Vertical well horizontal seam fracturing site construction control method

Abstract

The invention relates to the technical field of oil production engineering, in particular to a vertical well horizontal seam fracturing site construction control method. The method comprises the steps that a fractured target well is determined, basic data of the fractured target well are obtained, and the prepad fluid dosage, the temporary plugging frequency and the temporary plugging agent dosage of single temporary plugging are calculated according to the obtained basic data; opening a formation test pump, and recording the pump stopping pressure A; fracturing construction is conducted on the fractured target well, a temporary plugging agent is put in, the pressure rise of the fractured target well is observed, and whether single temporary plugging takes effect or not is judged according to the pressure rise; under the condition that single temporary plugging is effective, fracturing fluid continues to be added into the fracturing target well for construction, the pump is stopped, and the pump stopping pressure B is recorded; and observing whether the pump stop pressure A and the pump stop pressure B are equal, if not, repeating the operation until the two pressures are equal, and stopping. The method provided by the invention is high in controllability, convenient and simple to operate, safe and effective.

Description

Technical Field

[0001] The invention relates to the technical field of oil production engineering, and in particular to a method for controlling on-site construction of horizontal fracture fracturing of a vertical well. Background Art

[0002] At present, the field construction control of horizontal seam fracturing and temporary plugging and diverting fracturing in wells mainly relies on the experience of technicians, and there is no systematic field construction control method. Therefore, in the actual construction site, it is very easy to have problems such as excessive increase in construction pressure after temporary plugging and insufficient increase in construction pressure after temporary plugging, which makes it impossible to ensure the effectiveness of temporary plugging in horizontal seams while ensuring construction safety. Therefore, in view of the above shortcomings, a field construction control method for horizontal seam fracturing in vertical wells is proposed. Summary of the invention

[0003] 1. Technical issues to be resolved The present invention provides a method for controlling the on-site construction of horizontal fractures in vertical wells, so as to overcome the problems in the prior art where there is no systematic on-site construction control method, which easily leads to the problems of excessive increase in construction pressure after temporary plugging, insufficient increase in construction pressure after temporary plugging, and the inability to ensure the effectiveness of temporary plugging in horizontal fractures.

[0004] (II) Technical solution In order to solve the above problems, the present invention provides a method for controlling the on-site construction of horizontal fracture fracturing in a vertical well, comprising: Step S1: determine the target well for fracturing and obtain basic data of the target well for fracturing; Step S2: Calculate the amount of pre-fluid, the number of temporary plugging times, and the amount of temporary plugging agent for a single temporary plugging according to the basic data of the target fracturing well obtained in step S1; Step S3: performing pre-fluid fracturing on the target well of the fracturing in step S1, pressurizing the formation and recording the pump stop pressure A; Step S4: After the pump stop pressure is measured in step S3, the pre-fluid and sand addition construction is performed according to the calculation result of S2; Step S5: After reaching the temporary plugging agent delivery time calculated in step S2, the temporary plugging agent is delivered, and the time required for the temporary plugging agent to reach the front end of the horizontal seam of the target well for fracturing and the time of adding the temporary plugging agent are calculated according to the basic data of the field environment, and the speed of delivering the temporary plugging agent is controlled according to the result of the temporary plugging agent dosage in step S2; Step S6: observing the pressure increase of the target well during the calculation time of step S5, and judging whether the single temporary plugging is effective according to the pressure increase; Step S7: if it is determined that the single temporary plugging in step S6 is effective, then continue to add fracturing fluid to the target well, stop the pump and record the pump stop pressure B; Step S8: Observe whether the pump stop pressure A in step S3 and the pump stop pressure B in step S7 are equal. If not, repeat the process from step S4 to step S7 until the two are equal, and then stop the operation.

[0005] Preferably, in step S1, the target well for fracturing is a horizontal fracture of a vertical well, and the basic data of the target well for fracturing includes reservoir transformation radius, bottom depth of target layer, internal volume of pipeline, liquid efficiency, temporary plugging length of the front end of horizontal fracture and fracture height of horizontal fracture.

[0006] Preferably, in step S4, the sand addition volume is 2m 3 / min-5m 3 / min, the sand ratio is 5%-10%, and the sand ratio is the ratio of the volume of sand to the volume of fracturing fluid.

[0007] Preferably, the types of sand include quartz sand, resin sand, ceramic gravel or coated proppant.

[0008] Preferably, in step S5, the time of adding the temporary plugging agent is calculated according to the construction displacement and the on-site delivery speed, and the time of adding the temporary plugging agent is when 1 minute remains before the end of sand addition.

