Method for identifying water-bearing property of reservoir based on light hydrocarbon logging

Abstract

The invention provides a method for identifying the water content of a reservoir based on light hydrocarbon logging. The method comprises the following steps: acquiring light hydrocarbon logging data of an oil and gas reservoir to be evaluated; selecting total hydrocarbon abundance, benzene and toluene / benzene in the light hydrocarbon logging data as light hydrocarbon parameters; establishing a two-dimensional atlas through the intersection of benzene and toluene / benzene in the light hydrocarbon parameters, establishing a three-dimensional atlas through the total hydrocarbon abundance and the change of benzene and toluene / benzene, dividing the boundaries of an oil layer, an oil-water layer and an oil-containing water layer, and quantitatively explaining and evaluating the fluid properties of the reservoir. According to the method, the light hydrocarbon logging technology is utilized, two-dimensional and three-dimensional interpretation maps are formed through intersection by selecting light hydrocarbon parameters such as total hydrocarbon abundance, benzene and methylbenzene, the interface and the water content of the reservoir fluid are quantitatively recognized, the coincidence rate of actual interpretation and evaluation of the reservoir fluid is increased, the exploration and development cost of an oil field is effectively reduced, and the purpose of improving the oil testing effect is achieved; the method is easy to operate, high in identification and evaluation accuracy, high in universality and wide in application range.

Description

Technical Field

[0001] The invention belongs to the technical field of oil and gas exploration and development, and relates to a method for identifying reservoir water content based on light hydrocarbon logging. Background Art

[0002] Mud logging comprehensive interpretation and evaluation is an important evaluation technology for oil and gas exploration and development. Conventional oil and gas layer logging interpretation and evaluation technology has been widely used through years of practice and summary, and has achieved good results. Mud logging comprehensive evaluation technology includes multiple single logging technologies, among which light hydrocarbon logging is one of the evaluation technologies frequently used in the exploration and development of oil and gas fields. Although it has been widely used, in the identification of reservoir oil-water interface and the evaluation of reservoir water content, due to the large number of parameters, they are only in a qualitative and semi-quantitative state, and some parameters have not been deeply explored.

[0003] Light hydrocarbon logging is a logging method that combines sample pretreatment technology with gas chromatography analysis technology, takes cuttings, drilling fluid, borehole coring and rock cores as research objects, and interprets and evaluates reservoir fluid properties by detecting the content, composition and distribution characteristics of light hydrocarbons in reservoir samples and applying geochemical theories. There are many light hydrocarbon parameters obtained through light hydrocarbon logging, and the oil content of the reservoir can be interpreted based on its physical and chemical properties. It can quickly and accurately evaluate oil, gas and water layers, but the water content of the reservoir cannot be quantitatively evaluated.

[0004] CN 111221050A discloses a method and device for identifying oil and water layers, the method comprising: obtaining continuous light hydrocarbon logging data of different depths; extracting data pairs corresponding to nC6, nC7 and nC8 of different depths from the continuous light hydrocarbon logging data in the form of data pairs of "retention time, relative percentage of components", all of which are oil and gas light hydrocarbon components; performing data fitting on the data pairs corresponding to nC6, nC7 and nC8 of different depths respectively, and determining the corresponding morphological factors of different depths; and performing qualitative identification and quantitative interpretation of oil and water layers according to the corresponding morphological factors of different depths. The method is to perform data fitting based on light hydrocarbon logging data, but the fitting function used in the data fitting and the obtained morphological factors have a narrow application range, have different application ranges for reservoirs of different depths, and cannot perform an overall evaluation of reservoir fluid properties.

[0005] CN 107392505A discloses a comprehensive interpretation and evaluation method for logging engineering in exploration and development of natural gas hydrates, which includes: real-time acquisition, processing, storage, recording and calculation by gas detection analyzer, engineering logging instrument and light hydrocarbon analyzer to obtain various logging parameters; classifying and screening all acquired logging parameters, analyzing and determining data items that can be used as comprehensive interpretation and evaluation parameters for logging engineering of natural gas hydrates; integrating key parameters and geological anomaly degree with the screened determined data to divide reservoirs; substituting logging engineering interpretation and evaluation parameters into various interpretation and evaluation standards to obtain comprehensive interpretation conclusions. This method mainly conducts comprehensive interpretation and evaluation on natural gas hydrate reservoirs, which is equivalent to the evaluation of gas-bearing reservoirs. The selected parameter data items are numerous and do not involve the evaluation of reservoir water content.

[0006] In summary, for the identification of oil-water interface in oil and gas reservoirs and the evaluation of reservoir water content, it is also necessary to select appropriate light hydrocarbon logging parameters, and use the correlation between parameters to quantitatively interpret and evaluate the properties of reservoir fluids, improve the compliance rate of reservoir interpretation and evaluation, and reduce the cost of oil and gas resource exploration and development. Summary of the invention

[0007] In view of the problems existing in the prior art, the purpose of the present invention is to provide a method for identifying the water content of reservoirs based on light hydrocarbon logging. The method utilizes light hydrocarbon logging technology to select light hydrocarbon parameters such as total hydrocarbon abundance, benzene, toluene, etc., to form two-dimensional and three-dimensional maps, so as to quantitatively identify the water content of reservoir fluids, improve the compliance rate of actual interpretation and evaluation of reservoir fluids, effectively reduce the cost of oilfield exploration and development, and achieve the purpose of improving the effect of oil testing.

