Method for analyzing sand body scale and connection mode under multi-layer perforation condition

Abstract

The present application belongs to the field of fine description of oil and gas field underground reservoir, and specifically discloses a method for analyzing sand body scale and connection mode under multi-layer perforation conditions, comprising the following steps: step 1, classification of interference testing; step 2, division of formation units; step 3, selection of interference testing well groups and numbering; step 4, spatial matching classification; step 5, quantitative analysis; and step 6, determination of sand body scale and connection mode under the conditions of same-layer perforation and adjacent-layer perforation according to the spatial matching result obtained in step 4 and the intensity of interference signals obtained in step 5. In the present application, quantitative analysis of interference signals is used to determine sand body scale and connection mode under multi-layer perforation conditions, and both static data and dynamic data are considered, so that the characterization result is more accurate and the argument is more sufficient. Meanwhile, the interference testing data is applied to the determination of conventional sand body scale without distinguishing perforation horizons, so that the application field and effect of interference testing data are effectively improved.

Description

Technical Field

[0001] This invention belongs to the field of fine description of underground reservoirs in oil and gas fields, specifically relating to a method for analyzing the size and connectivity of sand bodies under multi-layer perforation conditions. Background Technology

[0002] Currently, both domestically and internationally, there are several common methods for determining the size of underground reservoir sand bodies in oil and gas fields:

[0003] Method 1: In densely populated well areas, reservoir dissection is carried out using drilling, logging, and well logging data and reservoir configuration analysis methods. Based on this, statistical analysis methods are used to determine the size of sand bodies (parameters such as length and width).

[0004] Method 2: Using ancient outcrop and modern river sediment observation data, fit the corresponding empirical formula; secondly, use well logging and other data of the studied area to calculate relevant parameters; finally, substitute the obtained relevant parameters into the empirical formula to calculate the sand body size (length, width and other parameters).

[0005] Method 3: Parameters such as the length-to-width ratio and width-to-thickness ratio of the sand body are obtained through physical simulation; then, the thickness data of the sand body is obtained using drilling data from the study area; the thickness data is combined with the length-to-width ratio and width-to-thickness ratio parameters to estimate the size of the sand body (length, width, etc.).

[0006] Method 4: Use horizontal well data to determine the size of the sand body (length, width, and other parameters);

[0007] Method 5: Using the production dynamic data of the wells in production, under the given conceptual model and boundary conditions, use dynamic methods such as numerical simulation and well test interpretation to calculate the sand body boundary and obtain the sand body size (length, width and other parameters).

[0008] All methods have limitations, mainly in the following aspects: Method 1 relies solely on geological dissection, making it impossible to assess the reliability of its results; Methods 2 and 3, which establish empirical formulas or aspect ratios (length / width / width / thickness ratios) through various methods, lack validation regarding their applicability to the geological conditions of the study area, making accurate assessment of their calculation results impossible; Method 4 utilizes horizontal well data to determine the size of sand bodies. However, during actual drilling, the spatial location of the sand body and its alignment with the horizontal well trajectory significantly impact the dissection results. Furthermore, the interpretation of mudstone encountered in horizontal wells varies, with some considering the same mudstone segment as an internal layer within the sand body, while others interpret it as muddy sediment between two sand bodies. This ambiguity means there is no clear standard for determining which mudstone segment marks the end of the sand body. Consequently, the discrepancy between the dissection results and the actual underground conditions cannot be evaluated; Method 5, which purely utilizes numerical simulation or well test interpretation, typically requires treating the formation as a mean model and then using dynamic data to simulate and interpret relevant parameters, neglecting geological methods, resulting in results lacking geological basis. Furthermore, it fails to account for multi-layer perforation scenarios, resulting in statistically significant interpretations. Additionally, when using interference tests for analysis, the application is often qualitative; the presence of interference signals indicates connectivity, while the absence of such signals suggests otherwise, without considering the speed and intensity of signal transmission.

