Methods for determining the quality of interlayers in bottom-water heavy oil reservoirs

Abstract

This invention relates to a method for judging the quality of interlayers in bottom-water heavy oil reservoirs. Based on thickness, physical properties, and planar distribution characteristics, it identifies interlayers and strata within the reservoir or flow unit of a target reserve unit. It analyzes the influence of parameters of interlayers within the reservoir or flow unit of the target reserve unit on their characteristics. It statistically analyzes the thickness, permeability, sealing degree, and development location of interlayers within the reservoir or flow unit of the target reserve unit as parameters reflecting interlayer quality. These parameters are displayed as circular scatter points on a four-dimensional spider web quantitative identification chart to classify and evaluate interlayers in bottom-water heavy oil reservoirs. Connecting threshold points on different coordinate axes divides the reservoir into bottom-water conical regions, optimal synergy regions, and poor reserve utilization regions. Interlayers with all evaluation parameters in the optimal synergy region are classified as Class I; those with two or more parameters in the optimal synergy region are classified as Class II; and those with fewer than two evaluation parameters in the optimal synergy region are classified as Class III.

Description

Technical Field

[0001] This invention relates to the field of oilfield development, and in particular to a method for rapid evaluation of the quality of interlayers in bottom water heavy oil reservoirs. Background Technology

[0002] Steam injection horizontal well development is an effective method for developing bottom water heavy oil reservoirs. However, interlayers are an important geological factor that causes the water flooding pattern to become more complex and the thermal recovery effect to be uneven.

[0003] Extensive field data demonstrates that for bottom-water heavy oil reservoirs, interlayer development can effectively delay bottom water coning vertically, expand the water-drive swept volume, effectively improve reserve utilization, and enhance development performance. Interlayer development can, to some extent, inhibit steam upwelling, ensuring that injected steam flows only within a defined oil layer, thereby delaying heat diffusion. The increased heating time of heavy oil leads to greater overall reservoir utilization. However, larger interlayer thickness and wider distribution can result in effective shielding of bottom water, insufficient bottom water energy supply, and reduced development effectiveness. Therefore, the difference between heavy oil bottom-water interlayer research and traditional interlayer studies lies in the fact that the interlayer with the best shielding effect is not necessarily the optimal configuration for development performance. A concise, intuitive, and effective interlayer quality classification method is urgently needed to determine the optimal interlayer quality configuration based on development performance, serving as the foundation for well network deployment in development plans.

[0004] Domestic research institutions have conducted extensive research on interlayer classification methods, but most studies focus on identifying the genetic type of interlayers, vertical combinations, or using well logging parameters to comprehensively identify the physical and lithological properties of interlayers. There is little research on classifying development effects based on interlayer quality in development practice. Summary of the Invention

[0005] To address the aforementioned problems, the purpose of this invention is to provide a method for rapid evaluation of interlayer quality in heavy oil bottom-water reservoirs. Based on interlayer quality analysis affecting development effectiveness, the method quickly completes the analysis of the basic well network scope and subsequent remaining oil distribution.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A method for determining the quality of interlayers in bottom-water heavy oil reservoirs includes the following steps:

[0008] Based on thickness, physical properties, and planar distribution characteristics, the interlayers and interlayers in the reservoir or flow unit within the target reserve unit are identified;

[0009] The influence of parameters of interlayers within reservoirs or flow units in the target reserve unit is characterized by a feature analysis. Through comparative analysis of development effects, including cumulative oil production and water breakthrough time, quantitative threshold ranges for interlayer parameters are defined.

[0010] The thickness, permeability, sealing degree, and development location of interlayers within the reservoir or flow unit of the target reserve unit are statistically analyzed as evaluation parameters for interlayer quality. These evaluation parameters are then plotted as circular scatter points on a four-dimensional spider web quantitative identification chart. Based on the position of the threshold point within the quantitative interval threshold, the interlayers in bottom water heavy oil reservoirs are classified and evaluated.

[0011] The distinction between interlayers and interlayers is based on the following: an interlayer is a non-permeable rock layer that can separate different connected bodies and prevent seepage within the connected bodies, while an interlayer is a low-permeability rock layer inside a single connected body.

[0012] The quantitative range thresholds for parameters that classify interlayers include: based on core calibration, conventional physical property analysis and well logging interpretation results, statistical interlayer characterization parameters that characterize the interlayer barrier effect, and statistical threshold ranges for the interlayer characteristics and their impact on mitigating bottom water coning and improving the degree of reservoir utilization based on the interlayer characterization parameters.