[0008] To achieve this object, the present invention adopts the following technical solutions:

[0009] The present invention provides a method for identifying reservoir water content based on light hydrocarbon logging, the method comprising the following steps:

[0010] (1) Obtaining light hydrocarbon logging data of the oil and gas reservoir to be evaluated;

[0011] (2) selecting total hydrocarbon abundance, benzene and toluene / benzene in the light hydrocarbon logging data of step (1) as light hydrocarbon parameters;

[0012] (3) A two-dimensional map is established by the intersection of benzene and toluene / benzene in the light hydrocarbon parameters of step (2), and a three-dimensional map is established by the changes in total hydrocarbon abundance, benzene and toluene / benzene, so as to delineate the boundaries of oil layers, oil-water layers and oil-water layers, and quantitatively interpret and evaluate the fluid properties of the reservoir.

[0013] In the present invention, the exploration and development of oil and gas fields requires an understanding of the characteristics of reservoirs at different locations. By adopting light hydrocarbon logging technology, light hydrocarbon logging data of reservoirs at different depths are obtained. Then, according to the needs of interpretation and evaluation of reservoir fluid properties, such as water content, total hydrocarbon abundance, benzene (BZ), and toluene (TOL) of light hydrocarbons are selected as main preferred parameters. A two-dimensional interpretation map is established through the intersection of benzene and toluene / benzene. A visual three-dimensional interpretation map is established through the changes in total hydrocarbon abundance, benzene, and toluene / benzene. The properties of reservoir fluids and the boundaries of different reservoir oil layers, oil-water layers, and oil-water layers are quantitatively and accurately determined, the oil and water content of the reservoir is effectively identified, the compliance rate of actual interpretation and evaluation of reservoir fluids is improved, the oil test effect is better, and a scientific basis is provided for the selection of oil test layers, thereby reducing the cost of oil field exploration and development.

[0014] The following are preferred technical solutions of the present invention, but are not intended to be limitations of the technical solutions provided by the present invention. Through the following technical solutions, the technical objectives and beneficial effects of the present invention can be better achieved and realized.

[0015] As a preferred technical solution of the present invention, the light hydrocarbon logging data in step (1) is obtained by combining sample pretreatment technology and gas chromatography technology.

[0016] In the present invention, the process of obtaining light hydrocarbon logging parameters includes: sealing the rock cuttings or drilling fluid returned to the ground during the drilling process in a bottle, desorbing and volatilizing the gas through changes in pressure and temperature of the sample, and gradually achieving a gas-liquid equilibrium state between the volatile components in the bottle and the headspace gas, injecting the gas-liquid equilibrium sample into the instrument, separating each compound through changes in different temperatures, so that each component is retained by the stationary phase for a different time, and thus flows out of the stationary phase in a certain order, and finally obtaining a chromatogram of the light hydrocarbon component and a peak area integral after detection by a detector, and then obtaining light hydrocarbon parameters. The relationship between the gas phase of the light hydrocarbon parameters and the volatile hydrocarbons in the liquid phase can be described by Raoult's law.

[0017] Preferably, the light hydrocarbons in step (1) include C1-C9 alkanes and aromatic hydrocarbons, and the alkanes include normal alkanes, isoalkanes and cycloalkanes.

[0018] In the present invention, the components that can be analyzed by the light hydrocarbon logging instrument include normal alkanes, isoalkanes, cycloalkanes and aromatic hydrocarbons, which are important components of petroleum and natural gas. The oil content of the reservoir is interpreted based on the physical and chemical properties of the above hydrocarbon compounds, and the oil, gas and water layers and water-washed / flooded layers can be quickly and accurately evaluated.

[0019] Preferably, the sample points in the oil and gas reservoir in step (1) are selected from particle samples at different depths.

[0020] As a preferred technical solution of the present invention, the total hydrocarbon abundance in the light hydrocarbon parameter in step (2) is related to the oil abundance of different reservoirs.

[0021] Preferably, the total hydrocarbon abundance of the oil layer is greater than the total hydrocarbon abundance of the oil-water layer and the oil-water layer in the same region.

[0022] In the present invention, the selection of the light hydrocarbon parameters focuses on the fact that the content and distribution of light hydrocarbon compounds in crude oil not only depend on the genesis type of crude oil, but also depend to a greater extent on the degree of thermal evolution and the intensity of secondary evolution it has suffered. The oil and gas in the same block and adjacent strata can be simply considered to have the same degree of thermal evolution and the same intensity of secondary evolution. The difference in their light hydrocarbon parameters is related to the reservoir properties. Based on this change, the optimization of parameters for light hydrocarbon logging to evaluate reservoir fluid properties must follow three factors: one is the abundance and distribution of light hydrocarbons, the second is chemical stability, and the third is the solubility of light hydrocarbons in water.

[0023] The total hydrocarbon abundance of light hydrocarbons is related to the oil abundance of the oil layer. Under the same analysis and sampling conditions, the light hydrocarbon abundance of the oil layer in the same area is much greater than that of the oil-water layer and other reservoirs. The relative size of the light hydrocarbon content and integral value can be used to determine the properties of the reservoir fluid.

[0024] As a preferred technical solution of the present invention, the benzene and toluene described in step (2) have the highest solubility and sensitivity to water among the light hydrocarbon logging parameters.

[0025] Preferably, as the water content in the reservoir increases, the light hydrocarbon parameters of benzene and toluene decrease.

[0026] Preferably, the decreasing rate of benzene is higher than the decreasing rate of toluene.

