Abstract
Directional drilling is an extremely important area of technology for the extraction of oil and gas from earthen formations. The technology of the present application relates to improved positioning elements for directional drilling assemblies. It also relates to drilling directional wellbores using the guidance positioning members of the present technology.
Claims
1. A downhole directional drilling apparatus configured to attach to a drill string, the apparatus comprising, a drill bit, the drill bit having a cutting structure; a bent housing positive displacement motor; and a positioning element mounted proximal a bend angle of the drilling apparatus, wherein the positioning element comprises a first fixed blade generally on a scribe side of the drilling apparatus having an outermost surface with a first fixed radius from an axial centerline of the drilling apparatus, the first fixed radius equal to a fixed value that is from 0.91 to 1.05 of a nominal radius of the drill bit, and the positioning element having a surface on the bend side of the drilling apparatus, the surface having a second fixed radius from the axial centerline, the second fixed radius having a fixed value that is less than 0.90 of the nominal radius of the drill bit and greater than a nominal radius of a housing of the drilling apparatus, wherein the first fixed blade is stationary relative to the axial centerline of the drilling apparatus.
2. The apparatus of claim 1 further comprising a kick pad generally adjacent and above the bend angle of the drilling apparatus.
3. The apparatus of claim 1 further comprising a distal positioning element mounted distal the bend angle of the drilling apparatus, wherein the distal positioning element comprises a distal fixed blade generally on the bend side of the drilling apparatus, the distal fixed blade having a distal fixed blade radius from the axial centerline of the drilling apparatus, and the distal positioning element comprising a distal surface generally on the scribe side of the drilling apparatus where the distal surface generally has a distal surface fixed radius that is less than the distal blade radius, wherein the distal fixed blade is stationary relative to the axial centerline of the drilling apparatus.
4. The apparatus of claim 1 wherein the positioning element includes at least one of a tapered transition or curved transition between the first fixed blade surface and the drilling apparatus.
5. The apparatus of claim 3 wherein both the distal positioning element and the positioning element include tapered or curved transitions between the fixed blade surfaces and a tool body of the drilling apparatus.
6. The apparatus of claim 5 wherein an outermost surface of the distal fixed blade generally on the bend side of the distal positioning element comprises the distal fixed radius from the axial centerline of the drilling apparatus equal to a fixed value that is from 0.91 to 1.05 of the nominal radius of the drill bit; and wherein the distal surface fixed radius of the distal surface generally on the scribe side of the distal positioning element comprises a fixed value that is less than 0.90 of the nominal radius of the drill bit.
7. The apparatus of claim 5 wherein the outermost surfaces of the distal fixed blades of the distal positioning element are relieved in a proximal direction.
8. The apparatus of claim 5 wherein the outermost surface of the distal fixed blades of the distal positioning element are tapered in a proximal direction.
9. The apparatus of claim 1, wherein the positioning element is circumferentially asymmetric.
10. The apparatus of claim 9, wherein the positioning element is axially asymmetric.
11. A bent housing configured for attachment to a wellbore downhole assembly comprising: a bent housing positive displacement motor having a scribe side and a bend side wherein the bent housing comprises a bend angle; a positioning element mounted on the bent housing positive displacement motor proximal the bend angle, wherein the positioning element comprises a first fixed blade generally on the scribe side that has an outermost surface with a first fixed radius from an axial centerline of the bent housing positive displacement motor, and wherein the positioning element comprises a surface on the bend side that has a second fixed radius from the axial centerline, wherein the second fixed radius is less than the first fixed radius; a kick pad on the bent housing positive displacement motor, the kick pad positioned adjacent the bend angle; and a distal positioning element mounted distal the bend angle, wherein the distal positioning element comprises a distal fixed blade generally on the bend side, the distal fixed blade having a distal blade fixed radius from the axial centerline, and the distal positioning element having a distal surface generally on the scribe side, wherein the distal surface generally has a distal surface fixed radius that is less than the distal blade fixed radius; wherein the outermost surface of the first fixed blade generally on the scribe side of the positioning element comprises a fixed radius from the axial centerline of the assembly equal to a fixed value that is from 0.91 to 1.05 of a nominal radius of the drill bit; wherein the surface on the bend side of the positioning element comprises a fixed radius from the axial centerline of the tool having a fixed value that is less than 0.90 of the nominal radius of the drill bit; and wherein the outermost surface of the distal fixed blade generally on the bend side of the distal positioning element comprises the distal fixed radius from the axial centerline equal to a fixed value that is from 0.91 to 1.05 of the nominal radius of the drill bit wherein the distal surface fixed radius of the distal surface generally on the scribe side of the distal positioning element comprises a fixed value that is less than 0.90 of the nominal radius of the drill bit.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) FIG. 1 shows a side view of a prior art slick assembly steerable PDM directional assembly.