[0013] The interval of the scale unit is determined according to the thickness distribution range of the interlayer. The larger the interval of the scale unit, the better the interlayer's barrier performance.

[0014] Interlayer permeability characterizes the interlayer's control over fluid seepage capacity.

[0015] Logarithmic scales are used for the ordinate representing the interlayer permeability.

[0016] The degree of interlayer sealing is expressed as the ratio of the interlayer area to the horizontal well drainage area.

[0017] The location of the interlayer development is the distance from the top of the water layer. The smaller the value of the interlayer development location, the closer it is to the lower water layer, and the larger the value of the interlayer development location, the more it is located in the upper part of the reservoir and far away from the water layer.

[0018] The evaluation parameters of interlayer quality are projected into a four-dimensional spider web quantitative identification chart in the form of circular scatter points to classify and evaluate interlayers in bottom water heavy oil reservoirs. Specifically, the four coordinate axes in the four-dimensional spider web quantitative identification chart represent interlayer thickness, interlayer permeability, interlayer sealing degree, and interlayer development location, respectively. Each circular scatter point on the four-dimensional spider web quantitative identification chart represents the interlayer characteristics within a proven reserve unit, and the color of the circular scatter point represents the planar block or vertical stratigraphic position to which each interlayer belongs.

[0019] The bottom water coning zone, the optimal synergy zone, and the poor reserve utilization zone are divided according to the threshold points connected on different coordinate axes. The optimal synergy zone is located in the middle of the threshold points. If all the evaluation parameters of the interlayer quality are in the optimal synergy zone, it is classified as Class I; if more than two evaluation parameters of the interlayer quality are in the optimal synergy zone, it is classified as Class II; and if less than two evaluation parameters of the interlayer quality are in the optimal synergy zone, it is classified as Class III.

[0020] The present invention has the following advantages due to the adoption of the above technical solutions:

[0021] 1. This invention studies the quality characteristics of interlayers in the special development method of thermal injection horizontal wells in bottom water heavy oil reservoirs (especially offshore bottom water heavy oil reservoirs). Compared with the traditional single evaluation method that only considers the strength of seepage barrier capacity, it more systematically considers the key factors affecting the development effect of thermal injection horizontal wells in bottom water heavy oil reservoirs, and tries to balance the three development effects of suppressing bottom water coning velocity, expanding water drive sweep volume and improving reserve utilization.

[0022] 2. Using interlayer thickness, permeability, sealing degree, and location as key parameters, a four-dimensional spider web quantitative identification chart was established to classify and evaluate interlayers in bottom-water heavy oil reservoirs. The chart is simple and intuitive, with high operability and practicality, allowing developers with limited research experience to quickly grasp the quality characteristics of interlayers in bottom-water heavy oil reservoirs.

[0023] The use of this invention can not only guide the deployment of basic well networks, but also further guide the analysis of remaining oil distribution, and can be widely applied in the field of bottom water heavy oil reservoir development. Attached Figure Description

[0024] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts. In the drawings:

[0025] Figure 1 This is a schematic diagram of the interlayers in the core observation and logging interpretation of an oilfield in this invention;

[0026] Figure 2 This is a schematic diagram of key factors for evaluating interlayers in an oilfield in this invention;

[0027] Figure 3 This is a schematic diagram illustrating the threshold calculation using the single-factor breakpoint method for interlayers in an oilfield according to the present invention; and

[0028] Figure 4 This is a comprehensive schematic diagram of a rapid evaluation chart for the interlayer quality of bottom-water heavy oil reservoirs according to the present invention.

[0029] Meaning of reference numerals in the attached diagram:

[0030] 1. Silty interlayer; 2. Physical property interlayer; 3. First clay interlayer; 4. Second clay interlayer; 5. First clay barrier; 6. Second clay barrier. Detailed Implementation

[0031] Exemplary embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the invention are shown in the drawings, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the invention and to fully convey the scope of the invention to those skilled in the art.

[0032] According to some embodiments of this application, the method for determining the quality of interlayers in bottom-water heavy oil reservoirs provided by this invention includes the following steps:

[0033] 1. Identify the mezzanine features that affect development outcomes and require consideration of quality types.

[0034] 1.1 Divide the interlayer into partitions and sandwich layers.

[0035] A stratum is a relatively thick, stably distributed non-permeable rock layer that, under certain conditions, separates different connected bodies and prevents seepage from the connected bodies.

[0036] Interlayers are relatively thin, unstable, and low-permeability rock layers within a single connected body.