[0027] In the present invention, due to the long-term coexistence of oil and water in the same layer, under the action of water, the secondary evolution degree is high, resulting in the reduction or disappearance of light hydrocarbons that are easily soluble in water and chemically unstable. Among them, benzene and toluene have the highest solubility and sensitivity to water in the light hydrocarbon logging parameters. According to this change factor of light hydrocarbons, the present invention mainly selects the light hydrocarbon total hydrocarbon abundance, benzene, and toluene as the main preferred parameters;

[0028] The basis for the division of oil layers, oil-water layers and oil-water layers: 1) When the reservoir is saturated with oil, the total hydrocarbon abundance of light hydrocarbons, benzene and toluene parameter values ​​are relatively high; 2) When the reservoir is not saturated with oil and contains water, the aromatic hydrocarbons in the light hydrocarbon compounds, mainly benzene and toluene, will undergo regular changes. The decreasing rate of benzene is higher than that of toluene, which is due to the difference in their solubility in water; 3) The toluene / benzene relationship was selected based on the difference in the solubility of benzene and toluene in water, and the boundary of the reservoir oil layer, oil-water layer and oil-water layer was determined by the relationship between the two and the change in total hydrocarbon abundance.

[0029] As a preferred technical solution of the present invention, the two-dimensional spectrum in step (3) has the light hydrocarbon parameter value of benzene as the horizontal coordinate and the light hydrocarbon parameter value of toluene / benzene as the vertical coordinate.

[0030] Preferably, the two-dimensional map in step (3) is divided into oil layer area, oil-water same layer area and oil-water layer area.

[0031] As a preferred technical solution of the present invention, the horizontal coordinate range of the oil layer area is 30-150, for example, 30, 40, 50, 60, 80, 100, 120, 140 or 150, etc.; the vertical coordinate range is 0-3.5, for example, 0.1, 0.5, 1, 1.5, 2, 2.5, 3 or 3.5, etc., but is not limited to the listed values, and other unlisted values ​​within the respective numerical ranges are also applicable.

[0032] Preferably, the oil-water co-layer area is L-shaped, with one side having a horizontal coordinate ranging from 16 to 150, for example, 20, 30, 40, 50, 60, 80, 100, 120 or 150, etc.; a vertical coordinate ranging from 3.5 to 5.5, for example, 3.5, 4, 4.5, 5 or 5.5, etc.; a horizontal coordinate ranging from 16 to 30 on the other side, for example, 16, 18, 20, 22, 25, 27 or 30, etc.; a vertical coordinate ranging from 0 to 3.5, for example, 0.1, 0.5, 1, 1.5, 2, 2.5, 3 or 3.5, etc.; but it is not limited to the listed values, and other unlisted values ​​within their respective numerical ranges are equally applicable.

[0033] Preferably, the oil-water layer region is L-shaped, with one side having a horizontal coordinate ranging from 0 to 150, for example, 1, 5, 10, 15, 20, 30, 50, 80, 100, 120 or 150, etc.; a vertical coordinate ranging from 5.5 to 10, for example, 5.5, 6, 6.5, 7, 7.5, 8, 9 or 10, etc.; a horizontal coordinate ranging from 0 to 16 on the other side, for example, 0.5, 1, 2, 4, 6, 8, 10, 12 or 16, etc.; a vertical coordinate ranging from 0 to 5.5, for example, 0.1, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 5 or 5.5, etc.; but it is not limited to the listed values, and other unlisted values ​​within their respective numerical ranges are equally applicable.

[0034] In the present invention, the original intention of establishing the atlas is to intuitively and accurately evaluate the properties of the reservoir fluid by establishing a relationship map of the three in the interpretation and evaluation; in the two-dimensional atlas, the ordinate is the light hydrocarbon parameter toluene / benzene, which functions to control the boundary of the reservoir fluid properties, and the abscissa is the light hydrocarbon parameter benzene, which functions to evaluate the fluid properties of the reservoir, which is equivalent to the quality of the fluid properties of the reservoir and gives the corresponding boundaries; among them, the regions of the oil and gas reservoirs are different, that is, the oil and gas reservoirs located in different regions, and the maximum range of the region in the corresponding established atlas can be extended according to the regional characteristics.

[0035] As a preferred technical solution of the present invention, the three-dimensional map in step (3) uses the light hydrocarbon parameter value of benzene as the X coordinate, the light hydrocarbon parameter value of toluene / benzene as the Z coordinate, and the light hydrocarbon parameter value of total hydrocarbon abundance as the Y coordinate.

[0036] Preferably, the three-dimensional map in step (3) is a visualized three-dimensional map, which divides the boundaries of the oil layer area, the oil-water same layer area and the oil-water layer area according to the selection of the light hydrocarbon parameter value of each coordinate.

[0037] As a preferred technical solution of the present invention, in the three-dimensional map, the range of the X coordinate and the Z coordinate in each area corresponds to the range of the coordinate value in the two-dimensional map.

[0038] Preferably, in the three-dimensional atlas, the Y coordinate of the oil layer area ranges from 10000 to 40000, for example, 10000, 15000, 20000, 25000, 30000, 35000 or 40000, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0039] Preferably, in the three-dimensional atlas, the Y coordinate of the oil-water same layer area ranges from 5000 to 40000, for example, 5000, 10000, 15000, 20000, 25000, 30000, 35000 or 40000, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0040] Preferably, in the three-dimensional atlas, the Y coordinate of the oil-water layer area ranges from 0 to 20,000, such as 100, 1,000, 2,500, 5,000, 8,000, 10,000, 15,000 or 20,000, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0041] In the present invention, in the three-dimensional map, the Y coordinate is the light hydrocarbon parameter total hydrocarbon abundance, which functions to control the limit of reservoir fluid abundance, the X coordinate is the light hydrocarbon parameter benzene, and the Z coordinate is the light hydrocarbon parameter toluene / benzene, and the corresponding functions are the same as the horizontal and vertical coordinates in the two-dimensional map.

[0042] As a preferred technical solution of the present invention, the fluid properties of the reservoir in step (3) include the division of the oil-water interface of the reservoir, the water content of the reservoir and the degree of water flooding of the reservoir.

[0043] Preferably, the water content of the oil layer area is 0 to 20wt%, for example 0.1wt%, 0.5wt%, 1wt%, 2wt%, 5wt%, 8wt%, 10wt%, 12wt%, 15wt%, 18wt% or 20wt%, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0044] Preferably, the water content of the oil-water co-layer area is 20 to 80wt%, for example 20wt%, 30wt%, 40wt%, 50wt%, 60wt%, 70wt% or 80wt%, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0045] Preferably, the water content of the oil-water layer area is above 80wt%, for example 80wt%, 82wt%, 85wt%, 88wt%, 90wt% or 95wt%, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0046] In the present invention, the fluid in the oil-water layer area is mainly water. When the crude oil production is higher than the dry layer standard, its water content is not less than 80wt%. When the crude oil production is lower than the reserve calculation standard, the water content at this time is not less than 50wt%, for example, 50wt%, 60wt%, 70wt%, 80wt% or 85wt%.

[0047] As a preferred technical solution of the present invention, the method comprises the following steps:

[0048] (1) Obtaining light hydrocarbon logging data of the oil and gas reservoir to be evaluated, wherein the light hydrocarbon logging data is obtained by combining sample pretreatment technology with gas chromatography technology, wherein the light hydrocarbons include C1-C9 alkanes and aromatic hydrocarbons, wherein the alkanes include normal alkanes, isoalkanes and cycloalkanes, and wherein particle samples at different depths are selected as sample points in the oil and gas reservoir;

[0049] (2) selecting the total hydrocarbon abundance, benzene and toluene / benzene in the light hydrocarbon logging data of step (1) as light hydrocarbon parameters; the total hydrocarbon abundance in the light hydrocarbon parameters is related to the oil abundance of different reservoirs, the total hydrocarbon abundance of the oil layer is greater than the total hydrocarbon abundance of the oil-water layer and the oil-water layer in the same region, and the solubility and sensitivity of benzene and toluene to water are the highest in the light hydrocarbon logging parameters; when the water content in the reservoir increases, the light hydrocarbon parameters of benzene and toluene decrease, and the decreasing rate of benzene is higher than the decreasing rate of toluene;

[0050] (3) establishing a two-dimensional map by the intersection of benzene and toluene / benzene in the light hydrocarbon parameters of step (2), wherein the two-dimensional map is divided into an oil layer area, an oil-water layer area and an oil-water layer area with the light hydrocarbon parameter value of benzene as the horizontal coordinate and the light hydrocarbon parameter value of toluene / benzene as the vertical coordinate, wherein the oil layer area has a horizontal coordinate range of 30 to 150 and a vertical coordinate range of 0 to 3.5; the oil-water layer area is L-shaped, with one side having a horizontal coordinate range of 16 to 150 and a vertical coordinate range of 3.5 to 5.5, and the other side having a horizontal coordinate range of 16 to 30 and a vertical coordinate range of 0 to 3.5; the oil-water layer area is L-shaped, with one side having a horizontal coordinate range of 0 to 150 and a vertical coordinate range of 5.5 to 10, and the other side having a horizontal coordinate range of 0 to 16 and a vertical coordinate range of 0 to 5.5; establishing a three-dimensional map by the changes in total hydrocarbon abundance, benzene and toluene / benzene, wherein the three-dimensional map is based on the light hydrocarbon parameter value of benzene. The invention relates to a method for quantitatively interpreting and evaluating the fluid properties of a reservoir, wherein the fluid properties of the reservoir include the division of the oil-water interface of the reservoir, the water content of the reservoir and the degree of flooding of the reservoir. The water content of the reservoir is 0-20wt%, the water content of the oil-water layer is 20-80wt%, and the water content of the oil-water layer is more than 80wt%.

[0051] Compared with the prior art, the present invention has the following beneficial effects:

[0052] (1) The method of the present invention utilizes light hydrocarbon logging technology, selects light hydrocarbon parameters such as total hydrocarbon abundance, benzene, toluene, etc., and intersects to form two-dimensional and three-dimensional interpretation maps, quantitatively identifies the interface and water content of reservoir fluids, and provides technical support for accurate identification of reservoir flooding degree in the development stage, thereby improving the compliance rate of actual interpretation and evaluation of reservoir fluids, effectively reducing the cost of oilfield exploration and development, and achieving the purpose of improving oil testing results;

[0053] (2) The method of the present invention is simple to operate, has high recognition and evaluation accuracy, is highly versatile, and has a wide range of applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 It is a two-dimensional interpretation map established by the intersection of light hydrocarbon parameters benzene and toluene / benzene in the oil well test section of the oil reservoir provided in Example 1 of the present invention;

[0055] Figure 2 It is a three-dimensional interpretation map established by the intersection of total hydrocarbon abundance, benzene and toluene / benzene of light hydrocarbon parameters in the oil zone reservoir test well section provided by Example 1 of the present invention;

