CN113622889B - Radial well volume fracturing method - Google Patents
Radial well volume fracturing method Download PDFInfo
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- 238000000034 method Methods 0.000 title claims abstract description 90
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 70
- 238000006073 displacement reaction Methods 0.000 claims abstract description 59
- 238000002347 injection Methods 0.000 claims abstract description 52
- 239000007924 injection Substances 0.000 claims abstract description 52
- 230000035699 permeability Effects 0.000 claims abstract description 8
- 239000004568 cement Substances 0.000 claims description 14
- 239000012530 fluid Substances 0.000 claims description 13
- 239000004576 sand Substances 0.000 claims description 10
- 230000015572 biosynthetic process Effects 0.000 claims description 6
- 239000007788 liquid Substances 0.000 claims description 6
- 238000005507 spraying Methods 0.000 claims description 4
- 238000007599 discharging Methods 0.000 claims description 3
- 239000004215 Carbon black (E152) Substances 0.000 claims 1
- 229930195733 hydrocarbon Natural products 0.000 claims 1
- 150000002430 hydrocarbons Chemical class 0.000 claims 1
- 206010017076 Fracture Diseases 0.000 description 53
- 238000003801 milling Methods 0.000 description 9
- 238000002018 water-jet injection Methods 0.000 description 9
- 238000004519 manufacturing process Methods 0.000 description 8
- 239000011435 rock Substances 0.000 description 6
- 206010053206 Fracture displacement Diseases 0.000 description 5
- 239000007921 spray Substances 0.000 description 5
- 230000000694 effects Effects 0.000 description 4
- 238000000227 grinding Methods 0.000 description 4
- 230000009286 beneficial effect Effects 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 238000002474 experimental method Methods 0.000 description 3
- 238000010998 test method Methods 0.000 description 3
- 208000010392 Bone Fractures Diseases 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 238000005553 drilling Methods 0.000 description 2
- 238000009662 stress testing Methods 0.000 description 2
- 238000010408 sweeping Methods 0.000 description 2
- 238000013459 approach Methods 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 238000012790 confirmation Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
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- 239000000243 solution Substances 0.000 description 1
- 238000012496 stress study Methods 0.000 description 1
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/25—Methods for stimulating production
- E21B43/26—Methods for stimulating production by forming crevices or fractures
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Abstract
The invention relates to the technical field of later exploitation of oil and gas fields, and discloses a radial well volume fracturing method which comprises the following steps: step 100: selecting a target layer of the radial fracturing well to be implemented, and determining the horizontal maximum principal stress and horizontal minimum principal stress directions of the target layer; step 200: determining fracturing displacement and fracturing length; step 300: determining the number of radial water jet holes according to the fracturing displacement and the fracturing fracture length in the step 200; step 400: performing directional windowing and radial water jet flow along a direction forming a certain angle with the horizontal minimum main stress direction, and executing the jet process until the total radial water jet flow holes are counted; step 500: and after the injection process is finished, executing the fracturing process until the number of all fracturing strips is finished. The invention realizes volume fracturing in the reservoir section by means of radial water jet in the vertical well, realizes the purpose of fracturing similar to a horizontal well, enlarges the swept area of the crack, effectively uses the oil and gas reserves, and can greatly improve the single well yield of the low permeability oil and gas well compared with the conventional one-time fracturing.
Description
Technical Field
The invention relates to the technical field of later exploitation of oil and gas fields, in particular to a radial well volume fracturing method.
Background
At present, most of the oil and gas fields in China enter a later exploitation stage, and the old well is required to be dug to search residual oil and the old well is required to be repeatedly fractured, acidified and increased in yield so as to achieve the purpose of effective exploitation. Radial well technology is one of the very effective approaches to find the remaining reserves in older wells. But for low permeability fields, fracturing is also required to obtain good development effect. At present, the fracturing of a radial well is basically simple one-time fracturing, the modification scale is small, multi-crack fracturing is not realized, and the productivity cannot be effectively released.
Disclosure of Invention
The invention aims to solve the problems of simple fracturing process and low productivity in the prior art, and provides a radial well volume fracturing method, wherein the volume fracturing is realized in a reservoir section by means of radial water jet in a vertical well, the purpose of fracturing similar to a horizontal well is realized, the swept area of a crack is enlarged, the oil and gas reserves are effectively utilized, and compared with the conventional one-time fracturing, the single well yield of a low-permeability oil and gas well can be greatly improved.
