CN114325868B - Method, device, equipment and storage medium for characterizing drillability of gravel formation - Google Patents
Method, device, equipment and storage medium for characterizing drillability of gravel formation Download PDFInfo
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Abstract
The invention provides a method, a device, equipment and a storage medium for describing the drillability of a gravel stratum. The method comprises the steps of obtaining a first mapping relation between the content of calcium carbonate in rock of a gravel stratum and stratum depth, wherein the first mapping relation is used for representing lithology deposition rules of the gravel stratum, obtaining a second mapping relation between an abrasion index of the rock of the gravel stratum and stratum depth and a third mapping relation between an impact index and stratum depth based on logging interpretation data of the gravel stratum, wherein the second mapping relation is used for representing the abrasion degree of sandstone of the gravel stratum, the third mapping relation is used for representing the impact degree of the gravel stratum on a drill bit, and outputting the first mapping relation, the second mapping relation and the third mapping relation to describe drillability of the gravel stratum through the three mapping relations. The invention describes the drillability of the gravel stratum through lithology deposition rules, the abrasiveness degree of sandstone and the impact degree of the gravel on the drill bit.
Description
Technical Field
The invention relates to an oil and gas exploitation technology, in particular to a method, a device, equipment and a storage medium for describing the drillability of a gravel stratum.
Background
In the oil and gas exploitation process, a drill bit is required to drill through a stratum to form a shaft, so that various exploration equipment can reach an oil and gas production layer. Wherein the drillability of formations of different lithology (i.e., properties of rock composition, structure, etc.) is different. Currently, common drill bits are roller cone drill bits, polycrystalline diamond compact (polycrystalline diamond compact, PDC) drill bits, and the like. For PDC bits, how to characterize the drillability of the formation is critical in determining whether the PDC bit is reasonably selected and how to drill.
Currently, for PDC bits, micro-bit testing may be used to characterize the drillability of the formation. In using this method, it is first necessary to take a rock sample from the formation to be investigated and then use a micro drill bit to form cutting marks on the rock sample. The drillability of the formation is characterized by the amount of pressure applied to the micro drill bit and the depth of the cutting marks on the rock sample.
However, the above method is only suitable for characterizing drillability of homogeneous formations, and is not capable of characterizing drillability of heterogeneous gravel formations. Therefore, how to characterize the drillability of gravel formations for PDC bits is a major challenge.
Disclosure of Invention
The invention provides a method, a device, equipment and a storage medium for describing the drillability of a gravel stratum, which are used for solving the technical problem of how to describe the drillability of the gravel stratum aiming at a PDC drill bit.
In a first aspect, the present invention provides a method of characterizing the drillability of a gravel formation, comprising:
Acquiring a first mapping relation between the content of calcium carbonate in the rock of the gravel stratum and the stratum depth, wherein the first mapping relation is used for representing lithologic deposition rules of the gravel stratum;
acquiring a second mapping relation between the grinding index of the rock of the gravel stratum and the stratum depth and a third mapping relation between the impact index and the stratum depth based on logging interpretation data of the gravel stratum, wherein the second mapping relation is used for representing the grinding degree of sandstone of the gravel stratum, and the third mapping relation is used for representing the impact degree of the gravel stratum on a drill bit;
Outputting the first mapping relation, the second mapping relation and the third mapping relation, wherein the first mapping relation, the second mapping relation and the third mapping relation are used for describing the drillability of the gravel stratum.
Optionally, the obtaining a first mapping relationship between the calcium carbonate content of the rock of the gravel stratum and the stratum depth includes:
Receiving the mass of cuttings from different formation depths of the gravel formation and the calcium carbonate mass of the cuttings;
The calcium carbonate content of the rock from each stratum depth is obtained by the quotient of the calcium carbonate mass of the rock scraps from each stratum depth and the rock scraps mass;
And obtaining the first mapping relation according to the calcium carbonate content of the rock from each stratum depth.
Optionally, the acquiring, based on the log interpretation data of the gravel stratum, a second mapping relationship between the grinding index of the rock of the gravel stratum and the stratum depth includes:
acquiring the mudstone volume ratio of the rock at each stratum depth according to the gamma values of the rock at different stratum depths in the logging interpretation data;
Acquiring the sandstone volume ratio of the rock of each stratum depth according to the mudstone volume ratio of the rock of each stratum depth and the porosity, mudstone density, sandstone density and fluid density of the rock of each stratum depth in the logging interpretation data;
Acquiring the grinding index of the rock at each stratum depth according to the sandstone volume ratio of the rock at each stratum depth and the sonic wave time difference of the rock at each stratum depth in the logging interpretation data, wherein the grinding index of the rock is positively correlated with the sandstone volume ratio of the rock;
and acquiring the second mapping relation according to the grinding index of the rock of each stratum depth.
Optionally, the obtaining the mudstone volume ratio of the rock at each formation depth according to the gamma values of the rock at different formation depths in the logging interpretation data includes:
acquiring a mudstone index of the rock with each stratum depth according to gamma values corresponding to different stratum depths in the logging interpretation data;
and obtaining the mudstone volume ratio of the rock of each stratum depth according to the mudstone index of the rock of each stratum depth.
