Well logging interpretation method and system for rock thermal parameters
阅读说明：本技术 岩石热学参数测井解释方法及系统 (Well logging interpretation method and system for rock thermal parameters ) 是由 师振贵 李海泉 刘健 朱青奇 邢倩 王汗 朱咸涛 周颖 于 2019-03-05 设计创作，主要内容包括：公开了一种岩石热学参数测井解释方法及系统。该方法可以包括：确定多个岩心样品的岩性,对不同岩性的岩心样品进行热学性质测试,获得对应的热导率；结合岩心样品的岩性与对应的热导率,绘制岩性-热导率的交会图；绘制每一种岩性的自然伽马值-热导率的交会图,确定每一种岩性的自然伽马值-热导率的拟合公式；根据每一种岩性的自然伽马值-热导率的拟合公式与岩性-热导率的交会图,拟合综合岩性-热导率解释模型；根据未知岩心的自然伽马值与综合岩性-热导率解释模型,计算未知岩心的热导率。本发明通过岩性与热学性质模型,通过自然伽马值计算任意未知岩性的岩石的热导率,在复杂的地热开发过程中具有较广泛的应用价值。(A well logging interpretation method and system for rock thermal parameters are disclosed. The method can comprise the following steps: determining the lithological properties of a plurality of rock core samples, and testing the thermal properties of the rock core samples with different lithological properties to obtain corresponding thermal conductivity; combining the lithology and the corresponding thermal conductivity of the core sample, and drawing a lithology-thermal conductivity intersection graph; drawing an intersection graph of the natural gamma value-thermal conductivity of each lithology, and determining a fitting formula of the natural gamma value-thermal conductivity of each lithology; fitting a comprehensive lithology-thermal conductivity explanation model according to a natural gamma value-thermal conductivity fitting formula of each lithology and an intersection graph of the lithology-thermal conductivity; and calculating the thermal conductivity of the unknown core according to the natural gamma value of the unknown core and the comprehensive lithology-thermal conductivity explanation model. The invention calculates the thermal conductivity of the rock with any unknown lithology through the lithology and thermal property models and the natural gamma value, and has wider application value in the complex geothermal development process.)
1. A method for well interpretation of thermal parameters of rock, comprising:
determining the lithological properties of a plurality of rock core samples, and testing the thermal properties of the rock core samples with different lithological properties to obtain corresponding thermal conductivity;
combining the lithology and the corresponding thermal conductivity of the core sample, and drawing a lithology-thermal conductivity intersection graph;
determining natural gamma values corresponding to different depths aiming at each lithology, drawing an intersection graph of the natural gamma values and the thermal conductivity of each lithology according to the difference of the lithology, and determining a fitting formula of the natural gamma values and the thermal conductivity of each lithology;
fitting a comprehensive lithology-thermal conductivity interpretation model according to an intersection graph of a fitting formula of natural gamma value-thermal conductivity of each lithology and the lithology-thermal conductivity;
and calculating the thermal conductivity of the unknown core according to the natural gamma value of the unknown core and the comprehensive lithology-thermal conductivity interpretation model.
2. The rock thermal parameter log interpretation method of claim 1 wherein the comprehensive lithology-thermal conductivity interpretation model is:
λ3＝A×lnGr+C (1)
wherein, lambda is thermal conductivity, A is thermoelectric coefficient, Gr is natural gamma value, and C is calculation coefficient.
3. The rock thermal parameter log interpretation method of claim 1, wherein said determining natural gamma values corresponding to different depths comprises:
drawing a logging curve according to the core sample;
and acquiring a natural gamma value of a corresponding depth according to the logging curve.
4. The well logging interpretation method of rock thermal parameters of claim 1, wherein said fitting formula is a linear relationship, and the correlation coefficient of said fitting formula with real points of natural gamma value-thermal conductivity is greater than 0.8.
5. The rock thermal parameter log interpretation method of claim 1, wherein the lithology comprises: limestone, dolomite, gypsum, sandstone, shale, marl, conglomerate, rock salt.
Determining a natural gamma value-thermal conductivity fitting formula corresponding to the lithology according to the lithology of the unknown rock core;
and calculating the thermal conductivity of the unknown core according to the natural gamma value of the unknown core and a fitting formula of the natural gamma value-thermal conductivity.