To achieve the above object, the present invention provides a radial well volume fracturing method comprising the steps of:
step 100: selecting a target layer of a radial fracturing well to be implemented, and determining the horizontal maximum principal stress and horizontal minimum principal stress directions of the target layer;
step 200: determining fracturing displacement and fracturing length;
step 300: determining the number of radial water jet holes according to the fracturing displacement and the fracturing fracture length in the step 200;
step 400: performing directional windowing and radial water jet flow along a direction forming a certain angle with the horizontal minimum main stress direction, and executing a jet process until the number of all radial water jet holes is completed;
step 500: and after the injection process is finished, executing a fracturing process until the number of all fracturing strips is finished.
Preferably, the method further comprises step 600: closing the well, confirming that the crack is closed, and then discharging the liquid.
Preferably, the step 300 specifically includes:
the aperture of the radial water jet is 50mm;
the radial water jet flow arranged in different directions has the same flow holes.
Preferably, the step 300 specifically includes: when the thickness of the target layer is 3-10m, the number of holes of the radial water jet is not less than 6 holes along the horizontal minimum principal stress direction;
when the thickness of the target layer is 10-20m, the number of holes of the radial water jet is not less than 10 holes along the horizontal minimum principal stress direction;
when the thickness of the target layer is more than 20m, the number of holes of the radial water jet is not less than 12 holes along the horizontal minimum principal stress direction.
Preferably, the lowest hole site of the radial water jet is arranged at a position above 2.0m of the bottom boundary of the target layer.
Preferably, the hole sites of the rest of the radial water jets except the lowest hole site are evenly distributed according to the thickness of the oil and gas layers.
Preferably, the certain angle in the step 400 is 0 ° -45 ° from the horizontal minimum principal stress direction; the length of the radial water jet is 90-110m.
Preferably, the step 400 further includes: and when the radial water jet retreats, jetting for 1-5 minutes at the preset jetting points, wherein the positions of the preset jetting points are determined according to the intervals of the fracturing cracks.
Preferably, the injection process in the step 400 further includes: a plurality of different orientations are replaced and repeated.
Preferably, the fracturing process in the step 500 specifically includes:
when fracturing, the minimum displacement is adopted as the fracturing displacement for fracturing, and the fracturing displacement is gradually increased after fracturing; the minimum displacement is the displacement with the smallest value in all displacements up to the formation fracture pressure.
Preferably, the fracturing process in the step 500 specifically includes: and after sand adding is completed, displacing sand-carrying fluid in the radial shaft to the forefront position of the radial well by using displacement fluid.
Preferably, the fracturing process in step 500 is started again after the completion of each fracturing and waiting for the fracture to close.
Preferably, in the fracturing process in the step 500, if the objective layer contains an interval that has been perforated and fractured, the interval that has been perforated and fractured is plugged in advance by cement, and the plugging position is subjected to a pressure of 20MPa or more.
Through the technical scheme, the volume fracturing is realized in the reservoir section by means of radial water jet in the vertical well, the purpose of fracturing similar to a horizontal well is realized, the swept area of the crack is enlarged, the oil and gas reserves are effectively utilized, and compared with the conventional primary fracturing, the single well yield of the low-permeability oil and gas well can be greatly improved.
Drawings
FIG. 1 is a flow chart of the basic steps of the radial well volume fracturing method of the present invention.
Detailed Description
The following describes specific embodiments of the present invention in detail with reference to the drawings. It should be understood that the detailed description and specific examples, while indicating and illustrating the invention, are not intended to limit the invention.
In the present invention, unless otherwise specified, terms such as "upper, lower, left, and right" and "upper, lower, left, and right" are used generically to refer to the upper, lower, left, and right illustrated in the drawings; "inner and outer" generally refer to the inner and outer relative to the contour of the components themselves; "distal" and "proximal" generally refer to the distance relative to the contour of the components themselves.
As shown in fig. 1, the invention provides a radial well volume fracturing method, which mainly comprises the following steps:
step 100: selecting a target layer in a radial well bore, and determining the horizontal maximum principal stress and the horizontal minimum principal stress directions of the target layer, wherein the horizontal maximum principal stress directions are the principal directions of the extension of the fracturing fracture;
step 200: determining fracturing displacement and fracturing length;
step 300: determining the number of radial water jet holes according to the fracturing displacement and the fracturing fracture length in the step 200;
step 400: performing directional windowing and radial water jet flow along the direction which forms a preset angle with the horizontal minimum main stress direction, and executing the jet process until the total number of radial water jet flow is completed;
step 500: and after the injection process is finished, executing a fracturing process until the number of all fracturing strips is finished.