[0056] Figure 3 This is a light hydrocarbon interpretation result diagram of the oil well test section of the oil reservoir provided in Example 1 of the present invention;

[0057] Figure 4 It is a two-dimensional interpretation map established by the intersection of light hydrocarbon parameters benzene and toluene / benzene in the oil well test section of the oil reservoir provided in Example 2 of the present invention;

[0058] Figure 5 It is a three-dimensional interpretation map established by the intersection of total hydrocarbon abundance, benzene and toluene / benzene of light hydrocarbon parameters in the oil zone reservoir test well section provided by Example 2 of the present invention;

[0059] Figure 6 This is a light hydrocarbon interpretation result diagram of the oil well test section of the oil reservoir provided in Example 2 of the present invention;

[0060] Figure 7 It is a two-dimensional interpretation map established by the intersection of light hydrocarbon parameters benzene and toluene / benzene in the oil zone reservoir test well section provided by Example 3 of the present invention;

[0061] Figure 8 It is a three-dimensional interpretation map established by the intersection of total hydrocarbon abundance, benzene and toluene / benzene of light hydrocarbon parameters in the oil zone reservoir test well section provided by Example 3 of the present invention;

[0062] Fig. 9 This is a diagram of the light hydrocarbon interpretation results of the oil zone reservoir test well section provided in Example 3 of the present invention. DETAILED DESCRIPTION

[0063] In order to better illustrate the present invention and facilitate understanding of the technical solution of the present invention, the present invention is further described in detail below. However, the following embodiments are only simple examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

[0064] The specific implementation of the present invention provides a method for identifying reservoir water content based on light hydrocarbon logging, the method comprising the following steps:

[0065] (1) Obtaining light hydrocarbon logging data of the oil and gas reservoir to be evaluated;

[0066] (2) selecting total hydrocarbon abundance, benzene and toluene / benzene in the light hydrocarbon logging data of step (1) as light hydrocarbon parameters;

[0067] (3) A two-dimensional map is established by the intersection of benzene and toluene / benzene in the light hydrocarbon parameters of step (2), and a three-dimensional map is established by the changes in total hydrocarbon abundance, benzene and toluene / benzene, so as to delineate the boundaries of oil layers, oil-water layers and oil-water layers, and quantitatively interpret and evaluate the fluid properties of the reservoir.

[0068] The following are typical but non-limiting embodiments of the present invention:

[0069] Embodiment 1:

[0070] This embodiment provides a method for identifying reservoir water content based on light hydrocarbon logging. Taking the light-medium oil reservoir in Liaohe area as an example, the method includes the following steps:

[0071] (1) Obtaining light hydrocarbon logging data of the oil reservoir to be evaluated, wherein the light hydrocarbon logging data is obtained by combining sample pretreatment technology with gas chromatography technology, wherein the light hydrocarbons include C1-C9 alkanes and aromatic hydrocarbons, wherein the alkanes include normal alkanes, isoalkanes and cycloalkanes, and wherein particle samples at different depths are selected from the sample points in the oil and gas reservoir, wherein the depth of the sample points is 1690.0-1704.0 m, and the lithology of the test well section is brown-grey oil-stained fine sandstone, and 11 analysis samples are selected;

[0072] (2) selecting the total hydrocarbon abundance, benzene and toluene / benzene in the light hydrocarbon logging data of step (1) as light hydrocarbon parameters; the total hydrocarbon abundance in the light hydrocarbon parameters is related to the oil abundance of different reservoirs, and benzene and toluene have the highest solubility and sensitivity to water in the light hydrocarbon logging parameters; the light hydrocarbon parameter table of the analyzed sample is shown in Table 1;

[0073] Table 1 Light hydrocarbon parameters of samples analyzed in the oil reservoir test well section of Example 1

[0074] Well depth(m) Total hydrocarbon abundance benzene Toluene 1690.0 36341.93 31.48 760.81 1692.0 30508.19 43.68 695.28 1692.0 16443.58 25.68 524.73 1694.0 13429.99 19.69 353.14 1694.8 31024.64 28.23 132.60 1696.0 16363.79 55.11 178.09 1698.0 18136.44 25.94 71.48 1700.0 21915.80 28.45 55.73 1702.0 15085.84 8.77 32.37 1703.4 7307.60 3.98 85.53 1704.0 8979.81 4.97 35.68

[0075] (3) Establishing a two-dimensional interpretation map by the intersection of benzene and toluene / benzene in the light hydrocarbon parameters of step (2), such as Figure 1 As shown, the two-dimensional interpretation map is divided into oil layer area, oil-water layer area and oil-water layer area with the light hydrocarbon parameter value of benzene as the horizontal coordinate and the light hydrocarbon parameter value of toluene / benzene as the vertical coordinate. The horizontal coordinate range of the sample point on the two-dimensional interpretation map is 0-30, and the vertical coordinate range is 0-10; a three-dimensional interpretation map is established through the changes in total hydrocarbon abundance, benzene and toluene / benzene, such as Figure 2As shown, the three-dimensional interpretation map uses the light hydrocarbon parameter value of benzene as the X coordinate, the light hydrocarbon parameter value of toluene / benzene as the Z coordinate, and the light hydrocarbon parameter value of total hydrocarbon abundance as the Y coordinate. According to the selection of the light hydrocarbon parameter value of each coordinate, the boundaries of the oil layer area, the oil-water same layer area and the oil-water layer area are divided. The Y coordinate range of the sample point on the three-dimensional interpretation map is 4000-40000. The fluid properties of the reservoir are quantitatively interpreted and evaluated. The fluid properties of the reservoir include the division of the oil-water interface of the reservoir, the water content of the reservoir and the degree of flooding of the reservoir. The water content of the oil-water same layer area is 52.0wt%, and the water content of the oil-water layer area is above 85wt%.