[0009] Interference testing, as the most intuitive method for determining inter-well sand body connectivity, has a natural advantage in determining sand body size, yet its application is relatively limited. Furthermore, domestic oil and gas development often employs multi-layer perforation and multi-layer combined production, which further restricts the application of interference testing in determining sand body size. Summary of the Invention

[0010] In order to overcome the shortcomings of the prior art, the purpose of this invention is to provide a method for analyzing the size and connectivity of sand bodies under multi-layer perforation conditions, so as to solve the problem of inaccurate determination of the size of underground reservoir sand bodies in oil and gas fields in the prior art.

[0011] To achieve the above objectives, the present invention employs the following technical solution:

[0012] This invention provides a method for analyzing the size and connectivity of sand bodies under multi-layer perforation conditions, characterized by comprising:

[0013] Step 1: Classification of Interference Well Tests:

[0014] Obtain the interference test results and classify the interference test well groups into two categories based on the results: well groups with interference and well groups without interference.

[0015] Step 2: Division of stratigraphic units:

[0016] Conduct detailed stratigraphic analysis, dividing stratigraphic units into individual layers and numbering them;

[0017] Step 3: Select and number the interfering well groups:

[0018] A specific interfering well group was selected for analysis. The perforation points of the active wells and the perforation points of the observation wells in the selected interfering well group were numbered in combination with the corresponding single-layer number.

[0019] Step 4: Spatial matching classification:

[0020] The perforation-layer relationships of all perforation points in the selected interfering well groups and the perforation-layer relationships of all perforation points in the observation wells were compared one by one. The spatial matching of the perforation points and perforation-layer relationships of the selected interfering wells and the observation wells was classified to obtain the spatial matching results.

[0021] Step 5: Quantitative analysis: Quantitatively analyze the signal intensity of different interfering well groups to obtain the intensity of the interference signal;

[0022] Step 6: Based on the spatial matching results obtained in Step 4 and the intensity of the interference signal obtained in Step 5, determine the sand body size and connection mode under the conditions of perforation in the same layer and perforation in adjacent layers.

[0023] Furthermore, in step 2, the stratigraphic units are divided into single layers and numbered as follows: from bottom to top, the single layers are numbered as C1, C2, C3...Ct.

[0024] Furthermore, in step 3, the selection of a specific interfering well group for analysis, and the numbering of the perforation points of the active wells and the observation wells in the selected interfering well group in combination with the corresponding single-layer number, refers to:

[0025] A well group with interference was selected for analysis. The perforation points of the active well were numbered from bottom to top as J1, J2, J3...Jn; the perforation points of the observation well were numbered from bottom to top as G1, G2, G3...Gm; if the nth perforation point of the active well belongs to the tth layer, the relationship between the nth perforation point and the layer is marked as Jn-Ct; if the mth perforation point of the observation well belongs to the xth layer, the relationship between the mth perforation point and the layer is marked as Gm-Cx.

[0026] Furthermore, in step 4, the spatial matching of perforation points and perforation layer relationships between the excitation well and the observation well is classified. The classification process for perforations within the same layer is as follows:

[0027] If the perforation layer relationship between the activated well and the observed well has x = t, denoted as Jn-Ct-Gm, then the nth perforation point of the observed well and the mth perforation point of the activated well are both perforated at the same layer Ct. This situation is called same-layer perforation.

[0028] Furthermore, in step 4, the spatial matching of perforation points and perforation layer relationships in the excitation well and observation well is classified. The classification process for adjacent layer perforations is as follows:

[0029] If the relationship between the perforation layer of the excitation well and the perforation layer of the observation well is xt=1, denoted as Jn-(Ct-C(t+1))-Gm, then the nth perforation point of the observation well at layer Ct and the mth perforation point of the excitation well at layer Ct are simultaneously perforated at the one layer above them, C(t+1). This situation is called upper adjacent layer perforation.