6. A rock thermal parameter logging interpretation system, the system comprising:
a memory storing computer-executable instructions;
a processor executing computer executable instructions in the memory to perform the steps of:
determining the lithological properties of a plurality of rock core samples, and testing the thermal properties of the rock core samples with different lithological properties to obtain corresponding thermal conductivity;
combining the lithology and the corresponding thermal conductivity of the core sample, and drawing a lithology-thermal conductivity intersection graph;
determining natural gamma values corresponding to different depths aiming at each lithology, drawing an intersection graph of the natural gamma values and the thermal conductivity of each lithology according to the difference of the lithology, and determining a fitting formula of the natural gamma values and the thermal conductivity of each lithology;
calculating a comprehensive lithology-thermal conductivity explanation model according to an intersection graph of a fitting formula of natural gamma value-thermal conductivity of each lithology and the lithology-thermal conductivity;
and calculating the thermal conductivity of the unknown core according to the natural gamma value of the unknown core and the comprehensive lithology-thermal conductivity interpretation model.
7. The rock thermal parameter log interpretation system of claim 6 wherein the comprehensive lithology-thermal conductivity interpretation model is:
λ3＝A×lnGr+C (1)
wherein, lambda is thermal conductivity, A is thermoelectric coefficient, Gr is natural gamma value, and C is calculation coefficient.
8. The rock thermal log interpretation system of claim 6 wherein said determining natural gamma values corresponding to different depths comprises:
drawing a logging curve according to the core sample;
and acquiring a natural gamma value of a corresponding depth according to the logging curve.
9. The rock thermal log interpretation system of claim 6 wherein the fitting formula is a linear relationship and the fitting formula has a correlation coefficient with real points of natural gamma value-thermal conductivity greater than 0.8.
10. The rock thermal log interpretation system of claim 6 wherein the lithology comprises: limestone, dolomite, gypsum, sandstone, shale, marl, conglomerate, rock salt.
Technical Field
The invention relates to the field of resources and environment, in particular to a well logging interpretation method and system for rock thermal parameters.
Background
The thermal property, the reservoir lithology and the physical property are important parameters for evaluating the advantages and the disadvantages of the geothermal reservoir, and in the aspect of evaluating the geothermal reservoir, the properties such as the lithology, the physical property and the electrical property are basically adopted to comprehensively evaluate the advantages and the disadvantages of the geothermal reservoir, and the evaluation is mainly carried out according to the relationship among the lithology, the physical property and the electrical property. As a geothermal reservoir, thermal property parameters are required to be described, and the more intuitive and accurate degree can be achieved.
Disclosure of Invention
The invention provides a well logging interpretation method and system for rock thermal parameters, which can calculate the thermal conductivity of rocks with any unknown lithology through lithology and thermal property models and natural gamma values and have wider application value in a complex geothermal development process.
According to one aspect of the invention, a method for well interpretation of thermal parameters of rock is provided. The method may include: determining the lithological properties of a plurality of rock core samples, and testing the thermal properties of the rock core samples with different lithological properties to obtain corresponding thermal conductivity; combining the lithology and the corresponding thermal conductivity of the core sample, and drawing a lithology-thermal conductivity intersection graph; determining natural gamma values corresponding to different depths aiming at each lithology, drawing an intersection graph of the natural gamma values and the thermal conductivity of each lithology according to the difference of the lithology, and determining a fitting formula of the natural gamma values and the thermal conductivity of each lithology; fitting a comprehensive lithology-thermal conductivity interpretation model according to an intersection graph of a fitting formula of natural gamma value-thermal conductivity of each lithology and the lithology-thermal conductivity; and calculating the thermal conductivity of the unknown core according to the natural gamma value of the unknown core and the comprehensive lithology-thermal conductivity interpretation model.
Preferably, the comprehensive lithology-thermal conductivity interpretation model is:
λ3＝A×lnGr+C (1)
wherein, lambda is thermal conductivity, A is thermoelectric coefficient, Gr is natural gamma value, and C is calculation coefficient.
Preferably, the determining the natural gamma values corresponding to different depths comprises: drawing a logging curve according to the core sample; and acquiring a natural gamma value of a corresponding depth according to the logging curve.
