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CN-121993133-A - Method and device for fracturing casing-variable well in layering manner

CN121993133ACN 121993133 ACN121993133 ACN 121993133ACN-121993133-A

Abstract

The invention belongs to the technical field of oilfield development, and particularly relates to a casing variable well layered fracturing method and device, which are used for carrying out well dredging operation on a selected layered fracturing well, measuring variable diameter information through a well logging technology if the well dredging operation is blocked, judging that fracturing cannot be carried out if the variable diameter information is primary variable diameter, carrying out layered fracturing through a conventional tool if the variable diameter information is tertiary variable diameter, carrying out small-diameter layered fracturing operation if the variable diameter information is secondary variable diameter, carrying out first-stage > second-stage > third-stage of variable diameter severity, carrying out the small-diameter layered fracturing operation according to geological layering, putting a combined tool into a position above a casing variable point, putting the combined tool into a position corresponding to a fracturing target layer, determining optimal displacement, carrying out layered reconstruction on the multi-layer fracturing target layer by adopting different fracturing tools according to different variable diameter degrees of the casing variable well.

Inventors

  • HE ZENGJUN
  • LU YUFENG
  • ZHANG WENJIN
  • SONG CHENGLI
  • WANG GUOCHUN

Assignees

  • 中国石油天然气股份有限公司

Dates

Publication Date
20260508
Application Date
20241104

Claims (10)

  1. 1. The sleeve-changing well layering fracturing method is characterized by comprising the following specific steps of: selecting a layered fracturing well; performing well dredging operation on the selected layered fracturing well, and measuring the reducing information through a logging technology if the well dredging meets resistance; If the reducing information is primary reducing, judging that the fracturing cannot be performed, if the reducing information is tertiary reducing, performing layering fracturing through a conventional tool, and if the reducing information is secondary reducing, performing small-diameter layering fracturing operation; The small-diameter layered fracturing operation is carried out according to the geological layering launching combined tool, the combined tool is launched into a position above the sleeve change point, the combined tool is launched into a position corresponding to a fracturing target layer, and then the optimal displacement is determined.
  2. 2. The method of casing string fracturing according to claim 1, wherein said determining the optimal displacement further comprises the steps of: Determining a fracturing stress difference and a perforation throttling pressure difference, wherein the determining of the fracturing stress difference comprises the steps of determining that the average minimum horizontal main stress of each fracturing target interval is F a and the average minimum main stress of each interlayer interval is F b according to logging data, and taking F amix as a basic value, and taking F a -F amix or F b -F amix as the fracturing stress difference.
  3. 3. The method of casing string fracturing according to claim 2, wherein determining the hole restriction differential pressure comprises determining that the hole restriction differential pressure generated by the combination tool II at different fracturing target layers and at different displacements is F c according to the hole diameter, the hole number and the displacement.
  4. 4. A casing string fracturing method according to claim 3, characterized in that the acquired F a -F amix and F b -F amix are compared with the acquired F c to determine an optimal displacement, which is the displacement at which (F b -F amix ) mix ＞F c ＞(F a -F ami ) max .
  5. 5. The method of casing-changing well layering fracturing according to claim 4, wherein the determining of the optimal displacement further comprises the steps of determining a starting displacement, wherein the starting displacement is L mix for fracturing each fracturing target layer in the local area, the starting displacement is L mix m 3 /min as a basic value, bm 3 /min is used as a step size to be increased, and finally the difference between F c and F a -F ami ) max under the displacement is determined according to the step size to be increased on the basis of the starting displacement, and if F c ＞(F a -F ami ) max under the displacement of L mix +NB)m 3 /min is F c ≤(F a -F ami ) max under the displacement of L mix +(N－1)B)m 3 /min, the optimal displacement is (L mix +NB)m 3 /min).
  6. 6. The method of casing string fracturing according to claim 5, wherein the well bore is measured by 40 arm well bore imaging well bore technique.
  7. 7. A casing string fracturing device is characterized by being suitable for a casing string fracturing method according to any one of claims 1-6, comprising a conventional tool and a combination tool, wherein the conventional tool comprises a small-diameter packer (1) and a conventional sand blaster (2), the small-diameter packer and the conventional sand blaster (2) are alternately arranged, the small-diameter packer (1) is arranged at a mudstone interval, and the conventional sand blaster (2) is arranged at a fracturing objective interval.
  8. 8. The variable well casing and separate layer fracturing device comprises a conventional packer (3) and small-diameter sand blasters (4), wherein the conventional packer (3) is a first combination tool, the small-diameter sand blasters (4) are a second combination tool, the conventional packer (3) is arranged at a position, close to an uppermost fracturing target layer, of a mudstone section, and M small-diameter sand blasters (4) are arranged at the lower end of the conventional packer (3) in series.
  9. 9. The casing string fracturing device of claim 8, wherein the value of M corresponds to the number of corresponding well fracturing layers of interest.
  10. 10. The casing string fracturing device according to claim 8, wherein the tail of the lowest-diameter sand blaster (4) is sequentially connected with an oil pipe and a plug (5).