[0030] If the relationship between the perforation layer of the excitation well and the perforation layer of the observation well has tx = 1, denoted as Jn-(Ct-C(t-1))-Gm, then the nth perforation point of the observation well at layer Ct and the mth perforation point of the excitation well at layer Ct are simultaneously perforated in the next adjacent layer C(t-1). This situation is called lower adjacent layer perforation.

[0031] Furthermore, the quantitative analysis of signal strength for different interfering well groups described in step 5 specifically includes:

[0032] When the excitation well is opened, the bottom pressure of the observation well is P1, and when the test ends, the bottom pressure of the observation well is P2. The test time is t, and the distance between the excitation well and the observation well is h.

[0033]

[0034] M represents the intensity of the interference signal, measured in MPa / km·d; it indicates the degree of pressure drop per unit time and unit distance between the excitation well and the observation well, and the magnitude of M reflects the degree of connectivity between the two wells.

[0035] Furthermore, the method for determining the sand body size and connectivity in the case of perforation at the same layer, as described in step 6, is as follows:

[0036] When there is only one perforation in the same layer and the interference signal strength M is greater than 0.03 MPa / km·d, it is considered that the excitation well and the observation well encountered the same core bar sand body in the layer. The size of the core bar sand body is greater than the distance between the excitation well and the observation well, and its connection mode is internal connection within the same sand body.

[0037] When there is only one perforation in the same layer and the interference signal intensity M is less than 0.03 MPa / km·d, it is considered that the excitation well and the observation well encountered different core bar sand bodies in this layer. The portion of the core bar sand bodies encountered by the excitation well and the observation well between the two wells is less than half the distance between the two wells, and their connection mode is the connection of sandy braided water channels between the wells.

[0038] Furthermore, the method for determining the size and connectivity of the sand body in the case of perforation at the same layer, as described in step 6, also includes:

[0039] When there are two or more perforations in the same layer and the interference signal strength M is greater than 0.01 MPa / km·d, the excitation well and the observation well encounter the same core bar sand body in the same layer. The size of the core bar sand body is greater than the distance between the excitation well and the observation well, and its connection mode is internal connection within the same sand body.

[0040] When there are two or more perforations in the same layer and the interference signal intensity M is less than 0.01 MPa / km·d, the excitation well and the observation well encounter different core bar sand bodies. The portion of the core bar sand bodies encountered by the excitation well and the observation well between the two wells is less than half the distance between the two wells. Their connection mode is the connection of sandy braided water channels between the wells.

[0041] Furthermore, the method for determining the sand body size and connectivity in the case of adjacent-layer perforation described in step 6 is as follows:

[0042] When there is only one adjacent layer perforation and the interference signal intensity M is greater than 0.001 MPa / km·d, the core beach sand body encountered by the excitation well and the observation well is greater than half the distance between the two wells. Its connection mode is the adjacent well and adjacent layer incised phase composite connection mode.

[0043] When there is only one adjacent perforation and the interference signal strength M is less than 0.001 MPa / km·d, the sand bodies encountered by the excitation well and the observation well in the part between the two wells are less than half the distance between the two wells. The connection mode is the adjacent well and adjacent layer undercutting heterogeneous phase communication connection mode.

[0044] Furthermore, the method for determining the size and connectivity of the sand body in step 6 also includes:

[0045] If the same interfering well group has both perforations in the same layer and perforations in adjacent layers, then the corresponding interfering well group is determined to be a perforation in the same layer.

[0046] The present invention has at least the following beneficial effects:

[0047] This invention utilizes quantitative analysis of interference signals to determine sand body size and connectivity patterns under multi-perforation conditions. It considers both static and dynamic data, resulting in more accurate characterization and more comprehensive evidence. Furthermore, it avoids the indiscriminate application of interference test data to conventional sand body size determination without distinguishing perforation layers, effectively expanding the application scope and effectiveness of interference test data. Attached Figure Description

[0048] The accompanying drawings, which form part of this specification, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0049] Figure 1 This is a schematic diagram showing that the interconnection signal is strong within the same sand body and weak between different sand bodies in the same layer of perforation.