[0037] In the development of heavy oil, the main consideration is the effect of interlayers within the same fluid system on the development effect, with interlayers being the primary focus.

[0038] In practice, the same exploration unit is usually considered as a single connected body of the same fluid system, so the interlayers within the exploration unit are mainly selected for study.

[0039] Interlayers are defined based on the lower limit of the physical properties of the oilfield being developed, with a focus on interlayers within bottom water-oil layers.

[0040] 1.2 Statistical analysis of key characterization parameters for interlayers in bottom water-oil reservoirs.

[0041] Based on core calibration, conventional physical property analysis, and well logging interpretation results, key parameters that characterize the interlayer barrier effect are systematically statistically analyzed, generally including interlayer thickness, interlayer permeability, interlayer sealing degree, and interlayer location.

[0042] 2. Compare the differences in development effects by dividing the data into intervals based on single factors.

[0043] The influence of various parameters of the interlayer is characterized by feature analysis. By comparing and analyzing the development effects (including cumulative oil production, water breakthrough time, etc.), the threshold range of each parameter is divided into quantitative intervals.

[0044] The key parameters for characterizing the interlayer include:

[0045] A. Interlayer thickness ( H ):

[0046] Due to the different hydrodynamic conditions and sediment supply during different depositional periods, the thickness of the interlayer will inevitably vary. Therefore, the thickness of the interlayer is statistically analyzed as a key parameter.

[0047] The interval allocation is determined by statistically analyzing the distribution range of interlayers across the entire study area, and the scale unit interval is determined based on the distribution range of interlayer thickness. The larger this value, the better the interlayer barrier performance.

[0048] B. Interlayer permeability ( K ):

[0049] Using interlayer permeability K This is used to characterize the interlayer's control over fluid permeation capacity.

[0050] when K When ≤r mD, the interlayer can effectively suppress bottom water coning and the fluid cannot penetrate the interlayer, but the flow around the edge will lead to insufficient utilization of the reserves;

[0051] When r mD < K When ≤t mD, the interlayer has a certain degree of permeability, bottom water can permeate through the interlayer and significantly inhibit the coning velocity. At the same time, the secondary bottom water / side water drive formed by the bottom water around the edge can further expand the water drive sweep volume, to a certain extent achieving the "optimal synergy" state of inhibiting the bottom water coning velocity, expanding the water drive sweep range and improving the degree of reserve utilization.

[0052] when K When the value is greater than or equal to t mD, the bottom water cone advance rate is fast, the oil well is flooded earlier, and the degree of reserve utilization is worse. Here, r and t are statistical results of the study area.

[0053] Most of my country's heavy oil reservoirs are buried relatively shallowly (generally less than 2000 m). Due to the weak diagenesis they have undergone, the oil-bearing strata generally exhibit high permeability. In addition, the complex lithology of the interlayers leads to a large range of permeability variations. To avoid the distribution of scattered points on the coordinate graph being too concentrated and thus not conducive to analyzing the differences in permeability of the interlayers, a logarithmic coordinate is used for the vertical axis.

[0054] C. Degree of sealing of the interlayer ( S ):

[0055] The ratio of the interlayer area to the horizontal well drainage area represents the degree of interlayer sealing. , Sx For the mezzanine floor area, Sv (This refers to the drainage area of ​​a horizontal well).

[0056] when S When the value is less than or equal to r, the interlayer is insufficient to suppress bottom water coning.

[0057] when SWhen the temperature exceeds t, the fluid has difficulty bypassing the interlayer to provide energy, thus limiting the utilization of reserves.

[0058] D. Location of interlayer development ( L ):

[0059] The distance from the location of the interlayer development to the top of the water layer ( L () is used to characterize the location of interlayer development.

[0060] in, L The smaller the value, the closer it is to the lower water layer. L The larger the value, the higher the reservoir is located, far from the water layer.

[0061] The above four key parameters characterizing interlayers can basically reflect the multifaceted characteristics of interlayers within reservoir / flow unit. Therefore, their comprehensive application is beneficial for quickly determining the quality of interlayers and their impact on the development mode of steam injection horizontal wells in bottom water heavy oil reservoirs.

[0062] Based on the above key factors, the characteristics of interlayers and their impact on the threshold range of slowing down bottom water coning and improving the degree of reserve utilization were statistically analyzed.

[0063] 3. Draw a four-dimensional quantitative identification chart of spider webs.

