Method, device and equipment for determining connectivity of a single vertical well and a horizontal well in a well group

Abstract

The application discloses a kind of well group in single-port vertical well and horizontal well connectivity determination method, device and equipment.Communication coefficient between single-port vertical well and horizontal well in well group is determined by determining the weight corresponding to the response degree of three parameters of downhole temperature, daily liquid production and wellhead oil pressure of horizontal well in the production process of well group and obtaining the change range of downhole temperature, daily liquid production and wellhead oil pressure of horizontal well before and after single-port vertical well in well group is shut in, and the connectivity between each single-port vertical well and horizontal well in well group is accurately determined by using communication coefficient.In addition, it is also proposed to divide the connectivity between single-port vertical well and horizontal well according to communication coefficient, and to develop connectivity improvement measures for strong connectivity and no connectivity between single-port vertical well and horizontal well, so that a more balanced communication relationship is established between multiple vertical wells and horizontal wells, balanced displacement and oil discharge are achieved, and good injection-production effect and excellent economic benefits of well group are ensured.

Description

Technical Field

[0001] This invention relates to the field of heavy oil reservoir development technology, and in particular to a method, apparatus and equipment for determining the connectivity between a single vertical well and a horizontal well in a well group. Background Technology

[0002] China has abundant heavy oil resources, mainly distributed in oilfields such as Xinjiang, Liaohe, and Shengli. The main development method is steam injection, but the overall recovery rate is low. Taking the development of ordinary heavy oil and extra-heavy oil in Xinjiang oilfield as an example, the production declines rapidly in the later stage of steam injection, with high water content and low oil-steam ratio, while the recovery rate is only 20-30%. There are still large remaining resources, and it is necessary to explore alternative development technologies to improve the final recovery rate.

[0003] In recent years, oilfields such as Xinjiang and Liaohe have adopted the VHSD (Very High-Density Flooding and Dewatering) technology to replace the development of old heavy oil reservoirs by inter-well horizontal wells between the original steam-injection vertical wells. The VHSD development process is divided into two major stages: steam injection preheating and combined flooding and dewatering. In the steam injection preheating stage, vertical and horizontal wells simultaneously inject steam to gradually expand the steam sweep radius. After the preheating establishes connectivity, the development mode of combined flooding and dewatering is adopted, which involves steam injection from multiple vertical wells and oil production from horizontal wells. This method can effectively utilize the remaining oil between wells and further significantly improve the recovery rate. Since 2015, Xinjiang Oilfield has been conducting VHSD (Vacuum-High-Speed ​​Distillation) replacement development trials in old heavy oil areas. To date, it has implemented over a hundred well groups. Due to issues such as the distribution of interlayers, the development of vapor channeling channels, and low formation pressure coefficients in old areas, there are significant differences in the establishment of connectivity during the preheating and injection phase. During the combined development of displacement and drainage, the injection-production relationship between vertical and horizontal wells is poor. Some wells have severe vapor channeling, resulting in strong connectivity, and vapor channeling occurs immediately after injection. Other wells have not established connectivity, resulting in ineffective vapor injection. The key technology for VHSD development is to establish a balanced connectivity relationship between multiple vertical wells and one horizontal well to form an effective displacement and drainage mode. Therefore, scientifically determining the thermal connectivity and connectivity strength between the injection and production wells of multiple vertical and horizontal VHSD wells is a prerequisite for the balanced development of VHSD vapor chambers and the achievement of combined displacement and drainage development effects. It is also an important basis for injection-production control.

[0004] By searching publicly published scientific and technological literature and patents at home and abroad, current research on the connectivity between vertical and horizontal wells in VHSD mainly relies on numerical simulation methods. By considering the basic reservoir properties (porosity, permeability, and remaining oil saturation) and development history data, the steam sweep radius of the vertical and horizontal wells during the injection and discharge process is simulated. When the temperature field conditions between the vertical and horizontal wells are such that the crude oil is fluid, connectivity is considered to be established. Currently, Xinjiang Oilfield usually injects and discharges 2 to 3 times before transitioning to the stage of steam injection in vertical wells and oil displacement in horizontal wells. However, due to factors such as reservoir heterogeneity and high-permeability crossflow channels caused by previous steam injection and discharge, the connectivity between vertical and horizontal wells varies greatly. Therefore, the reliability of the connectivity determination results obtained by numerical simulation methods is low and deviates significantly from the actual field conditions. For example, the reasonable timing for switching to VHSD determined by numerical simulation in Block 98 of Xinjiang Oilfield is 2-3 cycles of simultaneous injection and discharge of vertical and horizontal wells. However, in actual production, after 3 cycles of simultaneous injection and discharge of vertical and horizontal wells, the switching and discharge processes are combined, resulting in severe steam leakage in some well groups, with steam leakage occurring immediately after injection, while some well groups do not respond to production and have ineffective steam injection, which seriously affects the development effect and economic benefits of VHSD.

[0005] Therefore, given that numerical simulation methods cannot accurately reflect the actual situation and have low reference value, there is an urgent need to provide an effective technical means to accurately determine the connectivity and connectivity strength between different vertical and horizontal wells in a well group. This would provide a basis for formulating targeted control measures for the connectivity between vertical and horizontal wells, thereby improving the effectiveness of VHSD development. Summary of the Invention

[0006] The purpose of this invention is to address the technical problem of low accuracy in connectivity determination results using conventional numerical simulation methods for VHSD vertical-horizontal wells. It provides a system and method for establishing connectivity between multiple vertical wells and a single horizontal well. This method is a comprehensive connectivity determination method based on the clear response relationship between relevant production parameters of the horizontal well during steam injection in VHSD vertical wells and production in the horizontal wells. Applying this method can accurately determine the connectivity relationship between multiple vertical wells and horizontal wells in a VHSD well group, and then take corresponding measures to establish a more balanced connectivity relationship between the multiple vertical wells and horizontal wells, thereby achieving effective oil displacement.