[0050] Figure 2 This is a schematic diagram showing a scenario where there is only one perforation in the same layer and the interference signal strength M is greater than 0.03 MPa / km·d.

[0051] Figure 3 This is a schematic diagram showing a scenario where there is only one perforation in the same layer and the interference signal strength M is less than 0.03 MPa / km·d.

[0052] Figure 4 A schematic diagram showing the existence of two or more perforations in the same layer;

[0053] Figure 5 This is a schematic diagram showing the existence of only one adjacent layer perforation and the interference signal strength M is greater than 0.001 MPa / km·d.

[0054] Figure 6 This is a schematic diagram showing a scenario where there is only one adjacent layer perforation and the interference signal strength M is less than 0.001 MPa / km·d. Detailed Implementation

[0055] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0056] The following detailed description is exemplary and intended to provide further detailed explanation of the invention. Unless otherwise specified, all technical terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used in this invention is for describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention.

[0057] A method for analyzing the size and connectivity of sand bodies under multi-layer perforation conditions, comprising:

[0058] Step 1: Classification of interference test results: Obtain interference test results and classify the interference test well groups into two categories based on the results: well groups with interference and well groups without interference. When performing quantitative analysis of interference signals, well groups with interference are usually used.

[0059] A well group with observed interference refers to a well group in which the bottomhole pressure of the observed well decreases after the activated well is put into production; a well group without observed interference refers to a well group in which the bottomhole pressure of the observed well remains unchanged or increases after the activated well is put into production.

[0060] An excitation well refers to a well whose operating regime is artificially altered during inter-well interference testing in order to cause interference to adjacent wells;

[0061] An observation well is a well specifically used during oilfield development to observe underground dynamics within the oilfield. This includes observing pressure variations in different oil layers, water cut patterns, and water flooding patterns in individual layers. It generally does not participate in production operations.

[0062] Step 2: Division of stratigraphic units: Conduct detailed stratigraphic division and correlation, divide stratigraphic units into individual layers and number them, numbering the individual layers from bottom to top as C1, C2, C3...Ct;

[0063] A single layer refers to a stratigraphic unit that is vertically composed of a single depositional period.

[0064] Step 3: Select and number the interfering well groups: Select a specific interfering well group for analysis. Number the perforation points of the active wells from bottom to top as J1, J2, J3...Jn; number the perforation points of the observation wells from bottom to top as G1, G2, G3...Gm; if the nth perforation point of the active well belongs to the tth layer, then mark the relationship between the nth perforation point and the layer as Jn-Ct (hereinafter referred to as the active well perforation-layer relationship); if the mth perforation point of the observation well belongs to the xth layer, then mark the relationship between the mth perforation point and the layer as Gm-Cx (hereinafter referred to as the observation well perforation-layer relationship).

[0065] Step 4: Spatial Matching Classification: The perforation-layer relationships of all perforation points in the selected interfering well groups and all perforation points in the observation wells are compared one by one. The spatial matching of the perforation points and perforation-layer relationships in the selected interfering well groups is classified to obtain the spatial matching results, including perforations in the same layer and perforations in adjacent layers. The specific classification process is as follows:

[0066] For a specific interfering well group, the following are the specific types:

[0067] (1) If the relationship between the perforation layer of the excitation well and the perforation layer of the observation well is x=t, it is marked as Jn-Ct-Gm, which means that the nth perforation point of the observation well and the mth perforation point of the excitation well are perforated at the same layer Ct. This situation is called same-layer perforation.

[0068] (2) If there is xt=1 between the perforation layer relationship of the excitation well and the perforation layer relationship of the observation well, it is marked as Jn-(Ct-C(t+1))-Gm, which means that the nth perforation point of the observation well at layer Ct and the mth perforation point of the excitation well at layer Ct are perforated at the adjacent upper layer C(t+1). This situation is called upper adjacent layer perforation.