[0064] 3.1 Create a spider web (radar) coordinate graph in Grapher software, where the four coordinate axes of the spider web represent the interlayer thickness ( H ), interlayer permeability ( K ), interlayer sealing degree ( S ) and location of interlayer development ( L ).

[0065] Each circular dot on the spider web coordinate map represents a layer feature within a proven reserve unit. The color of the circular dot represents the planar block or vertical stratum to which each layer belongs (set according to research needs; single unit analysis may not distinguish between blocks and strata).

[0066] 3.2 Connect threshold points on different coordinate axes to divide the bottom water coning region, the optimal coordination region, and the poor reserve utilization region. All interlayer evaluation parameters are in the optimal coordination region, which is Class I; more than two parameters are in the optimal coordination region, which is Class II; and less than two interlayer evaluation parameters are in the optimal coordination region, which is Class III.

[0067] 4. In Excel, statistically analyze the thickness, permeability, sealing degree, and development location of interlayers within the proven reserve unit / flow unit to be evaluated. These parameters reflect the quality of the interlayers. Plot these parameters as circular scatter points on a spider coordinate graph. Adjust the size and color of the circular scatter points according to the aesthetics of the graph and the needs of the research.

[0068] 5. Set the chart name to "Four-Dimensional Spider Web Quantitative Identification of Mezzanine Quality Chart", set the names and units of each coordinate axis, and set the legend according to the classification of the input scatter points.

[0069] Example:

[0070] The following detailed embodiments illustrate the rapid identification chart of interlayer quality in bottom-water heavy oil reservoirs produced using the interlayer type quality analysis method of the present invention, taking the proven reserves unit of the W oilfield as an example:

[0071] The W oilfield reservoir is buried at a depth of -650 to -850 m, and the crude oil viscosity is 892.1 to 1473.0 mPa·s, belonging to ordinary Class I-2 heavy oil.

[0072] The oilfield contains numerous oil-bearing formations with a large vertical span, including the first segment J1I of the Jiaowei Formation and the second segments J2I and J2II. 上 J2Ⅱ 下 And five oil groups including J2Ⅲ.

[0073] The viscosity of crude oil determines the development method of thermal recovery (steam huff and puff + steam drive).

[0074] In bottom-water reservoirs, the reservoir and the aquifer are in direct contact. While the water layer provides pressure protection for the oil layer, it also causes the bottom water ridge to seriously affect the development effect. The presence of interlayers can slow down the speed of bottom water ridge and increase the cumulative production of a single well.

[0075] Therefore, for the relatively well-developed interlayers in the transition zone and bottom water oil layer of this region, this invention is used for rapid identification of the quality of interlayers in bottom water heavy oil reservoirs, including the following steps:

[0076] 1. For example Figure 1 As shown, the interlayer and the sandwich layer are identified, including their thickness, physical properties, and planar distribution characteristics;

[0077] The bottom layer of J1I consists of a first mud layer 5 and a second mud layer 6. The first mud layer 5 and the second mud layer 6 are relatively thick (about 10m) and have a stable distribution. Based on the analysis of pressure measurement data and other auxiliary data, it is believed that they can prevent oil and gas from migrating upwards and have little impact on the development of the proven units inside J1I. Therefore, they will not be analyzed in this study.

[0078] The thickness of the silty interlayer 1 is 3.5m, and the lower part is a water layer. The quality of the interlayer will affect the development effect, so it will be the focus of this analysis.

[0079] Figure 1 This is a schematic diagram of the interlayers in the core observation and logging interpretation of an oilfield in this invention.

[0080] like Figure 1As shown, in well W-1, the silty interlayer 1 is 3.5m long; the clayey interlayer 5 is 12.3m long.

[0081] In well W-2, the physical property interlayer 2 is 2.1m deep;

[0082] In well W-2, the first clay interlayer 3 is 1.2m deep; the second clay interlayer 4 is 1.0m deep; and the clay separator 6 is 9.5m deep.

[0083] 2. Targeting key parameters affecting the quality of the interlayer (such as...) Figure 2 (As shown) Statistical analysis was conducted to divide the interval thresholds that affect the different effects of steam injection horizontal well development methods. Figure 2 This is a schematic diagram illustrating the key factors for evaluating interlayers in an oilfield in this invention. (Example:) Figure 2 As shown, the interlayer is located in the oil layer. The figure schematically illustrates the thickness of the interlayer and its location in the reservoir.