Optionally, the acquiring the sandstone volume ratio of the rock of each formation depth according to the mudstone volume ratio of the rock of each formation depth and the porosity, the mudstone density, the sandstone density and the fluid density of the rock of each formation depth in the logging interpretation data includes:
acquiring the pore volume ratio of the rock of each stratum depth according to the porosity of the rock of each stratum depth;
Acquiring the unit mass of the mudstone of the rock of each stratum depth according to the mud rock volume ratio of the rock of each stratum depth and the mud rock density;
obtaining the unit mass of the fluid in the pores of the rock with each stratum depth according to the porosity and the fluid density of the rock with each stratum depth;
And obtaining the sandstone volume ratio of the rock of each stratum depth according to the pore volume ratio of the rock of each stratum depth, the mudstone volume ratio of the rock of each stratum depth, the unit mass of the mudstone of the rock of each stratum depth, the unit mass of the fluid in the pores of the rock of each stratum depth, the sandstone density and a first constraint condition and a second constraint condition, wherein the first constraint condition is that the pore volume ratio of the rock, the sandstone volume ratio and the mudstone volume ratio are equal to 1, and the sum of the gravel volume ratio is that the unit mass of the rock is equal to the sum of the unit mass of the fluid, the unit mass of the gravel, the unit mass of the sandstone and the unit mass of the mudstone.
Optionally, the acquiring the grinding index of the rock at each stratum depth according to the sandstone volume ratio of the rock at each stratum depth and the sonic wave time difference of the rock at each stratum depth in the logging interpretation data includes:
And normalizing the quotient of the sandstone volume ratio and the acoustic wave time difference of the rock of each stratum depth to obtain the grinding index of the rock of each stratum depth.
Optionally, the acquiring, based on the log interpretation data of the gravel stratum, a third mapping relationship between the impact index of the rock of the gravel stratum and the stratum depth includes:
According to the acoustic time difference of the rock at different stratum depths in the logging interpretation data, the compressive strength of the rock at each stratum depth is obtained;
According to the compressive strength difference value of the rock at each stratum depth and the rock at the previous stratum depth and the stratum depth difference value, obtaining the impact index of the rock at each stratum depth, wherein the impact index of the rock is used for representing the change rate of the compressive strength of the rock;
And acquiring the third mapping relation according to the impact index of the rock of each stratum depth.
In a second aspect, the present invention provides a characterization device for the drillability of a gravel formation, comprising:
The system comprises a first acquisition module, a second acquisition module and a third acquisition module, wherein the first acquisition module is used for acquiring a first mapping relation between the content of calcium carbonate in the rock of the gravel stratum and the stratum depth, and the first mapping relation is used for representing lithologic deposition rules of the gravel stratum;
The system comprises a first acquisition module, a second acquisition module and a third acquisition module, wherein the first acquisition module is used for acquiring a first mapping relation between a grinding index of a gravel stratum and a stratum depth and a second mapping relation between an impact index and the stratum depth based on logging interpretation data of the gravel stratum, the first mapping relation is used for representing the degree of abrasiveness of sandstone of the gravel stratum, and the third mapping relation is used for representing the degree of impact of the gravel stratum on a drill bit;
the output module is used for outputting the first mapping relation, the second mapping relation and the third mapping relation, wherein the first mapping relation, the second mapping relation and the third mapping relation are used for describing the drillability of the gravel stratum.
In a third aspect, the present invention provides an electronic device comprising at least one processor, a memory;
The memory stores computer-executable instructions;
The at least one processor executes computer-executable instructions stored in the memory to cause the electronic device to perform the method of any one of the first aspects.
In a fourth aspect, the present invention provides a computer-readable storage medium having stored thereon computer-executable instructions which, when executed by a processor, implement the method of any of the first aspects.
According to the method, the device, the equipment and the storage medium for describing the drillability of the gravel stratum, provided by the invention, the rock in the gravel stratum is broken more easily by the PDC drill bit when the gravel of the gravel stratum contains limestone, and the main component of the limestone is calcium carbonate. Considering that the abrasion degree of PDC drill bit is larger when the content of quartz in sandstone of the gravel stratum is larger, the second mapping relation between the grinding index of rock of the gravel stratum and the stratum depth is used for representing the grinding degree of the sandstone of the gravel stratum. And, considering that the gravel of the gravel stratum can impact damage to the shoulder cutting teeth of the PDC drill bit, the invention uses the third mapping relation between the impact index of the rock of the gravel stratum and the stratum depth to represent the impact degree of the gravel stratum to the PDC drill bit. The limitation of the micro-drill testing method is overcome by the lithology deposition rule of the gravel stratum, the abrasive degree of the sandstone of the gravel stratum and the impact degree of the gravel stratum on the drill bit, and the drillability of the gravel stratum is characterized according to the practical failure principle of the PDC drill (failure peeling of diamond microcrystals of the PDC drill under the quartz grinding of the gravel stratum and failure peeling of the diamond material of the PDC drill under the fatigue fracture of the impact stress).