[0009] Preferably, the basic data of the on-site environment include the inner diameter of the oil pipe, the volume of the surface pipeline and the construction displacement.

[0010] Preferably, in step S5, the result limit value of the temporary plugging agent dosage is 100 kg. If the temporary plugging agent dosage is less than 100 kg, all the temporary plugging agent is added within 1 minute after the preset time for adding sand is reached; if the calculated temporary plugging agent dosage is greater than 100 kg, 100 kg of temporary plugging agent is added together with sand within 1 minute, and after 1 minute, the remaining temporary plugging agent is added at the same temporary plugging agent addition rate.

[0011] Preferably, in step S6, the limit value of the pressure increase is 3 MPa, and if the pressure increase exceeds 3 MPa, it proves that the temporary plugging is successful.

[0012] (III) Beneficial effects The on-site construction control method for horizontal seam fracturing of a vertical well provided by the present invention comprises five steps, namely, sand pre-treatment, calculation of the amount of temporary plugging agent, method of adding the temporary plugging agent, diagnosis of whether a single horizontal seam temporary plugging is successful, and diagnosis of whether the temporary plugging in the horizontal seam is successful. The construction method has strong controllability, is convenient and simple to operate, and is safe and effective. It can not only ensure the safety of the construction, but also ensure the success of temporary plugging of the horizontal seam. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a flow chart of a method for controlling on-site construction of horizontal fracture fracturing in a vertical well according to an embodiment of the present invention; Figure 2 This is a curve diagram of the on-site construction of a well fracturing according to an embodiment of the present invention. DETAILED DESCRIPTION

[0014] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0015] Figure 1 FIG. 1 is a flow chart of a method for controlling on-site construction of horizontal fracture fracturing in a vertical well according to an embodiment of the present invention. Figure 1 As shown, the present invention provides a method for controlling the on-site construction of horizontal fracture fracturing in a vertical well, comprising: Step S1: determine the target well for fracturing and obtain basic data of the target well for fracturing; Step S2: Calculate the amount of pre-fluid, the number of temporary plugging times, and the amount of temporary plugging agent for a single temporary plugging according to the basic data of the target fracturing well obtained in step S1; Step S3: performing pre-fluid fracturing on the target well of the fracturing in step S1, pressurizing the formation and recording the pump stop pressure A; Step S4: After the pump stop pressure is measured in step S3, the pre-fluid and sand addition construction is performed according to the calculation result of S2; Step S5: After reaching the temporary plugging agent delivery time calculated in step S2, the temporary plugging agent is delivered, and the time required for the temporary plugging agent to reach the front end of the horizontal seam of the target well for fracturing and the time of adding the temporary plugging agent are calculated according to the basic data of the field environment, and the speed of delivering the temporary plugging agent is controlled according to the result of the temporary plugging agent dosage in step S2; Step S6: observing the pressure increase of the target well during the calculation time of step S5, and judging whether the single temporary plugging is effective according to the pressure increase; Step S7: if it is determined that the single temporary plugging in step S6 is effective, then continue to add fracturing fluid to the target well, stop the pump and record the pump stop pressure B; Step S8: Observe whether the pump stop pressure A in step S3 and the pump stop pressure B in step S7 are equal. If not, repeat the process from step S4 to step S7 until the two are equal, and then stop the operation.

[0016] In practical applications, in step S1, the target well for fracturing is a horizontal fracture of a vertical well, and the basic data of the target well for fracturing includes reservoir transformation radius, bottom depth of target layer, internal volume of pipeline, liquid efficiency, temporary plugging length of the front end of horizontal fracture, and fracture height of horizontal fracture.

[0017] In this method, in step S2, the amount of pre-fluid, the number of temporary plugging times and the amount of temporary plugging agent for a single temporary plugging are calculated according to the basic data of the target fracturing well obtained in step S1.

[0018] In practical application, in step S4, the sand addition volume is 2m 3 / min-5m 3 / min, the types of sand added include quartz sand, resin sand, ceramic gravel or coated proppant, and the sand ratio is 5%-10%, which is the ratio of the volume of sand to the volume of fracturing fluid.

[0019] In this method, in step S5, the basic data of the field environment include the inner diameter of the oil pipe, the volume of the surface pipeline and the construction displacement. The time required for the temporary plugging agent to reach the front end of the target well for fracturing can be calculated based on the inner diameter of the oil pipe, the volume of the surface pipeline and the construction displacement. The time for adding the temporary plugging agent is calculated based on the construction displacement and the field delivery speed, and the temporary plugging agent is started to be delivered when there is 1 minute left before the end of sand addition.

[0020] In practical applications, in step S5, the result limit value of the temporary plugging agent dosage is 100 kg. If the temporary plugging agent dosage is less than 100 kg, all the temporary plugging agent is added within 1 minute after the preset time of adding sand is reached; if the calculated dosage of the temporary plugging agent is greater than 100 kg, 100 kg of the temporary plugging agent is added together with the sand within 1 minute, and after 1 minute, the remaining temporary plugging agent is added at the same temporary plugging agent addition rate.

[0021] In this method, in step S6, the limit value of the pressure increase is 3MPa. If the pressure increase exceeds 3MPa, it proves that the temporary plugging is successful. When the pressure increase is lower than 3MPa, the amount of temporary plugging agent can be increased until the pressure increase reaches 3MPa.

[0022] The following is a detailed description of the implementation process of this vertical well horizontal fracture fracturing field construction control method: In this embodiment, the target well for fracturing is determined, and basic data of the target well for fracturing is acquired.

[0023] Calculate the amount of pre-fluid, number of temporary plugging times, time of adding temporary plugging agent and the amount of temporary plugging agent for a single temporary plugging.

[0024] Press open the formation to measure and stop the pump, and record the pump stop pressure A.

[0025] In actual application, after the formation is opened, the pump stop pressure is tested to be 13.28MPa, and the bottom depth of the target layer is 1005.4m. Figure 2 As shown, the pump stop pressure gradient A=0.0232MPa / m is calculated.

[0026] In practical applications, through the first step of obtaining the basic data of the target well for fracturing, we can know that the reservoir transformation radius is 60m, the horizontal fracture height is 0.001m, and the front length of the horizontal fracture is 0.2m. Based on these data, the temporary plugging times are 3 times, and the amount of temporary plugging agent used each time is calculated to be 300kg.

[0027] In this embodiment, sand is added after the pre-fluid fracture formation is completed, and the time required for the temporary plugging agent to reach the front end of the horizontal fracture of the target well for fracturing is calculated. The time required for the temporary plugging agent to reach the front end of the target well for fracturing can be calculated according to the inner diameter of the oil pipe, the volume of the ground pipeline and the construction displacement. The time for adding the temporary plugging agent is calculated according to the construction displacement and the on-site delivery speed. In actual application, the temporary plugging agent is usually started to be delivered when there is 1 minute left before the end of sand addition. After the time for adding the temporary plugging agent is reached, the temporary plugging agent is started to be delivered, and the speed of delivering the temporary plugging agent is controlled according to the result of the temporary plugging agent dosage.

[0028] In practical applications, the pre-insertion fluid is first used to create the slit, followed by 3m 3 / min displacement, the type of sand added is quartz sand, the sand ratio is 10%, that is, at 20m 3 Add 2m3 of quartz sand to the volume of fracturing fluid 3 Since the single temporary plugging agent dosage exceeds 100kg, Figure 2 It can be seen that time E is the preset time, and there is 1 minute left from time E to the end of sand adding. When the time for adding sand reaches time E, 100 kg of temporary plugging agent is added from time E to the end of this sand adding. After the sand adding is completed, 200 kg of temporary plugging agent continues to be added at the same rate.

[0029] In this embodiment, the pressure increase of the target fracturing well is observed, and whether the single temporary plugging is effective is determined based on the pressure increase.

[0030] In actual application, the pressure increase value was read after temporary plugging, and the pressure increased from 26.4MPa to 29.6MPa, an increase of 3.2MPa, proving that the temporary plugging was successful.

[0031] In this embodiment, if it is determined that a single temporary plugging is effective, fracturing fluid is continued to be added to the target well, the pump is stopped and the pump stop pressure B is recorded, and it is observed whether the pump stop pressure A and the pump stop pressure B are equal. If not, the above-mentioned single temporary plugging process is repeated until the two are equal, and the operation is stopped.

[0032] In actual application, after a single temporary plugging is successful, the pump stop pressure B is measured to be 12.17MPa, A≠B, and the operation is repeated. Figure 2 As shown, F and G are the moments of the second and third injection of temporary plugging agent, respectively. The second and third pump stop pressures C and D are measured, respectively. The pump stop pressure C is 12.48 MPa, and the pump stop pressure D is 12.50 MPa. The pump stop pressure C≈D. Therefore, it is judged that the temporary plugging in the horizontal seam is successful.