From the above, the invention realizes volume fracturing in the reservoir section by means of radial water jet in the vertical well, realizes the purpose of fracturing similar to a horizontal well and forms a complex fracture system, expands the swept area of the fracture, effectively uses the oil and gas reserves, and can greatly improve the single well yield of the low permeability oil and gas well compared with the conventional one-time fracturing.
Further, in order to ensure the safety and stability of the subsequent operation, the present invention further includes step 600: closing the well, confirming that the crack is closed, and then discharging the liquid.
The above is the most important step in the radial well volume fracturing method provided by the invention, and the specific operation modes and parameter requirements in each step are further described below.
Specifically, in the step 100, the horizontal maximum principal stress and the horizontal minimum principal stress directions of the objective layer are determined by a core differential strain method or a wave velocity anisotropy method. The method is a common stress test method or a field fracture extension direction test method during fracturing, and the specific test method is not the key content to be protected in the invention and is not repeated here.
If desired, the fracturing displacement and the fracturing length may be determined by the thickness, porosity, permeability, fracture pressure, fracture height, and fracturing friction of the layer of interest in step 200. More specific details are set forth in the following detailed description of the embodiments with reference to the corresponding parameters.
Further, the step 300 specifically includes: the diameter of the radial water jet may be 50mm, and for a specific number of holes of the radial water jet, it is necessary to determine the diameter according to the thickness of the target layer. Such as: for radial water jet with the aperture of preferably 50mm, when the thickness of the target layer is 3-10m, the number of holes of the radial water jet is not less than 6 holes along the horizontal minimum principal stress direction, and the number of holes is consistent on two sides; when the thickness of the target layer is 10-20m, the number of holes of the radial water jet is not less than 10 holes along the horizontal minimum principal stress direction; when the thickness of the target layer is more than 20m, the number of holes of the radial water jet is not less than 12 holes along the horizontal minimum principal stress direction. The number of holes determined according to the thickness of the target layer can meet the actual process requirement.
In addition, in order to ensure the process effect, the position of the hole site of the radial water jet is also required correspondingly, and in general, the lowest position of the hole site of the radial water jet is more than 2.0m higher than the bottom boundary of the target layer. In order to ensure uniform stress, the rest hole sites except the lowest position hole site are evenly distributed according to the thickness of the oil and gas layers.
In practice, the certain angle in the step 400 is 0 ° -45 ° in order to ensure that the radial water jet has sufficient impact strength; the length of the radial water jet is 90-110m; when the radial water jet in the radial well is in the backward direction, the radial water jet is sprayed for 1-5 minutes at a preset key position, and the preset key position is determined according to the interval of the fracturing cracks.
In order to ensure that the spray impingement of the radial water jet is evenly achieved for each orientation, the spray process in step 400 is replaced with a plurality of different orientations and repeated.
In order to achieve the technical effect and control the process cost as much as possible, the fracturing process in the step 500 specifically includes: when fracturing, the minimum displacement is adopted as the fracturing displacement for fracturing, and the fracturing displacement is gradually increased after fracturing; the minimum displacement is the displacement with the smallest value in all displacements up to the formation fracture pressure.
In addition, the fracturing process in the step 500 specifically includes: and after sand adding is completed, displacing sand-carrying fluid in the radial shaft to the forefront position of the radial well by using displacement fluid.
Still further, the fracturing process in step 500 waits for the fracture to close after each fracture is completed and then starts the next fracture.
In addition, for the purpose layer which has been fractured, in order to avoid the extension of the fracture which is fractured earlier in radial fracturing, if the purpose layer contains the already fractured layer segments in the fracturing process in the step 500, the already fractured layer segments are plugged by cement in advance, and the pressure is tested to ensure that the plugged position is subjected to the pressure of more than 20 MPa.
According to the above, the radial well volume fracturing method provided by the invention is mainly used for increasing production and injection of oil and gas engineering, mainly is to put into production in a vertical well produced by perforation fracturing for a period of time by means of radial water jet or a new well of a tight reservoir, realizes volume fracturing in a reservoir section according to physical property conditions of stratum by combining radial water jet technology, reasonably segments, realizes segmented fracturing according to different fracturing construction displacement and fracturing pressure of the pressed stratum, achieves the purpose of fracturing approximately horizontal well, forms a complex fracture network communication network fracture system, enlarges fracture sweep area, effectively uses oil and gas reserves, and can greatly improve single well yield of a low-permeability oil and gas well compared with conventional primary fracturing.
The technical scheme of the present invention will be described in detail with reference to specific examples.
