Semi-submersible drilling platform casing length allocation optimization method and system, medium and terminal

Abstract

The invention provides a semi-submersible drilling platform casing length allocation optimization method, a semi-submersible drilling platform casing length allocation optimization system, a medium and a terminal, based on a dynamic programming algorithm, a semi-submersible drilling platform casing length allocation problem is converted into a 0-1 knapsack problem, the optimal allocation length closest to a target is calculated by establishing a dynamic programming model, and then an optimal casing string combination is traced back. The method is simple in calculation process, high in calculation speed, extremely small in error, high in stability, low in cost and beneficial to field popularization and application.

Description

Technical Field

[0001] The invention relates to the field of oil and gas well engineering in petroleum engineering, and in particular to a casing length optimization method, system, medium and terminal for a semi-submersible drilling platform. Background Art

[0002] The traditional method of matching casing length is through on-site supervision or manual matching by technicians, which is not accurate enough to match the well depth, and the error is usually 2 to 5 meters. In drilling operations on land or offshore jack-up platforms, when using general slip hangers, the casing can be cut to match the lowered casing with the well depth and the hanger position. At present, with the strategic deployment of a strong maritime nation, the process of deep-sea exploration and development has accelerated, and semi-submersible drilling platforms that can adapt to deeper water depths have been widely put into use. The casing hanger and casing at the underwater wellhead of the semi-submersible drilling platform are sealed with metal threads, and the length cannot be matched by cutting the casing. If the length of the matching casing string is too long or too short, the reserved pocket length will deviate from the design, affecting the cementing quality, and even causing the casing to fail to hang. The casing lowering condition of the semi-submersible drilling platform puts higher requirements on the accurate casing length matching algorithm. Summary of the invention

[0003] In view of the above-mentioned shortcomings of the prior art, the present invention provides a method, system, medium and terminal for optimizing the length of casing of a semi-submersible drilling platform, which can quickly determine the optimal casing running combination without cutting the casing.

[0004] To achieve the above-mentioned purpose and other related purposes, the present invention provides a method for optimizing the length of casing of a semi-submersible drilling platform, comprising:

[0005] Step 1, measuring the specification parameters of the casing on the site, recording the corresponding number and length of each casing to form a site casing table;

[0006] Step 2, determining the target length according to the well depth and the distance between the bottom surface of the casing hanger and the depth reference plane;

[0007] Step 3: The casing length matching problem of the semi-submersible drilling platform is regarded as a 0-1 knapsack problem, the casing number is regarded as the type of the item to be loaded, and the casing length is regarded as the value of the item to be loaded. The optimal casing string combination is determined according to the target length matching.

[0008] In one embodiment of the invention, the step 1 further includes:

[0009] Step 11: Determine the buckle type of the casing, and measure the total length of the casing having the buckle type according to a preset standard;

[0010] Step 12: Measure the buckle length of the sleeve. The length of the sleeve is calculated as the total length of the sleeve minus the buckle length of the sleeve.

[0011] In one embodiment of the invention, the step 2 further includes:

[0012] Step 21: Determine the middle completion depth H of the current well opening and the length d1 of the reserved pocket, measure the distance d2 between the bottom surface of the casing hanger and the base plate, measure the distance d3 between the base plate and the depth reference plane, measure the length d4 of the float collar, and measure the length d5 ​​of the float shoe. The required theoretical casing length D is: D = H-d1-d2-d3-d4-d5;

[0013] Step 22: Determine the single piece of casing that must be selected in the casing string according to the preset requirements, record the number of the single piece of casing, calculate the total length of the single piece of casing as d6, and the actual required casing length L=D-d6.

