. The fault record includes the number of faults, fault location and fault cause of the rotary wellbore coring instrument.

5. A method for optimizing a rotary wellbore coring instrument according to claim 1 or 2, characterized in that: In S5, the data of the layer to be cored include layer position, acoustic wave, density, temperature, and borehole diameter.

6. The method for optimizing a rotary wellbore coring instrument according to claim 2, characterized in that: In S5, the wellbore coring data required for the experimental analysis include coring size, recovery rate and integrity rate.

7. The method for optimizing a rotary wellbore coring instrument according to claim 6, characterized in that: The yield calculation formula is: The harvest rate = the number of harvested wall cores / the number of drilling attempts × 100%.

8. The method for optimizing a rotary wellbore coring instrument according to claim 6, characterized in that: The number of harvested wall cores includes the number of broken wall cores and the number of intact wall cores. The calculation formula for the integrity rate is: The completeness rate=1-the number of the broken wall cores / the number of the harvested wall cores×100%.

9. The method for optimizing a rotary wellbore coring instrument according to claim 4, characterized in that: In S6, the operation data of the rotary sidewall coring tool includes a failure rate of the rotary sidewall coring tool.

10. The method for optimizing a rotary wellbore coring instrument according to claim 9, characterized in that: The failure rate calculation formula of the rotary wellbore coring instrument is: The failure rate = 1 - the number of failures / the number of instrument operations × 100%.

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