[0069] (3) If there is a tx = 1 between the perforation layer relationship of the excitation well and the perforation layer relationship of the observation well, it is marked as Jn-(Ct-C(t-1))-Gm, which means that the nth perforation point of the observation well at layer Ct and the mth perforation point of the excitation well at layer Ct are perforated at the next lower layer C(t-1) adjacent to each other. This situation is called perforation of the next lower layer.

[0070] Step 5: Quantitative Analysis: Quantitatively analyze the signal intensity of different interfering well groups to obtain the intensity of the interference signal. Let P1 be the bottom hole pressure of the observation well when the excitation well is opened. Let P2 be the bottom hole pressure of the observation well at the end of the test. Let t be the test time and h be the distance between the excitation well and the observation well.

[0071]

[0072] M represents the intensity of the interference signal, measured in MPa / km·d; it indicates the degree of pressure drop per unit time and unit distance between the excitation well and the observation well. The magnitude of M reflects the degree of connectivity between the two wells.

[0073] like Figure 1 As shown, the interconnection signal within the same sand body is strong in perforations of the same layer, while the interconnection signal is weak in different sand bodies.

[0074] Step 6: Based on the spatial matching results obtained in Step 4 and the intensity of the interference signal obtained in Step 5, determine the sand body size and connection mode in the case of perforation in the same layer and perforation in adjacent layers.

[0075] (1) As Figure 2 As shown, when there is only one perforation in the same layer and the interference signal strength M is greater than 0.03 MPa / km·d

[0076] It is assumed that the excitation well and the observation well encountered the same core-shoal sand body in this layer, and the size of the core-shoal sand body is greater than the distance between the excitation well and the observation well. Their connectivity mode is that they are connected within the same sand body.

[0077] (2) Figure 3 As shown, when there is only one perforation in the same layer and the interference signal strength M is less than 0.03 MPa / km·d

[0078] It is assumed that the excitation well and the observation well encountered different core-shoal sand bodies in this layer, and their connection is due to the presence of sandy channels between the two wells. Based on the principle that the pinch-out location of the sand body is equidistant from the excitation well and the observation well, it can be determined that the portion of the core-shoal sand body encountered by both wells between the two wells is less than half the distance between the two wells. The connection mode is a sandy braided channel connection between the wells.

[0079] like Figure 4 As shown, (3) when there are two or more perforations in the same layer, and the interference signal strength M is greater than 0.01 MPa / km·d

[0080] Based on the curve morphology of the perforation locations of the excitation well and observation well in the same layer, if the curve morphology of a certain layer is similar, the interference signal is considered to be generated from that layer. This indicates that the excitation well and observation well encountered the same core-shoal sand body in that layer, and the size of the core-shoal sand body is greater than the distance between the excitation well and observation well. Their connectivity mode is internal connectivity within the same sand body.

[0081] (4) When there are two or more perforations in the same layer, and the interference signal strength M is less than 0.01 MPa / km·d

[0082] Based on the curve morphology of the perforation locations in the same layer of the excitation well and observation well, if the curve morphology of a certain layer is similar, the interference signal is considered to originate from that layer. This suggests that the excitation well and observation well encountered different core-shoal sand bodies in that layer, and their connection is due to the existence of sandy channels between the two wells. Following the principle that the pinch-out location of the sand body is equidistant from the excitation well and observation well, it can be determined that the portion of the core-shoal sand body encountered by both the excitation well and observation well between the two wells is less than half the well distance. The connection mode is a sandy braided channel connection between the wells.

[0083] (5) Figure 5 As shown, when there is only one adjacent layer perforation and the interference signal strength M is greater than 0.001 MPa / km·d

[0084] It is assumed that the excitation well and the observation well are connected in adjacent layers. This is because the sand bodies in adjacent layers overlap, causing the connection. Based on the principle that the distance from the pinch-out position of the sand body to the excitation well and the observation well is equal, it can be determined that the portion of the core beach sand body encountered by the excitation well and the observation well between the two wells is greater than half the distance between the two wells. The connection mode is a composite connection mode of adjacent wells and adjacent layers with incision and the same phase.