Example 1
In this embodiment, there is more residual reserves among the reservoir wells of a certain block sand river group, and the well A is selected as an experimental well to perform a radial well volume fracturing experiment. The objective layer of the well A is a sand river subgroup, the depth of an oil layer is 2000-2026m, and the thickness of the oil layer is 26m. The specific technical process comprises the following steps:
firstly, for the core of the A well sand river subgroup, a core differential strain method, a wave velocity anisotropy method and other stress testing methods are adopted in an experiment to obtain the horizontal maximum principal stress direction and the horizontal minimum principal stress direction of a target layer, and the method belongs to a relatively common stress testing method and is not an important point of protection required by the method and is not repeated herein. The horizontal maximum principal stress direction is 90 degrees and 270 degrees, and the horizontal minimum principal stress direction is 0 degrees and 180 degrees because the horizontal maximum principal stress direction is perpendicular to the horizontal minimum principal stress direction.
In view of the thickness of the target layer of 2000-2026m, the porosity of the target layer was 12%, the permeability was 5md, the fracture pressure was 40MPa, and the fracture height was 30m, and it was determined that the fracture displacement was 4.5m based on the above parameters 3 And/min, the crack length is 120m.
Next, the radial water jet aperture in this example was determined to be 50mm in terms of fracturing displacement and fracture length. Whereas for an aperture of 50mm, the basic relationship between the number of holes and the thickness of the layer is: for a 3-10m thick layer of interest, not less than 6 holes in the wellbore along the horizontal minimum principal stress direction, and consistent in number in the 0 ° and 180 ° directions; not less than 10 holes for a target layer 10-20m thick; for a target layer with a thickness of 20m or more, the number of holes is not less than 12. In addition, the lowest position of the radial water jet is 2m higher than the bottom boundary of the target layer, and the rest is evenly distributed according to the thickness of the oil and gas layer. In this embodiment, at the positions 2004m, 2008m, 2012m, 2016m, 2020m, and 2024m of the a well, respectively, at each position above the lowest position 2024m, the positions of all the holes are uniformly distributed in the depth direction, and one injection hole is designed in the directions of 0 ° and 180 ° in the radial direction, respectively, and the number of holes is 12 in total.
Because the radial well volume fracturing method provided by the invention can be applied to a vertical well produced for a period of time by perforation fracturing, for a target layer which is already fractured, cement is needed to seal the perforated well section in order to avoid the extension of cracks which are previously fractured during volume fracturing. And (3) providing a production string in the well, and cementing the lower cementing string with a cement truck pump to plug the interval produced by perforation and fracturing. After the plugged cement is solidified, drilling and sweeping a shaft after the plugging layer is tested to be at least 20MPa qualified so as to ensure that the shaft of the fracturing layer section is smooth; and for a layer of interest that has not been fractured, the layer is not plugged with cement. In this embodiment, the well a is once subjected to fracturing treatment at the beginning of production, so that the perforated interval needs to be plugged with cement.
Subsequently, a radial water jet injection phase is entered. The directional windowing and radial water jet injection are performed along an angle with the horizontal minimum principal stress direction, the injection direction is to ensure that the included angle with the horizontal minimum principal stress direction is 0-45 degrees, the diameter of a hole with 50mm is based on a shaft, and the radial water jet length is about 90-110m, in the embodiment, 100m. The specific process comprises the following steps: firstly, the oil layer sleeve at the injection point is worn through a sleeve grinding and milling tool by the oil pipe descending and injection special guide device in the 0 degree direction of 2024m and the continuous oil pipe descending and milling tool; after the oil layer casing is ground through, a casing grinding and milling tool is started, and then the casing is put into a jet pipeline through a continuous oil pipe; after being sprayed for 100m through the spray pipeline, the holes are cleaned and have no sundries as much as possible. It should be noted that, the above-mentioned "guide special for injection", "casing milling tool" and "coiled tubing" are all existing common devices, and are not described herein.
In the injection process, when the radial water jet injection is retreated, the injection is performed for 1-2 minutes at a preset injection point, and the injection time is prolonged to be different according to the hardness of the rock in actual operation, so that the rock breaking area at the injection point is enlarged, and the fracture at the injection point is facilitated in later fracturing. The predetermined injection points are selected according to the determined fracture spacing, and in this embodiment, if the fracture spacing is 30m, the injection point positions of 100m, 70m, and 40m are selected. That is, the interval between the injection points is 30m, which is consistent with the interval of the fracturing fracture. When the injection is completed in a radial borehole, the injection pipeline is started, the rotary guide rotates 180 degrees, the injection process is repeated in the rotated azimuth, the radial water jet is respectively completed in the directions of 0 degree and 180 degrees at 2020m, 0 degree and 180 degrees at 2016m, 0 degree and 180 degrees at 2012m, 0 degree and 180 degrees at 2008m, and 0 degree and 180 degrees at 2004m, the radial water jet is respectively completed in the directions of 100m in length and 50mm in diameter, and the injection holes are respectively injected at 100m, 70m and 40m positions for 1-2min. Until the full radial water jet number is completed.
