A method for identifying reservoir water content based on light hydrocarbon logging

Abstract

The present invention provides a method for identifying reservoir water content based on light hydrocarbon logging, the method comprising: obtaining light hydrocarbon logging data of an oil and gas reservoir to be evaluated; selecting total hydrocarbon abundance, benzene, and toluene / benzene from the light hydrocarbon logging data as light hydrocarbon parameters; establishing a two-dimensional map through the intersection of benzene and toluene / benzene among the light hydrocarbon parameters, and establishing a three-dimensional map through the changes in total hydrocarbon abundance, benzene, and toluene / benzene, thereby demarcating the boundaries of oil layers, oil-water layers, and oil-water layers, and quantitatively interpreting and evaluating the fluid properties of the reservoir. The method of the present invention utilizes light hydrocarbon logging technology, selects light hydrocarbon parameters such as total hydrocarbon abundance, benzene, and toluene, and intersects to form two-dimensional and three-dimensional interpretation maps, quantitatively identifying the interface and water content of the reservoir fluid, improving the compliance rate of the actual interpretation and evaluation of the reservoir fluid, effectively reducing the cost of oilfield exploration and development, and achieving 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.

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] Comprehensive interpretation and evaluation of mud logging is an important evaluation technology in 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. Comprehensive mud logging evaluation technology includes multiple single mud 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 terms of 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 combines sample pretreatment technology with gas chromatography analysis technology. It uses cuttings, drilling fluid, sidewall coring, and rock cores as research objects. By detecting the content, composition, and distribution characteristics of light hydrocarbons in reservoir samples and applying geochemical theories, it interprets and evaluates the properties of reservoir fluids. Light hydrocarbon logging can obtain numerous light hydrocarbon parameters, which can be used to interpret reservoir oil content based on their physical and chemical properties. It can quickly and accurately evaluate oil, gas, and water layers, but it is not possible to quantitatively evaluate the water content of reservoirs.

[0004] CN 111221050A discloses a method and apparatus for identifying oil and water layers. The method comprises: obtaining continuous light hydrocarbon logging data at different depths; extracting data pairs corresponding to nC6, nC7, and nC8 at different depths from the continuous light hydrocarbon logging data in the form of data pairs representing retention time and relative percentage of the component, where all three are light hydrocarbon components of oil and gas; performing data fitting on the data pairs corresponding to nC6, nC7, and nC8 at different depths to determine corresponding morphological factors at different depths; and qualitatively identifying and quantitatively interpreting the oil and water layers based on the corresponding morphological factors at different depths. This method performs data fitting based on the light hydrocarbon logging data, but the fitting function used in the data fitting and the resulting morphological factors have a narrow scope of application, differing in scope for reservoirs at different depths, making it impossible to comprehensively evaluate reservoir fluid properties.

[0005] CN 107392505A discloses a comprehensive interpretation and evaluation method for natural gas hydrate exploration and development mud logging projects. The method includes: obtaining various mud logging parameters through real-time acquisition, processing, storage, recording, and calculation using a gas detection analyzer, an engineering mud logger, and a light hydrocarbon analyzer; classifying and screening all acquired mud logging parameters, analyzing and determining data items that can be used as comprehensive interpretation and evaluation parameters for natural gas hydrate mud logging projects; integrating the screened data with key parameters and the degree of geological anomalies to perform reservoir segmentation; and substituting the mud logging project interpretation and evaluation parameters into various interpretation and evaluation criteria to draw comprehensive interpretation conclusions. This method primarily performs comprehensive interpretation and evaluation on natural gas hydrate reservoirs, which is equivalent to evaluating gas-bearing reservoirs. Numerous parameter data items are selected, and the method does not involve evaluating the water content of the reservoir.

[0006] In summary, for the identification of oil-water interfaces 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 response to 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., and intersect to form two-dimensional and three-dimensional maps 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 oil testing results.

[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 described in step (2), and a three-dimensional map is established by the changes in total hydrocarbon abundance, benzene, and toluene / benzene to delineate the boundaries of the oil layer, the oil-water layer, and the oil-water layer, 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 judged, the oil and water content of the reservoir is effectively identified, the compliance rate of the actual interpretation and evaluation of the reservoir fluid is improved, the oil test effect is better, and a scientific basis is provided for the selection of test oil 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 limit 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 preprocessing technology with gas chromatography technology.