Drawings
In order to more clearly illustrate the invention or the technical solutions of the prior art, the following description will be given for a brief introduction to the drawings used in the embodiments or the description of the prior art, it being obvious that the drawings in the following description are some embodiments of the invention and that other drawings can be obtained from these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic illustration of a construction of a gravel formation;
FIG. 2 is a schematic flow chart of a method for characterizing the drillability of a gravel formation according to the present invention;
FIG. 3 is a flowchart of a method for obtaining a second mapping relationship according to the present invention;
FIG. 4 is a flowchart of a method for obtaining a third mapping relationship according to the present invention;
FIG. 5 is a schematic flow chart of another method for characterizing the drillability of a gravel formation according to the present invention;
FIG. 6 is a schematic diagram of a device for characterizing the drillability of a gravel formation according to the present invention;
fig. 7 is a schematic structural diagram of an electronic device according to the present invention.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings, and it is apparent that the described embodiments are some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Gravel formations are formations that are deposited from weathered exfoliated rock that is moved a distance by water. FIG. 1 is a schematic illustration of a construction of a gravel formation. As shown in fig. 1, the gravel formation includes gravel, sandstone, and mudstone (in the gravel formation shown in fig. 1, the portions other than the gravel are filled with the sandstone and the mudstone).
The degree of compaction and lithology of gravel formations formed in different geologic ages are different. The longer the geologic period, the deeper the depth of burial, the better its diagenetic, the closer the geologic period, the shallower the depth of burial, and the worse its diagenetic. The gravel formation may be divided into an uncracked section, a quasi-diagenetic section, and a diagenetic section, depending on its diagenetic properties. The closer the gravel is to the source (where the weathered and exfoliated rock is before being exfoliated), the larger the gravel particle size, and the farther the gravel is from the source, the smaller the gravel Dan Lijing, i.e., the different sizes and uneven distribution of the gravel in the gravel layer.
It should be appreciated that the schematic of the triangular gravel illustrated in FIG. 1, however, the particular shape of the gravel included in the gravel formation includes, but is not limited to, the triangular shape described above, and other shapes, or gravel including a variety of shapes, are also possible.
Taking the gravel stratum in area a as an example, the lithology distribution rule of the gravel stratum in the area can be shown in table 1.
TABLE 1
Sortability refers to the degree of uniformity in gravel particle size. As can be seen from the gravel particle sizes corresponding to the different segments in table 1, the gravel particles included in each segment are different in size, i.e., the lithology sortability of each segment is poor. In addition, the gravel composition is also different for each of the intervals. That is, gravel particles in the gravel layer are different in size, uneven in distribution, and different in composition, that is, the gravel layer is strongly heterogeneous.
At present, a method for describing drillability of a stratum by a PDC drill bit by adopting a micro-drill bit test method in the prior art is only suitable for describing drillability of a homogeneous stratum, and can not describe drillability of a gravel stratum with strong heterogeneity.
The inventors found through research during the drilling process that the gravel stratum has mainly the following characteristics:
1. The more gravel a gravel formation contains limestone, the more likely the PDC bit breaks the rock in the gravel formation.
2. The more quartz is contained in the sandstone of the gravel formation, the greater the degree of wear on the PDC bit.
3. Because gravel exists in the gravel stratum, vortex motion is easy to form when the PDC drill bit is used for drilling the gravel stratum, and shoulder cutting teeth of the PDC drill bit are damaged by impact.
Therefore, considering the characteristics of the gravel stratum, the application provides a method for describing the drillability of the gravel stratum, which accurately describes the drillability of the gravel stratum to the PDC drill bit through the lithology deposition rule of the gravel stratum, the abrasiveness degree of sandstone and the impact degree of the gravel stratum to the drill bit.
For convenience of description, the PDC bit is simply referred to as a bit in the following examples. That is, the drill bit in the embodiments of the present invention is equivalent to a PDC drill bit.
The technical scheme of the present invention will be described in detail with reference to specific examples. The following embodiments may be combined with each other, and some embodiments may not be repeated for the same or similar concepts or processes.
In a specific implementation, the method provided by the invention can be executed by an electronic device, and the electronic device can be a server, a terminal and other devices with processing functions.
FIG. 2 is a schematic flow chart of a method for characterizing the drillability of a gravel formation according to the present invention. As shown in fig. 2, the method comprises the steps of:
S101, acquiring a first mapping relation between the content of calcium carbonate in the rock of the gravel stratum and the stratum depth.
It is considered that as the depth of the burial of the gravel formation increases, the more gravel the gravel formation contains limestone, the more gravel the drill bit is likely to break the rock in the gravel formation, and the main component of the limestone is calcium carbonate (CaCO 3). Therefore, the present invention uses a first mapping relationship of calcium carbonate content of rock of a gravel formation to formation depth to represent lithology deposition rules of the gravel formation.
The above-mentioned calcium carbonate content of the rock of the gravel formation may be obtained, for example, by performing a drilling operation on the gravel formation once to obtain the lithologic deposit law of the gravel formation by the calcium carbonate content of the cuttings produced during the drilling operation.
The electronics may receive the quality of cuttings from different formation depths of the gravel formation, as well as the calcium carbonate quality of the cuttings. And then the calcium carbonate content of the rock at each depth of the stratum is obtained by using the calcium carbonate mass of the rock scraps and the mass of the rock scraps as a quotient. Illustratively, the electronic device may receive the quality of the cuttings, the calcium carbonate quality of the cuttings, and the depth of the corresponding formation through an application program interface (application program interface, API) or a graphical user interface (GRAPHICAL USER INTERFACE, GUI).