After the completion of the total radial water jet number described above, a fracturing stage is then required to make the selected target layer more directional to fracture and more fracture. Specifically, a fracturing string is first lowered to install a fracturing wellhead. When fracturing, the minimum displacement is adopted firstly, and then the displacement is gradually increased after fracturing, so that the position with the minimum fracturing pressure is achieved. In general, whether the target layer has been fractured can be determined by whether the pressure is rapidly reduced during fracturing. Typically, the displacement at which formation fracture is achieved is the minimum displacement. After the fracturing sand adding is completed, displacing the sand carrying fluid in the radial shaft to the forefront position of the radial shaft by using displacement fluid, wherein the displacement fluid is calculated according to the quantity and the length of radial perforation, and in the embodiment, the radial water jet aperture is 50mm, radial water jet length is 100m, thus total displacement = wellbore displacement + radial well displacement (pi× (0.05/2) 2 X 100 x number of radial flow perforations).
After stopping the pump after fracturing, confirming that the fracturing cracks are closed through pressure drop inflection points appearing on a pressure drop curve, and starting the pump again to increase the displacement for fracturing; and the displacement is increased as much as possible within the allowable range of the well bore and wellhead pressure-proof requirements and the fracturing pump truck so as to fracture new cracks. The method for judging the fracture closure from the inflection point of the pressure drop curve is a method for confirming the fracture closure of the fracture, which is commonly used in the field, and the specific confirmation process is not repeated. Repeating the fracturing process until the preset number of fracturing strips is completed.
After the fracturing is finished, the well is closed, and after the closing of the fracture is confirmed, the liquid discharge is discharged.
Example two
In this embodiment, there is more remaining reserves in the 20 ° and 170 ° directions of a group of reservoir B wells that are organized by a field block, and radial well volume fracturing is performed to fully utilize these reserves. The depth of the oil layer is 2610-2619m, and the thickness of the oil layer is 9m. The early-stage ground stress research result shows that the horizontal maximum main stress direction is 95 degrees and 275 degrees, and the horizontal minimum main stress direction is 5 degrees and 185 degrees because the horizontal maximum main stress direction is perpendicular to the horizontal minimum main stress direction.
The specific technical process comprises the following steps:
in view of the thickness of the target layer being 2610-2619m, the reservoir porosity was 14%, the permeability was 8md, the fracture pressure was 45MPa, the fracture height was 15m, and it was determined from these parameters that the fracture displacement was 3m3/min and the fracture length was 90m.
Secondly, the radial water jet aperture in this example was determined to be 50mm in terms of fracture displacement and fracture length, whereas for an aperture of 50mm, the basic relationship between the number of holes and the thickness of the layers is: for a target layer with the thickness of 3-10m, the number of holes in a shaft along a certain angle with the horizontal minimum main stress direction is not less than 6, and the number of the holes is selected to be consistent between 20 degrees (15 degrees with the horizontal minimum main stress 5 degree direction) and 170 degrees (15 degrees with the horizontal minimum main stress 185 degree direction); in addition, the lowest position of the radial water jet is 2m higher than the bottom boundary of the target layer, and the rest is evenly distributed according to the thickness of the oil and gas layer. In this example, one injection hole was provided at each of the depth wellbore positions 2612m, 2614m, and 2617m of the B-well, and the total number of the injection holes was 6 in the directions of 20 ° and 170 °.
Because the radial well volume fracturing method provided by the invention can be applied to a vertical well produced for a period of time by perforation fracturing, in the spraying process, cement injection is needed to plug a perforated well section for the purpose of extending a fractured fracture along the earlier stage during volume fracturing. The construction process is as follows: and (3) providing a production string in the well, and cementing the lower cementing string with a cement truck pump to plug the interval produced by perforation and fracturing. After the plugged cement is solidified, drilling and sweeping a shaft after the plugging layer is tested to be at least 20MPa qualified so as to ensure that the shaft of the fracturing layer section is smooth; and for a layer of interest that has not been fractured, the layer is not plugged with cement. In this embodiment, the perforated interval needs to be plugged with cement because the B-well was once fractured at the beginning of production.