[0014] In one embodiment of the invention, step 3 further includes:

[0015] Step 31: The number in step 1 is the original site number. After executing step 2, the remaining available casings on the site are re-marked according to the natural number sequence to obtain the new site number corresponding to the casing. According to the on-site measurement accuracy requirements, the length of the casing l i and the target length L are normalized to integers; the casing length problem is converted into a 0-1 knapsack problem in dynamic programming, where the knapsack capacity is the target length L, the item type is the new site number of the casing, and the item value is the length l of the casing i ;

[0016] Step 32: Initialize the dynamic programming table: dp int ={0,-1,-1,…,-1,-1}, where the number of -1 is L, and L is the normalized target length;

[0017] Step 33: Traverse each casing according to the new site number. For each casing, change the length j from the target length L to the casing length l. iq Reverse order traversal, that is, j∈(L,L-1,L-2...l iq ), during the traversal, dp j Updated to dp j and The larger value of Simultaneously record dp j The new site number q of the casing during update is used to facilitate subsequent tracing back to the selected casing;

[0018] Step 34: After the traversal process is completed, read the last value of the dynamic programming table: dp L That is, when the required length is L, the total length of the casing that can be combined is closest to L;

[0019] Step 35: Start reverse tracing from the final dynamic planning table dp, and trace back the new site number q of the casing in the casing combination that can meet the target length matching. According to the corresponding relationship between the new site number and the original site number in step 31, further trace back the original site number of the casing in the casing combination that meets the target length matching.

[0020] In order to achieve the above-mentioned and other related purposes, the present invention also provides a semi-submersible drilling platform casing length calculation system, comprising:

[0021] A data acquisition module, which is used to obtain the number and length of the casing on the site, the target length, and the number corresponding to the single casing that must be used according to preset requirements;

[0022] A model operation module, the model operation module is used to establish a dynamic programming model, the dynamic programming model is established based on the casing length optimization method of the semi-submersible drilling platform, so as to calculate and obtain the optimal casing string combination;

[0023] The data output module is used to output the calculated optimal casing string combination to an electronic document, and the data in the electronic document includes the label of the optimal casing string combination, the length of the casing and the cumulative length of the casing.

[0024] To achieve the above-mentioned purpose and other related purposes, the present invention also provides a computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the method for optimizing the casing length of a semi-submersible drilling platform is implemented.

[0025] To achieve the above-mentioned object and other related objects, the present invention also provides an electronic terminal, including: a processor, a memory and a transceiver;

[0026] The transceiver is used to communicate with an external device; the memory is used to store a computer program, and the processor is used to execute the computer program stored in the memory, so that the electronic terminal executes the semi-submersible drilling platform casing length optimization method.

[0027] As described above, the method, system, medium and terminal for optimizing the length of casing of a semi-submersible drilling platform provided by the present invention have the following beneficial effects: the present invention solves the problem of optimizing the length of casing of a semi-submersible drilling platform based on a dynamic programming algorithm. The present invention has a simple calculation process, a short calculation time, and a calculation result that is definitely the global optimal solution, which effectively solves the length problem of casing of a semi-submersible drilling platform under the premise that the casing cannot be cut. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a flow chart of steps for establishing a method for optimizing casing length of a semi-submersible drilling platform;

[0029] Figure 2 It is an algorithm flow chart for establishing a casing length optimization method for a semi-submersible drilling platform;

[0030] Figure 3 It is a structural schematic diagram of a casing length calculation system for a semi-submersible drilling platform in one embodiment of the present invention;

[0031] Figure 4 It is a schematic diagram of the structure of an electronic terminal in one embodiment of the present invention.

[0032] Figure 5 This is a schematic diagram of the relative positions of the middle datum surface, base plate, hanger, float collar, float shoe, middle completion depth, etc. DETAILED DESCRIPTION

[0033] The following is a description of the implementation of the present invention by means of specific embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

[0034] It should be noted that the structures, proportions, sizes, etc. drawn in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention, so they have no substantial technical significance. Any modification of the structure, change of the proportional relationship or adjustment of the size should still fall within the scope of the technical content disclosed by the present invention without affecting the effects and purposes that can be achieved by the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of description, and are not used to limit the scope of the implementation of the present invention. The change or adjustment of their relative relationship should also be regarded as the scope of the implementation of the present invention without substantially changing the technical content.

