Disclosure of Invention
In view of the above, the invention aims to provide a fracturing and well completion method for controlling the reservoir volume of a horizontal well fracture of an unconventional reservoir. The unconventional reservoir horizontal well fracture reservoir control volume fracturing well completion method provided by the invention is high in recovery rate.
In order to achieve the above object, the present invention provides the following technical solutions:
the invention provides a fracturing and well completion method for controlling reservoir volume of unconventional reservoir horizontal well fractures, which comprises the following steps:
the geological dessert is tightly combined with the engineering dessert, the intervals are finely divided, the single section does not span the layer, and the production increasing measures are differentiated;
reducing the section length, shortening the cluster spacing and closely cutting the reservoir, wherein the section length is 30-50 m, and the cluster spacing is 5-8 m;
pressing open all perforation clusters by using a crack control agent to enable cracks to be communicated longitudinally and transversely to form a super complex three-dimensional crack network;
oil-gas displacement type instant nano fracturing fluid system is adopted to realize oil-water/gas-water displacement in the dynamic expansion fracture network;
high-strength liquid injection and high-strength sand paving are carried out along the horizontal shaft to form integral seepage, and large-scale three-dimensional matrix seepage is established for staged fracturing.
Preferably, when the distance between the perforation clusters is 15-20 m, the production area is controlled to be only near the main seam, and effective displacement does not exist between the seams.
Preferably, the reservoir permeability of the unconventional reservoir horizontal well is less than or equal to 200 nD.
Preferably, each cluster of the perforation clusters is perforated with 5-8 holes, and non-directional perforation is designed according to the length of 0.3m of each cluster of 6 holes, × 60 degrees and × clusters.
Preferably, the oil-gas displacement type instant nano fracturing liquid system comprises nano slick water and nano linear glue, wherein the volume ratio of the nano slick water to the nano linear glue is 2:1 or 3: 2.
Preferably, the sand is quartz sand and low-density ceramsite, the particle size of the quartz sand is 70/140 meshes, and the particle size of the ceramsite is 40/70 meshes, 30/50 meshes or 20/40 meshes.
Preferably, when the sand is paved, quartz sand is paved firstly, and then low-density ceramsite is paved, wherein the low-density ceramsite is used independently in 40/70 meshes, mixed in 40/70 meshes and 30/50 meshes or mixed in 30/50 meshes and 20/40 meshes.
Preferably, the volume ratio of the quartz sand to the ceramsite is 2:8 or 3: 1.
Preferably, during staged fracturing, the new well is mainly subjected to long-acting temporary plugging, and is provided with little bridge plug or no bridge plug; the old well is mainly used for long-acting temporary plugging of the whole well and is not provided with a mechanical packing tool.
Preferably, the control agent for long-acting temporary plugging is degradable biological composite resin, the dosage between clusters is 300-500 kg/time, and the dosage in the seam is 100-300 kg/time.
The invention provides a fracturing and well completion method for controlling reservoir volume of unconventional reservoir horizontal well fractures, which comprises the following steps: the geological dessert is tightly combined with the engineering dessert, the intervals are finely divided, the single section does not span the layer, and the production increasing measures are differentiated; reducing the section length, shortening the cluster spacing and closely cutting the reservoir, wherein the section length is 30-50 m, and the cluster spacing is 5-8 m; pressing open all perforation clusters by using a crack control agent to enable cracks to be communicated longitudinally and transversely to form a super complex three-dimensional crack network; oil-gas displacement type instant nano fracturing fluid system is adopted to realize oil-water/gas-water displacement in the dynamic expansion fracture network; high-strength liquid injection and high-strength sand paving are carried out along the horizontal shaft to form integral seepage, and large-scale three-dimensional matrix seepage is established for staged fracturing.
The invention inherits the integrated concept of geological oil reservoir, fracturing reconstruction and mining mode, shortens the interval of the section clusters, increases the fracture density and improves the sand adding strength (more than or equal to 3.0 m)3The production method comprises the following steps of (m) realizing pump-stop-free layer transfer through long-acting temporary plugging, pressing open perforation clusters by 100 percent, reducing or even not using bridge plugs (greatly improving the construction efficiency, wherein daily construction layer sections can be improved from 3 sections to 5-6 sections), strengthening the synchronization of crack control, energy supplement and imbibition displacement (using instant nano fracturing fluid), realizing 'full' recovery of reserves through seam control matrix units, greatly reducing the driving pressure difference required by oil and gas in the matrix, and greatly increasing the movable reserves; the fracture control volume fracturing can improve the single well recovery ratio by 25-40%, the interval design of the conventional volume fracturing segment cluster has the advantages that the effective control area is only near the main fracture, no effective displacement exists between the fractures, the fracture control volume fracturing increases the fracture control area by reducing the interval of the segment cluster, integrally reduces the production saturation, forms a connected control area, greatly increases the yield after the fracturing, realizes 'full' recovery,the driving pressure difference required by oil gas in the matrix is greatly reduced, and the movable reserve is greatly increased. The data of the embodiment well shows that the unconventional reservoir horizontal well fracture controlled-reservoir volume fracturing well completion method adopted by the invention can improve the average tested yield by more than 50% after pressing and improve the average accumulated yield by more than 30%.
Detailed Description
The invention provides a fracturing and well completion method for controlling reservoir volume of unconventional reservoir horizontal well fractures, which comprises the following steps:
the geological dessert is tightly combined with the engineering dessert, the intervals are finely divided, the single section does not span the layer, and the production increasing measures are differentiated;
reducing the section length, shortening the cluster spacing and closely cutting the reservoir, wherein the section length is 30-50 m, and the cluster spacing is 5-8 m;
pressing open all perforation clusters by using a crack control agent to enable cracks to be communicated longitudinally and transversely to form a super complex three-dimensional crack network;
oil-gas displacement type instant nano fracturing fluid system is adopted to realize oil-water/gas-water displacement in the dynamic expansion fracture network;
high-strength liquid injection and high-strength sand paving are carried out along the horizontal shaft to form integral seepage, and large-scale three-dimensional matrix seepage is established for staged fracturing.
In the invention, when the interval of the fractures of the unconventional reservoir horizontal well is preferably 15-20 m, the mining area is controlled to be only near the main fracture, and no effective displacement exists between the fractures; the seam distance is reduced, the seam control area is increased, the production saturation is integrally reduced, and a connecting piece control area is formed; the lower the permeability is, the more the reduction of the gap distance is beneficial to increasing the yield after pressing; when K is 0.1mD, the "seam control reserve" is increased by 2.2 and 3.5 times when the seam spacing is reduced to 20m and 10 m.
In the present invention, the lower the permeability, the more the number of cracks required, and the higher the cumulative production and the extraction degree.
In the invention, the permeability of the horizontal well reservoir of the unconventional reservoir is preferably less than or equal to 200 nD.
In the invention, when the permeability is reduced to be below 0.1mD, the starting pressure gradient of the fluid flowing from the matrix to the fracture is increased, and under the same flowing distance, the permeability is reduced by 1 order of magnitude, and the required flowing pressure difference is increased by 1 order of magnitude; due to the high start-up pressure differential, the distance over which the fluid can flow at the same time is short, and the effective volume for fluid flow is limited.
The method reduces the section length, shortens the cluster spacing and closely cuts the reservoir, wherein the section length is 30-50 m, and the cluster spacing is 5-8 m.
In the invention, each cluster is preferably provided with 5-8 holes, and non-directional perforation is designed according to the hole density of 6 holes × 60 degrees × 6 holes/foot.
The invention preferably utilizes the degradable biological composite resin crack control agent to press open all perforation clusters, so that the cracks are longitudinally and transversely communicated to form a super complex three-dimensional crack network. The source of the degradable biological composite resin crack control agent is not particularly limited in the present invention, and those known to those skilled in the art can be used.
The invention adopts an oil-gas displacement type instant nano fracturing fluid system to realize oil-water/gas-water displacement in a dynamic expansion fracture network.
In the invention, the instant nano fracturing liquid system comprises nano slick water and nano linear glue, and the volume ratio of the nano slick water to the nano linear glue is preferably 2:1 or 3: 1. The source of the nano slippery water and the nano linear glue is not particularly limited in the invention, and commercially available products well known to those skilled in the art can be adopted.
The invention forms integral seepage along the high-strength liquid injection and high-strength sand paving of the horizontal shaft, establishes large-scale three-dimensional matrix seepage and carries out staged fracturing.
In the invention, the sand is preferably quartz sand and low-density ceramsite, the particle size of the quartz sand is preferably 70/140 meshes, and the particle size of the ceramsite is preferably 40/70 meshes, 30/50 meshes or 20/40 meshes. In the present invention, 40/70 meshes means 40 meshes and 70 meshes, 30/50 meshes means 50 meshes and 30 meshes, and 20/40 meshes means 20 meshes and 40 meshes.
In the invention, when the sand is paved, the quartz sand is preferably paved, and then the low-density ceramsite is preferably used independently in 40/70 meshes, mixed in 40/70 meshes and 30/50 meshes or mixed in 30/50 meshes and 20/40 meshes.
In the invention, the volume ratio of the quartz sand to the ceramsite is preferably 2:8 or 3: 1.
In the invention, during the staged fracturing, the long-acting temporary plugging is preferably selected as the main part of the new well, few bridge plugs or no bridge plugs are used, and the long-acting temporary plugging of the whole well is preferably selected as the old well.
In the invention, the crack control agent used for long-acting temporary plugging is preferably a biological composite resin, the inter-cluster dosage is preferably 300-500 kg/time, and the intra-crack dosage is preferably 100-300 kg/time.
For further illustration of the present invention, the unconventional reservoir horizontal well fracture-control volume fracturing completion method provided by the present invention is described in detail below with reference to examples, but they should not be construed as limiting the scope of the present invention.
The idea of controlling the volume fracturing of the oil reservoir by hydraulic fractures is as follows:
1. seam spacing for enhanced crack containment
FIG. 1 shows the start pressure gradient of different permeabilities in different regions, FIG. 2 shows the percolation distance of different start pressure gradients, FIG. 3 shows the relationship between the percolation distance and the permeability of a fluid under different driving pressure differences, as can be seen from FIGS. 1 to 3, the permeability is reduced to less than 0.1mD, and the start pressure gradient of the fluid flowing from a substrate to a fracture is increased; at the same flow distance, the permeability is reduced by 1 order of magnitude, and the required flow pressure difference is increased by 1 order of magnitude; due to the high start-up pressure differential, the distance over which the fluid can flow at the same time is short, and the effective volume for fluid flow is limited.
When the gap between the seams is large, the effective control area is only near the main seam, and no effective displacement exists between the seams; the seam spacing is reduced, the seam control area is increased, the saturation is integrally reduced due to production, and a connecting piece control area is formed.
The lower the permeability is, the more the reduction of the gap distance is beneficial to increasing the yield after pressing; when K is 0.1mD, the "seam control reserve" is increased by 2.2 and 3.5 times when the seam spacing is reduced to 20m and 10 m.
And simulating the matching parameters of the reservoir condition fracture control interval and the extraction degree by combining a fracture expansion experiment and reservoir fluid parameters and based on a shortest matrix seepage theory and an interpeak stress interference theory, thereby realizing scientific and economic seam distribution.
2. Number of cracks for strengthening crack control
When the permeability of the reservoir is less than or equal to 0.1md, the lower the permeability of the reservoir is, the more fractures are needed for controlling the reserves by using the well, and the higher the accumulated yield and the extraction degree are.
3. Perforation optimization for enhanced fracture control
FIG. 4 is a pictorial representation of a 6 hole × 60 degrees × 6 hole/foot per cluster hole density design, with 5-8 holes per cluster and 1 foot cluster long as the choice for most perforation options over long-term practice, studies have also shown that for non-directional perforations, the × 60 degrees × 6 hole/foot per cluster 6 hole density design has the highest probability (68%) of locating at least two blastholes in the low stress arc of the surrounding wellbore, combined with greater formation connectivity, less near wellbore tortuosity, and relatively lower construction pressure than other designs.
4. Staged fracturing mode for strengthening crack reservoir control
The long-acting temporary plugging of a new well is mainly carried out, and a bridge plug is reduced or not;
the whole old well is long-acting temporarily blocked.
5. Whole course high strength sand adding
Fig. 5 is a graph showing the variation of the number of fracturing sand meshes of the pilaster basin, and as can be seen from fig. 5, the number of 100 fracturing sand meshes of the pilaster basin is dominant from 2015 to 2016, wherein 2016 is already more than 50%, and 20-40 fracturing sand accounts for a sharp decrease.
FIG. 6 is a graph showing the number change of DJ-Niobrara fracturing sand, and it can be seen from FIG. 6 that the DJ-Niobrara 40/70 fracturing sand gradually occupies the dominant position, the 2016 ratio reaches 70%, and the 20/40 fracturing sand ratio also sharply decreases.
With reference to fig. 5 to 6, it can be seen that the present invention aims at a horizontal section length of 1500 to 2000m, fracturing stages of 40 to 60 stages (240 to 360 clusters), sand addition amount per single well is set to 4500 to 10000 tons, and sand addition strength reaches 2.0 to 4.0m3/m。
6. Fracture reservoir control volume fracturing optimization design
1) Subdividing small layers, finely segmenting, optimizing perforation positions and process measures
The method is characterized by integrating the logging quality of a horizontal section (high gamma GR, high acoustic AC and low density DEN), the reservoir quality (high organic carbon content TOC, high porosity POR, high gas content or gas logging all hydrocarbon), the compressibility (fracture fractal dimensional derivative representing the complexity of artificial fracture, the lower the value, the better the compressibility and the more complex the fracture), finely dividing small layers in the longitudinal direction, and enabling a single section not to span the small layers.
The perforation position selection not only comprehensively considers the logging quality, the reservoir quality and the compressibility, but also considers the factors of rupture pressure increment caused by three-way stress and interpeak interference, matching of perforation and productivity and the like, reduces the difference of opening of perforation clusters in the section, realizes uniform liquid feeding, and effectively forms seams.
And each section of targeted technological measures is selected according to the compressibility evaluation value.
2) Optimizing cluster spacing
Table 1 shows recommended values for the interval between the clusters of the oil and gas permeable reservoirs of different pores.
TABLE 1 recommendation values for interval between different pore-permeable oil and gas reservoir clusters
gas
|
|
|
|
|
K(md)
|
φ
|
U(mpa.s)
|
Ct
|
space(m)
|
0.0003
|
0.08
|
0.023
|
1.24E-02
|
1.14E+00
|
0.003
|
0.08
|
0.023
|
1.24E-02
|
3.59E+00
|
0.01
|
0.08
|
0.023
|
1.24E-02
|
6.56E+00
|
0.1
|
0.08
|
0.023
|
1.24E-02
|
2.08E+01
|
0.2
|
0.08
|
0.023
|
1.24E-02
|
2.94E+01
|
0.3
|
0.08
|
0.023
|
1.24E-02
|
3.59E+01
|
1
|
0.08
|
0.023
|
1.24E-02
|
6.56E+01
|
2
|
0.08
|
0.023
|
1.24E-02
|
9.28E+01
|
oil
|
|
|
|
|
0.001
|
0.1
|
1.623
|
1.20E-03
|
7.10E-01
|
0.10
|
0.1
|
1.623
|
1.20E-03
|
7.10E+00
|
1.00
|
0.1
|
1.623
|
1.20E-03
|
2.25E+01
|
10.00
|
0.1
|
1.623
|
1.20E-03
|
7.10E+01 |
Fig. 7 is a graph showing the relationship between gas well permeability and cluster spacing, and fig. 8 is a graph showing the relationship between oil well permeability and cluster spacing, and it can be seen from fig. 7 to 8 that the lower the permeability, the smaller the cluster spacing design, and the easier the matrix seepage is to be established.
3) Preferred fracturing fluids are: nanometer slickwater and nanometer linear glue
Fig. 9 is a comparison graph of the acting distance between the conventional slickwater and the nano slickwater, and fig. 10 is a comparison graph of the absorption between the conventional slickwater and the nano slickwater, and it can be seen from fig. 9-10 that the nano slickwater and the nano linear glue have good application effect, large acting distance and small absorption effect.
The initial 18-month yield of the nano slickwater and the nano linear rubber is obviously superior to that of the conventional slickwater, the adsorption of a reservoir can be reduced, the gas-water replacement is promoted, the functions of nano materials are exerted, and the yield of a single well is improved. And the fracturing fluid consisting of the nano slickwater and the nano linear glue does not need to be prepared, and a blending vehicle and a buffer tank are not needed.
The volume ratio of the nano slickwater to the nano linear glue is 2:1 or 3: 1.
4) Proppant optimization-strength and particle size selection
In the past, the proppant is preferable, only the closing pressure is considered, the actual effective stress of the proppant is neglected, the selection strength is too high, and the cost is increased too much. In the invention, the selection of the propping agent is determined by taking actual stress as a principle.
Initial stage after pressing: effective pressure ═ closing pressure (minimum principal stress) + fracture deformation stress-pump-stop pressure-hydrostatic column pressure
The production process comprises the following steps: effective pressure ═ closure pressure (minimum principal stress) + fracture deformation stress-bottom hole flow pressure
Table 2 shows the performance parameters of different proppant types, fig. 11 shows the stress analysis comparison graph of the proppant for the vertical well and the horizontal well, and it can be known from table 2 and fig. 11 that it is feasible to use quartz sand instead of medium-density high-strength ceramsite and high-strength ceramsite.
Through large-scale fracturing transformation, the yield is increased, the stress of the propping agent is reduced, the horizontal well is better than the vertical well, and the effective pressure of the propping agent of the horizontal well is only 50-60% of that of the vertical well. The prior preferred (69MPa closing pressure) for the propping agent is higher than the actual stress (16-25 MPa).
Table 2 performance parameters for different proppant types
Taking the M6004 well as an example, consider the proppant effective pressure: the depth of the middle part of the reservoir is 3900m, and the closing stress is 62 MPa. Table 3 shows the results of the experiment, which indicates that the actual stress of the proppant is much lower than 62 MPa.
Table 3 proppant effective pressure measurements
Phases
|
Effective rate of pressure increase
|
Time of action
|
①
|
0.1334MPa/d(7.5MPa-16.2MPa)
|
60d
|
②
|
0.0556MPa/d(16.2MPa-21.34MPa)
|
180d
|
③
|
0.056MPa/d(21.3MPa-20.5MPa)
|
240d |
Table 4 shows the prediction table of the fracture width of the proppant pack with different mesh sizes, and fig. 12 shows the schematic diagram of the proppant pack with different mesh sizes for the multi-scale fracture, as can be seen from table 4 and fig. 12, the particle size of the natural quartz sand is 70/140 mesh, 40/70 mesh, 30/50 mesh or 20/40 mesh. The 70/140 mesh silt acts to increase fracture complexity for dynamic steering. By researching the construction pressure conditions of 70/140-mesh silt and 40/70-mesh quartz sand, under the condition that the ratio of 70/140-mesh silt is respectively 50%, 75% and 60%, the pressure curve at the sand adding stage continuously fluctuates in a small range, which shows that a typical small transverse cutting seam develops, and the ESRV is obviously increased; the continuous sand adding of 70/140 mesh silt and 30/50 mesh silt can effectively open and fill the weak surface seam. From the above, the conventional knowledge is overturned by the functions of 70/140-mesh silt in dynamic steering, crack complexity improvement, ESRV increase and effective sand blockage reduction.
Fig. 13 is a schematic diagram of dynamic steering action of different ratios of 70/140 mesh silt under different well numbers and different sections, and it can be known from fig. 13 that 70/140 mesh silt has good grinding, filtration reduction and dynamic steering actions, and continuous linear sand addition has higher fracture complexity, wider sweep range and larger ESRV than that obtained by segment sand addition.
In the invention, when the sand is paved, 70/140-mesh natural quartz sand is paved, 40/70-mesh and 30/50-mesh natural quartz sand are paved in sequence, and finally 20/40-mesh natural quartz sand is used for sealing.
TABLE 4 fracture Width prediction Table for proppant pack with different mesh numbers
5) Optimized long-acting temporary plugging agent
Adopts degradable biological composite resin high-performance temporary plugging material.
For multi-stage fracturing in an unconventional horizontal well section, calculating the friction resistance of the holes and the opening number of the holes in the fracture and the fracture extension process in real time to judge the opening number and the fracture form of the fractures, determining the sand adding concentration at different time points, and calculating the final input dosage of the temporary plugging agent.
Table 5 shows the relationship between the perforation and the optimal displacement, Table 6 shows the relationship between the perforation and the displacement, the differential pressure inside and outside the perforation and the number of holes designed, FIG. 14 shows a single-hole displacement Q-Pf curve, and FIG. 15 shows Q-NminCurves, FIG. 16 is Q-NmaxCurve line.
