A kind of radioactive source storehouse and the drill collar with this radioactive source storehouse
Technical field:
A kind of radioactive source chamber structure that the present invention relates to geophysical exploration device has the drill collar of this source chamber structure.
Background technology:
The penetron using in geophysical exploration is with the gamma-ray irradiation stratum of radioactivity gamma ray source transmitting, measures formation bulk density according to Compton effect, thereby calculates the logger of the degree of porosity on wellbore stratum.Conventional radioactive source is 2 Curie's gamma ray source, and it has serious infringement to human body and environment, and therefore the safe handling of radioactive source is very important.
In with brill density log mode, the mode that adopts radioactive source to separate with shield at present, radioactive source is directly placed on drill collar, between radioactive source and probe, wedges shielding slab to avoid radioactive ray to enter probe without stratum direct projection, cause larger measure error.The radioactive source storehouse of this frame mode do not consider by the radioactivity of mud runner, and because radioactive source can make measure error increase without collimating aperture design around.
Summary of the invention:
The object of the invention is is exactly the defect existing for prior art, provides a kind of and is used in conjunction with boring density measuring instrument, can greatly improve certainty of measurement, and safe and reliable radioactive source storehouse and the drill collar with this radioactive source storehouse.
Technical scheme of the present invention comprises:
A kind of radioactive source storehouse, comprises matrix and is distributed in radioactive source chamber, the shield storehouse in matrix, has high density shield in shield storehouse.Radioactive source chamber is staged circular hole, is followed successively by from inside to outside radial hole, screwed hole, seal groove, jump-ring slot.Shield storehouse is the cup-shaped groove that covers on radial hole periphery, radioactive source chamber, and cup-shaped groove is embedded with high density shield, and the outer end of shield is by sprue shutoff.On shield, be radially carved with
Low-density window, this window communicates with the collimating aperture being located on matrix.The built-in low density material of collimating aperture.
Have the drill collar in aforementioned radioactive source storehouse, drill collar middle part is with the plural righting wing, and one of them righting wing is provided with groove, and groove is outside seals storehouse with cover plate mix proportion.On the same righting wing, be provided with radioactive source storehouse, radioactive source storehouse is near sealing storehouse one side, and the collimating aperture in radioactive source storehouse is to sealing storehouse lopsidedness.The axis of the center line of described collimating aperture and sealing storehouse axis, drill collar at grade, and collimating aperture center line and drill collar axis angle at 45 °.
Radioactive source storehouse in such scheme is used for depositing radioactive source, and sealing storehouse is for depositing the probe of Density Measuring Instrument, and drill collar is for coordinating with boring drilling well Density Measuring Instrument.
Effect of the present invention is: because radioactive source separates placement with shield, increased the safety in utilization of radioactive source.For after drill collar, even if measurement while drilling environment badly causes shield fragmentation or comes off, radioactive source is still fixed on boring on the drill collar of Density Measuring Instrument.Because radioactive source has shielding around and has collimating aperture design, be improved with the certainty of measurement of boring density instrument in addition.Whole apparatus structure is reasonable in design, and implementation method is simple.
Brief description of the drawings:
Fig. 1 is with the schematic diagram that bores the special drill collar of density instrument
Fig. 2 is the amplification profile along A-A line in Fig. 1
Fig. 3 is the amplification profile schematic diagram in radioactive source storehouse in Fig. 2
In figure: the 1st, drill collar, the 2nd, mud runner, the 3rd, sealing storehouse (or claiming probe storehouse), the 4th, source compartment, the 5th, shield (storehouse), the 6th, collimating aperture, the 7th, the righting wing, the 8th, radial hole, the 9th, screw thread mouth, the 10th, seal groove, the 11st, jump-ring slot, the 12nd, sprue, the 13rd, low-density window.
Detailed description of the invention:
Below in conjunction with Figure of description, the invention will be further described.
Embodiment 1, contrast accompanying drawing 2 and 3, radioactive source storehouse comprises that (matrix underpart is herein the drill collar 1 in Fig. 3 to matrix, matrix top be the righting wing 7 in Fig. 2, the namely joint portion of drill collar main body and the righting wing) and be distributed in radioactive source chamber 4, the shield storehouse 5 in matrix, in shield storehouse 5, there is high density shield.Radioactive source chamber 4 is staged circular hole, is followed successively by from inside to outside radial hole 8, screwed hole 9, seal groove 10, jump-ring slot 11.Shield storehouse 5 is the cup-shaped grooves that cover on radial hole 8 peripheries, radioactive source chamber, and cup-shaped groove is embedded with high density shield, and the outer end of shield is by sprue 12 shutoff.On shield, be radially carved with low-density window 13, this window be located at collimating aperture 6(on matrix referring to Fig. 1) communicate.Also carry out sealing with special glue at the interior wedging low density material of collimating aperture 6.
Embodiment 2, contrast Fig. 1, a kind of drill collar with aforementioned radioactive source storehouse, drill collar 1 adopts existing structure, and its two ends are upper and lower joints, and there is mud runner 2 centre.Mud to shaft bottom circulation, flows out by bit port in slurry channel 2, then returns to well head through the annular space between drill collar and stratum.Mud not only carries out landwaste, but also as the transmission medium of underground signal, density measurement passes to ground taking mud as carrier by data by MWD.By reference to the accompanying drawings 2, three righting wings 7 of drill collar middle part peripheral hardware.One of them righting wing 7 is provided with groove, and groove is outside seals storehouse 3 with cover plate mix proportion, and density detector is put into wherein.On the same righting wing, be provided with radioactive source storehouse (its structure is with reference to above-mentioned enforcement, 12 and 3 description by reference to the accompanying drawings), radioactive source storehouse is near sealing storehouse one side.The axis in probe storehouse 3 and radioactive source chamber 4 axis are at an angle of 90.The axis of the center line of collimating aperture 6 and axis, the drill collar 1 in sealing storehouse 3 at grade, and collimating aperture center line and drill collar axis angle at 45 °.There iing slurry channel 2 with boring density instrument drill collar 1 axis.
Supplementary notes: the jump ring in jump-ring slot 11 can ensure that radioactive source does not come off under adverse circumstances in well adopt specialist tools to carry out remote disassembling to avoid that operating personnel are caused to larger radiation injury in the process in handling source.Radioactive source adopts left-hand thread helicitic texture, is independently placed in radioactive source chamber 4.High density shield can the side of being the shapes such as cup type, cylinder be cup-shaped.Because the interior diameter in shield storehouse is greater than the external diameter of radioactive source chamber, axial length is greater than the length of radial hole, makes radioactive source chamber can all put into shield storehouse and can not contact with the perisporium in shield storehouse.Open a groove on shield storehouse and radioactive source chamber rightabout while-drilling density logger device drill collar surface, sprue is assembled in groove, and carry out welding procedure processing, carry out permanent fixing, even if shield fragmentation also can not come off.Because shield adopts cup type shape, wrap radioactive source completely, stop radioactive source by the radioactivity of mud runner, increase the security reliability in this radioactive source storehouse.