[0084] The specific steps are as follows:

[0085] 2.1 First, we statistically analyzed and compared the cumulative oil production of different key parameters within the target area under different distribution ranges. Figure 3 This is a schematic diagram illustrating the threshold calculation using the single-factor breakpoint method for interlayers in an oilfield according to this invention. The accumulated oil yield is related to the following factors: the distance of the interlayer from the water layer, the interlayer thickness, the interlayer permeability, and the degree of interlayer sealing. Figure 3 In this context, the cumulative oil volume is measured in units of 10. 4 m 3 The units for the distance between the interlayer and the water layer and the thickness of the interlayer are meters (m), the unit for the permeability of the interlayer is mD, and the unit for the degree of sealing of the interlayer is _____.

[0086] 2.2 Draw a curve according to the trend of output change to mark the peak output. The inflection points around the peak are the key parameter values ​​for the best interlayer quality. Take the nearest dividing point to the left and right as the interval threshold to classify the interlayer quality type under the single-factor standard.

[0087] 3. Create a spider web coordinate graph in Grapher software, where the four coordinate axes of the spider web represent the thickness of the interlayer (…). H ), interlayer permeability ( K ), interlayer sealing degree ( S ) and location of interlayer development ( L ).

[0088] The coordinate axes representing each key parameter are set according to the maximum and minimum values ​​of the distribution range. The threshold points on different coordinate axes are used to divide the bottom water coning area, the optimal coordination area, and the poor storage utilization area.

[0089] 4. In Excel, the thickness, permeability, sealing degree, and development location of the interlayers within the proven reserve units of the W Oilfield are statistically analyzed. Taking different proven units of the first member J1Ⅰ and the second member J2I of the Jiaowei Formation in the W Oilfield as a series, the characteristic parameter values of these interlayers are plotted into a cobweb coordinate diagram in the form of circular scatter points (or other scatter point shapes), and connected with straight lines, differentiated by different colors.

[0090] Judging from the comprehensive four parameters, the quality of the interlayers within the proven reserve units of the W Oilfield can be divided into three categories:

[0091] The physical property interlayer 2 has the best quality and belongs to Class I. It is mainly located in the J2Ⅲ oil zone, which can synergistically slow down the bottom water coning and achieve the best maximum reserve production;

[0092] The first argillaceous interlayer 3 and the second argillaceous interlayer 4 have the worst quality and belong to Class III. They are located in the J2I oil zone and are prone to bottom water coning;

[0093] Due to the strong reservoir storage and permeability capacity, the siltstone interlayer 1 belongs to Class II. It is located in the J1I oil zone and is prone to bottom water coning.

[0094] Compared with the traditional water injection development, which only evaluates the interlayers for water avoidance (only requiring a strong enough barrier effect), in thermal recovery development, water is needed to provide energy, but too much water will cause heat loss. Therefore, the best condition is in the middle of the thresholds of each parameter.

[0095] 5. Set the chart title as "Four - dimensional Cobweb Quantitative Identification Chart of Interlayer Quality", and set the names and units of each coordinate axis.

[0096] Figure 4 It is a comprehensive schematic diagram of the rapid evaluation chart of interlayer quality for the bottom - water heavy - oil reservoir of the present invention. In Figure 4 the items shown include: interlayer location (L) / m, interlayer thickness (H) / m, interlayer permeability (K) / mD, and interlayer blocking degree (S) / %. The interlayer quality categories are divided into Class I, Class II, and Class III. The rapid discrimination cobweb diagram visualizes the relationship between the interlayer location (L) / m, interlayer thickness (H) / m, interlayer permeability (K) / mD, and interlayer blocking degree (S) / %.

[0097] As Figure 4 shown, for the No. ① interlayer (siltstone interlayer 1), the interlayer location (L) is 3.7 m, the interlayer thickness (H) is 3.4 m, the interlayer permeability (K) is 220 mD, the interlayer blocking degree (S) is 117%, and the interlayer quality category is divided into Class II;

[0098] For the No. ② interlayer (physical property interlayer 2), the interlayer location (L) is 4.1 m, the interlayer thickness (H) is 2.1 m, the interlayer permeability (K) is 21 mD, the interlayer blocking degree (S) is 83%, and the interlayer quality category is divided into Class I;

[0099] The interlayer (first clay interlayer 3) has an interlayer location (L) of 8.5m, an interlayer thickness (H) of 1.2m, an interlayer permeability (K) of 172mD, an interlayer shading degree (S) of 33%, and an interlayer quality category of Class III.

[0100] The interlayer No. 4 (second clay interlayer 4) has an interlayer location (L) of 0m, an interlayer thickness (H) of 1.0m, an interlayer permeability (K) of 114mD, an interlayer shading degree (S) of 33%, and an interlayer quality category of Class III.