[0016] In the present invention, the process of obtaining light hydrocarbon logging parameters includes: bottling and sealing the rock cuttings or drilling fluid returned to the ground during the drilling process, desorbing and volatilizing the gas in the sample through changes in pressure and temperature, 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 the various compounds through changes in different temperatures, so that the components are retained by the stationary phase for different times, and thus flow out of the stationary phase in a certain order, and finally obtaining a chromatogram of the light hydrocarbon components and the peak area integral after detection by the detector, and then obtaining the 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 oil and natural gas. The oil content of the reservoir is interpreted based on the physical and chemical properties of the above hydrocarbon compounds, and 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 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-bearing 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 to a greater extent on the degree of thermal evolution and the intensity of secondary evolution it has experienced. The oil and gas in the same block and adjacent layers can be simply considered to have experienced the same degree of thermal evolution and the same intensity of secondary evolution. The differences in their light hydrocarbon parameters are 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: first, the abundance and distribution of light hydrocarbons, second, chemical stability, and third, 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, when 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 that of toluene.

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

[0028] The basis for the division of oil layers, oil-water layers and oil-water layers is as follows: 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 rate of decrease of benzene is higher than that of toluene. This 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. The relationship between the two and the change in total hydrocarbon abundance are used to determine the boundaries of the reservoir oil layer, oil-water layers and oil-water layers.

[0029] As a preferred technical solution of the present invention, the two-dimensional spectrum in step (3) uses 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 to 150, such as 30, 40, 50, 60, 80, 100, 120, 140 or 150, etc.; the vertical coordinate range is 0 to 3.5, such as 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, and the horizontal coordinate range of one side is 16 to 150, for example, 20, 30, 40, 50, 60, 80, 100, 120 or 150; the vertical coordinate range is 3.5 to 5.5, for example, 3.5, 4, 4.5, 5 or 5.5; the horizontal coordinate range of the other side is 16 to 30, for example, 16, 18, 20, 22, 25, 27 or 30; the vertical coordinate range is 0 to 3.5, for example, 0.1, 0.5, 1, 1.5, 2, 2.5, 3 or 3.5; but it is not limited to the listed values, and other unlisted values within the respective numerical ranges are also applicable.

[0033] Preferably, the oil-water layer region is L-shaped, with the horizontal coordinate range of one side being 0 to 150, such as 1, 5, 10, 15, 20, 30, 50, 80, 100, 120 or 150, etc.; the vertical coordinate range is 5.5 to 10, such as 5.5, 6, 6.5, 7, 7.5, 8, 9 or 10, etc.; the horizontal coordinate range of the other side is 0 to 16, such as 0.5, 1, 2, 4, 6, 8, 10, 12 or 16, etc.; the vertical coordinate range is 0 to 5.5, such as 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 the respective numerical ranges are also applicable.

[0034] In the present invention, the original intention of establishing the atlas is to be able to intuitively and accurately evaluate the properties of the reservoir fluid by establishing a relationship map of the three during interpretation and evaluation; in the two-dimensional atlas, the ordinate is the light hydrocarbon parameter toluene / benzene, which serves to control the boundary of the reservoir fluid properties, and the abscissa is the light hydrocarbon parameter benzene, which serves 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 oil and gas reservoirs are in different regions, that is, the oil and gas reservoirs are located in different areas, 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 visual three-dimensional map, which divides the boundaries of the oil layer area, the oil-water 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 atlas, 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 atlas.

[0038] Preferably, in the three-dimensional atlas, the Y coordinate of the oil layer area ranges from 10,000 to 40,000, such as 10,000, 15,000, 20,000, 25,000, 30,000, 35,000 or 40,000, etc., 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 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, etc., 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 serves 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 their corresponding functions are the same as those of 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 this numerical range are also applicable.

[0044] Preferably, the water content of the oil-water co-layer area is 20 to 80 wt%, for example, 20 wt%, 30 wt%, 40 wt%, 50 wt%, 60 wt%, 70 wt% or 80 wt%, etc., but is not limited to the listed values, and other unlisted values within this 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 this 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 benzene and toluene have the highest solubility and sensitivity to water 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 decrease rate of benzene is higher than the decrease rate of toluene;

[0050] (3) A two-dimensional map is established 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 a horizontal coordinate range of 16 to 150 on one side and a vertical coordinate range of 3.5 to 5.5 on the other side, and a horizontal coordinate range of 16 to 30 on the other side and a vertical coordinate range of 0 to 3.5; the oil-water layer area is L-shaped, with a horizontal coordinate range of 0 to 150 on one side and a vertical coordinate range of 5.5 to 10 on the other side, and a horizontal coordinate range of 0 to 16 on the other side and a vertical coordinate range of 0 to 5.5; a three-dimensional map is established by the changes in total hydrocarbon abundance, benzene and toluene / benzene, wherein the three-dimensional map is The invention relates to a method for quantitatively interpreting and evaluating fluid properties of a reservoir, wherein the light hydrocarbon parameter value of toluene / benzene is used as the X coordinate, the light hydrocarbon parameter value of the total hydrocarbon abundance is used as the Y coordinate, and the boundaries of the oil layer area, the oil-water co-layer area, and the oil-water layer area are divided according to the selection of the light hydrocarbon parameter value of each coordinate. 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. The range of the Y coordinate of the oil layer area is 10,000-40,000, the range of the Y coordinate of the oil-water co-layer area is 5,000-40,000, and the range of the Y coordinate of the oil-water layer area is 0-20,000. The fluid properties of the reservoir include the demarcation of the oil-water interface of the reservoir, the water content of the reservoir, and the degree of water flooding of the reservoir. The water content of the oil layer area is 0-20 wt%, the water content of the oil-water co-layer area is 20-80 wt%, and the water content of the oil-water layer area is above 80 wt%.