Alternatively, the user may add a sufficient amount of hydrochloric acid solution (hydrogen chloride solution) to the cuttings to allow them to react sufficiently, and then weigh the remainder after the reaction is completed. The electronic device may receive the mass of the cuttings before reaction with the hydrochloric acid solution as a first mass and the mass of the remainder after complete reaction with the hydrochloric acid solution as a second mass. And then the electronic equipment makes the first mass and the second mass poor to obtain the mass of carbon dioxide generated by the reaction of the rock debris and the hydrochloric acid solution. And the electronic equipment obtains the calcium carbonate mass of the rock debris according to the corresponding relation between the carbon dioxide mass and the calcium carbonate mass in the following chemical equation (0).
CaCO3+2HCL→CaCL2+CO2↑+H2O (0)
The chemical equation shows that calcium carbonate (CaCO 3) reacts with Hydrogen Chloride (HCL) to form calcium chloride (CaCL 2), carbon dioxide (CO 2) gas, and water (H 2 O). The electronics can quotient the calcium carbonate mass of the cuttings with the first mass to obtain a calcium carbonate content of the rock at each formation depth. The electronic equipment takes the corresponding relation between the calcium carbonate quality of the rock scraps and the stratum depth as a first mapping relation after acquiring the calcium carbonate quality of the rock scraps and the stratum depth, and uses the first mapping relation to represent the lithologic deposition rule of the gravel stratum.
Or the electronic device may directly receive the first mapping relationship input by the user, or the first mapping relationship sent by the user to the electronic device through other devices.
S102, acquiring a second mapping relation between the grinding index of the rock of the gravel stratum and the stratum depth and a third mapping relation between the impact index and the stratum depth based on logging interpretation data of the gravel stratum.
During the drilling of the drill bit through the gravel formation, the drill bit breaks the rock under the influence of the shaft pressure and the rotational speed. At the same time, the mineral content of the sandstone of the rock can cause it to produce grinding damage. The ability of rock to wear the drill bit is referred to herein as the abrasiveness of the rock. Thus, the degree of abrasiveness of the sandstone of the gravel formation may be used to characterize the drillability of the gravel formation. The abrasiveness degree of the sandstone of the gravel stratum can be expressed by the abrasion index of the rock of the gravel stratum, wherein the higher the abrasion index is, the larger the abrasion degree is, the lower the abrasion index is, the smaller the abrasion degree is, or the higher the abrasion index is, the smaller the abrasion degree is, and the lower the abrasion index is, the larger the abrasion degree is.
Considering that the drill bit is prone to whirl and to impact damage to the shoulder cutting teeth when drilling different gravel formations, which impact damage is caused by the impact of the gravel formation on the drill bit, the degree of impact of the gravel formation on the drill bit can be used to characterize the drillability of the gravel formation. The impact degree of the sandstone of the gravel stratum can be expressed by the impact index of the rock of the gravel stratum, wherein the impact index is higher to indicate that the impact degree is higher, the impact index is lower to indicate that the impact degree is lower, or the impact index is higher to indicate that the impact degree is lower, and the impact degree is higher.
For example, the electronics can obtain geological information of the gravel formation from log interpretation data of the gravel formation, and then obtain a grinding index and an impact index of the rock of the gravel formation based on the geological information of the gravel formation. And then the electronic equipment takes the corresponding relation between the grinding index and the stratum depth as a second mapping relation and takes the corresponding relation between the impact index and the stratum depth as a third mapping relation.
S103, outputting the first mapping relation, the second mapping relation and the third mapping relation.
The electronic device may output the first mapping relationship, the second mapping relationship, and the third mapping relationship after obtaining the mapping relationship. The form of the mapping relationship outputted here may be a form of a graphic representation, a form of a table representation, or the like, and the present invention is not limited thereto. It should be understood that the output may be output from the electronic device through its own user interface, or sent to another display device for display, etc.
Taking the first mapping relationship as an example, the electronic device may output the first mapping relationship as illustrated, where the calcium carbonate content of the rock is used as X-axis data and the formation depth is used as Y-axis data. The diagram can more clearly show the change condition of the calcium carbonate content along with the depth of the stratum, and further more clearly describe the drillability of different gravel strata.
In this embodiment, considering that the more gravel the gravel formation contains limestone, the easier the PDC drill bit breaks the rock in the gravel formation, and the main component of the limestone is calcium carbonate, the present invention characterizes lithology deposition rules of the gravel formation by using the first mapping relationship between the content of calcium carbonate in the rock of the gravel formation and the formation depth. Considering that the abrasion degree of the PDC drill bit is larger when the content of quartz in the sandstone of the gravel stratum is larger, the second mapping relation between the grinding index of the rock of the gravel stratum and the stratum depth is used for representing the abrasiveness degree of the sandstone of the gravel stratum. And, considering that the gravel of the gravel stratum can impact damage to the shoulder cutting teeth of the PDC drill bit, the invention uses the third mapping relation between the impact index of the rock of the gravel stratum and the stratum depth to represent the impact degree of the gravel stratum to the PDC drill bit. The limitation of the micro-drill testing method is overcome by the lithology deposition rule of the gravel stratum, the abrasive degree of the sandstone of the gravel stratum and the impact degree of the gravel stratum on the drill bit, and the drillability of the gravel stratum is characterized according to the practical failure principle of the PDC drill (failure peeling of diamond microcrystals of the PDC drill under the quartz grinding of the gravel stratum and failure peeling of the diamond material of the PDC drill under the fatigue fracture of the impact stress).
