CN105089605A - Borehole construction method and method for hydraulic fracturing by using borehole - Google Patents
Borehole construction method and method for hydraulic fracturing by using borehole Download PDFInfo
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- CN105089605A CN105089605A CN201410215081.7A CN201410215081A CN105089605A CN 105089605 A CN105089605 A CN 105089605A CN 201410215081 A CN201410215081 A CN 201410215081A CN 105089605 A CN105089605 A CN 105089605A
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Abstract
The invention discloses a borehole construction method and a method for hydraulic fracturing by using the borehole. The method comprises the following steps: a circular common borehole is built in a target stratum to be fractured; and one part of the common borehole is transformed, so that the part has a noncircular section. The invention further provides a method for hydraulic fracturing by using a special-shaped borehole; and the method comprises the following steps: the special-shaped borehole is built in the fractured target stratum through the borehole construction method; and the special-shaped borehole is used for performing the hydraulic fracturing. By using the borehole construction method for hydraulic fracturing, the special-shaped borehole having the advantages of better controlling the crack initiation direction and needing lower cracking stress can be manufactured.
Description
Technical field
The invention belongs to petroleum works technical field, particularly relate to a kind of building method of well and a kind of method utilizing well to carry out fracturing.
Background technology
Fracturing is the well production increment measure of an extensive use, plays key effect to improving oil recovery factor and improving the economy of exploiting unconventionaloil pool Tibetan.Fracturing, by the fracturing fluid pressurization in pit shaft, makes rock breakdown produce crack, and proppant is clamp-oned crack prevention closing up of cracks, thus makes these cracks become the seepage channel of formation fluid.
Existing hydraulic fracturing technology carries out in the well of common circular cross-section.Generally that perforation is carried out to formation at target locations before pressure break.The borehole wall forms the duct on target penetration stratum, using this duct as the basis of fracture initiation and extension.Then carry out pit shaft packing, pump into fracturing fluid and pressurize and carry out pressure break.Conventional perforating methods comprises perforating gun perforation and jet perforation two kinds.There are some defects separately in these two kinds of perforating methods:
1) perforating gun perforating methods is the directed high-temperature high-pressure jet-flow pore-creating utilizing charge explodes to produce.Therefore, duct surrounding formation blocking is likely caused.Meanwhile, because perforating gun diameter must be less than pit shaft internal diameter ability lower going-into-well cylinder smoothly, therefore cause the distance of perforating bullet in different directions and shaft in wall to differ, cause the perforating quality of shaft in wall all directions inconsistent;
2) jet perforating methods, utilizes the liquid jet of high-pressure injection to penetrate and wears the borehole wall and stratum, form duct in the earth formation.This method, after duct is formed, can produce eddy current in liquid jet front end, hinders perforation to reach desired depth, and the degree of depth in formed duct can be made to broaden, be unfavorable for that top, duct stress is concentrated, and the crack affected in follow-up fracturing process generates and extends.
The common well adopting these existing perforating methods above-mentioned to construct can not the crack initiation direction of good control critical eigenvalue, and needs very large initial cracking pressure.
Summary of the invention
For the problems referred to above, the present invention proposes a kind of building method of the well for fracturing, described method comprises the steps: that the formation at target locations carrying out pressure break builds circular common well; A part in described common well is transformed into there is non-circular cross section.
Preferably, described non-circular cross section is ellipse, rectangle or date core shaped.A part for the edge contour of these shapes or manifold radius of curvature, be less than the radius of same area circle.When applying certain waterpower pressure in well inside, at the borehole wall position that these radius of curvature are less, concentrate owing to can there is stress, therefore, larger tensile stress will be born in the position less in described radius of curvature.And the position that radius of curvature is less, the tensile stress of bearing is larger, and therefore, the position that radius of curvature is less can more easily by pressure break.
Preferably, a part in described common well is transformed into and there is non-circular cross section and form special-shaped well, described special-shaped well comprise be arranged on described common well the borehole wall on, and along at least two borehole wall conduits that the axis of described common well is offered, wherein said borehole wall conduit points to the bearing of trend of fracturing fracture.
Preferably, the radius of curvature of the end of described borehole wall conduit is set to 0.02 to 0.15 times of the radius of curvature of described common well.