Preferably, the fitting formula is a linear relation, and a correlation coefficient of the fitting formula and a real measuring point of the natural gamma value-thermal conductivity is more than 0.8.
Preferably, the lithology comprises: limestone, dolomite, gypsum, sandstone, shale, marl, conglomerate, rock salt.
According to another aspect of the present invention, there is provided a rock thermal parameter logging interpretation system, comprising: a memory storing computer-executable instructions; a processor executing computer executable instructions in the memory to perform the steps of: determining the lithological properties of a plurality of rock core samples, and testing the thermal properties of the rock core samples with different lithological properties to obtain corresponding thermal conductivity; combining the lithology and the corresponding thermal conductivity of the core sample, and drawing a lithology-thermal conductivity intersection graph; determining natural gamma values corresponding to different depths aiming at each lithology, drawing an intersection graph of the natural gamma values and the thermal conductivity of each lithology according to the difference of the lithology, and determining a fitting formula of the natural gamma values and the thermal conductivity of each lithology; fitting a comprehensive lithology-thermal conductivity interpretation model according to an intersection graph of a fitting formula of natural gamma value-thermal conductivity of each lithology and the lithology-thermal conductivity; and calculating the thermal conductivity of the unknown core according to the natural gamma value of the unknown core and the comprehensive lithology-thermal conductivity interpretation model.
Preferably, the comprehensive lithology-thermal conductivity interpretation model is:
λ3＝A×lnGr+C (1)
wherein, lambda is thermal conductivity, A is thermoelectric coefficient, Gr is natural gamma value, and C is calculation coefficient.
Preferably, the determining the natural gamma values corresponding to different depths comprises: drawing a logging curve according to the core sample; and acquiring a natural gamma value of a corresponding depth according to the logging curve.
Preferably, the fitting formula is a linear relation, and a correlation coefficient of the fitting formula and a real measuring point of the natural gamma value-thermal conductivity is more than 0.8.
Preferably, the lithology comprises: limestone, dolomite, gypsum, sandstone, shale, marl, conglomerate, rock salt.
The beneficial effects are that: according to the invention, through thermal parameters and the combination of natural gamma values in the logging curve of the geothermal well, the logging explanation of thermal properties can be obtained, the thermal conductivity of rocks with unknown lithology can be calculated, the thermal properties of the rocks can be effectively explained, and the method has a wide application value in the complex geothermal development process.
The method and apparatus of the present invention have other features and advantages which will be apparent from or are set forth in detail in the accompanying drawings and the following detailed description, which are incorporated herein, and which together serve to explain certain principles of the invention.
Drawings
The above and other objects, features and advantages of the present invention will become more apparent by describing in more detail exemplary embodiments thereof with reference to the attached drawings, in which like reference numerals generally represent like parts.
FIG. 1 shows a flow chart of the steps of a rock thermal parameter log interpretation method according to the invention.
FIG. 2 shows a schematic diagram of a lithology-thermal conductivity cross plot, according to one embodiment of the present invention.
Fig. 3 shows a schematic diagram of a natural gamma-value-thermal conductivity cross plot for limestone according to one embodiment of the present invention.
Fig. 4 shows a schematic diagram of a natural gamma-value-thermal conductivity cross plot of dolomite according to an embodiment of the invention.
FIG. 5 shows a schematic of a natural gamma-thermal conductivity cross-plot for a gypsum rock according to one embodiment of the present invention.
FIG. 6 shows a schematic diagram of a comprehensive lithology-thermal conductivity interpretation model according to one embodiment of the invention.
Detailed Description
The invention will be described in more detail below with reference to the accompanying drawings. While the preferred embodiments of the present invention are shown in the drawings, it should be understood that the present invention may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.
FIG. 1 shows a flow chart of the steps of a rock thermal parameter log interpretation method according to the invention.