[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 to select light hydrocarbon parameters such as total hydrocarbon abundance, benzene, and toluene, and intersect to form two-dimensional and three-dimensional interpretation maps, thereby quantitatively identifying the interface and water content of reservoir fluids, and providing technical support for accurately identifying the degree of reservoir flooding during the development phase, 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 reservoir test well section provided by 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 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 reservoir test well section 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 reservoir test well section provided by Example 2 of the present invention;

[0058] Figure 5 The three-dimensional interpretation map is established by the intersection of total hydrocarbon abundance, benzene, and toluene / benzene of the light hydrocarbon parameters in the oil 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 reservoir test well section provided by Example 3 of the present invention;

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

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

[0063] 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 merely simplified 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 embodiment 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 described in step (2), and a three-dimensional map is established by the changes in total hydrocarbon abundance, benzene, and toluene / benzene to delineate the boundaries of the oil layer, the oil-water layer, and the oil-water layer, and quantitatively interpret and evaluate the fluid properties of the reservoir.

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

[0069] Example 1:

[0070] This embodiment provides a method for identifying reservoir water content based on light hydrocarbon logging. Taking the light-medium oil reservoir in the 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-gray 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) A two-dimensional interpretation map is established 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, as shown in FIG. 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 the 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 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 to 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 water flooding of the reservoir. The water content of the oil-water 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 analysis samples in the map mainly fall in the oil-water layer area and the oil-water layer area. The light hydrocarbon interpretation results are shown in the figure below. Figure 3 As shown by Figure 3 It can be seen that light hydrocarbons are interpreted as oil-water layers and oil-water layers. The initial daily oil production is 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] Example 2:

[0078] This embodiment provides a method for identifying reservoir water content based on light hydrocarbon logging. Taking the light-medium oil reservoir in the 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-stained 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) A two-dimensional interpretation map is established 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 the 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 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 to 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 water 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 below. 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] Example 3:

[0086] This embodiment provides a method for identifying reservoir water content based on light hydrocarbon logging. Taking the light-medium oil reservoir in the 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 sandstone and 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 among 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) A two-dimensional interpretation map is established 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, as shown in FIG. 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 the 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 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 20,000, 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 water 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 map mainly fall in the oil-water layer area, and the light hydrocarbon interpretation results are shown in the figure below. Figure 9 As shown by Figure 9 It can be seen that the light hydrocarbon interpretation is an oil-water layer, and the daily oil production is 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 examples, it can be seen that the method of the present invention utilizes light hydrocarbon logging technology to select light hydrocarbon parameters such as total hydrocarbon abundance, benzene, and toluene to form two-dimensional and three-dimensional interpretation maps, quantitatively identify the interface and water content of the reservoir fluid, and provide technical support for the accurate identification of the degree of reservoir flooding during the development stage, thereby improving the compliance rate of the actual interpretation and evaluation of the reservoir fluid, effectively reducing the cost of oilfield exploration and development, and achieving 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 uses the above-described embodiments to illustrate the detailed method of the present invention. However, the present invention is not limited to the above-described detailed method, that is, it does not mean that the present invention must rely on the above-described detailed method to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions for the present method, addition of auxiliary steps, selection of specific methods, etc., are all within the scope of protection and disclosure 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) establishing a two-dimensional map by the intersection of benzene and toluene / benzene in the light hydrocarbon parameters of step (2), and establishing a three-dimensional map by the changes in total hydrocarbon abundance, benzene and toluene / benzene, demarcating the boundaries of oil layers, oil-water layers and oil-water layers, and quantitatively interpreting and evaluating the fluid properties of the reservoir; The light hydrocarbon logging data in step (1) is obtained by combining sample pretreatment technology and gas chromatography technology; The light hydrocarbons in step (1) include C1-C9 alkanes and aromatic hydrocarbons, and the alkanes include normal alkanes, isoalkanes and cycloalkanes; Step (1) selecting particle samples at different depths at the sample points in the oil and gas reservoir; 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; The two-dimensional map in step (3) is divided into oil layer area, oil-water layer area and oil-water layer area; In step (3), the three-dimensional 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; The three-dimensional map in step (3) is a visual three-dimensional map, which divides the boundaries of the oil layer area, the oil-water layer area and the oil-water layer area according to the selection of the light hydrocarbon parameter value of each coordinate.

