A method for evaluating the effect of multi-cluster fracturing temporary plugging in a horizontal well section

Abstract

The application relates to a horizontal well section multi-cluster fracturing temporary plugging effect evaluation method, which comprises the following steps: acquiring construction data in real time, acquiring a temporary plugging agent in-place pressure increase value according to the construction data; acquiring construction pressures before and after a temporary plugging agent injection opportunity, wherein the sand concentration is zero and the discharge capacity is equal, and the difference is obtained to obtain a same discharge capacity pressure increase value; acquiring construction data points before and after the temporary plugging agent injection opportunity, wherein the sand concentration is equal and the discharge capacity is equal, and the curve superposition is carried out to calculate the percentage of construction data points with positive pressure difference before and after the temporary plugging agent injection opportunity, and the positive pressure difference ratio is obtained; determining temporary plugging effective time temporary plugging agent in-place pressure increase index value, same discharge capacity pressure increase index value and positive pressure difference ratio index value according to mechanical differences among clusters in a reservoir section; comparing the temporary plugging agent in-place pressure increase value, the same discharge capacity pressure increase value and the positive pressure difference ratio with corresponding index values to obtain three discrimination results, introducing a weight coefficient to integrate the three discrimination results, and determining whether the temporary plugging is effective in real time.

Description

Technical Field

[0001] This invention relates to the field of oil and gas development technology, and in particular to a method for evaluating the effect of temporary plugging of multiple clusters of fracturing in horizontal well sections. Background Technology

[0002] Multi-cluster fracturing technology within horizontal well sections is essential for the efficient development of unconventional oil and gas resources. Due to reservoir heterogeneity, inter-cluster mechanical differences, and inter-fracture stress interference, simultaneous initiation and balanced propagation of multiple cluster fractures within a section are difficult. Temporary plugging technology within the section increases net wellbore pressure by sealing perforations or fracture openings, forcing fluid flow diversion and contributing to balanced stimulation within the section. However, during temporary plugging fracturing, the erosive effect of proppant on the perforations makes it difficult to ensure that the pumped plugging agent effectively seals the eroded perforations. Furthermore, reservoir heterogeneity results in complex fracture openings and morphologies, leading to significant uncertainty in the effectiveness of temporary plugging. Real-time assessment of the effectiveness of temporary plugging within the section is crucial for timely adjustments to the plugging strategy.

[0003] Currently, methods for assessing the effectiveness of temporary plugging include microseismic testing, external optical fiber monitoring, and radioactive tracers. However, microseismic testing has low accuracy and cannot pinpoint perforation clusters; external optical fiber monitoring can monitor the amount of liquid and sand entering each perforation cluster in real time, but it is costly and difficult to implement in the field; radioactive tracers can monitor the distribution of proppant before and after temporary plugging, but this technology is a post-pressure assessment and cannot provide timely guidance for adjusting the temporary plugging plan.

[0004] In summary, there is currently no established method for evaluating the effectiveness of multi-cluster fracturing and temporary plugging in horizontal well sections to determine the effectiveness of temporary plugging in real time. Summary of the Invention

[0005] To address the problems of the prior art, this invention provides a method for evaluating the effect of multi-cluster fracturing and temporary plugging in horizontal well sections. This method accurately judges the effect of multi-cluster fracturing and temporary plugging in horizontal well sections in real time, adjusts the temporary plugging scheme in a timely manner, achieves balanced transformation within the section, and improves single-well production.

[0006] This invention is achieved through the following technical solution:

[0007] This invention provides a method for evaluating the effect of multi-cluster fracturing and temporary plugging in horizontal well sections, comprising the following steps:

[0008] Step 1: Establish a serial port data channel to obtain real-time data on displacement, sand concentration, construction pressure, and timing of temporary plugging agent application at the fracturing construction site;

[0009] Step 2: Based on the timing of the temporary plugging agent injection and the construction pressure data obtained in Step 1, obtain the pressure boost value of the temporary plugging agent upon arrival on the construction pressure curve segment corresponding to the pumping stage of the temporary plugging agent.

[0010] Step 3: Based on the data obtained in Step 1, obtain the construction pressure before and after the temporary plugging agent is applied when the sand concentration is zero and the discharge rate is equal. The difference between the two is used to obtain the pressure increase value for the same discharge rate.

[0011] Step 4: Based on the data obtained in Step 1, obtain construction data points with equal sand concentration and discharge rate before and after the temporary plugging agent is applied. Then, use the construction data points with equal sand concentration and discharge rate before and after the temporary plugging agent is applied to create a curve overlay. Calculate the percentage of construction data points where the pressure difference is positive after the temporary plugging agent is applied compared to before the application, and obtain the positive pressure difference ratio.

[0012] Step 5: Determine the pressurization index value when the temporary plugging agent is in place, the pressurization index value at the same displacement, and the positive pressure difference ratio index value when the temporary plugging is effective, based on the mechanical differences between clusters within the reservoir section;

[0013] Step Six: Compare the relationship between the pressure increase value of the temporary plugging agent, the pressure increase value of the same displacement, and the positive pressure difference ratio with the corresponding index values. Introduce weighting coefficients to integrate the three benchmarking results and determine online in real time whether the temporary plugging is effective.

[0014] In the above method, preferably, the step of setting up a serial data channel to obtain data on displacement, sand concentration, construction pressure, and timing of temporary plugging agent administration in real time at the fracturing construction site includes: configuring a nine-pin serial channel in the main control room of the fracturing site; connecting the nine-pin serial channel to an external computer via a serial data cable; and setting the data transmission order of the data transmitter to displacement, sand concentration, and construction pressure.

[0015] In the above method, preferably, the step of obtaining the pressure boost value of the temporary plugging agent on the construction pressure curve segment corresponding to the temporary plugging agent delivery stage based on the timing and construction pressure data of the temporary plugging agent delivery obtained in step 1 includes: during the temporary plugging agent delivery stage, the discharge rate is kept constant to eliminate the interference of the discharge rate on the pressure, so that the pressure change is only caused by the temporary plugging; the construction pressure rises, and the difference between the pressure at the starting point and the pressure at the ending point of the rise represents the pressure boost value of the temporary plugging agent on the spot.

[0016] In the above method, preferably, the step of obtaining the construction pressure before and after the temporary plugging agent is applied, where the sand concentration is zero and the discharge rate is equal, based on the data obtained in step 1, to eliminate the influence of sand concentration and discharge rate on the construction pressure, and obtaining the pressure increase value for the same discharge rate by subtracting the two, includes: before the temporary plugging agent is applied, the sand concentration drops to 0 and is maintained for more than 10 minutes, and the construction pressure is read; after the temporary plugging agent is applied, the sand concentration is 0 and is maintained for more than 10 minutes at the same discharge rate as before the application of the temporary plugging agent, and the construction pressure is read; the pressure increase value for the same discharge rate is obtained by subtracting the construction pressure before the application of the temporary plugging agent from the construction pressure after the application of the temporary plugging agent.

[0017] In the above method, preferably, the step of obtaining construction data points with equal sand concentration and discharge rate before and after the temporary plugging agent is applied, based on the data obtained in step 1, and then superimposing curves using these data points to eliminate the influence of sand concentration and discharge rate on construction pressure, and calculating the percentage of construction data points with a positive pressure difference between the time before and after the temporary plugging agent is applied, to obtain the positive pressure difference ratio, includes: dividing the construction data points transmitted to the external computer into two stages, namely before and after the temporary plugging agent is applied; in the stage after the temporary plugging agent is applied, the sand addition method should be consistent with that before the application, and the discharge rate should be consistent; through program data comparison, quickly find the construction data points with equal discharge rate and sand concentration before and after the application of the temporary plugging agent; and superimpose curves using the program and calculate the percentage of construction data points with a positive pressure difference between the time before and after the application of the temporary plugging agent.

[0018] In the above method, preferably, determining the pressure boosting index value, the same-displacement pressure boosting index value, and the positive pressure difference ratio value for effective temporary plugging based on the mechanical differences between clusters within the reservoir section includes: based on the comprehensive interpretation data of well logging and segmented cluster data, reading the minimum horizontal principal stress data points within a 1m range of each perforation cluster within the section, calculating the average value as the minimum horizontal principal stress of that perforation cluster, searching for the maximum and minimum values ​​of the minimum horizontal principal stress in each perforation cluster and subtracting them to obtain the minimum horizontal principal stress difference between clusters. The pressure boosting index value and the same-displacement pressure boosting index value are equal to the minimum horizontal principal stress difference between clusters; when the minimum horizontal principal stress difference between clusters is within 1-3 MPa, the positive pressure difference ratio value is 30%-100%; when the minimum horizontal principal stress difference between clusters is greater than 3 MPa, the positive pressure difference ratio value is 70%-100%.

[0019] In the above method, preferably, the comparison of the relationship between the temporary plugging agent arrival pressure increase value, the same displacement pressure increase value, and the positive pressure difference ratio and the index value, and the integration of the three benchmark judgment results by introducing weight coefficients, determines the effectiveness of temporary plugging in real time online, including: the temporary plugging agent arrival pressure increase value is greater than the temporary plugging agent arrival pressure increase index value, indicating that the temporary plugging is effective, and 'a' is defined as 1, otherwise 'a' is defined as 0; the same displacement pressure increase value is greater than the same displacement pressure increase index value, and 'b' is defined as 1, otherwise 'b' is defined as 0; the positive pressure difference ratio obtained by curve superposition is within the range of the positive pressure difference ratio index value, and 'c' is defined as 1, otherwise 'c' is defined as 0; weight coefficients of 0.2, 0.3, and 0.5 are introduced, that is, the comprehensive judgment result D = 0.2a + 0.3b + 0.5c; when D ≥ 0.6, the temporary plugging is effective; when D < 0.6, the temporary plugging is ineffective.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] Establishing a method for judging the effectiveness of temporary plugging requires comprehensive consideration of cost, timeliness, and accuracy. During temporary plugging fracturing operations, pumping data is the most direct and economical first-hand evidence. Therefore, a method for judging the effectiveness of temporary plugging based on pumping data is the most economical. This invention fully utilizes the on-site construction pumping curves to obtain displacement, sand concentration, construction pressure, and the timing of temporary plugging agent administration. Real-time analysis of the construction pumping curves and in-depth mining of temporary plugging information can meet the requirements of timeliness and accuracy. On the other hand, the entire process of temporary plugging and diversion fracturing involves three stages: temporary plugging of the dominant channel, initiation of new fractures, and stable propagation of new fractures. The temporary plugging agent in place pressurization method can determine whether the temporary plugging agent has temporarily plugged the dominant channel, the same displacement pressurization method can determine whether a new fracture has been opened, and the curve superposition method can determine whether a new fracture can be stably propagated. Using a single method to judge the effect of temporary plugging and diversion fracturing is unreliable. This invention integrates the three methods of temporary plugging agent in place pressurization, same displacement pressurization, and curve superposition, and introduces a weighting coefficient, which can accurately judge the effect of temporary plugging of multiple clusters of fracturing in horizontal well sections in real time, guide the fracturing construction to adjust the construction plan in a timely manner, and improve the single well stimulation volume and oil and gas production capacity.

[0022] Furthermore, during the process of obtaining the pressure increase value of the temporary plugging agent, the discharge rate is kept constant during the temporary plugging agent delivery stage to eliminate the interference of the discharge rate on the pressure, so that the pressure change is only caused by the temporary plugging.

[0023] Furthermore, during the process of obtaining the same displacement pressure value, the sand concentration is kept to be zero and the displacement is equal before and after the temporary plugging agent is added, thereby eliminating the influence of sand concentration and displacement on construction pressure.

[0024] Furthermore, by superimposing construction data points with equal sand concentration and discharge rate before and after the application of the temporary plugging agent, the influence of sand concentration and discharge rate on construction pressure can be eliminated. Attached Figure Description

[0025] Figure 1 This is a flowchart of the method for evaluating the effect of multi-cluster fracturing and temporary plugging in horizontal well sections in an embodiment of the present invention;

[0026] Figure 2 This is a diagram illustrating the method for obtaining the pressure boost value of the temporary plugging agent in place, as described in this embodiment of the invention.

[0027] Figure 3 This is a diagram illustrating the method for obtaining boost pressure values ​​for the same displacement in an embodiment of the present invention;

[0028] Figure 4 This is a diagram illustrating the method for obtaining the positive pressure difference ratio using the curve overlay method in an embodiment of the present invention. Detailed Implementation

[0029] In order to provide a clearer understanding of the technical features, objectives and beneficial effects of the present invention, the technical solution of the present invention will now be described in detail below, but it should not be construed as limiting the scope of implementation of the present invention.

[0030] Example

[0031] This embodiment provides a method for evaluating the effect of multi-cluster fracturing and temporary plugging in horizontal well sections. Taking the effect of multi-cluster fracturing and temporary plugging in the second stage section of well A as an example, such as... Figure 1 As shown, it includes the following steps:

[0032] S101: Establish a serial port data channel to acquire real-time data on displacement, sand concentration, construction pressure, and timing of temporary plugging agent application at the fracturing construction site; specifically:

[0033] The fracturing site control room is equipped with a nine-pin serial port channel and is connected to an external computer via a serial data cable; the data transmission end is set to transmit data in the order of displacement, sand concentration and construction pressure.

[0034] S102: Based on the timing of the temporary plugging agent injection, obtain the pressure boost value of the temporary plugging agent upon arrival on the construction pressure curve segment corresponding to the pumping stage of the temporary plugging agent; specifically:

[0035] During the temporary plugging agent injection phase, the discharge rate remains constant, and the pressure rises. The difference between the initial pressure and the final pressure represents the pressure boost value of the temporary plugging agent upon arrival. Figure 2 As shown, the pressure boost value of the temporary plugging agent upon arrival is 11.8 MPa.

[0036] S103: Obtain the construction pressure before and after the temporary plugging agent is applied, when the sand concentration is zero and the discharge rate is equal. The difference between these two pressures yields the pressure increase value for the same discharge rate. Specifically:

[0037] Before the temporary plugging agent is applied, the sand concentration is reduced to 0 and maintained for 10 minutes, and the construction pressure is recorded. After the temporary plugging agent is applied, the sand concentration is reduced to 0 and maintained at the same discharge rate for 10 minutes, and the construction pressure is recorded. The pressure increase value at the same discharge rate is obtained by subtracting the construction pressure before the application of the temporary plugging agent from the construction pressure after application. Figure 3 As shown, the boost pressure for the same displacement is 13 MPa.

[0038] S104: Obtain construction data points with equal sand concentration and discharge rate before and after the temporary plugging agent is applied, overlay curves, and calculate the percentage of positive pressure differential data points; specifically:

[0039] The construction data transmitted to the external computer is divided into two segments: before and after the temporary plugging agent is applied. In the post-application stage, the sand addition method and discharge rate should remain consistent with those before application. Through program data comparison, data points with equal discharge rates and sand concentrations before and after application are quickly identified. These data points are then used to plot a superimposed curve, and the proportion of positive pressure differential data points is calculated. Figure 4 As shown, the positive pressure differential ratio is 61%.

[0040] S105: Determine the pressurization index values ​​for temporary plugging agent arrival, pressurization index values ​​for the same displacement, and positive pressure difference ratio values ​​when temporary plugging is effective based on the mechanical differences between clusters within the reservoir section; specifically:

[0041] Based on the comprehensive interpretation data from well logging and segmented cluster data, the minimum horizontal principal stress data points within a 1m range of each perforation cluster within a segment are read, and the average value is calculated as the minimum horizontal principal stress of that perforation cluster. The maximum and minimum values ​​of the minimum horizontal principal stress in each perforation cluster are searched and the difference is calculated. The difference between the maximum and minimum values ​​of the minimum horizontal principal stress in the second perforation cluster of Well A is 2.5MPa. Therefore, the index values ​​for the effectiveness of the temporary plugging are: temporary plugging agent arrival pressure increase index value 2.5MPa, same displacement pressure increase index value 2.5MPa, and positive pressure difference ratio index value 30%-100%.

[0042] S106: By comparing the relationship between the pressure increase value of the temporary plugging agent upon arrival, the pressure increase value of the same displacement, and the positive pressure difference ratio obtained by curve superposition with each corresponding indicator, a weighting coefficient is introduced to integrate the three benchmarking results to determine the effectiveness of the temporary plugging in real time online; specifically:

[0043] The pressure increase value of the temporary plugging agent in the second stage of Well A is 11.8 MPa, which is greater than 2.5 MPa. Therefore, this method determines the temporary plugging to be effective, and 'a' is assigned a value of 1. The pressure increase value at the same discharge rate is 13 MPa, which is also greater than 2.5 MPa. Therefore, this method determines the temporary plugging to be effective, and 'b' is assigned a value of 1. The positive pressure difference ratio of the curve superposition is 61%, which is within the range of 30%-100%. Therefore, this method determines the temporary plugging to be effective, and 'c' is assigned a value of 1. Weighting coefficients of 0.2, 0.3, and 0.5 are introduced, resulting in a comprehensive judgment result D = 0.2a + 0.3b + 0.5c = 1. Since D = 1 ≥ 0.6, the comprehensive judgment is that the multi-cluster fracturing temporary plugging within the second stage of Well A is effective.

Claims

1. A method for evaluating the effect of temporary plugging of multiple clusters of fracturing in a horizontal well section, characterized in that, Including: Obtaining construction data in real time, where the construction data includes displacement, sand concentration, construction pressure, and the timing of plugging agent injection; According to the timing of plugging agent injection and the construction pressure, obtaining the pressure increase value when the plugging agent arrives on the corresponding construction pressure curve segment during the plugging agent injection stage, specifically including: during the plugging agent injection stage, the displacement remains constant, the construction pressure rises, and the difference in construction pressure between the starting point and the ending point of the rise is the pressure increase value when the plugging agent arrives; According to the construction data obtained in real time, obtaining the construction pressures when the sand concentration is zero and the displacement is equal before and after the timing of plugging agent injection, and subtracting the two construction pressures to obtain the pressure increase value at the same displacement, specifically including: before the plugging agent injection, the sand concentration drops to 0 and remains for a set time, and the construction pressure is read; after the plugging agent injection, the sand concentration is 0 and remains for the same displacement as before the plugging agent injection for a set time, and the construction pressure is read; subtracting the construction pressure after the plugging agent injection from the construction pressure before the plugging agent injection to obtain the pressure increase value at the same displacement; According to the construction data obtained in real time, obtaining the construction data points where the sand concentration is equal and the displacement is equal before and after the timing of plugging agent injection, and using the construction data points where the sand concentration is equal and the displacement is equal before and after the timing of plugging agent injection for curve superposition, calculating the percentage of the construction data points where the pressure difference after the timing of plugging agent injection and before the timing of plugging agent injection is a positive pressure difference, and obtaining the positive pressure difference ratio; Determining the pressure increase index value when the plugging agent arrives, the pressure increase index value at the same displacement, and the positive pressure difference ratio index value when the plugging is effective according to the mechanical differences between clusters within the reservoir section; Comparing the relationships between the pressure increase value when the plugging agent arrives, the pressure increase value at the same displacement, and the positive pressure difference ratio and the corresponding index values, obtaining three discrimination results, introducing weight coefficients to integrate the three discrimination results to determine in real time whether the plugging is effective, specifically including: if the pressure increase value when the plugging agent arrives is greater than the pressure increase index value when the plugging agent arrives, define a to be assigned 1, otherwise a is assigned 0; if the pressure increase value at the same displacement is greater than the pressure increase index value at the same displacement, define b to be assigned 1, otherwise b is assigned 0; if the positive pressure difference ratio is within the positive pressure difference ratio index value range, define c to be assigned 1, otherwise c is assigned 0; introducing weight coefficients A, B, and C, and the comprehensive discrimination result D = Aa + Bb + Cc; when D ≥ E, the plugging is effective; when D < E, the plugging is ineffective, A is 0.2, B is 0.3, C is 0.5, and E is 0.

6.

2. The method for evaluating the effect of multi-cluster fracturing and temporary plugging in horizontal well sections according to claim 1, characterized in that, The obtaining of the construction data in real time specifically includes: configuring a nine-pin serial port channel in the main control room of the fracturing site and connecting it to an external computer through a serial data cable, and transmitting the construction data from the main control room of the fracturing site to the external computer, where the transmission order of the construction data is set as displacement, sand concentration, and construction pressure.

3. The method for evaluating the effect of multi-cluster fracturing and temporary plugging in horizontal well sections according to claim 1, characterized in that, The set time is more than 10 minutes.

4. The method for evaluating the effect of multi-cluster fracturing and temporary plugging in horizontal well sections according to claim 1, characterized in that, Based on real-time acquired construction data, construction data points with equal sand concentration and discharge rate before and after the temporary plugging agent is applied are obtained. These data points are then overlaid with curves to calculate the percentage of construction data points where the pressure difference is positive before and after the application of the temporary plugging agent. This positive pressure difference ratio is calculated, including cases where the sand addition method and discharge rate remain consistent after the application of the temporary plugging agent. Furthermore, through program data comparison, construction data points with equal discharge rate and sand concentration before and after the application of the temporary plugging agent are identified and their curves are overlaid. The percentage of construction data points with a positive pressure difference before and after the application of the temporary plugging agent is then calculated to obtain the positive pressure difference ratio.

5. The method for evaluating the effect of multi-cluster fracturing and temporary plugging in horizontal well sections according to claim 1, characterized in that, The determination of the temporary plugging agent arrival pressure boosting index, same-displacement pressure boosting index, and positive pressure difference ratio index based on the mechanical differences between clusters within the reservoir section when the temporary plugging is effective includes: based on the comprehensive interpretation data of well logging and segmented cluster data, reading the minimum horizontal principal stress data points within the set distance range of each perforation cluster within the section, calculating the average value as the minimum horizontal principal stress of the perforation cluster, searching for the maximum and minimum values ​​of the minimum horizontal principal stress in each perforation cluster and subtracting them to obtain the minimum horizontal principal stress difference between clusters; the temporary plugging agent arrival pressure boosting index and same-displacement pressure boosting index are equal to the minimum horizontal principal stress difference between clusters; when the minimum horizontal principal stress difference between clusters is within 1-3 MPa, the positive pressure difference ratio index is 30%-100%; when the minimum horizontal principal stress difference between clusters is greater than 3 MPa, the positive pressure difference ratio index is 70%-100%.

6. The method for evaluating the effect of multi-cluster fracturing and temporary plugging in horizontal well sections according to claim 5, characterized in that, The set distance is 1m.

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