[0033] The on-site construction control method for horizontal seam fracturing of a vertical well provided by the present invention comprises five steps, namely, sand pre-treatment, calculation of the amount of temporary plugging agent, method of adding the temporary plugging agent, diagnosis of whether a single horizontal seam temporary plugging is successful, and diagnosis of whether the temporary plugging in the horizontal seam is successful. The construction method has strong controllability, is convenient and simple to operate, and is safe and effective. It can not only ensure the safety of the construction, but also ensure the success of temporary plugging of the horizontal seam.

[0034] The above implementation modes are only used to illustrate the present invention, but not to limit the present invention. Ordinary technicians in the relevant technical field can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions also belong to the scope of the present invention. The patent protection scope of the present invention should be defined by the claims.

Claims

1. A method for controlling the on-site construction of horizontal fracture fracturing in a vertical well, characterized in that: include: Step S1: determine the target well for fracturing and obtain basic data of the target well for fracturing; Step S2: Calculate the amount of pre-fluid, the number of temporary plugging times, and the amount of temporary plugging agent for a single temporary plugging according to the basic data of the target fracturing well obtained in step S1; Step S3: performing pre-fluid fracturing on the target well of the fracturing in step S1, pressurizing the formation and recording the pump stop pressure A; Step S4: After the pump stop pressure is measured in step S3, the pre-fluid and sand addition construction is performed according to the calculation result of S2; Step S5: After reaching the temporary plugging agent delivery time calculated in step S2, the temporary plugging agent is delivered, and the time required for the temporary plugging agent to reach the front end of the horizontal seam of the target well for fracturing and the time of adding the temporary plugging agent are calculated according to the basic data of the field environment, and the speed of delivering the temporary plugging agent is controlled according to the result of the temporary plugging agent dosage in step S2; Step S6: observing the pressure increase of the target well during the calculation time of step S5, and judging whether the single temporary plugging is effective according to the pressure increase; Step S7: if it is determined that the single temporary plugging in step S6 is effective, then continue to add fracturing fluid to the target well, stop the pump and record the pump stop pressure B; Step S8: Observe whether the pump stop pressure A in step S3 and the pump stop pressure B in step S7 are equal. If not, repeat the process from step S4 to step S7 until the two are equal, and then stop the operation.

2. The vertical well horizontal fracture field construction control method according to claim 1, characterized in that: In step S1, the target well for fracturing is a horizontal fracture of a vertical well, and the basic data of the target well for fracturing includes reservoir transformation radius, bottom depth of target layer, internal volume of pipeline, liquid efficiency, temporary plugging length of the front end of horizontal fracture and fracture height of horizontal fracture.

3. The vertical well horizontal fracture fracturing field construction control method according to claim 1, characterized in that: In step S4, the sand addition volume is 2m 3 / min-5m 3 / min, the sand ratio is 5%-10%, and the sand ratio is the ratio of the volume of sand to the volume of fracturing fluid.

4. The vertical well horizontal fracture fracturing field construction control method according to claim 3 is characterized in that: The types of sand include quartz sand, resin sand, ceramic gravel or coated proppant.

5. The vertical well horizontal fracture fracturing field construction control method according to claim 1, characterized in that: In step S5, the time of adding the temporary plugging agent is calculated according to the construction displacement and the on-site delivery speed, and the time of adding the temporary plugging agent is when 1 minute remains before the end of sand addition.

6. The vertical well horizontal fracture field construction control method according to claim 1, characterized in that: In step S5, the basic data of the on-site environment includes the inner diameter of the oil pipe, the volume of the surface pipeline and the construction displacement.

7. The vertical well horizontal fracture fracturing field construction control method according to claim 1, characterized in that: In step S5, the result limit value of the temporary plugging agent dosage is 100 kg. If the temporary plugging agent dosage is less than 100 kg, all the temporary plugging agent is added within 1 minute after the preset time of adding sand is reached; if the calculated temporary plugging agent dosage is greater than 100 kg, 100 kg of temporary plugging agent is added together with sand within 1 minute, and after 1 minute, the remaining temporary plugging agent is added at the same temporary plugging agent addition rate.

8. The vertical well horizontal fracture fracturing field construction control method according to claim 1, characterized in that: In step S6, the limit value of the pressure increase is 3MPa. If the pressure increase exceeds 3MPa, it proves that the temporary plugging is successful.

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