[0076] In this embodiment, Figure 1 and Figure 2 It can be seen that the points of the analyzed samples in the spectrum mainly fall in the oil-water layer area and the oil-water layer area. The light hydrocarbon interpretation results are shown in the figure Figure 3 As shown by Figure 3 It can be seen that the light hydrocarbons are interpreted as oil-water layers and oil-water layers. After the initial oil test, the daily oil production was 5.9m 3 / d, daily water production 6.4m 3 / d, demonstrating the accuracy of light hydrocarbon interpretation; through the above interpretation and evaluation, the quantitative interpretation of light hydrocarbon identification reservoir water content was achieved, with high accuracy and compliance, effectively reducing the cost of oilfield exploration and development.

[0077] Embodiment 2:

[0078] This embodiment provides a method for identifying reservoir water content based on light hydrocarbon logging. Taking the light-medium oil reservoir in Liaohe area as an example, the method includes the following steps:

[0079] (1) Obtaining light hydrocarbon logging data of the oil reservoir to be evaluated, wherein the light hydrocarbon logging data is obtained by combining sample pretreatment technology with gas chromatography technology, wherein the light hydrocarbons include C1-C9 alkanes and aromatic hydrocarbons, wherein the alkanes include normal alkanes, isoalkanes and cycloalkanes, and wherein particle samples at different depths are selected from the sample points in the oil and gas reservoir, wherein the depth of the sample points is 2608.0-2616.0 m, and the lithology of the test well section is gray-black oil-spotted basalt, and 7 analysis samples are selected;

[0080] (2) selecting the total hydrocarbon abundance, benzene and toluene / benzene in the light hydrocarbon logging data of step (1) as light hydrocarbon parameters; the total hydrocarbon abundance in the light hydrocarbon parameters is related to the oil abundance of different reservoirs, and benzene and toluene have the highest solubility and sensitivity to water in the light hydrocarbon logging parameters; the light hydrocarbon parameter table of the analyzed sample is shown in Table 2;

[0081] Table 2 Light hydrocarbon parameters of samples analyzed in the oil reservoir test well section of Example 2

[0082] Well depth(m) Total hydrocarbon abundance benzene Toluene 2608.0 18062.94 33.69 39.38 2609.0 14001.96 32.53 39.06 2610.0 10749.41 30.12 20.20 2611.0 19080.27 33.00 38.45 2612.0 8760.00 30.50 31.25 2614.0 12762.53 31.10 28.66 2616.0 11716.04 29.78 30.62

[0083] (3) Establishing a two-dimensional interpretation map by the intersection of benzene and toluene / benzene in the light hydrocarbon parameters of step (2), such as Figure 4 As shown, the two-dimensional interpretation map is divided into oil layer area, oil-water layer area and oil-water layer area with the light hydrocarbon parameter value of benzene as the horizontal coordinate and the light hydrocarbon parameter value of toluene / benzene as the vertical coordinate. The horizontal coordinate range of the sample point on the two-dimensional interpretation map is 30-150, and the vertical coordinate range is 0-3.5; a three-dimensional interpretation map is established through the changes in total hydrocarbon abundance, benzene and toluene / benzene, as shown in FIG. Figure 5 As shown, the three-dimensional interpretation map uses the light hydrocarbon parameter value of benzene as the X coordinate, the light hydrocarbon parameter value of toluene / benzene as the Z coordinate, and the light hydrocarbon parameter value of total hydrocarbon abundance as the Y coordinate. According to the selection of the light hydrocarbon parameter value of each coordinate, the boundaries of the oil layer area, the oil-water same layer area and the oil-water layer area are divided. The Y coordinate range of the sample point on the three-dimensional interpretation map is 1000-40000, and the fluid properties of the reservoir are quantitatively interpreted and evaluated. The fluid properties of the reservoir include the division of the oil-water interface of the reservoir, the water content of the reservoir and the degree of flooding of the reservoir. The water content of the oil layer area is less than 2wt%.

[0084] In this embodiment, Figure 4 and Figure 5 It can be seen that the points of the analyzed samples in the spectrum mainly fall in the oil layer area, and the light hydrocarbon interpretation results are shown in the figure Figure 6 As shown by Figure 6 It can be seen that the light hydrocarbon interpretation oil layer has an initial daily oil production of 8.6m 3 / d, demonstrating the accuracy of light hydrocarbon interpretation; through the above interpretation and evaluation, the quantitative interpretation of light hydrocarbon identification reservoir water content was achieved, with high accuracy and compliance, effectively reducing the cost of oilfield exploration and development.