[0035] In order to facilitate those skilled in the art to better understand the technical solution of the present invention, the definitions of professional terms are as follows (which can be combined with Figure 5 To understand):

[0036] Medium completion depth: the distance from the reference plane to the current completion position of the drilling. Reserved pocket length: the length of the space from the bottom of the casing string to the bottom of the well reserved for the safety of lowering the casing. Float collar: a short section of casing coupling equipped with a check valve, generally installed between the lowest few casings. Float shoe: a short section of a check valve installed at the end of the casing string, used in conjunction with the float collar. Single piece of casing: the single piece of casing in the present invention refers to a single piece of casing of a specific length that must be added to the casing string for reasons such as depth calibration and positioning.

[0037] The present application provides a method, system, medium and terminal for optimizing casing length of a semi-submersible drilling platform, which can quickly and accurately provide a solution for optimizing the combination of casing strings according to target length.

[0038] The essence of this invention is a new application invention of the "knapsack problem", that is, for the first time, the "knapsack problem" is applied to the casing length matching problem of a semi-submersible drilling platform, specifically, the hanger casing length matching problem of the underwater wellhead of a semi-submersible drilling platform. Among them, the "knapsack problem" is an NP-complete problem of combinatorial optimization. The problem can be described as: given a set of items, each item has its own weight and price. Within the limited total weight, how can we choose to make the total price of the items the highest, combined with Figure 1 and Figure 5 The semi-submersible drilling platform casing length optimization method involved in this application comprises the following steps:

[0039] Step 1, measure the casing on the site, record the casing number (i.e., site number) and length, and form a site casing table; Step 2, determine the target length according to the well depth and the distance between the bottom of the casing hanger and the depth reference plane; Step 3, regard the casing length problem of the semi-submersible drilling platform as a 0-1 knapsack problem, regard the site casing number as the type of items to be loaded, and regard the site casing length as the value of the items to be loaded, and determine the optimal casing string combination according to the target length.

[0040] In one embodiment of the invention, step 1 also includes: step 11: determine the buckle type of the sleeve, and measure the length of the buckle type sleeve according to relevant standards; step 12: measure the buckle length of the sleeve, and calculate the required sleeve length as the total length of the sleeve minus the buckle length of the sleeve.

[0041] S1. Measure the field casing, record the casing number and length data, and form a field casing table. The specific steps for measuring the casing length are:

[0042] S11. Determine the buckle type of the casing, measure the length of all available casings of the model required for the current opening according to the buckle type measurement standard, record the total number of suitable casings as N, mark the original site number of each casing as i, and record the length of each casing as l' i ;

[0043] S12, measure the buckle length of the buckle type as k, and update the length of the sleeve l i =l' i -k.

[0044] S2. Determine the target length according to the well depth, the length of the reserved pocket, the distance between the bottom of the casing hanger and the depth reference plane, and the length of the single casing that must be used. The steps for determining the target length include:

[0045] S21, determine the middle completion depth H of the current well opening, reserve the pocket length d1, measure the distance d2 between the bottom surface of the casing hanger and the base plate, measure the distance d3 between the base plate and the depth reference plane, measure the length d4 of the float collar, and measure the length d5 ​​of the float shoe. The required casing length D is: D = H-d1-d2-d3-d4-d5;

[0046] S22. Determine the single casing that must be selected in the casing string according to the electrical positioning requirements or other requirements, and record its field marking i1, i2…i n , where n is the number of single casings that must be selected in the casing string, and their lengths (minus the buckle length) are li1, li2…li n , then the actual casing length L that needs to be calculated is:

[0047] S3. The casing length matching problem of the semi-submersible drilling platform is regarded as a 0-1 knapsack problem, the casing number of the site is regarded as the type of the item to be loaded, and the casing length of the site is regarded as the value of the item to be loaded. The optimal combination of casing strings is determined according to the target length matching. The steps for determining the optimal combination of casing strings include:

[0048] S31. Re-mark the remaining site casings, and the new site number is q, q∈(0,1,2...Nn). The new site number does not cover the original site number. The accuracy of the on-site measurement of the casing length is generally retained to three decimal places. i Multiply the target length L by 1000. At this time, the casing length problem is converted into a 0-1 knapsack problem in dynamic programming, with the knapsack capacity being L, the item type being the casing site number i, and the item value being the casing length li:

[0049] S32, define the dynamic programming table dp, whose list length is L+1, dp j Indicates the maximum total length of the casing that can be allocated when the length is j. Initialize the dynamic planning table dp: dp int ={0,-1,-1,…,-1,-1}, where the number of -1 is L, and L is the normalized target length.

[0050] S33, traverse each casing q∈(0,1,2...Nn), for each casing q, change j from L to l iq Reverse order traversal, j∈(L,L-1,L-2...l iq ), during the traversal, dp j Updated to dp j and The larger value of: During the traversal, record dp j The new site number q of the casing is updated to facilitate subsequent tracing of which casings are selected.

[0051] S34, after the traversal is completed, dp L That is, when the required length is L, the total length that the site casing can combine to be closest to L.

[0052] S35, from dp L Start reverse tracking and trace back to the new site number q of the casing that meets the target length casing combination.

[0053] S36, according to the correspondence between the new site number q and the original site number i, find the original site number i and the casing length l that meet the target matching length casing combination i , this is the most optimized casing length solution.

[0054] like Figure 2 As shown, an algorithm flow chart of a casing length optimization model corresponding to a casing length optimization method for a semi-submersible drilling platform in one embodiment of the present invention is shown. In this embodiment, the input of the casing length optimization model includes a target length, a field casing table (including a number and casing length), and a required accuracy, and the output of the model is an optimal combination of casing strings that constitute the target length.

[0055] It is worth noting that the traditional method of matching casing length is through on-site supervision or manual matching by technicians, and the matching with the well depth is not accurate, and the error is usually 2 to 5 meters. When using a cava-type hanger on an existing self-elevating platform or on land, the lowered casing can be matched with the well depth and the hanger position by cutting the casing. At present, with the advancement of marine oil and gas exploration and development into the deep sea, semi-submersible drilling platforms that can adapt to deeper water depths are widely put into use. The casing hanger and casing at the underwater wellhead of a semi-submersible drilling platform are often sealed with metal threads, and the length cannot be matched by cutting the casing, which puts forward more precise requirements for the casing length matching algorithm. The casing length optimization method of the present invention has a simple calculation process, short time consumption, and the error is generally within 0.5m. The error can be completely eliminated by adjusting the pocket length, which is conducive to on-site promotion and application.

[0056] Those skilled in the art can understand that all or part of the steps of implementing the above-mentioned method embodiments can be completed by hardware related to the computer program. The aforementioned computer program can be stored in a computer-readable storage medium. When the program is executed, the steps of the above-mentioned method embodiments are executed; and the aforementioned storage medium includes: ROM, RAM, magnetic disk or optical disk and other media that can store program codes.

[0057] like Figure 3As shown, a schematic diagram of the structure of a semi-submersible drilling platform casing length calculation system (which can be referred to as a casing length optimization system) in one embodiment of the present invention is shown. The semi-submersible drilling platform casing length calculation system includes a data acquisition module 31, a model operation module 32 and a data output module 33; wherein the data acquisition module 31 is used to obtain the target length, the site casing table data (including the number and the casing length), the required accuracy, the number and length of the single casing that must be used; the model operation module 32 is used to establish a dynamic programming algorithm model, and calculate the optimal casing string combination based on the semi-submersible drilling platform casing length optimization method provided by the present invention; the data output module 33 is used to output the calculated optimal casing string combination data to an electronic document, such as a csv or excel file, and the output data includes the number of the optimal casing string combination, the length of the casing and the cumulative length of the casing.