Preferably, the radius of curvature of the end of described borehole wall conduit is 3mm to 10mm.
Preferably, the width of described borehole wall conduit and the ratio of the degree of depth are 1:5 to 1:3, and the width of described borehole wall conduit is 15mm to 30mm, and the degree of depth is 45mm to 300mm.
The present invention also provides a kind of and utilizes special-shaped well to carry out the method for fracturing, comprises the steps:
Special-shaped well is built by the building method of the described well for fracturing in the formation at target locations of pressure break; This special-shaped well is utilized to carry out fracturing.
According to the present invention, for the building method of the well of fracturing.First, build common well in the formation at target locations will carrying out pressure break, described common well cross sectional shape is circular.Secondly, the borehole wall offers at least two borehole wall conduits along the axis of described common well, wherein said borehole wall conduit has certain cross sectional shape, the circular cross-section basis being formed in common well is thus attached with the profiled shape of the cross sectional shape of borehole wall conduit.End radius of curvature due to borehole wall conduit is less and be 3mm, and the ratio of borehole wall conduit A/F and the degree of depth is 1:5 to 1:3.Therefore, the width of borehole wall conduit is set to 15mm to 30mm, and the degree of depth is set to 45mm to 300mm.According to the present invention, borehole wall A/F optimum value is 30mm, and the degree of depth is 90mm.Due to, defeat by force in identical well internal water, the tensile stress that the small curvature radius place borehole wall bears is comparatively large, can reach more than 7 times of the borehole wall stress of typical circular well.Therefore, break at first in the channel ends small curvature radius position of borehole wall conduit, and the bearing of trend in crack is the direction that small curvature radius position is pointed to.The special-shaped well utilizing the method to construct can well control critical eigenvalue crack initiation direction, not only constructability, energy-saving consumption and only need lower initial cracking pressure just can realize the pressure break of the borehole wall, greatly reduce the damage risk of power tool.Effectively reduce fracturing fluid leakage, reduce because the too much invaded formation of fracturing fluid cannot the row of returning and the reservoir damage that causes completely simultaneously.
Accompanying drawing explanation
Also will be described in more detail the present invention with reference to accompanying drawing based on embodiment hereinafter.Wherein:
Fig. 1 is the inside overall structure schematic diagram of the present invention's abnormity well.
In the accompanying drawings, identical parts use identical Reference numeral.Accompanying drawing is not according to the ratio of reality.
Detailed description of the invention
Below in conjunction with accompanying drawing, the invention will be further described.
According to the present invention, the building method of the described well for fracturing is included in the step that the formation at target locations will carrying out pressure break builds circular common well.Described common well is circular.Easy understand, is well-known to those skilled in the art owing to building typical circular well, therefore no longer describes in detail in the present invention.
Also comprise according to the building method of the well for fracturing in the present invention and the part in described common well is transformed into the step with non-circular cross section.According to the present invention, described non-circular cross section is oval, rectangle or date core shaped and irregularly shaped.In a specific embodiment, the part in described common well is transformed into and there is non-circular cross section and form special-shaped well.Described special-shaped well comprise be arranged on described common well the borehole wall on, and along at least two borehole wall conduits that the axis of described common well is offered.Wherein, described borehole wall conduit points to the bearing of trend of fracturing fracture.
Wherein, described borehole wall conduit has certain cross sectional shape.After fluting, the cross section of common well is no longer circular, but on the basis of circular cross-section the profiled shape of additional channels cross sectional shape.In the present embodiment, most preferred profiled shape is irregularly shaped, i.e. additional one or more of borehole wall conduit on the basis of common well, and Formation cross-section has the special-shaped well of profiled shape thus.
Refer to Fig. 1, it is the inside overall structure schematic diagram of the present invention's abnormity well.As shown in the figure, according to the present invention, the overall structure of the special-shaped well 10 formed according to the building method of the above-mentioned well for fracturing comprises common well 1 and borehole wall conduit 2.Wherein, the cross sectional shape of common well 1 is circular, and the radius of curvature of the channel ends 3 of borehole wall conduit 2 is 0.02 times of the borehole wall curvature of common well 1 to 0.15 times.