[0007] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0008] A method for determining the connectivity between a single vertical well and a horizontal well in a well group, the method comprising:

[0009] Determine the weights of the response of three parameters—downhole temperature, daily fluid production, and wellhead oil pressure—in the horizontal well group production process.

[0010] The range of changes in downhole temperature, daily fluid production, and wellhead oil pressure of the horizontal well before and after shutting in a single vertical well in the well group was obtained.

[0011] Based on the weights of the response of the three parameters of downhole temperature, daily fluid production and wellhead oil pressure of the horizontal well during the production process of the well group, and the range of changes in downhole temperature, daily fluid production and wellhead oil pressure of the horizontal well before and after the shut-in of the single vertical well, the connectivity coefficient between the single vertical well and the horizontal well is determined.

[0012] Based on the determined connectivity coefficient between the single vertical well and the horizontal well, the connectivity between the single vertical well and the horizontal well in the well group is determined.

[0013] As a further improvement of the present invention, the connectivity coefficient between a single vertical well and a horizontal well is determined based on the weights corresponding to the response degrees of the three parameters of downhole temperature, daily fluid production, and wellhead oil pressure of the horizontal well during the production process of the well group, and the range of changes in downhole temperature, daily fluid production, and wellhead oil pressure of the horizontal well before and after shutting in the single vertical well. This is determined by the following formula:

[0014] C=α×(T1-T0)+β×(Q1-Q0)+γ×(P1-P0);

[0015] In the formula, C is the connectivity coefficient between a single vertical well and a horizontal well; α is the weight corresponding to the downhole temperature response of the horizontal well; β is the weight corresponding to the daily fluid production of the horizontal well; γ is the weight corresponding to the wellhead oil pressure of the horizontal well; T1 is the downhole temperature of the horizontal well before shutting in the single vertical well; T0 is the downhole temperature of the horizontal well after shutting in the single vertical well; Q1 is the daily fluid production of the horizontal well before shutting in the single vertical well; Q0 is the daily fluid production of the horizontal well after shutting in the single vertical well; P1 is the wellhead oil pressure of the horizontal well before shutting in the single vertical well; P0 is the wellhead oil pressure of the horizontal well after shutting in the single vertical well.

[0016] As a further improvement of the present invention, the determination of the connectivity between a single vertical well and a horizontal well in a well group based on the determined connectivity coefficient between the single vertical well and the horizontal well specifically involves:

[0017] The greater the connectivity coefficient between a single vertical well and a horizontal well, the stronger the connectivity between the two wells.

[0018] As a further improvement of the present invention, the well group is a multi-vertical well-single horizontal well group.

[0019] As a further improvement of the present invention, the step of obtaining the range of changes in downhole temperature, daily fluid production, and wellhead oil pressure of the horizontal well before and after shutting in a single vertical well in the well group includes the following steps:

[0020] Multiple vertical wells in the well group were selected for simultaneous and continuous steam injection for 5-10 days.

[0021] From the selected vertical wells, each vertical well is closed sequentially from the toe of the horizontal well to the heel of the horizontal well. Three production parameters are collected for each vertical well before and after closure, and for the horizontal well before and 5-10 days after closure: fluid production, downhole temperature, and wellhead oil pressure.

[0022] Based on the three production parameters collected before and 5-10 days after well shut-in of the horizontal well—the production volume, downhole temperature, and wellhead oil pressure—the range of changes in downhole temperature, daily production volume, and wellhead oil pressure of the horizontal well before and after shut-in of a single vertical well is determined.

[0023] As a further improvement of the present invention, the step of simultaneously and continuously injecting steam into multiple vertical wells in the well group for 5-10 days includes:

[0024] Multiple vertical wells are selected intersecting on both sides of the horizontal well and continuously injected with steam for 5-10 days. Among the selected vertical wells, there are no two adjacent vertical wells along the direction of the horizontal well or in the direction perpendicular to the horizontal well.

[0025] As a further improvement of the present invention, the step of simultaneously and continuously injecting steam into multiple vertical wells in the well group for 5-10 days includes:

[0026] For the remaining intersecting vertical wells on both sides of the horizontal well, steam is continuously injected for 5-10 days. Among the remaining intersecting vertical wells, there are no two vertical wells adjacent to each other along the direction of the horizontal well or in the direction perpendicular to the horizontal well.

[0027] As a further improvement of the present invention, the method further includes:

[0028] Based on the determined connectivity coefficient between the single vertical well and the horizontal well, the connectivity between the single vertical well and the horizontal well is classified into three levels of intensity. The three levels of intensity classification include:

[0029] When 0 < connectivity coefficient < 1 / 3C, it is classified as disconnected;

[0030] When 1 / 3C ≤ connectivity coefficient ≤ 2 / 3C, it is classified as moderately connected;

[0031] When 2 / 3C < connectivity coefficient ≤ C, it is classified as strongly connected.

[0032] As a further improvement of the present invention, the method further includes:

[0033] Based on the intensity classification results, measures were formulated to improve connectivity between single vertical and horizontal wells, both with and without strong or no connectivity.

[0034] The improvement measure for strongly connected single vertical wells and horizontal wells is to implement plugging measures;

[0035] The improvement measure between unconnected single vertical wells and horizontal wells is to carry out reservoir stimulation;

[0036] After connectivity improvement measures are implemented, the connectivity strength level between the single vertical well and the horizontal well is reassessed until the connectivity between the single vertical well and the horizontal well is moderate.