(2) FIG. 1a shows a cross section view of the kick/wear pad of the prior art assembly of FIG. 1.
(3) FIG. 2 shows a side view of a prior art near bit partially stabilized steerable PDM directional assembly.
(4) FIG. 2a shows a cross section view of the kick/wear pad of the prior art assembly of FIG. 2.
(5) FIG. 2b shows a cross section view of the near bit stabilizer of the prior art assembly of FIG. 2.
(6) FIG. 3 shows a side view of a prior art fully stabilized steerable PDM directional assembly.
(7) FIG. 3a shows a cross section view of the kick/wear pad of the prior art assembly of FIG. 3.
(8) FIG. 3b shows a cross section view of the near bit stabilizer of the prior art assembly of FIG. 3.
(9) FIG. 3c shows a cross section view of the upper stabilizer of the prior art assembly of FIG. 3.
(10) FIG. 4 shows a generalized cross section view of aspects of the technology of the steerable PDM directional assembly of this application.
(11) FIG. 5 shows a side view of an embodiment of a modified steerable PDM directional assembly consistent with the technology of the present application.
(12) FIG. 5a shows a cross section view of the near bend kick/wear pad of FIG. 5.
(13) FIG. 5d shows a cross section view of a scribe side above bend enlarged primary structure radius positioning element consistent with the technology of the present application.
(14) FIG. 6 shows a side view of an alternative embodiment of a modified steerable PDM directional assembly consistent with the technology of the present application.
(15) FIG. 6a shows a cross section view of the near bend kick/wear pad of FIG. 6.
(16) FIG. 6e shows a cross section view of an alternative embodiment of a scribe side above bend enlarged primary structure radius positioning element consistent with the technology of the present application.
(17) FIG. 7 is a side view of a modified steerable PDM directional assembly incorporating both a scribe side above bend enlarged primary structure radius positioning element and a bend side enlarged primary structure radius lower sleeve positioning element consistent with the technology of the present application.
(18) FIG. 7a shows a cross section view of the near bend kick/wear pad of FIG. 7.
(19) FIG. 7d shows a cross section view of an embodiment of a scribe side above bend enlarged primary structure radius positioning element consistent with the technology of the present application.
(20) FIG. 7f shows a cross section view of a bend side enlarged primary structure radius lower sleeve element consistent with the technology of the present application.
(21) FIG. 8 shows a side view of a modified steerable PDM directional assembly incorporating both a scribe side above bend enlarged primary structure radius positioning element and a bend side enlarged primary structure radius lower sleeve positioning element consistent with the technology of the present application.
(22) FIG. 8a shows a cross section view of the near bend kick/wear pad of FIG. 8.
(23) FIG. 8e shows a cross section view of an alternative embodiment of a scribe side above bend enlarged primary structure radius positioning element consistent with the technology of the present application.
(24) FIG. 8g shows a cross section view of an alternative embodiment of a bend side enlarged primary structure radius lower sleeve element consistent with the technology of the present application.
(25) FIG. 9i shows a side view of a modified steerable PDM directional assembly incorporating a spiraled blade scribe side above bend primary structure radius positioning element and a bend side primary structure radius lower sleeve positioning element consistent with the technology of the present application.
(26) FIG. 9j shows a scribe side view of the modified steerable PDM directional assembly of FIG. 9i.
(27) FIG. 9a shows a cross section view of the near bend kick/wear pad of FIG. 9i.
(28) FIG. 9g shows a cross section view of an alternative embodiment of a bend side enlarged primary structure radius lower sleeve element consistent with the technology of the present application.
(29) FIG. 9h shows a cross section view of an alternative embodiment of a spiraled scribe side above bend enlarged primary structure radius positioning element consistent with the technology of the present application.
(30) FIG. 10a shows a cross section of an alternative embodiment of a positioning element of the technology.
(31) FIG. 10b shows a cross section of an additional alternative embodiment of a positioning element of the technology.
(32) FIG. 10c shows a cross section of an additional alternative embodiment of a positioning element of the technology.
(33) FIG. 11 is a chart of calculated build rates (BUR) for various assembly bend angles of assemblies employing the technology of the present application.
DETAILED DESCRIPTION
(34) FIG. 1 shows a side view of a prior art slick assembly steerable PDM directional assembly 100. Assembly 100 includes bend 101, drill bit 102, and kick/wear pad 103.
(35) FIG. 1a shows a cross section 104 of kick/wear pad 103 taken across a-a of FIG. 1.
(36) FIG. 2 shows a side view of a prior art near bit stabilized steerable PDM directional assembly 200. Assembly 200 includes bend 101, drill bit 102, and kick/wear pad 103. It also includes near bit stabilizer 205.
(37) FIG. 2a shows a cross section 104 of kick/wear pad 103 taken across a-a of FIG. 2.
(38) FIG. 2b shows a cross section 206 of near bit stabilizer 205 taken across b-b of FIG. 2 with symmetric circumferential blades shown at 207.
(39) FIG. 3 shows a side view of a prior art fully stabilized steerable PDM directional assembly 300. Assembly 300 includes bend 101, drill bit 102, and kick/wear pad 103. It also includes near bit stabilizer 205 and above bend stabilizer 308.
(40) FIG. 3a shows a cross section 104 of kick/wear pad 103 taken across a-a of FIG. 3.
(41) FIG. 3b shows a cross section 206 of near bit stabilizer 205 taken across b-b of FIG. 3 with symmetric circumferential blades shown at 207.
(42) FIG. 3c shows a cross section 309 of above bend stabilizer 308 taken across c-c of FIG. 3 with symmetric circumferential blades shown at 310.
(43) FIG. 4 shows a generalized cross section view 400 of aspects of the technology of the steerable PDM directional assembly of this application. FIG. 4 shows center point 490, nominal bit diameter 491, housing or sleeve minor diameter 492, nominal bit radius 493, and nominal housing or sleeve minor radius 494. FIG. 4 also shows demarcation diameter 495. Radial zone 496 falls inside the demarcation diameter 495 and covers the zone of maximum radial surface of a secondary positioning element structure of a given near bit or above bend positioning element. In the technology of the present application, radial zone 496 is greater than or equal to the housing or sleeve minor diameter 492 and is less than or equal to 0.90 of the nominal bit radius 493. Radial zone 497 falls outside the demarcation diameter 495 and covers the zone of maximum radial surface of a primary positioning element structure of a given near bit or above bend positioning element. In the technology of the present application, radial zone 497 is greater than or equal to 0.91 of the nominal bit radius 493 and less than or equal to 1.05 of the nominal bit radius 493. From the above description, it can be seen that the demarcation diameter 495 occupies the narrow zone between 0.90 and 0.91 of the nominal bit radius 493.
(44) FIG. 5 shows a side view of an assembly 500 consistent with one embodiment of the technology of the present application. Assembly 500 includes bend 101, drill bit 102, and kick/wear pad 103. It also shows above bend positioning element 509.
(45) FIG. 5a shows cross section 104 of kick/wear pad 103 taken across a-a of FIG. 5.
(46) FIG. 5d shows cross section 510 of above bend positioning element 509 taken across d-d of FIG. 5. FIG. 5d also shows primary positioning element structure 511.
(47) FIG. 6 shows a side view of an assembly 600 consistent with another embodiment of the technology of the present application. Assembly 600 includes bend 101, drill bit 102, and kick/wear pad 103. Assembly 600 also shows above bend positioning element 609.
(48) FIG. 6a shows cross section 104 of kick/wear pad 103 taken across a-a of FIG. 6.
(49) FIG. 6e shows cross section 610 of above bend positioning element 609 taken across e-e of FIG. 6. FIG. 6e also shows primary positioning element structure blades 611.
(50) FIG. 7 shows a side view of an assembly 700 consistent with another embodiment of the technology of the present application. Assembly 700 includes bend 101, drill bit 102, and kick/wear pad 103. Assembly 700 also shows above bend positioning element 509. Assembly 700 also shows near bit positioning element 715. It should be noted that kick/wear pad 103 is optional at designer discretion in the embodiment of FIG. 7.
(51) FIG. 7a shows cross section 104 of kick/wear pad 103 taken across a-a of FIG. 7. It should be noted that kick/wear pad 103 is optional at designer discretion in the embodiment of FIG. 7.
(52) FIG. 7d shows cross section 510 of above bend positioning element 509 taken across d-d of FIG. 7. FIG. 7d also shows primary positioning element structure 511.
(53) FIG. 7f shows cross section 716 of near bit positioning element 715 taken across f-f of FIG. 7. FIG. 7f also shows primary positioning element structure 717.
(54) FIG. 8 shows a side view of an assembly 800 consistent with another embodiment of the technology of the present application. Assembly 800 includes bend 101, drill bit 102, and kick/wear pad 103. Assembly 800 also shows above bend positioning element 609. Assembly 800 also shows near bit positioning element 817. It should be noted that kick/wear pad 103 is optional at designer discretion in the embodiment of FIG. 8.
(55) FIG. 8a shows cross section 104 of kick/wear pad 103 taken across a-a of FIG. 8. It should be noted that kick/wear pad 103 is optional at designer discretion in the embodiment of FIG. 8.
(56) FIG. 8e shows cross section 610 of above bend positioning element 609 taken across e-e of FIG. 8. FIG. 8e also shows primary positioning element structure blades 611.