As previously described, the electronics can obtain a second mapping of the grinding index of the rock of the gravel formation to the formation depth based on the log interpretation data of the gravel formation. For this process, fig. 3 is a schematic flow chart of a method for obtaining the second mapping relationship according to the present invention. As shown in fig. 3, the method comprises the steps of:
s201, acquiring the mudstone volume ratio of the rock at each stratum depth according to the gamma values of the rock at different stratum depths in the logging interpretation data.
For example, first the electronics can obtain gamma values for rock at different formation depths from the log interpretation data, and then obtain the mudstone index for rock at each formation depth according to equation (1).
I_GR=(GR–GR0)÷(GR100–GR0) (1)
Wherein, I_GR represents the mudstone index of the rock with each stratum depth, GR represents the gamma value of the rock with different stratum depths, GR0 represents the gamma value corresponding to the calibrated pure sandstone in the gravel stratum, and GR100 represents the gamma value corresponding to the calibrated clear clay rock in the gravel stratum. Illustratively, GR0 and GR100 may be pre-stored in the electronic device or may be received through an API or GUI. The values of GR0 and GR100 may be, for example, 15 and 115, respectively.
After the electronic device obtains the mudstone index of each stratum, the mudstone volume ratio (or called the mudstone volume fraction) of the rock of each stratum depth can be obtained according to the formula (2).
V_sh=0.083×(23.7×I_GR-1) (2)
Where V_sh represents the mudstone volume fraction of rock at each formation depth. The above formula (2) may also be called Larionov model, wherein constants of 0.083, 3.7, etc. may be values calibrated by the user according to actual logging experience.
Or the electronic device can also obtain the mudstone volume ratio of the rock with different formation depths according to the gamma value of the rock with different formation depths in the logging interpretation data through a formula (3).
Wherein GR, GR0, and GR100 are as defined above.
It should be understood that the specific implementation method for acquiring the mudstone volume ratio of the rock of each stratum depth by the electronic device according to the gamma values of the rock of different stratum depths in the logging interpretation data is not limited. The method is only a possible implementation manner provided by the invention, and the electronic equipment can also obtain the mudstone volume ratio of the rock at each stratum depth by other methods.
S202, acquiring the sandstone volume ratio of the rock of each stratum depth according to the mudstone volume ratio of the rock of each stratum depth and the porosity, mudstone density, sandstone density and fluid density of the rock of each stratum depth in logging interpretation data.
For example, after the electronics obtain the mudstone volume fractions of the rock at each formation depth, the electronics may also obtain the porosity of the rock at each formation depth from the log interpretation data. The porosity may be that after compensated neutron calibration (Compensated Neutron Calibrated, CNC) to make the porosity acquired by the electronics more accurate, and thus the calculation process more accurate. The electronics can then take this porosity as the pore volume ratio of the rock at each formation depth.
In addition, the electronics can also obtain the sandstone density, mudstone density, gravel density, and fluid density (e.g., water, oil, etc.) in the pores for each formation depth from the log interpretation data. The fluid density is illustratively the density of water if only water is in the rock pores of the gravel formation, the density of oil if only oil is in the rock pores of the gravel formation, or the fluid density may also be the average density of the fluid in the pores, or the density of the fluid that is the greater or lesser of the fluid, etc.
Then the electronic equipment can obtain the sandstone volume ratio of the rock of each stratum depth by taking the formula (4) and the formula (5) as a first constraint condition and a second constraint condition respectively.
V_SAND+V_sh+V_Other+CNC=1 (4)
ρ(SAND)×V_SAND+ρ(sh)×V_sh+ρ(Other)×V_Other+ρ(formation fluid)×CNC=ZDEN (5)
Wherein equation (4) represents the sandstone volume of rock as a ratio v_sad, mudstone volume as a ratio v_sh, gravel volume as a ratio v_other, and the sum of the pore volume as a ratio CNC is equal to 1. Equation (5) represents that the sum of the unit mass of fluid, the unit mass of gravel, the unit mass of sandstone, and the unit mass of mudstone is equal to the unit mass of rock. In formula (5), ρ (SAND) is the sandstone density of the rock, for example, ρ (SAND) may be 2.65, i.e., ρ (SAND) ×V_SAND represents the unit mass of sandstone. ρ (sh) is the mudstone density of the rock, for example ρ (sh) may be 2.64, i.e. ρ (sh) x v_sh represents the unit mass of mudstone. ρ (Other) represents the density of the gravel, i.e., ρ (Other) ×v_other represents the unit mass of the gravel. ρ (formation fluid) represents the density of the fluid in the pores of the rock, i.e., ρ (formation fluid) ×cnc represents the unit mass of the fluid in the pores of the rock. ZDEN denotes the unit mass of rock.
It should be understood that the specific implementation method of the electronic device for obtaining the sandstone volume ratio of the rock of each formation depth according to the mudstone volume ratio of the rock of each formation depth and the porosity, the mudstone density, the sandstone density and the fluid density of the rock of each formation depth in the logging interpretation data is not limited. The method is only a possible implementation mode provided by the invention, and the electronic equipment can acquire the sandstone volume ratio of the rock at each stratum depth by other methods.
S203, acquiring the grinding index of the rock at each stratum depth according to the sandstone volume ratio of the rock at each stratum depth and the sonic wave time difference of the rock at each stratum depth in the logging interpretation data.
In one possible implementation, the electronics can also obtain the sonic time difference for the rock at each formation depth from the acquired log interpretation after the rock sandstone volume fraction is acquired. The sonic wave time difference refers to the time taken for a sonic wave to travel a unit distance (e.g., 1 meter) in the formation, and then the grinding index of the rock for each formation depth is obtained according to equation (6).
Wherein, abrasion Index represents the grinding Index of the rock of each stratum depth, DT represents the sonic time difference of the rock of each stratum depth, normalize represents normalization treatment to the quotient of V_SAND and DT so that the grinding Index of the rock is in a certain range, such as (0, 1), thereby the grinding indexes are in the same order of magnitude, and further the drillability of the gravel stratum is conveniently depicted.
It should be understood that the specific implementation method for acquiring the grinding index of the rock at each formation depth by the electronic device according to the sandstone volume ratio of the rock at each formation depth and the sonic time difference of the rock at each formation depth in the logging interpretation data is not limited. The method is only a possible implementation manner provided by the invention, and the electronic equipment can also obtain the grinding index of the rock at each stratum depth by other methods. For example, the electronics can also directly take the quotient of the sandstone volume ratio of the rock and the sonic jet lag as the grinding index of the rock for each formation depth.
S204, acquiring a second mapping relation according to the grinding index of the rock of each stratum depth.
The grinding index of the rock of different formation depths can be used to characterize the degree of abrasiveness of the sandstone of different formations, and when the grinding index is higher, the stronger the abrasiveness of the rock to the drill bit, the more likely the drill bit will wear, i.e., the lower the drillability of the formation. The electronics can characterize the abrasiveness of the sandstone of the gravel formation as a second mapping from the grinding index of the rock at each formation depth to the formation depth.
As previously mentioned, the greater the amount of quartz contained in the sandstone of the gravel formation, the greater the degree of wear on the PDC bit. Thus, the greater the sandstone volume ratio in the rock, the greater the degree of wear on the PDC bit.
In this embodiment, the grinding index of the rock of each formation depth is obtained by the sandstone volume ratio of the rock of each formation depth and the sonic wave time difference of the rock of each formation depth, and then the second mapping relationship is obtained according to the grinding index of the rock of each formation depth, where the second mapping relationship may be used to characterize the abrasiveness degree of the sandstone of the gravel formation. Thus, by the method of this example, the failure spalling of the diamond crystallites of the PDC bit during drilling, which occurs under the quartz abrasion of the gravel formation, was characterized. This spalling failure is the true cause of the abrasive failure of the PDC bit. That is, by the method of the embodiment, the technical problem that the grinding failure reasons of different PDC drill bits are difficult to establish connection with the drillability of the gravel stratum is solved.
As described above, the electronic device may obtain a third mapping relationship between the impact index of the rock of the gravel layer and the depth of the layer based on the log interpretation data of the gravel layer. For this process, fig. 4 is a schematic flow chart of a method for obtaining the third mapping relationship according to the present invention. As shown in fig. 4, the method comprises the steps of:
s301, according to the acoustic time difference of the rock at different stratum depths in the logging interpretation data, the compressive strength of the rock at each stratum depth is obtained.
The compressive strength may be, for example, uniaxial compressive strength, which refers to the load that a rock can bear per unit area when it is pressed unidirectionally until it breaks (i.e., during drilling by a drill bit), and triaxial compressive strength. For example, the electronics can obtain the single-axis compressive strength of the rock at each formation depth based on the sonic time differences of the rock at different formation depths and Golubev empirical formulas.
Wherein Golubev is shown in the empirical formula (7):
In equation (7), UCS represents uniaxial compressive strength of rock for each formation depth, and values of 2.44, 109.4, 145, etc. may be values calibrated according to artificial experience.
S302, according to the compressive strength difference value of the rock of each stratum depth and the rock of the previous stratum depth and the stratum depth difference value, obtaining the impact index of the rock of each stratum depth.
Considering that the rate of change of compressive strength of rock is directly related to impact damage of a drill bit, the rate of change of compressive strength of rock can be regarded as an impact index of rock. Wherein, the change rate refers to the change rate of the compressive strength of the rock along with the depth of the stratum. For example, after obtaining the values of the compressive strength of the respective formation depths, the electronic device may obtain the rate of change of the compressive strength of the rock according to equation (8), and thus obtain the impact index of the rock of the respective formation depths.
Wherein, impact Index represents an Impact Index of the rock, Δucs represents a rate of change of compressive strength of the rock, UCS (i+1) represents a compressive strength of the rock at the (i+1) th formation depth, UCS (i) represents a compressive strength of the rock at the (i) th formation depth, and Δmd represents a difference between the (i+1) th formation depth and the (i) th formation depth.
S303, acquiring a third mapping relation according to the impact index of the rock of each stratum depth.
The impact index of rock of different formation depths can be used to characterize the degree of impact of the gravel of different gravel formations on the drill bit, and when the impact index is higher, the stronger the impact of the rock on the drill bit, the more likely the drill bit is to produce impact damage, i.e. the lower the drillability of the formation. The electronics can use the correspondence between the impact index of the rock at each formation depth and the formation depth as a third mapping to characterize the degree of impact of the gravel formation on the drill bit.