[0085] Embodiment 3:

[0086] This embodiment provides a method for identifying reservoir water content based on light hydrocarbon logging. Taking the light-medium oil reservoir in Liaohe area as an example, the method includes the following steps:

[0087] (1) Obtaining light hydrocarbon logging data of the oil reservoir to be evaluated, wherein the light hydrocarbon logging data is obtained by combining sample pretreatment technology with gas chromatography technology, wherein the light hydrocarbons include C1-C9 alkanes and aromatic hydrocarbons, wherein the alkanes include normal alkanes, isoalkanes and cycloalkanes, and wherein particle samples at different depths are selected from the sample points in the oil and gas reservoir, wherein the depth of the sample points is 2354.0-2364.0 m, and the lithology of the test well section is gray oil-stained conglomerate, and 10 analysis samples are selected;

[0088] (2) selecting the total hydrocarbon abundance, benzene and toluene / benzene in the light hydrocarbon logging data of step (1) as light hydrocarbon parameters; the total hydrocarbon abundance in the light hydrocarbon parameters is related to the oil abundance of different reservoirs, and benzene and toluene have the highest solubility and sensitivity to water in the light hydrocarbon logging parameters; the light hydrocarbon parameter table of the analyzed sample is shown in Table 3;

[0089] Table 3 Light hydrocarbon parameters of samples analyzed in the oil reservoir test well section of Example 3

[0090]

[0091]

[0092] (3) Establishing a two-dimensional interpretation map by the intersection of benzene and toluene / benzene in the light hydrocarbon parameters of step (2), such as Figure 7 As shown, the two-dimensional interpretation map is divided into oil layer area, oil-water layer area and oil-water layer area with the light hydrocarbon parameter value of benzene as the horizontal coordinate and the light hydrocarbon parameter value of toluene / benzene as the vertical coordinate. The horizontal coordinate range of the sample point on the two-dimensional interpretation map is 0-16, and the vertical coordinate range is 0-10; a three-dimensional interpretation map is established through the changes in total hydrocarbon abundance, benzene and toluene / benzene, such as Figure 8 As shown, the three-dimensional interpretation map uses the light hydrocarbon parameter value of benzene as the X coordinate, the light hydrocarbon parameter value of toluene / benzene as the Z coordinate, and the light hydrocarbon parameter value of total hydrocarbon abundance as the Y coordinate. According to the selection of the light hydrocarbon parameter value of each coordinate, the boundaries of the oil layer area, the oil-water same layer area and the oil-water layer area are divided. The Y coordinate range of the sample point on the three-dimensional interpretation map is 0 to 20000, and the fluid properties of the reservoir are quantitatively interpreted and evaluated. The fluid properties of the reservoir include the division of the oil-water interface of the reservoir, the water content of the reservoir and the degree of flooding of the reservoir. The water content of the oil-water layer area is 97.6wt%.

[0093] In this embodiment, Figure 7 and Figure 8 It can be seen that the points of the analyzed samples in the spectrum mainly fall in the oil-bearing water layer area, and the light hydrocarbon interpretation results are shown in the figure Fig. 9 As shown by Fig. 9 It can be seen that the light hydrocarbon interpretation of the oil-bearing water layer has a daily oil production of 0.5m 3 / d, daily water production 20.4m 3 / d, demonstrating the accuracy of light hydrocarbon interpretation; through the above interpretation and evaluation, the quantitative interpretation of light hydrocarbon identification reservoir water content was achieved, with high accuracy and compliance, effectively reducing the cost of oilfield exploration and development.

[0094] From the above embodiments, it can be seen that the method of the present invention utilizes light hydrocarbon logging technology, selects light hydrocarbon parameters such as total hydrocarbon abundance, benzene, toluene, etc., and intersects to form two-dimensional and three-dimensional interpretation maps, quantitatively identifies the interface and water content of the reservoir fluid, and provides technical support for the accurate identification of the degree of reservoir flooding in the development stage, improves the compliance rate of the actual interpretation and evaluation of the reservoir fluid, effectively reduces the cost of oilfield exploration and development, and achieves the purpose of improving the oil test effect; the method is simple to operate, has high identification and evaluation accuracy, is highly versatile, and has a wide range of applications.

[0095] The applicant declares that the present invention illustrates the detailed method of the present invention through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned detailed method, that is, it does not mean that the present invention must rely on the above-mentioned detailed method to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of the method of the present invention, addition of auxiliary steps, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for identifying reservoir water content based on light hydrocarbon logging, characterized in that: The method comprises the following steps: (1) Obtaining light hydrocarbon logging data of the oil and gas reservoir to be evaluated; (2) selecting total hydrocarbon abundance, benzene and toluene / benzene in the light hydrocarbon logging data of step (1) as light hydrocarbon parameters; (3) A two-dimensional map is established by the intersection of benzene and toluene / benzene in the light hydrocarbon parameters of step (2), and a three-dimensional map is established by the changes in total hydrocarbon abundance, benzene and toluene / benzene, so as to delineate the boundaries of oil layers, oil-water layers and oil-water layers, and quantitatively interpret and evaluate the fluid properties of the reservoir.

2. The method according to claim 1, characterized in that The light hydrocarbon logging data in step (1) is obtained by combining sample pretreatment technology and gas chromatography technology; Preferably, the light hydrocarbons in step (1) include C1-C9 alkanes and aromatic hydrocarbons, and the alkanes include normal alkanes, isoalkanes and cycloalkanes; Preferably, the sample points in the oil and gas reservoir in step (1) are selected from particle samples at different depths.

3. The method according to claim 1 or 2, characterized in that: The total hydrocarbon abundance in the light hydrocarbon parameter in step (2) is related to the oil abundance of different reservoirs; Preferably, the total hydrocarbon abundance of the oil layer is greater than the total hydrocarbon abundance of the oil-water layer and the oil-water layer in the same region.

4. The method according to any one of claims 1 to 3, characterized in that: In step (2), the benzene and toluene have the highest solubility and sensitivity to water among the light hydrocarbon logging parameters; Preferably, when the water content in the reservoir increases, the light hydrocarbon parameters of benzene and toluene decrease; Preferably, the decreasing rate of benzene is higher than the decreasing rate of toluene.