TABLE 5 relationship of perforation to optimal Displacement
TABLE 6 relationship between perforation and discharge, differential pressure inside and outside perforation and design hole number
In the field application case:
example 1: high-strength sand adding of reduction section, cluster spacing, oil well nano fracturing fluid and whole-process quartz sand
The rest of the Songliao basin is supported by dense oil, the distance between a shortening section and a cluster is shortened, the interference between seams is increased, and a complex crack is formed;
area of thickened oil left in Songliao basin: 10000km2
Oil layer burial depth: 1850 to 2600m
Oil layer thickness: 2 to 10m (maximum thickness 40m)
Single well production: 0.5 to 3t/d, 20t/d at the maximum
Physical properties: the porosity is 6-10%, and the permeability is 0.01-1 mD
Crude oil Properties: the density is 0.8 to 0.86g/cm3Viscosity: 3 to 15mPa · s
The formation pressure coefficient is 0.97-1.06
The superior source and reservoir configuration relationship is the key to the formation of the remaining dense oil
The remaining oil layer is stored up and down: source to reservoir proximity
A hydrocarbon source rock: qingyi lake Xiang mudstone
Reservoir bed: four-section delta sand body
And (3) supporting the residual oil layer (the thickness of the oil layer is 4.2m, the porosity is 13-16%, and the permeability is 1mD), actually drilling the horizontal section 2660m, and explaining the oil layer 1158.6 m.
The well adopts a casing fracturing, fast drilling bridge plug and temporary plugging segmented flow limiting fracturing process (11 segments 332 clusters are designed), and nanometer fracturing fluid (slickwater: linear glue: 3:2) with the total amount of 59608.0m is squeezed into the well3Adding 5084m of coated quartz sand3。
Fig. 17 is a curve for obtaining yield by post-pressure drainage, and it can be seen from fig. 17 that a large increase in production is achieved by the completion method provided by the present invention.
Example 2: fine subsection hole distribution and targeted fracturing process
JY52-6 HF-subdivision small layer, fine subsection hole distribution, one section and one strategy
Table 7 shows JY52-6 HF-fine-segment small layer and fine segmented hole distribution data, and as can be seen from Table 7, the structure is complex, the burial depth is increased (2883-3861 m), and the span of the layer passing through is large (layer ① - ⑨ and Jiancao ditch).
TABLE 7 JY52-6 HF-subdivision small layer, fine segment hole distribution data
Number of well
|
Structure of the device
|
Horizon of traversal
|
Vertical depth (m)
|
Horizontal segment length (m)
|
Number of stages
|
5HF
|
Wujiang nose
|
① - ⑨ turbid sand
|
3105-3200
|
1100.38
|
17
|
6HF
|
White horse syncline
|
④-⑧
|
3397-3647
|
1056
|
17
|
8HF
|
Horizontal bridge back-off slope
|
③
|
2883-3011
|
1585.55
|
22
|
69-2HF
|
Syncline of water-lifting rock
|
① - ⑦ Jiancao trench
|
3502-3722
|
1574
|
24
|
81-2HF
|
Back slope of coke-rock dam
|
① - ⑨ Jiancao trench
|
2968-3861
|
1917
|
28
|
60-5HF
|
Syncline of stone door
|
①~③
|
3231-3816
|
1742
|
25 |
TABLE 8 comparative well production data
The unconventional reservoir horizontal well fracture control volume fracturing well completion technology inherits the integrated concept of geological oil reservoir, fracturing modification and exploitation modes, shortens the cluster spacing, increases the fracture density, and improves the sand adding strength (more than or equal to 2.0 m)3And/m), realizing non-stop pumping and layer transfer through long-acting temporary plugging, pressing open perforation clusters by 100 percent, reducing or even not using bridge plugs (greatly improving the construction efficiency, the daily construction layer section can be improved from 3 sections to 5-6 sections), strengthening the synchronization of crack control and storage, energy supplement and imbibition displacement, using instant nano fracturing fluid, realizing 'full' recovery through a seam control matrix unit, greatly reducing the driving pressure difference required by natural gas in the matrix, and greatly increasing the movable reserve.
The fracture volume control fracturing can improve the single well recovery ratio by 25-40%.
The current volume fracturing cluster space design is large, the effective control area is near the main seam, and no effective displacement exists between the seams; the seam-controlled volume fracturing increases the seam-controlled area by reducing the cluster spacing, and the production saturation is reduced integrally to form a connected control area, which is beneficial to increasing the yield after fracturing.
Compared with the existing volume fracturing, the test yield after the crack volume control fracturing can be averagely improved by more than 50 percent, and the accumulated yield can be averagely improved by more than 30 percent.
The foregoing is merely a preferred embodiment of the invention and is not intended to limit the invention in any manner. It should be noted that, for those skilled in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be construed as the protection scope of the present invention.