Subsequently, a radial water jet injection phase is entered. And respectively carrying out directional windowing and radial water jet injection along the directions of 20 degrees and 170 degrees, wherein the length of the radial water jet is 90m. The specific process comprises the following steps: firstly, a special guide device for injection is put into the oil pipe, and a milling tool for running the casing pipe into the continuous oil pipe is used for milling the casing pipe at a position of 2617m at 20 degrees; after the oil layer casing is ground through, a casing grinding and milling tool is started, and then the casing is put into a jet pipeline through a continuous oil pipe; after being sprayed for 100m through the spray pipeline, the holes are cleaned and have no sundries as much as possible.
In the injection process, when the radial water jet injection retreats, the injection is carried out for 1-2 minutes at the preset injection point, so that the rock breaking area at the injection point is enlarged, and the rock breaking area is beneficial to breaking at the later fracturing. The predetermined injection points are selected according to the determined fracturing fracture spacing, and in the embodiment, the fracturing fracture spacing is selected to be 35m, and the injection point positions of 100m, 65m and 30m are selected. That is, the interval between the injection points is 30m, which is consistent with the interval of the fracturing fracture. After injection is completed in a radial wellbore, the injection line is started. The director was rotated to another orientation of 170 deg. and the above-described spraying process was repeated. The radial water jet 90m long and 50mm diameter jet holes are respectively finished in the directions of 2614m20 degrees, 170 degrees and 2612m at 20 degrees and 170 degrees in sequence, and the jet holes are respectively sprayed for 1-2min at the positions of 100m, 65m and 30m.
And then the fracturing stage. Specifically, a fracturing string is first lowered, and a fracturing wellhead is installed. When fracturing, firstly adopting minimum displacement, and gradually increasing the displacement after fracturing so as to reach the position with minimum fracturing pressure; the minimum displacement is the minimum displacement at which formation fracture is achieved. After the fracturing sand adding is completed, displacing sand-carrying fluid in the radial shaft to the forefront position of the radial well by using displacing fluid, wherein the displacing amount is calculated according to the number and the length of radial perforation, and the total displacing amount=the shaft displacing amount+the displacing amount in the radial shaft (pi× (0.05/2) 2×100×the number of holes of the radial flow perforation), and in the embodiment, the radial water jet diameter is 50mm, the radial water jet length is 100m, and the number of holes is 6.
After stopping the pump, confirming that the fracturing crack is closed through a pressure drop inflection point appearing on a pressure drop curve, and starting the pump again for fracturing; and the displacement is increased as much as possible within the allowable range of the well bore and wellhead pressure-proof requirements and the fracturing pump truck so as to fracture new cracks. Repeating the fracturing process until the preset number of fracturing strips is completed.
After the fracturing is finished, the well is closed, and after the closing of the fracture is confirmed, the liquid discharge is discharged.
Example III
In this embodiment, the capacity of a new well group formed by a certain oilfield block after conventional fracturing production is low, and the requirement of economic and effective development cannot be met, so that the volume fracturing experiment of the radial well is performed on the new well C. The depth of the oil layer is 2500-2518m, and the thickness of the oil layer is 18m. The results of the early-stage ground stress study are that the horizontal maximum main stress direction is 80 degrees and 260 degrees on average, and the horizontal minimum main stress direction is 350 degrees and 170 degrees because the horizontal maximum main stress direction is perpendicular to the horizontal minimum main stress direction.
The specific technical process comprises the following steps:
in view of the thickness of the target layer being 2500-2518m, the reservoir porosity being 8%, the permeability being 1md, the fracture pressure being 50MPa, the fracture height being 25m, it was determined from these parameters that the fracture displacement was 4.0m3/min and the fracture length being 150m.
Secondly, the radial water jet aperture in this example was determined to be 50mm in terms of fracture displacement and fracture length, whereas for an aperture of 50mm, the basic relationship between the number of holes and the thickness of the layers is: for a 3-10m thick target layer, not less than 6 holes are formed in the shaft along a certain angle with the horizontal minimum main stress direction, and for a 10-20m thick target layer, not less than 10 holes are formed; for a target layer with a thickness of 20m or more, the number of holes is not less than 12. The well is perforated at 350 degrees and 170 degrees in the horizontal minimum main stress direction, and the number of the wells is consistent; in addition, the lowest position of the radial water jet is 2m higher than the bottom boundary of the target layer, and the rest is evenly distributed according to the thickness of the oil and gas layer. In this example, one injection hole was designed at each of the 2503m, 2506m, 2509m, 2512m, 2515m depth wellbore positions of the C-well, and the total number of injection holes was 10 in the directions of 350 ° and 170 °.
Since the C well is a new well, conventional perforations have not been made, cement plugging of the perforated interval is not required.