5. The method according to any one of claims 1 to 4, characterized in that: The two-dimensional spectrum of step (3) has the light hydrocarbon parameter value of benzene as the horizontal coordinate and the light hydrocarbon parameter value of toluene / benzene as the vertical coordinate; Preferably, the two-dimensional map in step (3) is divided into oil layer area, oil-water same layer area and oil-water layer area.

6. The preparation method according to claim 5, characterized in that: The abscissa range of the oil reservoir area is 30 to 150, and the ordinate range is 0 to 3.5; Preferably, the oil-water co-layer region is L-shaped, with one side having a horizontal coordinate ranging from 16 to 150 and a vertical coordinate ranging from 3.5 to 5.5, and the other side having a horizontal coordinate ranging from 16 to 30 and a vertical coordinate ranging from 0 to 3.5; Preferably, the oil-water layer region is L-shaped, with one side having a horizontal coordinate ranging from 0 to 150 and a vertical coordinate ranging from 5.5 to 10, and the other side having a horizontal coordinate ranging from 0 to 16 and a vertical coordinate ranging from 0 to 5.5; Preferably, for oil and gas reservoirs in different regions, the maximum coordinate range of the region in the corresponding established map is extended according to the regional characteristics.

7. The method according to any one of claims 1 to 6, characterized in that: The three-dimensional map of step (3) uses the light hydrocarbon parameter value of benzene as the X coordinate, the light hydrocarbon parameter value of toluene / benzene as the Z coordinate, and the light hydrocarbon parameter value of total hydrocarbon abundance as the Y coordinate; Preferably, the three-dimensional map in step (3) is a visualized three-dimensional map, which divides the boundaries of the oil layer area, the oil-water same layer area and the oil-water layer area according to the selection of the light hydrocarbon parameter value of each coordinate.

8. The method according to claim 7, characterized in that In the three-dimensional map, the range of the X coordinate and the Z coordinate in each area corresponds to the range of the coordinate value in the two-dimensional map; Preferably, in the three-dimensional atlas, the Y coordinate of the oil layer area ranges from 10000 to 40000; Preferably, in the three-dimensional atlas, the Y coordinate of the oil-water same layer region ranges from 5000 to 40000; Preferably, in the three-dimensional atlas, the Y coordinate of the oil-water layer region ranges from 0 to 20,000.

9. The method according to any one of claims 1 to 8, characterized in that: The fluid properties of the reservoir in step (3) include the division of the oil-water interface of the reservoir, the water content of the reservoir, and the degree of water flooding of the reservoir; Preferably, the water content of the oil layer region is 0 to 20 wt%; Preferably, the water content of the oil-water co-layer region is 20 to 80 wt%; Preferably, the water content of the oil-water layer region is above 80 wt%.

10. The method according to any one of claims 1 to 9, characterized in that: The method comprises the following steps: (1) Obtaining light hydrocarbon logging data of the oil and gas reservoir to be evaluated, wherein the light hydrocarbon logging data is obtained by combining sample pretreatment technology with gas chromatography technology, wherein the light hydrocarbons include C1-C9 alkanes and aromatic hydrocarbons, wherein the alkanes include normal alkanes, isoalkanes and cycloalkanes, and wherein particle samples at different depths are selected as sample points in the oil and gas reservoir; (2) selecting the total hydrocarbon abundance, benzene and toluene / benzene in the light hydrocarbon logging data of step (1) as light hydrocarbon parameters; the total hydrocarbon abundance in the light hydrocarbon parameters is related to the oil abundance of different reservoirs, the total hydrocarbon abundance of the oil layer is greater than the total hydrocarbon abundance of the oil-water layer and the oil-water layer in the same region, and the solubility and sensitivity of benzene and toluene to water are the highest in the light hydrocarbon logging parameters; when the water content in the reservoir increases, the light hydrocarbon parameters of benzene and toluene decrease, and the decreasing rate of benzene is higher than the decreasing rate of toluene; (3) establishing a two-dimensional map by the intersection of benzene and toluene / benzene in the light hydrocarbon parameters of step (2), wherein the two-dimensional map is divided into an oil layer area, an oil-water layer area and an oil-water layer area with the light hydrocarbon parameter value of benzene as the horizontal coordinate and the light hydrocarbon parameter value of toluene / benzene as the vertical coordinate, wherein the oil layer area has a horizontal coordinate range of 30 to 150 and a vertical coordinate range of 0 to 3.5; the oil-water layer area is L-shaped, with one side having a horizontal coordinate range of 16 to 150 and a vertical coordinate range of 3.5 to 5.5, and the other side having a horizontal coordinate range of 16 to 30 and a vertical coordinate range of 0 to 3.5; the oil-water layer area is L-shaped, with one side having a horizontal coordinate range of 0 to 150 and a vertical coordinate range of 5.5 to 10, and the other side having a horizontal coordinate range of 0 to 16 and a vertical coordinate range of 0 to 5.5; establishing a three-dimensional map by the changes in total hydrocarbon abundance, benzene and toluene / benzene, wherein the three-dimensional map is based on the light hydrocarbon parameter value of benzene. The invention relates to a method for quantitatively interpreting and evaluating the fluid properties of a reservoir, wherein the fluid properties of the reservoir include the division of the oil-water interface of the reservoir, the water content of the reservoir and the degree of flooding of the reservoir. The water content of the reservoir is 0-20wt%, the water content of the oil-water layer is 20-80wt%, and the water content of the oil-water layer is more than 80wt%.

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