In this embodiment, a rock thermal parameter log interpretation method according to the invention may comprise: step 101, determining lithological properties of a plurality of rock core samples, and performing thermal property test on the rock core samples with different lithological properties to obtain corresponding thermal conductivity; step 102, combining the lithology and the corresponding thermal conductivity of the rock core sample, and drawing a lithology-thermal conductivity intersection graph; 103, determining natural gamma values corresponding to different depths for each lithology, drawing an intersection graph of the natural gamma values and the thermal conductivity of each lithology according to the difference of the lithology, and determining a fitting formula of the natural gamma values and the thermal conductivity of each lithology; step 104, fitting a comprehensive lithology-thermal conductivity explanation model according to a fitting formula of natural gamma values-thermal conductivity of each lithology and an intersection graph of the lithology-thermal conductivity; and 105, calculating the thermal conductivity of the unknown core according to the natural gamma value of the unknown core and the comprehensive lithology-thermal conductivity explanation model.
In one example, the comprehensive lithology-thermal conductivity interpretation model is:
λ3＝A×lnGr+C (1)
wherein, lambda is thermal conductivity, A is thermoelectric coefficient, Gr is natural gamma value, and C is calculation coefficient.
In one example, determining the natural gamma values corresponding to the different depths includes: drawing a logging curve according to the core sample; and acquiring a natural gamma value of a corresponding depth according to the logging curve.
In one example, the fitting equation is a linear relationship, and the correlation coefficient of the fitting equation with real points of natural gamma value-thermal conductivity is greater than 0.8.
In one example, lithology includes: limestone, dolomite, gypsum, sandstone, shale, marl, conglomerate, rock salt.
Specifically, the rock thermal parameter logging interpretation method according to the invention may comprise:
and determining the lithology of a plurality of core samples according to the standard specified flow of 'rock thin sheet identification SY/T5368-2000', and testing the thermal properties of the core samples with different lithologies by using a TCi-Test428 instrument to obtain corresponding thermal conductivity.
And combining the lithology and the corresponding thermal conductivity of the core sample, and drawing an intersection graph of the lithology and the thermal conductivity.
Aiming at each lithology, drawing a logging curve according to a rock core sample, obtaining a natural gamma value corresponding to the depth according to the logging curve, drawing an intersection graph of the natural gamma value and the thermal conductivity of each lithology according to different lithologies, determining a fitting formula of the natural gamma value and the thermal conductivity of each lithology, and calculating a correlation coefficient of an intersection point of the fitting formula and the natural gamma value and the thermal conductivity, wherein the correlation coefficient R is2The fitting degree of a fitting formula to actual measuring points is shown, and the accuracy of the fitting formula is determined by R2Is judged by the value of R2The value range of (A) is 0-1, and the closer to 1, the higher the accuracy of the fitting formula is; for the geological parameters, the correlation coefficient is more than 0.8, and the correlation coefficient and the geological parameters are considered to be closely related.
And fitting the comprehensive lithology-thermal conductivity interpretation model according to the intersection graph of the natural gamma value-thermal conductivity fitting formula of each lithology and the lithology-thermal conductivity.
The method comprises the steps of integrating a natural gamma value-thermal conductivity intersection graph and a fitting formula drawn under different lithological conditions, finding that a nonlinear relation exists between the thermal conductivity and the natural gamma value by combining the lithological-thermal conductivity intersection graph, describing the nonlinear relation by using a binary cubic equation, finding that the fitting degree of an ln function is the highest through fitting of numerical calculation software, and therefore selecting the ln function, and selecting the binary cubic equation and the ln function to describe the nonlinear relation. Compiling numerical calculation software, testing input parameters, obtaining an equation form, importing data for equation fitting, and compiling codes to obtain a high-precision binary-cubic comprehensive lithology-thermal conductivity interpretation model as a formula (1) by adopting the numerical calculation software based on a Grapher calculation frame.
According to the natural gamma value of the unknown core and a calculation formula of the comprehensive lithology-thermal conductivity explanation model, the thermal conductivity of the unknown core is calculated, the heat absorption coefficient can be calculated through the thermal conductivity, the heat absorption coefficient is in positive correlation with the thermal conductivity, the higher the thermal conductivity is, the larger the heat absorption coefficient is, and the heat absorption coefficient of the rock is an index for reflecting the heat insulation effect of the rock.
The method calculates the thermal conductivity of the rock with any unknown lithology through the lithology and thermal property models and the natural gamma value, and has wider application value in the complex geothermal development process.
Application example
To facilitate understanding of the solution of the embodiments of the present invention and the effects thereof, a specific application example is given below. It will be understood by those skilled in the art that this example is merely for the purpose of facilitating an understanding of the present invention and that any specific details thereof are not intended to limit the invention in any way.