Subsequently, a radial water jet injection phase is entered. And respectively carrying out directional windowing and radial water jet injection along the directions of 350 degrees and 170 degrees, wherein the length of the radial water jet is 100m. The specific process comprises the following steps: firstly, a special guide device for injection is put into the casing through an oil pipe, and a milling tool of the casing is put into the casing through a continuous oil pipe at a position 2515m in a direction of 350 degrees; after the oil layer casing is ground through, a casing grinding and milling tool is started, and then the casing is put into a jet pipeline through a continuous oil pipe; after being sprayed for 100m through the spray pipeline, the holes are cleaned and have no sundries as much as possible.
In the injection process, when the radial water jet injection retreats, the injection is carried out for 1-2 minutes at the preset injection point, so that the rock breaking area at the injection point is enlarged, and the rock breaking area is beneficial to breaking at the later fracturing. The predetermined injection points are selected according to the determined fracture spacing, and in this embodiment, the fracture spacing is selected to be 25m, and the injection point positions of 100m, 75m, 50m and 25m are selected. After injection is completed in a radial wellbore, the injection line is started. The director was rotated to another orientation of 170 deg. and the above-described spraying process was repeated. The radial water jet 110m is respectively provided with injection holes with the length of 50mm and the diameter of 50mm in the directions of 2512m350 DEG and 170 DEG, 2509m350 DEG and 170 DEG, 2506m350 DEG and 170 DEG, 2503m350 DEG and 170 DEG in sequence, and the injection holes are respectively provided with multiple injection at the positions of 100m, 75m, 50m and 25m for 1-2min.
And then the fracturing stage. Specifically, a fracturing string is first lowered, and a fracturing wellhead is installed. When fracturing, firstly adopting minimum displacement, and gradually increasing the displacement after fracturing so as to reach the position with minimum fracturing pressure; the minimum displacement is the minimum displacement at which formation fracture is achieved. After the fracturing sand adding is completed, displacing sand-carrying fluid in the radial shaft to the forefront position of the radial well by using displacement fluid, wherein the displacement amount is calculated according to the number and the length of radial perforation, the total displacement amount=the displacement amount of the shaft+the displacement amount in the radial shaft (pi× (0.05/2) 2×100×the number of holes of radial flow perforation), and in the embodiment, the radial water jet flow diameter is 50mm, and the radial water jet flow length is 110m and the number of holes is 10.
After stopping the pump, confirming that the fracturing crack is closed through a pressure drop inflection point appearing on a pressure drop curve, and starting the pump again for fracturing; and the displacement is increased as much as possible within the allowable range of the well bore and wellhead pressure-proof requirements and the fracturing pump truck so as to fracture new cracks. Repeating the fracturing process until the preset number of fracturing strips is completed.
After the fracturing is finished, the well is closed, and after the closing of the fracture is confirmed, the liquid discharge is discharged.
According to the three embodiments, the radial well volume fracturing is realized through the process, and the method has good effects in the well digging of the old well of the low-permeability oil-gas field of the oil-gas field block and the production of the new well of the compact oil-gas field. Practice proves that the radial well volume fracturing method provided by the invention has the advantage that the single well yield is averagely improved by more than 2 times compared with the prior art without the method. In addition, the application of the process is beneficial to flowback after pressing and environmental protection, the single well operation cost and risk are greatly reduced, and the process has outstanding advantages in terms of technology, environment and economy.
The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, the technical solution of the invention can be subjected to a plurality of simple variants, for example, the steps in the method can be combined and used in practical application according to the parameter conditions of the specific target layer. The various possible combinations of the invention are not described in detail in order to avoid unnecessary repetition. Such simple variations and combinations are likewise to be regarded as being within the scope of the present disclosure.