Description

Method and device for fracturing casing-variable well in layering manner Technical Field The invention belongs to the technical field of oilfield development, and particularly relates to a method and a device for fracturing a set of variable well in a layered manner. Background The problems of frequent casing change well caused by long development time, long water injection time and the like of the land old oil field are that various fracturing measures cannot be normally implemented, so that partial oil layers cannot be effectively used, and reserve loss is caused. The current well fracturing technology for the sleeve transformer mainly comprises technical means of large repair and sleeve taking, sleeve expanding, sleeve repairing, sidetracking, small-diameter packer and the like, but the working procedure is complex, the cost is high, partial well sleeve damage positions are broken in an oil layer, the large repair cannot be repaired, and the geological reserves have no effective submerging means due to well condition problems. In recent years, layering is realized by adopting a mode of adding high-pressure temporary plugging agents for many times by a chemical method, and the temporary plugging agents are high in input amount, high in cost and not up to the standard in benefit digging. Meanwhile, due to the fact that part of the sleeve variable well is small in diameter, the conventional small-diameter packer (with the outer diameter of 95 mm) for the oil field cannot be put below the sleeve variable point of less than 95mm for effective layering, and aiming at the factors, the more serious sleeve variable well (with the inner diameter of less than 95 mm) is formed, and the conventional fracturing technology does not exist. Disclosure of Invention Aiming at the problems, the invention provides a sleeve-type well-changing layering fracturing method, which comprises the following specific steps: selecting a layered fracturing well; performing well dredging operation on the selected layered fracturing well, and measuring the reducing information through a logging technology if the well dredging meets resistance; If the reducing information is primary reducing, judging that the fracturing cannot be performed, if the reducing information is tertiary reducing, performing layering fracturing through a conventional tool, and if the reducing information is secondary reducing, performing small-diameter layering fracturing operation; The small-diameter layered fracturing operation is carried out according to the geological layering launching combined tool, the combined tool is launched into a position above the sleeve change point, the combined tool is launched into a position corresponding to a fracturing target layer, and then the optimal displacement is determined. Further, the determining the optimal displacement further comprises the steps of: Determining a fracturing stress difference and a hole throttling pressure difference, wherein the determining of the fracturing stress difference comprises the steps of determining that average minimum horizontal main stress of each fracturing target interval is Fa and average minimum main stress of each interlayer interval is Fb according to logging data, and taking Famix as a basic value, and taking Fa-Famix or Fb-Famix as the fracturing stress difference. Further, the determining the hole throttling pressure difference comprises the steps of determining the hole throttling pressure difference generated by the second combined tool at different fracturing target layers and at different displacements to be Fc according to the hole diameter, the hole number and the displacement. Further, the acquired Fa-Famix and Fb-Famix are compared with the acquired Fc to determine an optimal displacement, which is the displacement at which (Fb-Famix) mix > Fc > (Fa-Fami) max. Further, the method for determining the optimal displacement further comprises the steps of firstly determining a starting displacement, wherein the starting displacement is Lmix of a local area for fracturing each fracturing target layer, taking starting displacement Lmixm/min as a basic value, increasing by taking Bm3/min as a step length, finally increasing on the basis of the starting displacement according to the step length, determining a difference value between Fc and (Fa-Fami) max under the displacement, and if Fc (Fa-Fami) max under the displacement of (Lmix+NB) m3/min is greater than Fc (Fa-Fami) max under the displacement of (Lmix+N-1) B) m3/min, and the optimal displacement is (Lmix+NB) m3/min. Further, the well diameter is measured by a 40 arm well diameter imaging well logging technique in the well logging technique. The invention further provides a casing variable well layered fracturing device which is suitable for the casing variable well layered fracturing method in any one of the above steps, and the casing variable well layered fracturing device comprises a conventional tool and a combination