The well logging interpretation method of the rock thermal parameters according to the invention can comprise the following steps:
determining the lithological properties of a plurality of core samples to be limestone, dolomite and gypsum according to the standard specified flow of 'rock thin sheet identification SY/T5368-2000', and carrying out thermal property Test on core samples with different lithological properties by a TCi-Test428 instrument to obtain corresponding thermal conductivity.
FIG. 2 shows a schematic diagram of a lithology-thermal conductivity cross plot, according to one embodiment of the present invention.
And (3) combining the lithology and the corresponding thermal conductivity of the core sample, drawing a lithology-thermal conductivity intersection graph, as shown in fig. 2, wherein a thermal conductivity concentrated region of each lithology is in a circle, and the graph shows that the thermal conductivity of the gypsum rock, the dolomite rock and the limestone rock is gradually reduced.
And aiming at each lithology, drawing a logging curve according to the core sample, and acquiring a natural gamma value of a corresponding depth according to the logging curve, wherein the lithology, the thermal conductivity and the natural gamma value of the core sample are shown in a table 1.
TABLE 1
Numbering
Lithology
Natural gamma
Thermal conductivity
Numbering
Lithology
Natural gamma
Thermal conductivity
A02
Limestone
17.9
3.15
C07
Limestone
15.7
2.41
A09
Limestone
18.4
3.33
D05
Limestone
17.6
2.95
A10
Limestone
18.1
3.28
D07
Limestone
14.6
1.89
B02
Dolomitic rock
16.2
3.05
D08
Limestone
17.6
3.32
B03
Dolomitic rock
15.3
2.75
D12
Limestone
19.7
4.31
B04
Dolomitic rock
15.2
2.85
D13
Limestone
20.1
4.08
B05
Dolomitic rock
15.4
2.93
D15
Limestone
21.6
4.4
B06
Dolomitic rock
15.9
3.11
D17
Limestone
20.6
4.03
B07
Dolomitic rock
16.3
3.32
D19
Limestone
21.3
4.78
B08
Dolomitic rock
15.3
2.57
D20
Limestone
21.5
4.21
B09
Dolomitic rock
15.7
3.11
D21
Limestone
15.8
2.28
B10
Dolomitic rock
13.5
1.68
D23
Limestone
17.5
2.89
B11
Dolomitic rock
15.9
3.16
D24
Limestone
18.9
3.54
B12
Dolomitic rock
15.4
2.79
D26
Limestone
19.4
4.19
B13
Dolomitic rock
14.8
2.46
D27
Limestone
18.1
3.71
B14
Dolomitic rock
15.1
2.56
D30
Limestone
18.6
3.59
B15
Dolomitic rock
15.8
2.97
E03
Gypsum rock
25.3
4.47
B20
Limestone
18.2
3.33
E04
Gypsum rock
26.2
4.88
B21
Limestone
19.4
3.85
E5
Gypsum rock
25.5
4.56
B22
Limestone
17.1
2.89
E6
Gypsum rock
25.9
4.8
B23
Limestone
16.8
2.67
E07
Gypsum rock
25.7
4.75
C01
Limestone
16.4
2.46
E08
Gypsum rock
25.3
4.25
C02
Limestone
17.4
3.14
E09
Gypsum rock
25.5
4.51
Fig. 3 shows a schematic diagram of a natural gamma-value-thermal conductivity cross plot for limestone according to one embodiment of the present invention.
Fig. 4 shows a schematic diagram of a natural gamma-value-thermal conductivity cross plot of dolomite according to an embodiment of the invention.
FIG. 5 shows a schematic of a natural gamma-thermal conductivity cross-plot for a gypsum rock according to one embodiment of the present invention.
And respectively drawing a natural gamma value-thermal conductivity intersection chart of the limestone, the dolomite and the gypsum according to different lithologies, as shown in figures 3-5. The fitting formula of the natural gamma value-thermal conductivity of the limestone is as follows:
λ＝0.387×Gr-3.708 (2)
the correlation coefficient is 0.921, and the fitting formula of the natural gamma value-thermal conductivity of the dolomite is as follows:
λ＝0.5674×Gr-5.9384 (3)
the correlation coefficient is 0.9307, and the fitting formula of the natural gamma value-thermal conductivity of the gypsum rock is as follows:
λ＝0.6071×Gr-10.953 (4)
the correlation coefficient is 0.8362, and the fitting graphs of other lithologies are similar to the three lithologies.