[0037] The process of redetermining the connectivity strength level between the single vertical well and the horizontal well includes the following steps:

[0038] Close all single vertical wells except those undergoing connectivity improvement measures;

[0039] After implementing connectivity improvement measures, single vertical wells should be shut down 5-10 days after steam injection.

[0040] Determine the connectivity coefficient of a single vertical well after the connectivity improvement measures have been implemented;

[0041] The connectivity strength level between the single vertical well and the horizontal well is re-determined based on the connectivity coefficient.

[0042] The present invention also provides a device for determining the connectivity between a single vertical well and a horizontal well in a well group, the device comprising:

[0043] The first determining unit is used to determine the weights of the response of the three parameters of downhole temperature, daily fluid production and wellhead oil pressure of the horizontal well during the well group production process.

[0044] The acquisition unit is used to acquire the range of changes in downhole temperature, daily fluid production, and wellhead oil pressure of the horizontal well before and after shutting in a single vertical well in the well group.

[0045] The second determining unit is used to determine the connectivity coefficient between a single vertical well and a horizontal well based on the weights corresponding to the response of the three parameters of downhole temperature, daily fluid production and wellhead oil pressure of the horizontal well during the production process of the well group, as well as the range of changes in downhole temperature, daily fluid production and wellhead oil pressure of the horizontal well before and after the single vertical well is shut in.

[0046] The determination unit is used to determine the connectivity between a single vertical well and a horizontal well in a well group based on the determined connectivity coefficient between the single vertical well and the horizontal well.

[0047] As a further improvement of the present invention, the second determining unit determines the connectivity coefficient between the single vertical well and the horizontal well based on the weights corresponding to the response degrees of the three parameters of downhole temperature, daily fluid production, and wellhead oil pressure of the horizontal well during the production process of the well group, and the range of changes in downhole temperature, daily fluid production, and wellhead oil pressure of the horizontal well before and after the shut-in of the single vertical well. The coefficient is determined by the following formula:

[0048] C=α×(T1-T0)+β×(Q1-Q0)+γ×(P1-P0);

[0049] In the formula, C is the connectivity coefficient between a single vertical well and a horizontal well; α is the weight corresponding to the downhole temperature response of the horizontal well; β is the weight corresponding to the daily fluid production of the horizontal well; γ is the weight corresponding to the wellhead oil pressure of the horizontal well; T1 is the downhole temperature of the horizontal well before shutting in the single vertical well; T0 is the downhole temperature of the horizontal well after shutting in the single vertical well; Q1 is the daily fluid production of the horizontal well before shutting in the single vertical well; Q0 is the daily fluid production of the horizontal well after shutting in the single vertical well; P1 is the wellhead oil pressure of the horizontal well before shutting in the single vertical well; P0 is the wellhead oil pressure of the horizontal well after shutting in the single vertical well.

[0050] As a further improvement of the present invention, the determination unit determines the connectivity between a single vertical well and a horizontal well in the well group based on the determined connectivity coefficient between the single vertical well and the horizontal well, specifically as follows:

[0051] The greater the connectivity coefficient between a single vertical well and a horizontal well, the stronger the connectivity between the two wells.

[0052] As a further improvement of the present invention, the well group is a multi-vertical well-single horizontal well group.

[0053] As a further improvement of the present invention, the acquisition unit acquires the range of changes in downhole temperature, daily fluid production, and wellhead oil pressure of the horizontal well before and after shutting in a single vertical well in the well group, including the following steps:

[0054] Multiple vertical wells in the well group were selected for simultaneous and continuous steam injection for 5-10 days.

[0055] From the selected vertical wells, each vertical well is closed sequentially from the toe of the horizontal well to the heel of the horizontal well. Three production parameters are collected for each vertical well before and after closure, and for the horizontal well before and 5-10 days after closure: fluid production, downhole temperature, and wellhead oil pressure.

[0056] Based on the three production parameters collected before and 5-10 days after well shut-in of the horizontal well—the production volume, downhole temperature, and wellhead oil pressure—the range of changes in downhole temperature, daily production volume, and wellhead oil pressure of the horizontal well before and after shut-in of a single vertical well is determined.

[0057] As a further improvement of the present invention, the acquisition unit selects multiple vertical wells in the well group to continuously inject steam for 5-10 days simultaneously, including:

[0058] Multiple vertical wells are selected intersecting on both sides of the horizontal well and continuously injected with steam for 5-10 days. Among the selected vertical wells, there are no two adjacent vertical wells along the direction of the horizontal well or in the direction perpendicular to the horizontal well.

[0059] As a further improvement of the present invention, the acquisition unit selects multiple vertical wells in the well group to continuously inject steam for 5-10 days simultaneously, including:

[0060] For the remaining intersecting vertical wells on both sides of the horizontal well, steam is continuously injected for 5-10 days. Among the remaining intersecting vertical wells, there are no two vertical wells adjacent to each other along the direction of the horizontal well or in the direction perpendicular to the horizontal well.

[0061] As a further improvement of the present invention, the device further includes:

[0062] The intensity classification unit is used to classify the connectivity between a single vertical well and a horizontal well into three levels based on the determined connectivity coefficient between the two wells. The three levels of intensity classification include: when 0 < connectivity coefficient < 1 / 3C, it is classified as no connectivity; when 1 / 3C ≤ connectivity coefficient ≤ 2 / 3C, it is classified as moderate connectivity; and when 2 / 3C < connectivity coefficient ≤ C, it is classified as strong connectivity.

[0063] The intensity classification unit is also used to formulate connectivity improvement measures for strongly connected and unconnected single vertical wells and horizontal wells based on the intensity classification results, and to redetermine the connectivity intensity level between the single vertical well and the horizontal well after the connectivity improvement measures are implemented, until the single vertical well and the horizontal well are of medium connectivity.

[0064] This invention also provides a device for determining the connectivity between a single vertical well and a horizontal well in a well group, the device comprising a processor and a memory; wherein,

[0065] The memory is used to store machine-executable instructions;

[0066] The processor is used to read and execute machine-executable instructions stored in the memory to implement the aforementioned method for determining the connectivity between a single vertical well and a horizontal well in a well group.

[0067] The beneficial effects of this invention are:

[0068] The present invention provides a method, apparatus, and equipment for determining the connectivity between single vertical and horizontal wells in a well group. By determining the weights corresponding to the response degrees of three parameters—downhole temperature, daily fluid production, and wellhead oil pressure—of the horizontal well during the well group's production process, and obtaining the range of changes in downhole temperature, daily fluid production, and wellhead oil pressure of the horizontal well before and after shutting in the single vertical well, the connectivity coefficient between the single vertical and horizontal wells in the well group is determined, thus successfully determining the connectivity between each single vertical and horizontal well in the well group. Through this method, the connectivity and connectivity strength relationship between different vertical and horizontal wells in the well group is accurately determined, ensuring good injection and production effects and excellent economic benefits for the well group. Furthermore, it provides a strong basis for formulating targeted connectivity control measures in the later stages, thereby ensuring the balanced development of steam chambers in the well group and achieving a combined development effect of displacement and drainage.

[0069] The present invention provides a method, apparatus, and equipment for determining the connectivity between a single vertical well and a horizontal well in a well group. The connectivity between a single vertical well and a horizontal well is classified by a connectivity coefficient. Based on the strength classification results, measures are formulated to improve the connectivity between a single vertical well and a horizontal well with strong connectivity and no connectivity. This enables the establishment of a relatively balanced connectivity relationship between multiple vertical wells and horizontal wells, and further achieves the purpose of balanced displacement and oil drainage.

[0070] The present invention provides a method, apparatus, and equipment for determining the connectivity between a single vertical well and a horizontal well in a well group. This method fully considers on-site production parameters, is practical and highly operable. Compared with commonly used numerical simulation connectivity determination methods, it has higher accuracy and can provide a basis for on-site production control and the formulation of governance strategies. It is expected to improve the production-injection ratio and oil-gas ratio of vertical-horizontal well groups in heavy oil old areas throughout their entire development life cycle, thereby significantly improving the efficiency and economic benefits of succession development of vertical-horizontal well groups in heavy oil old areas.

[0071] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures pointed out in the description, claims and drawings. Attached Figure Description

[0072] Figure 1 This is a flowchart of the method for determining the connectivity between a single vertical well and a horizontal well in a well group according to the present invention;

[0073] Figure 2 This is a schematic diagram of the VHSD well network in Embodiment 1 of the present invention. Detailed Implementation

[0074] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0075] This invention provides a method for determining the connectivity between a single vertical well and a horizontal well in a well group, such as... Figure 1 As shown, by determining the weights of the response levels of three parameters—downhole temperature, daily fluid production, and wellhead oil pressure—in the horizontal wells during the well group's production process, and obtaining the range of changes in downhole temperature, daily fluid production, and wellhead oil pressure of the horizontal wells before and after shutting in a single vertical well in the well group, the connectivity coefficient between the single vertical wells and horizontal wells in the well group is determined, thus successfully identifying the connectivity between each single vertical well and horizontal well in the well group. This method can accurately determine the connectivity and connectivity strength relationship between different vertical and horizontal wells in the well group, providing a basis for the formulation of targeted control measures in the later stages, thereby improving the effectiveness of VHSD development.

[0076] The specific implementation steps are described below:

[0077] This invention addresses the VHSD multi-vertical-single-horizontal-well pattern (please refer to...). Figure 1 As shown below, an accurate method for determining the connectivity between different single vertical and horizontal wells is provided, which mainly includes the following three parts:

[0078] (i) Obtain the range of changes in downhole temperature, daily fluid production, and wellhead oil pressure of horizontal wells before and after shutting in a single vertical well in the well group.

[0079] by Figure 1 Taking the VHSD well group shown as an example, this well group includes one production horizontal well (9) and eight vertical steam injection wells (1)-(8), where A is the heel of the horizontal well and B is the toe of the horizontal well. During the test, the steam injection in the vertical well and the production in the horizontal well were tested. The specific method for obtaining the variation range of the three parameters before and after the shut-in of a single vertical well is as follows:

[0080] First, select the first batch of vertical wells 1, 4, 5, and 8 for simultaneous and continuous steam injection for 5-10 days, setting the daily steam injection rate per well to 50t / d. Then, gradually shut down the wells in the order of vertical well 8, 5, 4, and 1. Use pumping units for lifting during horizontal well production. Maintain fixed nozzle size and pumping parameters during production. Collect three production parameters for each vertical well: fluid production, downhole temperature, and wellhead pressure before and during the 5-10 days after shutdown. This yields the range of changes in downhole temperature, daily fluid production, and wellhead pressure for each horizontal well before and after shutdown. Similarly, switch to the second batch of vertical wells 2, 3, 6, and 7, and follow the same steps to obtain the range of changes in downhole temperature, daily fluid production, and wellhead pressure for each of the three vertical wells before and after shutdown.

[0081] (II) Selection of Inter-well Response Relationship and Weights

[0082] During the production process, the changes in dynamic production parameters of a single vertical well within 5 to 10 days after its closure are tracked in a timely manner. These parameters include steam injection rate, daily fluid production, daily oil production, water cut, downhole temperature, and wellhead oil pressure. The inter-well response relationship after the closure of a single vertical well is clarified. After tracking a large number of field production practices, it was found that after changes in steam injection and closure of a vertical well, the three parameters of daily fluid production, downhole temperature, and wellhead oil pressure of the horizontal well have a significant response relationship. The larger the range of change of these three parameters, the stronger the inter-well response relationship and the better the connectivity.

[0083] Based on the response levels of three parameters—downhole temperature, daily fluid production, and wellhead oil pressure—which exhibit relatively clear response relationships, weights α, β, and γ are assigned to these three parameters, respectively, where α + β + γ = 1. The weights α, β, and γ vary depending on the reservoir conditions, thus establishing the formula for calculating the connectivity coefficient C, as shown in Equation 1.

[0084] C=α×(T1-T0)+β×(Q1-Q0)+γ×(P1-P0) (Equation 1)

[0085] Where: C—connectivity coefficient, dimensionless; α—downhole temperature weighting coefficient, decimal; β—daily fluid production weighting coefficient, decimal; γ—wellhead oil pressure weighting coefficient, decimal; T1—downhole temperature before shut-in, °C; T0—downhole temperature after shut-in, °C; Q1—daily fluid production before shut-in, t / d; Q0—daily fluid production after shut-in, t / d; P1—wellhead oil pressure before shut-in, kPa; P0—wellhead oil pressure after shut-in, kPa.

[0086] (III) Judgment of connectivity between different single vertical wells and horizontal wells and directions for improvement measures;

[0087] The connectivity coefficient C can quantitatively evaluate the degree of connectivity between vertical and horizontal wells; the larger the value, the greater the connectivity. Based on the magnitude of the connectivity coefficient C, well connectivity is classified into three categories: strong connectivity, moderate connectivity, and no connectivity. The specific classification method is as follows: when 0 < connectivity coefficient < 1 / 3C, it is classified as no connectivity; when 1 / 3C ≤ connectivity coefficient ≤ 2 / 3C, it is classified as moderate connectivity; when 2 / 3C < connectivity coefficient ≤ C, it is classified as strong connectivity. Simultaneously, based on the connectivity strength classification results, the following measures to improve the connectivity between the corresponding vertical and horizontal wells are clarified: 1) For wells with strong connectivity and steam leakage, implement plugging measures to block the major steam leakage channels; 2) For wells with moderate connectivity, maintain moderate connectivity and strengthen tracking and control to ensure balanced and effective displacement between wells; 3) For wells without connectivity, implement reservoir stimulation measures to improve well connectivity and thereby reduce ineffective steam injection. Subsequently, the connectivity strength level between the single vertical well and the horizontal well was reassessed after connectivity improvement measures were implemented. The aforementioned improvement measures were repeated for single vertical wells with strong or no connectivity until the connectivity between the vertical and horizontal wells was transformed into moderate connectivity. The method for reassessing the connectivity strength level between a single vertical well and the horizontal well is as follows: 1. Shut down all single vertical wells except those that underwent connectivity improvement measures; 2. Inject steam into the single vertical wells after connectivity improvement measures for 5-10 days and then shut them down; 3. Reassess the connectivity coefficient of the single vertical wells after connectivity improvement measures using the aforementioned method; 4. Reassess the connectivity strength level between the single vertical well and the horizontal well based on the connectivity coefficient.

[0088] The present invention also provides a device for determining the connectivity between a single vertical well and a horizontal well in a well group. The device includes a first determining unit for determining the weights corresponding to the response levels of three parameters—downhole temperature, daily fluid production, and wellhead oil pressure—of the horizontal well during the well group's production process; an acquiring unit for obtaining the range of changes in downhole temperature, daily fluid production, and wellhead oil pressure of the horizontal well before and after shutting down the single vertical well in the well group; a second determining unit for determining the connectivity coefficient between the single vertical well and the horizontal well based on the weights corresponding to the response levels of the three parameters and the obtained range of changes in downhole temperature, daily fluid production, and wellhead oil pressure of the horizontal well before and after shutting down the single vertical well; and a determining unit for determining the connectivity between the single vertical well and the horizontal well in the well group based on the determined connectivity coefficient. Sometimes the device may also include an intensity division unit for classifying the connectivity between a single vertical well and a horizontal well into three levels based on a determined connectivity coefficient between the two wells, and for developing connectivity improvement measures for strongly connected and unconnected single vertical wells and horizontal wells based on the intensity division results. The three levels of intensity division are: strongly connected, moderately connected, and unconnected.

[0089] Regarding the system in the above embodiments, the specific manner in which each unit performs operations has been described in detail in the embodiments related to the method, and will not be elaborated here.

[0090] The present invention also provides a device for determining the connectivity between a single vertical well and a horizontal well in a well group. The device includes a processor and a memory. The memory is used to store machine-executable instructions. The processor is used to read and execute the machine-executable instructions stored in the memory to implement the aforementioned method for determining the connectivity between a single vertical well and a horizontal well in a well group.

[0091] The following specific embodiments illustrate the effectiveness of the method for determining the connectivity between a single vertical well and a horizontal well in a well group provided by this invention:

[0092] Example 1

[0093] This embodiment provides a method for determining the connectivity between a single vertical well and a horizontal well in a multi-vertical-single-horizontal well group. Specifically, connectivity determination is performed on a pair of VHSD well groups in the Xinjiang Oilfield. Figure 2 As shown, the VHSD well group includes 8 vertical wells (1)-(8) and 1 horizontal well (9), where A is the heel of the horizontal well and B is the toe of the horizontal well. The daily steam injection rate of a single well is 50t / d, and the horizontal well is pumped out using a 30mm nozzle with a 3m stroke and a stroke rate of 7 times / min. The specific judgment process is as follows:

[0094] The production mode of simultaneously injecting steam for 10 days in vertical wells 1, 4, 5, and 8 and producing oil from horizontal wells was adopted. After 10 days of steam injection, the wells were gradually shut down in the order of vertical well 8, 5, 4, and 1. Three production parameters were collected: fluid production, temperature, and oil pressure of the horizontal wells before and 5 to 10 days after the shut-down of each vertical well.

[0095] Similarly, after injecting steam into vertical wells 2, 3, 6, and 7 simultaneously for 10 days, the wells are gradually shut down in the order of vertical well 7, 6, 3, and 2. The production parameters of the horizontal wells—production volume, temperature, and oil pressure—are collected before and during the 5-10 days after shutting down each vertical well.

[0096] Comprehensive analysis revealed that the temperature response was the strongest during the production process of this well group, followed by fluid production and then oil pressure. Therefore, the corresponding weights were set to 0.6, 0.3, and 0.1, respectively, i.e., α = 0.6, β = 0.3, and γ = 0.1. Simultaneously, with a daily steam injection rate of 50 t / d for a single vertical well, closing the well resulted in a decrease in daily fluid production ranging from 0 to 30 t / d, a decrease in temperature ranging from 0 to 30℃, and a decrease in oil pressure ranging from 0 to 50 kPa. Therefore, the formula for calculating the connectivity coefficient C is shown in Equation 2.

[0097] C = 0.6 × (T1 - T0) + 0.3 × (Q1 - Q0) + 0.1 × (P1 - P0) (Equation 2)

[0098] Therefore, based on the range of variation of the three parameters and the degree of response, the connectivity coefficient C was calculated to be between 0 and 32. According to the value of C, the connectivity of the VHSD well group was divided into three categories: a. 20 < C ≤ 32, strong connectivity; b. 10 ≤ C ≤ 20, medium connectivity; c. C < 10, no connectivity.

[0099] Based on the collected production parameters (temperature, production rate, and oil pressure) from the eight vertical wells during the 5-10 days after shut-in, the connectivity assessment and classification results for these eight wells are shown in the table below:

[0100] well Straight well 1 straight well 2 straight well 3 straight well 4 straight well 5 straight well 6 straight well 7 straight well 8 C 7.3 17.5 14.1 22.7 11.2 23.2 4.6 12.9 Connectivity none medium medium powerful medium powerful none medium

[0101] For the two strongly interconnected wells, vertical well 4 (C=22.7) and vertical well 6 (C=23.2), sealing measures were implemented to block the steam flow channels. After the measures were implemented, the remaining vertical wells were shut down, and the controlled wells were re-injected with steam for 10 days before being shut down again. Production parameters were collected over 5 to 10 days, and the connectivity coefficients of vertical well 4 and vertical well 6 were calculated to be 14.3 and 12.5, respectively, proving that the sealing measures were effective.

[0102] For two unconnected wells, Vertical Well 1 (C=7.3) and Vertical Well 7 (C=4.6), reservoir stimulation measures were implemented to overcome the obstruction and establish thermal connectivity with the horizontal wells. After the measures were implemented, the remaining vertical wells were shut in, and the well with the measures were re-injected with steam for 10 days before being shut in again. Production parameters were collected over 5 to 10 days, and the connectivity coefficients of Vertical Well 1 and Vertical Well 7 were calculated to be 17.1 and 15.9, respectively, proving that the reservoir stimulation measures were effective.

[0103] In summary, the method, apparatus, and equipment for determining the connectivity between single vertical and horizontal wells in a well group provided by this invention determine the weights corresponding to the response degrees of three parameters—downhole temperature, daily fluid production, and wellhead oil pressure—of the horizontal well during the well group's production process, and obtain the range of changes in downhole temperature, daily fluid production, and wellhead oil pressure of the horizontal well before and after shutting in the single vertical well in the well group. This allows for the determination of the connectivity between each single vertical and horizontal well in the well group, thus successfully determining the connectivity between them. Through this method, accurate determination of the connectivity and connectivity strength relationship between different vertical and horizontal wells in a well group is achieved, ensuring good injection-production effects and excellent economic benefits for the well group. Furthermore, it provides a strong basis for formulating targeted connectivity control measures in the later stages, thereby ensuring the balanced development of steam chambers in the well group and achieving a combined development effect of displacement and drainage. Meanwhile, the method, apparatus, and equipment for determining the connectivity of a single vertical well and horizontal well in a well group provided by this invention classifies the connectivity between a single vertical well and a horizontal well based on a connectivity coefficient. Based on the strength classification results, measures are formulated to improve the connectivity between single vertical wells and horizontal wells with strong or no connectivity, thereby establishing a relatively balanced connectivity relationship between multiple vertical and horizontal wells, further achieving balanced displacement and oil drainage. Furthermore, the method, apparatus, and equipment for determining the connectivity of a single vertical well and horizontal well in a well group provided by this invention fully considers on-site production parameters, is practically applicable, and highly operable. Compared with commonly used numerical simulation connectivity determination methods, it has higher accuracy and can provide a basis for on-site production control and the formulation of remediation strategies. It is expected to improve the production-injection ratio and oil-gas ratio throughout the entire life cycle of vertical-horizontal well groups in heavy oil old areas, thereby significantly improving the efficiency and economic benefits of succession development of vertical-horizontal well groups in heavy oil old areas.

[0104] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for determining the connectivity between a single vertical well and a horizontal well in a well group, the method comprising: Determine the weights of the response of three parameters—downhole temperature, daily fluid production, and wellhead oil pressure—in the horizontal well group production process. The range of changes in downhole temperature, daily fluid production, and wellhead oil pressure of the horizontal well before and after shutting in a single vertical well in the well group was obtained. Based on the weights of the response of the three parameters of downhole temperature, daily fluid production and wellhead oil pressure of the horizontal well during the production process of the well group, and the range of changes in downhole temperature, daily fluid production and wellhead oil pressure of the horizontal well before and after the shut-in of the single vertical well, the connectivity coefficient between the single vertical well and the horizontal well is determined. The connectivity coefficient between a single vertical well and a horizontal well is determined based on the weights corresponding to the response levels of three parameters—downhole temperature, daily fluid production, and wellhead oil pressure—during the production process of the horizontal well, and the range of changes in downhole temperature, daily fluid production, and wellhead oil pressure of the horizontal well before and after shutting in a single vertical well. This is determined using the following formula: ； In the formula, C is the connectivity coefficient between a single vertical well and a horizontal well; α is the weight corresponding to the downhole temperature response of the horizontal well; β is the weight corresponding to the daily fluid production of the horizontal well; γ is the weight corresponding to the wellhead oil pressure of the horizontal well; T1 is the downhole temperature of the horizontal well before shutting in the single vertical well; T0 is the downhole temperature of the horizontal well after shutting in the single vertical well; Q1 is the daily fluid production of the horizontal well before shutting in the single vertical well; Q0 is the daily fluid production of the horizontal well after shutting in the single vertical well; P1 is the wellhead oil pressure of the horizontal well before shutting in the single vertical well; P0 is the wellhead oil pressure of the horizontal well after shutting in the single vertical well. Based on the determined connectivity coefficient between the single vertical well and the horizontal well, the connectivity between the single vertical well and the horizontal well in the well group is determined.

2. The method for determining the connectivity between a single vertical well and a horizontal well in a well group according to claim 1, wherein, The determination of the connectivity between a single vertical well and a horizontal well in a well group based on the determined connectivity coefficient between the single vertical well and the horizontal well specifically involves: The greater the connectivity coefficient between a single vertical well and a horizontal well, the stronger the connectivity between the two wells.

3. The method for determining the connectivity between a single vertical well and a horizontal well in a well group according to claim 1, wherein, The well group is a multi-vertical well-single horizontal well group.

4. The method for determining the connectivity between a single vertical well and a horizontal well in a well group according to claim 1, wherein, The steps for obtaining the changes in downhole temperature, daily fluid production, and wellhead oil pressure of the horizontal well before and after shutting in a single vertical well in the well group include: Multiple vertical wells in the well group were selected for simultaneous and continuous steam injection for 5-10 days. From the selected vertical wells, each vertical well is closed sequentially from the toe of the horizontal well to the heel of the horizontal well. Three production parameters are collected for each vertical well before and after closure, and for the horizontal well before and 5-10 days after closure: fluid production, downhole temperature, and wellhead oil pressure. Based on the three production parameters collected before and 5-10 days after well shut-in of the horizontal well—the production volume, downhole temperature, and wellhead oil pressure—the range of changes in downhole temperature, daily production volume, and wellhead oil pressure of the horizontal well before and after shut-in of a single vertical well is determined.

5. The method for determining the connectivity between a single vertical well and a horizontal well in a well group according to claim 4, wherein, The selection of multiple vertical wells in the well group for simultaneous continuous steam injection for 5-10 days includes: Multiple vertical wells are selected intersecting on both sides of the horizontal well and continuously injected with steam for 5-10 days. Among the selected vertical wells, there are no two adjacent vertical wells along the direction of the horizontal well or in the direction perpendicular to the horizontal well.

6. The method for determining the connectivity between a single vertical well and a horizontal well in a well group according to claim 5, wherein, The selection of multiple vertical wells in the well group for simultaneous continuous steam injection for 5-10 days includes: For the remaining intersecting vertical wells on both sides of the horizontal well, steam is continuously injected for 5-10 days. Among the remaining intersecting vertical wells, there are no two vertical wells adjacent to each other along the direction of the horizontal well or in the direction perpendicular to the horizontal well.

7. The method for determining the connectivity between a single vertical well and a horizontal well in a well group according to claim 1, wherein, The method further includes: Based on the determined connectivity coefficient between the single vertical well and the horizontal well, the connectivity between the single vertical well and the horizontal well is classified into three levels of intensity. The three levels of intensity classification include: When 0 < connectivity coefficient < 1 / 3C, it is classified as disconnected; When 1 / 3C ≤ connectivity coefficient ≤ 2 / 3C, it is classified as moderately connected; When 2 / 3C < connectivity coefficient ≤ C, it is classified as strongly connected.

8. The method for determining the connectivity between a single vertical well and a horizontal well in a well group according to claim 7, wherein, The method further includes: Based on the intensity classification results, measures were formulated to improve connectivity between single vertical and horizontal wells, both with and without strong or no connectivity. The improvement measure for strongly connected single vertical wells and horizontal wells is to implement plugging measures; The improvement measure between unconnected single vertical wells and horizontal wells is to carry out reservoir stimulation; After connectivity improvement measures are implemented, the connectivity strength level between the single vertical well and the horizontal well is reassessed until the connectivity between the single vertical well and the horizontal well is moderate. The process of redetermining the connectivity strength level between the single vertical well and the horizontal well includes the following steps: Close all single vertical wells except those undergoing connectivity improvement measures; After implementing connectivity improvement measures, single vertical wells should be shut down 5-10 days after steam injection. Determine the connectivity coefficient of a single vertical well after the connectivity improvement measures have been implemented; The connectivity strength level between the single vertical well and the horizontal well is re-determined based on the connectivity coefficient.

9. A device for determining the connectivity between a single vertical well and a horizontal well in a well group, the device comprising: The first determining unit is used to determine the weights of the response of the three parameters of downhole temperature, daily fluid production and wellhead oil pressure of the horizontal well during the well group production process. The acquisition unit is used to acquire the range of changes in downhole temperature, daily fluid production, and wellhead oil pressure of the horizontal well before and after shutting in a single vertical well in the well group. The second determining unit is used to determine the connectivity coefficient between a single vertical well and a horizontal well based on the weights corresponding to the response of the three parameters of downhole temperature, daily fluid production and wellhead oil pressure of the horizontal well during the production process of the well group, as well as the range of changes in downhole temperature, daily fluid production and wellhead oil pressure of the horizontal well before and after the single vertical well is shut in. The second determining unit determines the connectivity coefficient between the single vertical well and the horizontal well based on the weights corresponding to the response levels of the three parameters—downhole temperature, daily fluid production, and wellhead oil pressure—of the horizontal well during the production process of the well group, as well as the range of changes in downhole temperature, daily fluid production, and wellhead oil pressure of the horizontal well before and after shutting in the single vertical well. This coefficient is determined using the following formula: ； In the formula, C is the connectivity coefficient between a single vertical well and a horizontal well; α is the weight corresponding to the downhole temperature response of the horizontal well; β is the weight corresponding to the daily fluid production of the horizontal well; γ is the weight corresponding to the wellhead oil pressure of the horizontal well; T1 is the downhole temperature of the horizontal well before shutting in the single vertical well; T0 is the downhole temperature of the horizontal well after shutting in the single vertical well; Q1 is the daily fluid production of the horizontal well before shutting in the single vertical well; Q0 is the daily fluid production of the horizontal well after shutting in the single vertical well; P1 is the wellhead oil pressure of the horizontal well before shutting in the single vertical well; P0 is the wellhead oil pressure of the horizontal well after shutting in the single vertical well. The determination unit is used to determine the connectivity between a single vertical well and a horizontal well in a well group based on the determined connectivity coefficient between the single vertical well and the horizontal well.

10. The device for determining the connectivity between a single vertical well and a horizontal well in a well group according to claim 9, wherein, The determination unit determines the connectivity between a single vertical well and a horizontal well in the well group based on the determined connectivity coefficient between the single vertical well and the horizontal well. Specifically, the determination is as follows: The greater the connectivity coefficient between a single vertical well and a horizontal well, the stronger the connectivity between the two wells.

11. The device for determining the connectivity between a single vertical well and a horizontal well in a well group according to claim 9, wherein, The well group is a multi-vertical well-single horizontal well group.

12. The device for determining the connectivity between a single vertical well and a horizontal well in a well group according to claim 9, wherein, The acquisition unit acquires the changes in downhole temperature, daily fluid production, and wellhead oil pressure of the horizontal well before and after shutting in a single vertical well in the well group, including the following steps: Multiple vertical wells in the well group were selected for simultaneous and continuous steam injection for 5-10 days. From the selected vertical wells, each vertical well is closed sequentially from the toe of the horizontal well to the heel of the horizontal well. Three production parameters are collected for each vertical well before and after closure, and for the horizontal well before and 5-10 days after closure: fluid production, downhole temperature, and wellhead oil pressure. Based on the three production parameters collected before and 5-10 days after well shut-in of the horizontal well—the production volume, downhole temperature, and wellhead oil pressure—the range of changes in downhole temperature, daily production volume, and wellhead oil pressure of the horizontal well before and after shut-in of a single vertical well is determined.

13. The device for determining the connectivity between a single vertical well and a horizontal well in a well group according to claim 12, wherein, The acquisition unit selects multiple vertical wells in the well group to continuously inject steam for 5-10 days simultaneously, including: Multiple vertical wells are selected intersecting on both sides of the horizontal well and continuously injected with steam for 5-10 days. Among the selected vertical wells, there are no two adjacent vertical wells along the direction of the horizontal well or in the direction perpendicular to the horizontal well.

14. The device for determining the connectivity between a single vertical well and a horizontal well in a well group according to claim 13, wherein, The acquisition unit selects multiple vertical wells in the well group to continuously inject steam for 5-10 days simultaneously, including: For the remaining intersecting vertical wells on both sides of the horizontal well, steam is continuously injected for 5-10 days. Among the remaining intersecting vertical wells, there are no two vertical wells adjacent to each other along the direction of the horizontal well or in the direction perpendicular to the horizontal well.

15. The device for determining the connectivity between a single vertical well and a horizontal well in a well group according to claim 9, wherein, The device further includes: The intensity classification unit is used to classify the connectivity between a single vertical well and a horizontal well into three levels based on the determined connectivity coefficient between the two wells. The three levels of intensity classification include: when 0 < connectivity coefficient < 1 / 3C, it is classified as no connectivity; when 1 / 3C ≤ connectivity coefficient ≤ 2 / 3C, it is classified as moderate connectivity; and when 2 / 3C < connectivity coefficient ≤ C, it is classified as strong connectivity. The intensity classification unit is also used to formulate connectivity improvement measures for strongly connected and unconnected single vertical wells and horizontal wells based on the intensity classification results, and to redetermine the connectivity intensity level between the single vertical well and the horizontal well after the connectivity improvement measures are implemented, until the single vertical well and the horizontal well are of medium connectivity.

16. A device for determining the connectivity between a single vertical well and a horizontal well in a well group, the device comprising a processor and a memory; wherein, The memory is used to store machine-executable instructions; The processor is configured to read and execute machine-executable instructions stored in the memory to implement the method as described in any one of claims 1 to 8.

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