[0101] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for judging the quality of interlayers in bottom-water heavy oil reservoirs, characterized in that, Includes the following steps: Based on thickness, physical properties, and planar distribution characteristics, the interlayers and interlayers in the reservoir or flow unit within the target reserve unit are identified; The influence of parameters of interlayers within reservoirs or flow units in the target reserve unit is characterized by feature analysis. Through comparative analysis of development effects, including cumulative oil production and water breakthrough time, the quantification range thresholds of the interlayer parameters are defined. The thickness, permeability, sealing degree, and development location of interlayers within the reservoir or flow unit of the target reserve unit are statistically analyzed as evaluation parameters for interlayer quality. These evaluation parameters are then plotted as circular scatter points in a four-dimensional spider web quantitative identification chart. Based on the position of the threshold point within the quantification interval, the interlayers in the bottom water heavy oil reservoir are classified and evaluated. The evaluation parameters of interlayer quality are projected into a four-dimensional spider web quantitative identification chart in the form of circular scatter points to classify and evaluate interlayers in bottom water heavy oil reservoirs. Specifically, the four coordinate axes in the four-dimensional spider web quantitative identification chart represent interlayer thickness, interlayer permeability, interlayer sealing degree, and interlayer development location, respectively. Each circular scatter point on the four-dimensional spider web quantitative identification chart represents the interlayer characteristics within a proven reserve unit, and the color of the circular scatter point represents the planar block or vertical layer to which each interlayer belongs. The coordinate axes representing each key parameter are set according to the maximum and minimum values ​​of the distribution range. The threshold points on different coordinate axes are connected to divide the bottom water coning area, the optimal synergy area, and the poor reserve utilization area. The thickness, permeability, sealing degree and development location of the interlayers in the proven reserve units of the oilfield are statistically analyzed. According to the different proven units of the oilfield, the interlayer characteristic parameter values ​​are put into the spider coordinate map in the form of circular scatter points, connected by straight lines and distinguished by different colors. The bottom water coning region, the optimal coordination region, and the poor reserve utilization region are divided according to the threshold points connected on different coordinate axes. The optimal coordination region is located in the middle of the threshold points. If all the evaluation parameters of interlayer quality are in the optimal coordination region, it is classified as Class I. If two or three evaluation parameters of interlayer quality are in the optimal coordination region, it is classified as Class II. If zero or one evaluation parameter of interlayer quality is in the optimal coordination region, it is classified as Class III.

2. The method for judging the quality of interlayers in bottom-water heavy oil reservoirs according to claim 1, characterized in that, The distinction between interlayers and interlayers is based on the following: the interlayer is a non-permeable rock layer that can separate different connected bodies and prevent seepage from the connected bodies, while the interlayer is a low-permeability rock layer inside a single connected body.

3. The method for judging the quality of interlayers in bottom-water heavy oil reservoirs according to claim 1, characterized in that, The threshold range for the parameters that define the interlayer includes: based on core calibration, conventional physical property analysis and well logging interpretation results, statistical interlayer characterization parameters that characterize the interlayer barrier effect, and statistical threshold ranges for the interlayer characteristics and their impact on mitigating bottom water coning and improving the degree of reserve utilization based on the interlayer characterization parameters.

4. The method for judging the quality of interlayers in bottom-water heavy oil reservoirs according to claim 3, characterized in that, The interval of the scale unit is determined according to the thickness distribution range of the interlayer. The larger the interval of the scale unit, the better the interlayer's barrier performance.

5. The method for judging the quality of interlayers in bottom-water heavy oil reservoirs according to claim 3, characterized in that, The interlayer permeability characterizes the interlayer's control over fluid permeation capacity.

6. The method for judging the quality of interlayers in bottom-water heavy oil reservoirs according to claim 5, characterized in that, Logarithmic scales are used for the ordinate representing the interlayer permeability.

7. The method for judging the quality of interlayers in bottom-water heavy oil reservoirs according to claim 3, characterized in that, The degree of interlayer sealing is expressed as the ratio of the interlayer area to the horizontal well drainage area.

8. The method for judging the quality of interlayers in bottom-water heavy oil reservoirs according to claim 1, characterized in that, The interlayer development location is the distance from the top of the water layer. The smaller the value of the interlayer development location, the closer it is to the lower water layer. The larger the value of the interlayer development location, the more it is located in the upper part of the reservoir and far away from the water layer.

Images