And fitting the comprehensive lithology-thermal conductivity interpretation model according to the intersection graph of the natural gamma value-thermal conductivity fitting formula of each lithology and the lithology-thermal conductivity.
FIG. 6 shows a schematic diagram of a comprehensive lithology-thermal conductivity interpretation model according to one embodiment of the invention.
The method comprises the steps of integrating an intersection graph and a fitting formula of natural gamma value-thermal conductivity drawn under three different lithological conditions, finding that a nonlinear relation exists between the thermal conductivity and the natural gamma value by combining the intersection graph of lithological property-thermal conductivity, describing the nonlinear relation by using a two-dimensional cubic equation, finding that the fitting degree of an ln function is the highest through fitting of numerical calculation software, selecting the ln function, and therefore, selecting the two-dimensional cubic equation and the ln function to describe the nonlinear relation. Compiling numerical calculation software, testing input parameters, obtaining an equation form, importing data for equation fitting, compiling codes to obtain a high-precision binary-cubic comprehensive lithology-thermal conductivity explanation model by adopting the numerical calculation software based on a Grapher calculation frame, wherein the fitting formula is as follows as shown in FIG. 6:
λ3＝116.57×lnGr-298.77 (5)
the similarity coefficient is 0.9094.
And substituting the natural gamma value of the unknown core into a calculation formula of the comprehensive lithology-thermal conductivity explanation model, and calculating the value of the thermal conductivity of the unknown core to be 3.95.
In conclusion, the invention calculates the thermal conductivity of the rock with any unknown lithology through the lithology and thermal property models and the natural gamma value, and has wider application value in the complex geothermal development process.
It will be appreciated by persons skilled in the art that the above description of embodiments of the invention is intended only to illustrate the benefits of embodiments of the invention and is not intended to limit embodiments of the invention to any examples given.
According to an embodiment of the invention, there is provided a rock thermal parameter logging interpretation system, comprising: a memory storing computer-executable instructions; a processor executing computer executable instructions in the memory to perform the steps of: determining the lithological properties of a plurality of rock core samples, and testing the thermal properties of the rock core samples with different lithological properties to obtain corresponding thermal conductivity; combining the lithology and the corresponding thermal conductivity of the core sample, and drawing a lithology-thermal conductivity intersection graph; determining natural gamma values corresponding to different depths aiming at each lithology, drawing an intersection graph of the natural gamma values and the thermal conductivity of each lithology according to the difference of the lithology, and determining a fitting formula of the natural gamma values and the thermal conductivity of each lithology; fitting a comprehensive lithology-thermal conductivity explanation model according to a natural gamma value-thermal conductivity fitting formula of each lithology and an intersection graph of the lithology-thermal conductivity; and calculating the thermal conductivity of the unknown core according to the natural gamma value of the unknown core and the comprehensive lithology-thermal conductivity explanation model.
In one example, the comprehensive lithology-thermal conductivity interpretation model is:
λ3＝A×lnGr+C (1)
wherein, lambda is thermal conductivity, A is thermoelectric coefficient, Gr is natural gamma value, and C is calculation coefficient.
In one example, determining the natural gamma values corresponding to the different depths includes: drawing a logging curve according to the core sample; and acquiring a natural gamma value of a corresponding depth according to the logging curve.
In one example, the fitting equation is a linear relationship, and the correlation coefficient of the fitting equation with real points of natural gamma value-thermal conductivity is greater than 0.8.
In one example, lithology includes: limestone, dolomite, gypsum, sandstone, shale, marl, conglomerate, rock salt.
The system calculates the thermal conductivity of the rock with any unknown lithology through the lithology and thermal property models and the natural gamma value, and has wider application value in the complex geothermal development process.
It will be appreciated by persons skilled in the art that the above description of embodiments of the invention is intended only to illustrate the benefits of embodiments of the invention and is not intended to limit embodiments of the invention to any examples given.
Having described embodiments of the present invention, the foregoing description is intended to be exemplary, not exhaustive, and not limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments.