Staged fracturing transformation process for increasing single well yield of ultra-low permeability reservoir horizontal well

A single-well production, staged fracturing technology, applied in wellbore/well valve devices, wellbore/well components, drilling equipment, etc., can solve the problem of underdeveloped natural fractures, strong heterogeneity, and ultra-low permeability problems such as low reservoir brittleness index, to achieve the effect of reducing operating costs, improving the pertinence of stimulation, and reducing the scale of stimulation

Inactive Publication Date: 2018-11-06
PETROCHINA CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
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AI Technical Summary

Problems solved by technology

[0003] Due to the low brittleness index, relatively few natural fractures, and strong heterogeneity of ultra-low permeability reservoirs, they are different from the “network” fractures formed by volume fracturing of Chang 7 tight oil in the Ordos Basin. According to the seismic test results, the artificial fractures are mainly single transverse fractures, and the formation microseismic response signals are concentrated during the fracturing process, rather than forming "network" fractures. Therefore, the existing volume fracturing cannot be applied to low-permeability oil. Improvement of Single Well Production of Reservoir Horizontal Wells

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  • Staged fracturing transformation process for increasing single well yield of ultra-low permeability reservoir horizontal well

Examples

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Effect test

Embodiment 1

[0030] This example provides a staged fracturing reconstruction process for improving the production of a single well of a horizontal well in an ultra-low permeability reservoir, including determining the fracturing operation according to the characteristics that the natural fractures of the ultra-low permeability reservoir do not develop and the artificial fracture is a single fracture. The displacement is 3-4m 3 / min, and then use the coiled tubing fracturing string for fracturing.

[0031] In view of the low brittleness index of ultra-low permeability reservoirs, the relative lack of natural fractures, and the characteristics of artificial fractures mainly forming single fractures rather than "network" fractures, the fracturing displacement was reduced, and the displacement was reduced from 6 to 8m for volume fracturing. 3 / min reduced to 4m for conventional fracturing 3 / min.

[0032] Coiled tubing 4 under pressure operation method: on the one hand, because the fracturin...

Embodiment 2

[0034] On the basis of Embodiment 1, this embodiment provides a staged fracturing reconstruction process for increasing single-well production of horizontal wells in ultra-low permeability reservoirs, which also includes determining the interval between fractures to be 40-50m.

[0035] According to the downhole microseismic test results under low displacement conditions, the interval between sections is changed from the original 6m 3 / min volume fracturing 80-100m, reduced to 4m 3 40-50m / min under conventional fracturing, the contact area between hydraulic fractures and reservoirs is greatly increased by densely distributed fractures and increasing the number of fracturing stages.

[0036] Wherein, the permeability of the ultra-low permeability reservoir is less than 10 -3 μm 2 .

[0037] If the cracks are not developed, there are 1-2 groups of cracks with an interval of more than 1m.

[0038] In view of the characteristics of low brittleness index (less than 40) and relat...

Embodiment 3

[0040] On the basis of Embodiment 1, this embodiment provides a staged fracturing reconstruction process for increasing the single-well production of a horizontal well in an ultra-low permeability reservoir. The coiled tubing fracturing includes the following steps:

[0041] Step 1) Put the sealing ball 3 into the coiled tubing fracturing string, seat the sealing ball 3 into the ball seat 9, place the coiled tubing fracturing string in the well to be operated, and perform hydraulic sandblasting single shower through the spray gun 8 Hole operation and crack initiation test;

[0042] Step 2) Inject liquid through the annular space to establish a reverse circulation channel, carry the sealing ball 3 out of the ground, and open the channel 10 of the sand mixer;

[0043] Step 3) Through the spray gun 8 and the sand mixer 10 of the coiled tubing fracturing string, inject a high-sand ratio sand-carrying fluid into the well with a displacement of 3-4m 3 / min;

[0044] Step 4) Displa...

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Abstract

The invention provides a staged fracturing transformation process for increasing the single well yield of an ultra-low permeability reservoir horizontal well. The staged fracturing transformation process comprises the steps that according to the characteristics that natural cracks in an ultra-low permeability reservoir are not developed and artificial cracks are single cracks, the fracturing construction displacement is determined to be 3-4 m<3> / min, and then fracturing is conducted through a continuous tubing fracturing pipe string. The traditional technical idea of staged multi-cluster volume fracturing of the ultra-low permeability horizontal well is changed, meanwhile, the intra-segment double-cluster mode in the past is changed into the intra-segment single-cluster mode, the single-segment transformation scale is lowered, the operation cost is lowered, and the transformation pertinence is improved; the segment separation distance is decreased from 80-100 m under 6 m<3> / min volumefracturing in the past into 40-50 m under 4 m<3> / min fracturing, and through dense seam laying and increasing of the number of fracturing transformation segments, the contact area of the hydraulic cracks and the reservoir is greatly increased; and through the matched continuous tubing operation technology, inter-segment fracturing liquid is not sprayed, on the basis of improving the construction efficiency, the formation energy is increased, and yield decreasing is delayed.

Description

technical field [0001] The invention belongs to the technical field of oil recovery technology in oilfields, and in particular relates to a staged fracturing reconstruction technology for improving the production of a single well of a horizontal well in an ultra-low permeability reservoir. Background technique [0002] Coiled tubing fracturing technology is a safe, economical and efficient oilfield service technology. It has been applied in oil and gas fields since the 1990s. It is especially suitable for layer-by-layer fracturing operations and water wells with multiple thin layers and gas layers. Flat well staged fracturing operation. Compared with the traditional hydrojet staged multi-cluster fracturing, after the first stage is completed, it needs to blow out, wash the well, and lift the string to the second stage for fracturing. With the coiled tubing operation technology, the fracturing fluid between stages does not need to be blown out. , On the basis of improving th...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): E21B43/26E21B17/08E21B34/06
CPCE21B17/08E21B34/06E21B43/26
Inventor 张同伍陈文斌张彦军鲜晟杨晓刚邓咸安闫永萍吕昌盛陈强胡超彭长江郭钢
Owner PETROCHINA CO LTD
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