[0058] It should be noted that it should be understood that the division of the various modules of the above device is only a division of logical functions. In actual implementation, they can be fully or partially integrated into one physical entity, or they can be physically separated. And these modules can all be implemented in the form of software calling through processing elements; they can also be all implemented in the form of hardware; some modules can also be implemented in the form of software calling through processing elements, and some modules can be implemented in the form of hardware. The implementation method of the semi-submersible drilling platform casing lengthening system in this embodiment is similar to the implementation method of the semi-submersible drilling platform casing lengthening method mentioned above, so it will not be repeated.

[0059] like Figure 4 As shown, a schematic diagram of the structure of an electronic terminal in an embodiment of the present invention is shown. The electronic terminal provided in this example includes: a processor 41, a memory 42, a transceiver 43, a communication interface 44 and a system bus 45; the memory 42 and the communication interface 44 are connected to the processor 41 and the transceiver 43 through the system bus 45 and complete the communication between them, the memory 42 is used to store computer programs, the communication interface 44 and the transceiver 43 are used to communicate with other devices, and the processor 41 is used to run the computer program, so that the electronic terminal executes the various steps of the semi-submersible drilling platform casing lengthening method as above.

[0060] The system bus mentioned above can be a Peripheral Pomponent Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus, etc. The system bus can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, only one thick line is used in the figure, but it does not mean that there is only one bus or one type of bus. The communication interface is used to realize the communication between the database access device and other devices (such as clients, read-write libraries, and read-only libraries). The memory may include random access memory (RAM), and may also include non-volatile memory, such as at least one disk storage.

[0061] The above-mentioned processor can be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it can also be a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components.

[0062] Furthermore, the following provides a specific application implementation case of the casing length optimization method for a semi-submersible drilling platform. A semi-submersible drilling platform undertakes a specific exploratory well drilling operation in a certain sea area. The well depth is 1912m in the third opening, the hanger is 16.87m from the depth reference plane, the float shoe length is 0.7m, the float collar length is 0.25m, and the reserved pocket depth is 5m. In order to determine the optimal casing string combination, the following steps are performed according to the optimization method of the present invention:

[0063] The first step is to measure the length of the field casing and mark the field number of the casing to form a field casing table, as shown in Table 1:

[0064] Table 1 Site casing table (length without buckle)

[0065]

[0066]

[0067] The second step is to determine the target length. The completion depth of the third well is 1912m, the hanger is 16.87m from the depth reference plane, the float shoe length is 0.7m, the float collar length is 0.25m, the reserved pocket depth is 5m, and no specific casing is required. According to step 2 of the present invention, the target casing length is 1889.18m.

[0068] In the third step, the site casing table and the target length are used as input data, and the semi-submersible drilling platform casing length optimization method of the present invention is used to construct and calculate the dynamic planning casing length optimization model, and output the optimal casing string combination, as shown in Table 2. The final actual casing length is 1889.18m, and the error with the target casing length is 0.

[0069] Table 2 Optimized casing string combination

[0070]

[0071]

[0072] In summary, the present invention provides a method, system, storage medium and electronic terminal for optimizing the length of casing of a semi-submersible drilling platform. The present invention is based on a dynamic programming algorithm, which converts the length problem of the semi-submersible drilling platform into a 0-1 knapsack problem, calculates the optimal length closest to the target by establishing a dynamic programming model, and then backtracks to optimize the casing string combination. The method has a simple calculation process, fast calculation speed, extremely small error, strong stability, and low cost, which is conducive to on-site promotion and application. Therefore, the present invention effectively overcomes the various shortcomings of the prior art and has a high industrial utilization value.