The number of borehole wall conduit 2 can be two or many, can determine according to the embody rule situation of 10 of this special-shaped well.Described borehole wall conduit 2 charges into the borehole wall along horizontal direction, and axially extends along common well 1.The length optimum of described borehole wall conduit 2 can be 30m.If the size of borehole wall conduit 2 is long, then the rigidity of the borehole wall possibly cannot ensure, therefore may cause difficulty to underground work.So the length of borehole wall conduit 2 can be set to 30m.The degree of depth that the A/F of described borehole wall conduit 2 and described borehole wall conduit 2 charge into the borehole wall is proportional.According to the present invention, the proportion of described width and the degree of depth can be 1:5 to 1:3.Width is set to 15mm to 40mm, and the degree of depth is set to 45mm to 300mm.In the present embodiment, the A/F optimum of described borehole wall conduit 2 is set to 30mm, and the degree of depth optimum charging into the borehole wall is set to 90mm.Thus, the channel ends 3 of borehole wall conduit 2 can obtain larger crack initiation stress, thus makes this place's preferential tear.
According to the present invention, the tensile stress of bearing due to channel ends 3 increases along with the reduction of the radius of curvature of channel ends 3, and therefore, the preferable range of the radius of curvature of channel ends 3 is 3mm to 10mm.When the radius of curvature of described channel ends 3 is set to 3mm, when the borehole wall ID of described common well 1 is set to 150mm, more than 7 times of the tensile stress that the tensile stress that then channel ends 3 bears is born for common well 1, therefore, the small curvature radius position preferential tear of the channel ends 3 of borehole wall conduit 2, the bearing of trend in crack is the direction that described small curvature radius points to.Thus, the crack initiation position of the borehole wall and the bearing of trend in crack is effectively controlled.Therefore, when utilizing this special-shaped well 10 to carry out pressure break, crack and the bearing of trend thereof of design can be obtained, and improve the quality of fracturing greatly.
According to the present invention, described special-shaped well 10 can realize pressure break under less waterpower pressure, this is because due to the radius of curvature of the channel ends 3 of the borehole wall conduit 2 in special-shaped well 10 less, therefore can obtain larger local stress.And then the waterpower pressure applied in special-shaped well 10 does not need the pressure reached needed for shaft wall fracture, and the tensile stress only needing the small curvature radius place of the channel ends 3 of borehole wall conduit 2 to obtain reaches the pressure needed for shaft wall fracture, just can realize fracturing.And, the shape of special-shaped well 10 that the building method of the described well for fracturing not only can control crack initiation direction well and will design, and constructability, energy-saving consumption, only need lower initial cracking pressure just can realize the pressure break of the borehole wall, greatly reduce the damaged condition of power tool, effectively reduce fracturing fluid leakage and reduce because the too much invaded formation of fracturing fluid cannot the row of returning and the reservoir damage that causes completely.
According to the present invention, the detailed process utilizing described special-shaped well 10 to carry out fracturing is as follows.First, a common well 1 is built in the formation at target locations will carrying out pressure break.The cross sectional shape of described common well 1 is circular.Secondly, offer at least one borehole wall conduit 2 in the side of common well 1, wherein, borehole wall conduit 2 has certain cross sectional shape, thus form the special-shaped well with odd-shaped cross section.Next, pit shaft packing is carried out in the common well 1 of the front and back end of borehole wall conduit 2.Then, waterpower pressure is applied to the well section of packing, because the radius of curvature of channel ends 3 is less, the therefore borehole wall herein tensile stress of bearing 7 times of tensile stress suffered by common well.Afterwards, start to produce crack at the small curvature radius place of the channel ends 3 of borehole wall conduit 2, and the bearing of trend in crack is the direction that channel ends 3 points to.Thus, required pressing crack construction can be completed.
Easy understand, because other operation after above-mentioned fracturing is configured to special-shaped well is well known to those skilled in the art, therefore no longer describes in detail in this article.
In hydraulic fracturing process process, owing to have employed the building method by the described well for fracturing, therefore, the special-shaped well 10 of design can be obtained, and described special-shaped well 10 well can control the crack initiation direction in borehole wall crack.
Although invention has been described with reference to preferred embodiment, without departing from the scope of the invention, various improvement can be carried out to it and parts wherein can be replaced with equivalent.Especially, only otherwise there is structural hazard, the every technical characteristic mentioned in each embodiment all can combine in any way.The present invention is not limited to specific embodiment disclosed in literary composition, but comprises all technical schemes fallen in the scope of claim.
Claims (9)
1., for a building method for the well of fracturing, described method comprises the steps:
Circular common well is built in the formation at target locations will carrying out pressure break;
A part in described common well is transformed into there is non-circular cross section.
2. the building method of the well for fracturing according to claim 1, is characterized in that, a part for the edge contour in described non-circular cross section or many parts have the radius of curvature being less than the common well radius of described circle.
3. the building method of the well for fracturing according to claim 2, is characterized in that, described non-circular cross section is ellipse, rectangle or date core shaped.
4. the building method of the well for fracturing according to claim 1, it is characterized in that, a part in described common well is transformed into and there is non-circular cross section and form special-shaped well, described special-shaped well comprise be arranged on described common well the borehole wall on, and along at least two borehole wall conduits that the axis of described common well is offered, wherein said borehole wall conduit points to the bearing of trend of fracturing fracture.
5. the building method of the well for fracturing according to claim 4, is characterized in that, the radius of curvature of the end of described borehole wall conduit is set to 0.02 to 0.15 times of the radius of curvature of described common well.
6. the building method of the well for fracturing according to claim 5, is characterized in that, the radius of curvature of the end of described borehole wall conduit is 3mm to 10mm.
7. the building method of the well for fracturing according to any one of claim 4 to 6, is characterized in that, the width of described borehole wall conduit and the ratio of the degree of depth are 1:5 to 1:3.
8. the building method of the well for fracturing according to claim 7, is characterized in that, the width of described borehole wall conduit is 15mm to 30mm, and the degree of depth is 45mm to 90mm.
9. utilize special-shaped well to carry out a method for fracturing, it is characterized in that, comprise the steps:
Method according to any one of claim 1 to 8 is constructed by construct special-shaped well in the formation at target locations of pressure break;
This special-shaped well is utilized to carry out fracturing.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410215081.7A CN105089605A (en) | 2014-05-21 | 2014-05-21 | Borehole construction method and method for hydraulic fracturing by using borehole |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410215081.7A CN105089605A (en) | 2014-05-21 | 2014-05-21 | Borehole construction method and method for hydraulic fracturing by using borehole |
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| CN105089605A true CN105089605A (en) | 2015-11-25 |
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| CN201410215081.7A Pending CN105089605A (en) | 2014-05-21 | 2014-05-21 | Borehole construction method and method for hydraulic fracturing by using borehole |
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6283214B1 (en) * | 1999-05-27 | 2001-09-04 | Schlumberger Technology Corp. | Optimum perforation design and technique to minimize sand intrusion |
| US20030070805A1 (en) * | 2001-10-13 | 2003-04-17 | Yakov Bassin | Method of increasing productivity of oil, gas and hydrogeological wells |
| US20030168216A1 (en) * | 2000-04-26 | 2003-09-11 | Nicholson Elizabeth Diane | Method for reducing sand production |
| WO2007112387A3 (en) * | 2006-03-27 | 2008-02-21 | Potter Drilling Llc | Method and system for forming a non-circular borehole |
| CN101180446A (en) * | 2005-05-17 | 2008-05-14 | 国际壳牌研究有限公司 | Method for drilling stable borehole |
-
2014
- 2014-05-21 CN CN201410215081.7A patent/CN105089605A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6283214B1 (en) * | 1999-05-27 | 2001-09-04 | Schlumberger Technology Corp. | Optimum perforation design and technique to minimize sand intrusion |
| US20030168216A1 (en) * | 2000-04-26 | 2003-09-11 | Nicholson Elizabeth Diane | Method for reducing sand production |
| US20030070805A1 (en) * | 2001-10-13 | 2003-04-17 | Yakov Bassin | Method of increasing productivity of oil, gas and hydrogeological wells |
| CN101180446A (en) * | 2005-05-17 | 2008-05-14 | 国际壳牌研究有限公司 | Method for drilling stable borehole |
| WO2007112387A3 (en) * | 2006-03-27 | 2008-02-21 | Potter Drilling Llc | Method and system for forming a non-circular borehole |
Non-Patent Citations (1)
| Title |
|---|
| 郭小哲编著: "《中国陆上油气开发技术发展趋势》", 31 December 2013 * |
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Application publication date: 20151125 |