2. The method according to claim 1, characterized in that The total hydrocarbon abundance in the light hydrocarbon parameter in step (2) is related to the oil abundance of different reservoirs.

3. The method according to claim 2, characterized in that 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 area.

4. The method according to claim 1, wherein Benzene and toluene in step (2) have the highest solubility and sensitivity to water among the light hydrocarbon logging parameters.

5. The method according to claim 4, characterized in that When the water content in the reservoir increases, the light hydrocarbon parameters of benzene and toluene decrease.

6. The method according to claim 4, characterized in that The decreasing rate of benzene is higher than that of toluene.

7. The preparation method according to claim 1, characterized in that In the two-dimensional map, the horizontal coordinate range of the oil layer area is 30~150, and the vertical coordinate range is 0~3.

5.

8. The method according to claim 1, characterized in that In the two-dimensional map, the oil-water layer area is L-shaped, with the horizontal coordinate range of one side being 16-150 and the vertical coordinate range being 3.5-5.5, and the horizontal coordinate range of the other side being 16-30 and the vertical coordinate range being 0-3.

5.

9. The method according to claim 1, characterized in that In the two-dimensional map, the oil-water layer region is L-shaped, with the horizontal coordinate range of one side being 0-150 and the vertical coordinate range being 5.5-10, and the horizontal coordinate range of the other side being 0-16 and the vertical coordinate range being 0-5.

5.

10. The method according to claim 1, characterized in that In the two-dimensional atlas, for oil and gas reservoirs in different regions, the maximum coordinate range of the region in the corresponding established atlas is extended according to the regional characteristics.

11. The method according to claim 1, wherein In the three-dimensional atlas, 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 atlas.

12. The method according to claim 1, characterized in that In the three-dimensional map, the Y coordinate of the oil layer area ranges from 10,000 to 40,000.

13. The method according to claim 1, wherein In the three-dimensional atlas, the Y coordinate of the oil-water layer region ranges from 5000 to 40000.

14. The method according to claim 1, wherein In the three-dimensional map, the Y coordinate of the oil-water layer region ranges from 0 to 20,000.

15. The method according to claim 1, wherein 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.

16. The method according to claim 15, characterized in that The water content of the oil layer area is 0-20wt%.

17. The method according to claim 15, characterized in that The water content of the oil-water co-layer area is 20-80 wt%.

18. The method according to claim 15, characterized in that The water content of the oil-water layer region is above 80 wt%.

19. The method according to claim 1, wherein 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 benzene and toluene have the highest solubility and sensitivity to water 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 decrease rate of benzene is higher than the decrease rate of toluene; (3) A two-dimensional map is established 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 30-150 and a vertical coordinate range of 0-3.5; the oil-water layer area is L-shaped, with the horizontal coordinate range of one side being 16-150 and the vertical coordinate range of 3.5-5.5, and the horizontal coordinate range of the other side being 16-30 and the vertical coordinate range of 0-3.5; the oil-water layer area is L-shaped, with the horizontal coordinate range of one side being 0-150 and the vertical coordinate range of 5.5-10, and the horizontal coordinate range of the other side being 0-16 and the vertical coordinate range of 0-5.5; a three-dimensional map is established by the changes in the total hydrocarbon abundance, benzene and toluene / benzene, wherein the three-dimensional map is The X coordinate is used, the Z coordinate is used for the light hydrocarbon parameter value of toluene / benzene, and the Y coordinate is used for the light hydrocarbon parameter value of total hydrocarbon abundance. Based on the selection of the light hydrocarbon parameter value of each coordinate, the boundaries of the oil layer area, the oil-water layer area, and the oil-water layer area are divided. In the three-dimensional map, the range of the X coordinate and the Z coordinate in each area corresponds to the coordinate value range in the two-dimensional map. The Y coordinate range of the oil layer area is 10,000-40,000, the Y coordinate range of the oil-water layer area is 5,000-40,000, and the Y coordinate range of the oil-water layer area is 0-20,000. The fluid properties of the reservoir are quantitatively interpreted and evaluated. The fluid properties of the reservoir include the demarcation of the oil-water interface of the reservoir, the water content of the reservoir, and the degree of water flooding of the reservoir. The water content of the oil layer area is 0-20wt%, the water content of the oil-water layer area is 20-80wt%, and the water content of the oil-water layer area is greater than 80wt%.

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