[0073] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A method for optimizing casing length of a semi-submersible drilling platform, characterized in that: include: Step 1, measuring the specification parameters of the casing on the site, recording the corresponding number and length of each casing to form a site casing table; Step 2, determining the target length according to the well depth and the distance between the bottom surface of the casing hanger and the depth reference plane; Step 3: The casing length matching problem of the semi-submersible drilling platform is regarded as a 0-1 knapsack problem, the casing number is regarded as the type of the item to be loaded, and the casing length is regarded as the value of the item to be loaded. The optimal casing string combination is determined according to the target length matching.

2. The method for optimizing casing length of a semi-submersible drilling platform according to claim 1, characterized in that: The step 1 also includes: Step 11: Determine the buckle type of the casing, and measure the total length of the casing having the buckle type according to a preset standard; Step 12: Measure the buckle length of the sleeve. The length of the sleeve is calculated as the total length of the sleeve minus the buckle length of the sleeve.

3. The method for optimizing casing length of a semi-submersible drilling platform according to claim 1, characterized in that: The step 2 also includes: Step 21: Determine the middle completion depth H of the current well opening and the length d1 of the reserved pocket, measure the distance d2 between the bottom surface of the casing hanger and the base plate, measure the distance d3 between the base plate and the depth reference plane, measure the length d4 of the float collar, and measure the length d5 ​​of the float shoe. The required theoretical casing length D is: D = H-d1-d2-d3-d4-d5; Step 22: Determine the single piece of casing that must be selected in the casing string according to the preset requirements, record the number of the single piece of casing, calculate the total length of the single piece of casing as d6, and the actual required casing length L=D-d6.

4. The method for optimizing casing length of a semi-submersible drilling platform according to claim 1, characterized in that: The step 3 also includes: Step 31: The number in step 1 is the original site number. After executing step 2, the remaining available casings on the site are re-marked according to the natural number sequence to obtain the new site number corresponding to the casing. According to the on-site measurement accuracy requirements, the length of the casing l i and the target length L are normalized to integers; the casing length problem is converted into a 0-1 knapsack problem in dynamic programming, where the knapsack capacity is the target length L, the item type is the new site number of the casing, and the item value is the length l of the casing i ; Step 32: Initialize the dynamic programming table: dp int ={0,-1,-1,…,-1,-1}, where the number of -1 is L, and L is the normalized target length; Step 33: Traverse each casing according to the new site number. For each casing, change the length j from the target length L to the casing length l. iq Reverse order traversal, that is, j∈(L,L-1,L-2...l iq ), during the traversal, dp j Updated to dp j and The larger value of Simultaneously record dp j The new site number q of the casing during update is used to facilitate subsequent tracing back to the selected casing; Step 34: After the traversal process is completed, read the last value of the dynamic programming table: dp L That is, when the required length is L, the total length of the casing that can be combined is closest to L; Step 35: Start reverse tracing from the final dynamic planning table dp, and trace back the new site number q of the casing in the casing combination that can meet the target length matching. According to the corresponding relationship between the new site number and the original site number in step 31, further trace back the original site number of the casing in the casing combination that meets the target length matching.

5. A semi-submersible drilling platform casing length calculation system, characterized in that: include: A data acquisition module, which is used to obtain the number and length of the casing on the site, the target length, and the number corresponding to the single casing that must be used according to preset requirements; A model operation module, the model operation module is used to establish a dynamic programming model, the dynamic programming model is established based on the casing length optimization method of the semi-submersible drilling platform as claimed in any one of claims 1 to 4, so as to calculate and obtain the optimal casing string combination; The data output module is used to output the calculated optimal casing string combination to an electronic document, and the data in the electronic document includes the label of the optimal casing string combination, the length of the casing and the cumulative length of the casing.

6. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method for optimizing casing length of a semi-submersible drilling platform as claimed in any one of claims 1 to 4 is implemented.

7. An electronic terminal, characterized in that: include: processors, memory and transceivers; The transceiver is used to communicate with an external device; the memory is used to store a computer program, and the processor is used to execute the computer program stored in the memory, so that the electronic terminal executes the semi-submersible drilling platform casing length optimization method as described in any one of claims 1 to 4.

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