As described above, when the drill bit drills a gravel stratum, whirling is easily formed, and the shoulder cutting teeth of the drill bit are damaged by impact. In this embodiment, the impact index of the rock at each formation depth is obtained according to the compressive strength of the rock at each formation depth and the formation depth, and then the third mapping relationship is obtained according to the impact index of the rock at each formation depth. Wherein the third mapping relationship may be used to characterize a degree of impaction of gravel of the gravel formation on the drill bit. Thus, by the method of this example, failure spalling of the diamond material of the PDC bit to fatigue fracture under impact stress is delineated. This spalling failure is the true cause of the PDC bit impact failure. That is, by the method of the embodiment, the technical problem that the impact failure reasons of different PDC drill bits are difficult to establish connection with the drillability of the gravel stratum is solved.
Based on all the above embodiments, fig. 5 is a schematic flow chart of another method for describing the drillability of a gravel stratum according to the present invention. As shown in fig. 5, the electronics may, for example, obtain the mass of cuttings produced during the drilling process as a first mass. Then, the user adds a sufficient amount of hydrochloric acid solution into the rock debris to enable the rock debris and the hydrochloric acid solution to react fully, and then the reaction residues are weighed. The electronic equipment obtains the mass of the reaction residue as a second mass, then the first mass and the second mass are subjected to difference to obtain the mass of carbon dioxide generated by the reaction of the rock debris and the hydrochloric acid solution, and then the electronic equipment obtains the calcium carbonate mass of the rock debris according to the corresponding relation between the mass of the carbon dioxide and the mass of the calcium carbonate in the chemical equation (0). And then, the calcium carbonate content of the rock scraps is obtained by using the calcium carbonate mass of the rock scraps and the rock scraps as the quotient. The electronic equipment acquires a first mapping relation according to the calcium carbonate content of the rock scraps and the stratum depth, and is used for representing lithologic deposition rules of the gravel stratum and further can be used for describing drillability of the gravel stratum.
The electronic device may also obtain gamma values for the rock at different formation depths from the log interpretation data, obtain a mudstone index for the rock at each formation depth based on the gamma values, and then obtain a mudstone volume fraction for the rock using the mudstone index. The electronic device may then obtain a sandstone volume ratio of rock for each formation depth based on the first constraint and the second constraint. And obtaining the grinding index of the rock of each stratum depth by using the acoustic time difference in the logging interpretation data and the sandstone volume ratio of the rock of each stratum depth. The electronic device may then use the corresponding relationship between the grinding index of the rock at each formation depth and the formation depth as a second mapping relationship to characterize the abrasiveness degree of the sandstone of the gravel formation, and may further be used to characterize the drillability of the gravel formation.
The electronic device may also obtain the acoustic time differences of the rock of different formation depths from the log interpretation data, and obtain the uniaxial compressive strength of the rock of each formation depth according to the Golubev empirical formula. The rate of change of the uniaxial compressive strength with formation depth is then used as the impact index of the rock at each formation depth. The electronic device can use the corresponding relation between the impact index of the rock of each stratum depth and the stratum depth as a third mapping relation to represent the impact degree of the gravel stratum on the drill bit, and can be further used for describing the drillability of the gravel stratum.
Among the first, second, and third mapping relationships, the same formation depth may be used, or different formation depths may be used. For example, the formation depth interval in the first mapping relationship may take 50 meters, the formation depth interval in the second mapping relationship may take 5 meters, and the formation depth interval in the third mapping relationship may take 2 meters. It should be understood that the above-described formation depth interval is merely exemplary, and that other values may be used for the formation depth interval in actual practice. Or the formation depth interval may also vary with the depth of the gravel formation, e.g., the deeper the gravel formation, the smaller the formation depth interval.
The electronic device may also output the first mapping relationship, the second mapping relationship, and the third mapping relationship in a graphical or tabular manner, so as to implement more clear drillability of describing the gravel stratum.
FIG. 6 is a schematic diagram of a device for characterizing the drillability of a gravel formation according to the present invention. As shown in fig. 6, the apparatus includes:
the first obtaining module 41 is configured to obtain a first mapping relationship between a calcium carbonate content of a rock of the gravel stratum and a stratum depth, where the first mapping relationship is used to characterize a lithologic deposition rule of the gravel stratum.
A second obtaining module 42, configured to obtain a second mapping relationship between a grinding index of a rock of the gravel stratum and a stratum depth, and a third mapping relationship between an impact index and a stratum depth, based on log interpretation data of the gravel stratum, where the second mapping relationship is used to represent a degree of abrasiveness of the sandstone of the gravel stratum, and the third mapping relationship is used to represent a degree of impact of the gravel stratum on a drill bit.
And the output module 43 is configured to output the first mapping relationship, the second mapping relationship, and the third mapping relationship, where the first mapping relationship, the second mapping relationship, and the third mapping relationship are used to characterize drillability of the gravel stratum.
Optionally, the first obtaining module 41 is specifically configured to receive the mass of the rock debris from the gravel stratum and the calcium carbonate mass of the rock debris, obtain the calcium carbonate content of the rock from each stratum depth according to the mass of the rock debris from each stratum depth and the calcium carbonate mass of the rock debris, and obtain the first mapping relationship according to the calcium carbonate content of the rock from each stratum depth.