[0085] (6) Figure 6 As shown, when there is only one adjacent layer perforation and the interference signal strength M is less than 0.001 MPa / km·d

[0086] It is assumed that the excitation well and the observation well are connected in adjacent layers. This is because the sand bodies in adjacent layers overlap, causing them to connect with each other. Based on the principle that the distance from the pinch-out position of the sand body to the excitation well and the observation well is equal, it can be determined that the portion of the sand body encountered by the excitation well and the observation well between the two wells is less than half the distance between the two wells. The connection mode is a cross-phase communication mode between adjacent wells and adjacent layers.

[0087] (7) If the same interfering well group has both perforations in the same layer and perforations in adjacent layers, the corresponding interfering well group is determined to be a perforation in the same layer.

[0088] 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 it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for analyzing the scale and connectivity of sand bodies under multi-layer perforation conditions, characterized in that, include: Step 1: Classification of Interference Well Tests: Obtain the interference test results and classify the interference test well groups into two categories based on the results: well groups with interference and well groups without interference. Step 2: Division of stratigraphic units: Conduct detailed stratigraphic analysis, dividing stratigraphic units into individual layers and numbering them; Step 3: Select and number the interfering well groups: A specific interfering well group was selected for analysis. The perforation points of the active wells and the perforation points of the observation wells in the selected interfering well group were numbered in combination with the corresponding single-layer number. Step 4: Spatial matching classification: The perforation-layer relationships of all perforation points in the selected interfering well groups and the perforation-layer relationships of all perforation points in the observation wells were compared one by one. The spatial matching of the perforation points and perforation-layer relationships of the selected interfering wells and the observation wells was classified to obtain the spatial matching results. Step 5: Quantitative analysis: Quantitatively analyze the signal intensity of different interfering well groups to obtain the intensity of the interference signal; The quantitative analysis of signal intensity from different interfering well groups specifically includes: When the excitation well is opened, the bottom pressure of the observation well is P1, and when the test ends, the bottom pressure of the observation well is P2. The test time is t, and the distance between the excitation well and the observation well is h. M represents the strength of the interference signal, measured in units of... ; indicates the degree of pressure decrease per unit time and unit distance between the excitation well and the observation well; the magnitude of M reflects the degree of connectivity between the two wells; Step 6: Based on the spatial matching results obtained in Step 4 and the intensity of the interference signal obtained in Step 5, determine the sand body size and connection mode under the conditions of perforation in the same layer and perforation in adjacent layers.

2. The method for analyzing sand body size and connectivity under multi-layer perforation conditions according to claim 1, characterized in that, Step 2 describes dividing the stratigraphic units into single layers and numbering them as follows: from bottom to top, the single layers are numbered as C1, C2, C3...Ct.

3. The method for analyzing sand body size and connectivity under multi-layer perforation conditions according to claim 1, characterized in that, Step 3, which involves selecting a specific interfering well group for analysis and assigning numbers to the perforation points of the active wells and observation wells within the selected interfering well group, in conjunction with their corresponding single-layer numbers, refers to: A well group with interference was selected for analysis. The perforation points of the active well were numbered from bottom to top as J1, J2, J3...Jn; the perforation points of the observation well were numbered from bottom to top as G1, G2, G3...Gm; if the nth perforation point of the active well belongs to the tth layer, the relationship between the nth perforation point and the layer is marked as Jn-Ct; if the mth perforation point of the observation well belongs to the xth layer, the relationship between the mth perforation point and the layer is marked as Gm-Cx.

4. The method for analyzing sand body size and connectivity under multi-layer perforation conditions according to claim 3, characterized in that, The spatial matching of perforation points and perforation layer relationships in step 4, as described above, is as follows: The classification process for perforations within the same layer is as follows: If the perforation layer relationship between the activated well and the observed well has x=t, denoted as Jn-Ct-Gm, then the nth perforation point of the observed well and the mth perforation point of the activated well are both perforated at the same layer Ct. This situation is called same-layer perforation.

5. The method for analyzing sand body size and connectivity under multi-layer perforation conditions according to claim 4, characterized in that, The spatial matching of perforation points and perforation layer relationships in step 4, as described above, involves classifying perforations in adjacent layers as follows: If the relationship between the perforation layer of the excitation well and the perforation layer of the observation well has xt=1, marked as Jn-(Ct- C(t+1))-Gm, then the nth perforation point of the observation well at layer Ct and the mth perforation point of the excitation well at layer Ct are simultaneously perforated at the one layer above them, C(t+1). This situation is called perforation of the upper adjacent layer. If the relationship between the perforation layer of the excitation well and the perforation layer of the observation well has tx=1, marked as Jn-(Ct-C(t-1))-Gm, then the nth perforation point of the observation well at layer Ct and the mth perforation point of the excitation well at layer Ct are simultaneously perforated in the next adjacent layer C(t-1). This situation is called perforation in the next adjacent layer.

6. The method for analyzing sand body size and connectivity under multi-layer perforation conditions according to claim 1, characterized in that, The method for determining the sand body size and connectivity in step 6 under the condition of perforation at the same layer is as follows: There is only one perforation at the same layer, and the interference signal strength M is greater than 0.

03. At that time, it was believed that the excitation well and the observation well encountered the same core bar sand body in this layer. The size of the core bar sand body was larger than the distance between the excitation well and the observation well, and its connection mode was that the sand body was connected within the same sand body. There is only one perforation at the same layer, and the interference signal strength M is less than 0.

03. At that time, it was believed that the excitation well and the observation well encountered different core bar sand bodies in this layer. The portion of the core bar sand bodies encountered by the excitation well and the observation well between the two wells was less than half the distance between the two wells, and their connection mode was the connection of sandy braided water channels between the wells.

7. The method for analyzing sand body size and connectivity under multi-layer perforation conditions according to claim 1, characterized in that, The methods for determining the size and connectivity of the sand body in the case of perforation at the same layer in step 6 also include: There are two or more perforations in the same layer, and the interference signal strength M is greater than 0.

01. At that time, the excitation well and the observation well encountered the same core bar sand body in this layer. The size of the core bar sand body was larger than the distance between the excitation well and the observation well, and its connection mode was that the sand body was connected within the same sand body. There are two or more perforations in the same layer, and the interference signal strength M is less than 0.

01. At that time, the excitation well and the observation well encountered different core bar sand bodies. The portion of the core bar sand bodies encountered by the excitation well and the observation well between the two wells was less than half the distance between the two wells. Their connection mode was the connection of sandy braided water channels between the wells.

8. The method for analyzing the scale and connectivity of sand bodies under multi-layer perforation conditions according to claim 1, characterized in that, The method for determining the sand body size and connectivity in step 6 under the condition of perforation in adjacent layers is as follows: There is only one adjacent layer perforation, and the interference signal strength M is greater than 0.

001. At that time, the core sand body encountered by the excitation well and the observation well was greater than half the distance between the two wells, and its connection mode was a composite connection mode of adjacent wells and adjacent layers cutting down and the same phase. There is only one adjacent layer perforation, and the interference signal strength M is less than 0.

001. At that time, the sand bodies encountered by the excitation well and the observation well were both less than half the distance between the two wells, and their connection mode was the inter-phase communication mode of adjacent wells and adjacent layers.

9. The method for analyzing the scale and connectivity of sand bodies under multi-layer perforation conditions according to claim 6, characterized in that, The methods for determining the size and connectivity of sand bodies in step 6 also include: If the same interfering well group has both perforations in the same layer and perforations in adjacent layers, then the corresponding interfering well group is determined to be a perforation in the same layer.

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