Claims (9)
1. A radial well volume fracturing method, the method comprising the steps of:
step 100: selecting a target layer of a radial fracturing well to be implemented, and determining the horizontal maximum principal stress and horizontal minimum principal stress directions of the target layer;
step 200: determining fracturing displacement and fracturing length; in the step 200, determining the fracturing displacement and the fracturing fracture length by the thickness, porosity, permeability, fracturing pressure, fracture height, and fracturing friction of the target layer;
step 300: determining the number of holes of radial water jet according to the fracturing displacement and the fracturing fracture length in the step 200;
the step 300 specifically includes: the radial water jet flow arranged in different directions has the same number of holes;
the step 300 specifically includes: when the thickness of the target layer is 3-10m, the number of holes of the radial water jet is not less than 6 holes along the horizontal minimum principal stress direction;
when the thickness of the target layer is 10-20m, the number of holes of the radial water jet is not less than 10 holes along the horizontal minimum principal stress direction;
when the thickness of the target layer is more than 20m, the number of holes of the radial water jet is not less than 12 holes along the horizontal minimum principal stress direction;
step 400: performing directional windowing and radial water jet flow along a direction forming a certain angle with the horizontal minimum main stress direction, and executing an injection process until the injection of all radial water jet flow holes is completed;
the certain angle in the step 400 is an included angle of 0-45 degrees with the horizontal minimum main stress direction;
the step 400 further includes: when the radial water jet retreats, jetting for 1-5 minutes at a preset jet point, wherein the position of the preset jet point is determined according to the interval of the fracturing fracture;
step 500: after the spraying process is finished, executing a fracturing process until fracturing of all fracturing stripes is finished;
in the fracturing process in the step 500, if the target layer contains an interval which is already perforated and fractured, plugging the interval which is already perforated and fractured in advance through cement, wherein the plugging position bears the pressure of more than 20 MPa;
the fracturing process in the step 500 specifically includes: when fracturing, the minimum displacement is adopted as the fracturing displacement for fracturing, and the fracturing displacement is gradually increased after fracturing;
the minimum displacement is the displacement with the smallest value in all displacements up to the formation fracture pressure.
2. The radial well volume fracturing method of claim 1, further comprising step 600: closing the well, confirming that the crack is closed, and then discharging the liquid.
3. The radial well volume fracturing method of claim 1, wherein said step 300 specifically comprises:
the diameter of the radial water jet is 50mm.
4. A radial well volumetric fracturing method according to claim 3, wherein the lowest hole site of said radial water jet is arranged at a position above the bottom boundary of said layer of interest by more than 2.0 m.
5. The radial well volumetric fracturing method of claim 4 wherein the remaining radial water jet holes outside of said lowest hole site are evenly distributed in hydrocarbon layer thickness.
6. The radial well volumetric fracturing method of claim 1, wherein the radial water jet has a length of 90-110m.
7. The radial well volume fracturing method of claim 1, wherein said jetting process in step 400 further comprises: a plurality of different orientations are replaced and repeated.
8. The radial well volume fracturing method of claim 1, wherein the fracturing process in step 500 specifically comprises: and after sand adding is completed, displacing sand-carrying fluid in the radial shaft to the forefront position of the radial well by using displacement fluid.
9. The radial well volume fracturing method of claim 1, wherein the fracturing process of step 500 waits for the fracture to close after each fracture is completed before starting the next fracture.
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Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100999990A (en) * | 2006-11-10 | 2007-07-18 | 大庆油田有限责任公司 | Low permeating oil layer vertical crack directional perforating crushing method |
| CN109236257A (en) * | 2018-10-11 | 2019-01-18 | 青岛大地新能源技术研究院 | A kind of radial bore volume fracturing method |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE112011103548T5 (en) * | 2010-10-20 | 2013-08-08 | Exxonmobil Upstream Research Co. | A method of creating a subsurface fracture network |
| CN104912485A (en) * | 2015-06-23 | 2015-09-16 | 北京泰坦通源天然气资源技术有限公司 | Well completion method with shale gas layer radial jetting drilling and volume fracturing combined |
| CN106845043A (en) * | 2017-04-07 | 2017-06-13 | 东方宝麟科技发展(北京)有限公司 | A kind of technological process of shale gas horizontal well refracturing and method for designing |
| CN110374574A (en) * | 2018-04-13 | 2019-10-25 | 中国石油化工股份有限公司 | The method of straight well directional well massive hydraulic fracture control critical eigenvalue complexity |
| CN110761763B (en) * | 2018-07-27 | 2021-10-08 | 中国石油化工股份有限公司 | Horizontal well repeated fracturing method |
-
2020
- 2020-05-07 CN CN202010378600.7A patent/CN113622889B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100999990A (en) * | 2006-11-10 | 2007-07-18 | 大庆油田有限责任公司 | Low permeating oil layer vertical crack directional perforating crushing method |
| CN109236257A (en) * | 2018-10-11 | 2019-01-18 | 青岛大地新能源技术研究院 | A kind of radial bore volume fracturing method |
Non-Patent Citations (3)
| Title |
|---|
| 侯冰等.页岩气储层变排量压裂的造缝机制.《岩土工程学报》.2014,第36卷(第11期),第2149-2152页. * |
| 房平亮等.致密储层低产井重复压裂方式及裂缝参数优化.《科学技术与工程》.2017,第17卷(第24期),全文. * |
| 页岩气储层变排量压裂的造缝机制;侯冰等;《岩土工程学报》;第36卷(第11期);第2149-2151页 * |
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