Optionally, the second obtaining module 42 is specifically configured to obtain a mudstone volume ratio of the rock at each formation depth according to the gamma value of the rock at different formation depths in the log interpretation data, obtain a sandstone volume ratio of the rock at each formation depth according to the mudstone volume ratio of the rock at each formation depth, and the porosity, the mudstone density, the sandstone density, and the fluid density of the rock at each formation depth in the log interpretation data, obtain a grinding index of the rock at each formation depth according to the sandstone volume ratio of the rock at each formation depth and the sonic time difference of the rock at each formation depth in the log interpretation data, and obtain the second mapping relationship according to the grinding index of the rock at each formation depth, where the grinding index of the rock is positively correlated with the sandstone volume ratio of the rock.
Optionally, the second obtaining module 42 is specifically configured to obtain a mudstone index of the rock at each formation depth according to gamma values corresponding to different formation depths in the logging interpretation data, and obtain a mudstone volume ratio of the rock at each formation depth according to the mudstone index of the rock at each formation depth.
Optionally, the second obtaining module 42 is specifically configured to obtain a pore volume ratio of the rock of each formation depth according to the porosity of the rock of each formation depth, obtain a unit mass of the mudstone of the rock of each formation depth according to the mudstone volume ratio of the rock of each formation depth and the mudstone density, obtain a unit mass of the fluid in the pores of the rock of each formation depth according to the porosity of the rock of each formation depth and the fluid density, obtain a unit mass of the fluid in the pores of the rock of each formation depth according to the porosity of the rock of each formation depth, obtain a unit mass of the mudstone of the rock of each formation depth according to the mudstone volume ratio of the rock of each formation depth, and obtain a unit mass of the fluid in the pores of the rock of each formation depth, and obtain a first constraint condition and a second constraint condition, wherein the first constraint condition is the pore volume ratio of the rock, the sand volume ratio, the gravel volume ratio, and the sand volume ratio are equal to about 1, the unit mass of the sand and the unit mass of the fluid.
Optionally, the second obtaining module 42 is specifically configured to normalize a quotient of a sandstone volume ratio and an acoustic time difference of the rock of each formation depth, so as to obtain a grinding index of the rock of each formation depth.
Optionally, the second obtaining module 42 is specifically configured to obtain compressive strength of the rock at each formation depth according to a sonic time difference of the rock at different formation depths in the log interpretation data, obtain an impact index of the rock at each formation depth according to a compressive strength difference between the rock at each formation depth and the rock at a previous formation depth and the formation depth difference, wherein the impact index of the rock is used for representing a change rate of the compressive strength of the rock, and obtain the third mapping relationship according to the impact index of the rock at each formation depth.
The depicting device for the drillability of the gravel stratum provided by the invention is used for executing the embodiment of the method, and the implementation principle and the technical effect are similar, and are not repeated.
Fig. 7 is a schematic structural diagram of an electronic device according to the present invention. As shown in fig. 7, the electronic device may include at least one processor 51 and a memory 52.
And a memory 52 for storing a program. In particular, the program may include program code including computer-operating instructions.
The memory 52 may comprise high-speed RAM memory or may further comprise non-volatile memory (non-volatile memory), such as at least one disk memory.
The processor 51 is configured to execute computer-executable instructions stored in the memory 52 to implement a method of characterizing the drillability of a gravel formation.
The processor 51 may be a central processing unit (Central Processing Unit, abbreviated as CPU), or an Application SPECIFIC INTEGRATED Circuit (ASIC), or one or more integrated circuits configured to implement embodiments of the present invention.
Alternatively, in a specific implementation, if the communication interface, the memory 52 and the processor 51 are implemented independently, the communication interface, the memory 52 and the processor 51 may be connected to each other through a bus and perform communication with each other. The bus may be an industry standard architecture (Industry Standard Architecture, abbreviated ISA) bus, an external device interconnect (PERIPHERAL COMPONENT, abbreviated PCI) bus, or an extended industry standard architecture (Extended Industry Standard Architecture, abbreviated EISA) bus, among others. Buses may be divided into address buses, data buses, control buses, etc., but do not represent only one bus or one type of bus.
Alternatively, in a specific implementation, if the communication interface, the memory 52 and the processor 51 are implemented on a single chip, the communication interface, the memory 52 and the processor 51 may complete communication through an internal interface.
The invention also provides a computer readable storage medium, which may include a usb disk, a removable hard disk, a Read-Only Memory (ROM), a random access Memory (RAM, random Access Memory), a magnetic disk, or an optical disk, where various media capable of storing program codes may be stored, and in particular, the computer readable storage medium stores program instructions, where the program instructions are used in the method in the foregoing embodiment.
The present application also provides a program product comprising execution instructions stored in a readable storage medium. The at least one processor of the electronic device may read the execution instructions from the readable storage medium, the execution instructions being executable by the at least one processor to cause the electronic device to implement the method of characterizing the drillability of a gravel formation provided by the various embodiments described above.
It should be noted that the above embodiments are merely for illustrating the technical solution of the present invention and not for limiting the same, and although the present invention has been described in detail with reference to the above embodiments, it should be understood by those skilled in the art that the technical solution described in the above embodiments may be modified or some or all of the technical features may be equivalently replaced, and these modifications or substitutions do not make the essence of the corresponding technical solution deviate from the scope of the technical solution of the embodiments of the present invention.
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