(57) FIG. 8g shows cross section 818 of near bit positioning element 817 taken across g-g of FIG. 8. FIG. 8g also shows primary positioning element structure blades 819.
(58) FIG. 9i shows a side view of an assembly 900 consistent with another embodiment of the technology of the present application. Assembly 900 includes bend 101, drill bit 102, and kick/wear pad 103. Assembly 900 also shows above bend positioning element 919. Assembly 900 also shows near bit positioning element 715. It should be noted that kick/wear pad 103 is optional at designer discretion in the embodiment of FIG. 8.
(59) FIG. 9a shows cross section 104 of kick/wear pad 103 taken across a-a of FIG. 9i. It should be noted that kick/wear pad 103 is optional at designer discretion in the embodiment of FIG. 9i.
(60) FIG. 9g shows cross section 818 of near bit positioning element 817 taken across g-g of FIG. 9i. FIG. 9g also shows primary positioning element structure blades 819.
(61) FIG. 9h shows cross section 920 of above bend positioning element 919. FIG. 9h also shows spiraled primary positioning element structure blades 921.
(62) FIG. 9j shows a scribe side view of assembly 900. FIG. 9j also shows scribe side of above bend positioning element 919 and scribe mark 922.
(63) FIG. 10a shows a cross section of an assembly 1000 of an alternative embodiment of a positioning element of the technology. Assembly 1000 includes two primary positioning element structure surfaces at 1001 and three secondary positioning element structure surfaces at 1002.
(64) FIG. 10b shows a cross section of an assembly 1010 of an additional alternative embodiment of a positioning element of the technology. Assembly 1010 includes three primary positioning element structure surfaces at 1011 and two secondary positioning element structure surfaces at 1012.
(65) FIG. 10c shows a cross section of an assembly 1020 of an additional alternative embodiment of a positioning element of the technology. Assembly 1010 includes one primary positioning element structure surface at 1021 and five secondary positioning element structure surfaces at 1022.
(66) As can be seen from FIGS. 10a, 10b, and 10c, the degrees of arc of the outer surfaces of the primary element structure may cover as little as approximately 25 degrees as in 10c, or greater amounts of degrees of arc as in 10a and 10b. In the technology of this application, the maximum degrees of arc of the outer surfaces of the primary element structure does not exceed 175 degrees.
(67) FIG. 11 is a chart of geometrically calculated build rates (BUR) for various assembly bend angles of assemblies employing the technology of the present application. In this example, a series of bend angles ranging from 1.25 degrees to 2.25 degrees are considered on an assembly with an exemplary nominal 8.750 bit diameter. A range of primary outer positioning element structure surfaces radial extensions are represented. These radial extensions range from just over 94% of the nominal bit radius to almost 103% of nominal bit radius. It can be seen that as the radial extension of the outer surfaces increase for a given bend angle, the BUR increases in degrees per 100 feet.
(68) As can be seen from the detailed figures in applying the technology of this application, the designer is free to radius or bevel the edges of the outer surfaces of the positioning element structures. Additionally the designer may choose to bevel, taper or curve the proximal and/or distal ends of the outer surfaces of the positioning element structures to transition or blend them with the tool or sleeve body.
(69) It should be additionally noted that the designer may taper the proximal portion of the primary outer surfaces of a near bit positioning element structure in order to reduce the stresses encountered in the slide to rotate stress condition referred to previously.
(70) In applying the technology of this application, the designer may choose to not employ traditional kick/wear pad at or near the bend of the assembly. It should be understood that the use of traditional kick/wear pad is at the discretion of the designer.
(71) As to manufacturing technique, it is also possible to create a modified bottom hole assembly according to the teachings of this application by selectively grinding or milling some of the outer surfaces of the blades of traditional directional BHA stabilizers to allow them to meet the limits of secondary outer positioning element structures while leaving the remaining blades unground or unmilled, or adding material to the remaining blades such as by welding, so as to cause them or allow them to meet the limits of primary outer positioning element structures. Additionally, flat top or dome top tungsten carbide or PDC inserts can be inserted into sockets formed in the primary outer positioning structure. These inserts can be placed for an exposure above the pad or surface of the positioning element primary structure to allow the structure to meet the limits of the primary outer surfaces of the technology.
(72) Although the technology of the present application has been described with reference to specific embodiments, these descriptions are not meant to be construed in a limiting sense. Various modifications of the disclosed embodiments, as well as alternative embodiments of the technology will become apparent to persons skilled in the art upon reference to the description of the invention. It should be appreciated by those skilled in the art that the conception and the specific embodiments disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the technology. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and equivalent constructions as set forth in the appended claims. It is, therefore, contemplated that the claims will cover any such modifications or embodiments that fall within the scope of the technology.
