High pressure underground gas well tube bottom gas-tight sealing and installation method
The invention belongs to underground gas storage well of high-pressure fuel gas wellbore bottom gas-tight sealing and this Unit Installation method.Adopt this device and installation method can effectively seal gas storage well bottom, to avoid gas leakage; Reverse operating also can be dismantled it.
At present, at CNG (compressed natural gas) supply station and gas peak regulation station, generally adopt well for storage to store high-pressure natural gas.Be 200510021839 at application number, name is called the patent documentation of " underground gas storage well shaft and fixation method thereof ", a kind of pit shaft body and connecting sleeve thereof of comprising disclosed, be located at the four-way control head of well head, be located at the one-way valve end socket and the basic fixed frame of bottom, liquid-discharging tube is at interior high-pressure gas underground gas storage pit shaft; Its fixation method for by slurry pump with cement slurry through the pit shaft inner chamber press off wellbore bottom one-way valve, make cement slurry from the shaft bottom along pit shaft and the annular space between the borehole wall from bottom to top be in the milk, mud face in pit shaft adds plug and by pumping into high pressure water remaining cement slurry in the pit shaft is extruded through bottom valve then, realizes well cementation and sealing by drainage and step-down, one-way valve return at last.This invention utilizes one-way valve not only to do construction with valve but also make the wellbore bottom end socket, can not be though overcome that the conventional well tube bottom adopts fixed seal head by the drawback of inner chamber grouting well cementation, and have installation, convenient fixing, characteristics such as reliable; Well cementation back pit shaft inner chamber easily pollutes, the cleaning amount is bigger but exist, and the cylindrical shell bottom is to the defectives such as sealing difference of high pressure air.And be that CN1837672A, name are called the patent documentation of " a kind of fixation method of underground gas storage well shaft " at publication number, then at above-mentioned defective, change into and intubate hung in the pit shaft inner chamber and by this intubate grout injection, after the well cementation intubate is taken out, thereby avoided cement slurry to pollute pit shaft inner chamber (air storing cavity); But still exist simple employing grouting to make bottom bulkhead, poor to the sealing of high-pressure natural gas with one-way valve, in the gas storage process, easily produce the drawback of leaking and having potential safety hazard.
Summary of the invention
The objective of the invention is defective, research and design a kind of high pressure underground gas well tube bottom gas-tight sealing and installation method at the background technique existence.With reach to gas storage well bore bottom carry out effectively, reliable sealing, avoiding, reduce high pressure underground gas well gas storage loss and guarantee purpose such as its safe operation at gas storage process mesohigh gas leakage.
Solution of the present invention is between the gas storage well bore bottom and one-way valve of background technique, sets up a gas-tight sealing; For not overslaugh well cementation, the finally sealed of this device carries out after the grouting well cementation.Therefore wellbore bottom gas-tight sealing of the present invention comprises cylindrical shell, key is that the inner chamber of cylindrical shell runs through whole cylindrical shell, also is provided with trapezoidal nut, the pressure spring of the cone core plug that comprises with trapezoidal mandrel, the spill thread bush that is placed in the mandrel bottom, band spring seat and is provided with the core plug assembly of the gland of mounting process screw and upper and lower screw thread in inner chamber; Then be provided with the core plug assembly connection chamber with a conical ring face core obturating plug in the middle part of cylinder lumen, core plug assembly is sealed and matched by core plug and this core obturating plug pressure type and is fastenedly connected by gland top screw thread and assembly connection chamber; In core plug assembly, the movable trapezoidal mandrel bottom that is placed in of spill thread bush, trapezoidal nut is anchored on the screw column on mandrel top, then seat is on the spring seat on this nut for pressure spring, and the gland bottom is placed under the pressure spring and by screw thread and spill thread bush and links into an integrated entity; Whole sealing device then is fastenedly connected with pit shaft lower end and one-way valve upper end sealed type respectively by the taper pipe thread of cylindrical shell upper/lower terminal.
Described be located on the gland the mounting process screw for the gland external thread rotary to opposite tapered thread hole, also be provided with a pilot hole on the top of tapped hole.
The installation method of above-mentioned high pressure underground gas well tube bottom gas-tight sealing comprises:
A, cylindrical shell is installed: at first the cylindrical shell upper and lower end with seal arrangement is fastenedly connected with pit shaft lower end and one-way valve upper end respectively, it is hung in the basic well, by after interpolation pipe well shaft fixing technology (CN1837672A) well cementation again, hangs out the grouting intubate;
B, mounting core plug assembly: head will be installed be fixed in grouting intubate bottom, again core plug assembly is anchored on by the installing technological hole on the gland and installs on the head, core plug assembly is hung in the seal arrangement cylindrical shell that is positioned at wellbore bottom by intubate then, by intubate gland is screwed in cylindrical shell and through spring, trapezoidal nut the core plug of assembly lower end and the core obturating plug in the cylinder lumen compressed sealing simultaneously, after gland puts in place, intubate continues to be threaded to and head is installed is withdrawed from gland and hang out pit shaft with intubate.
During above-mentioned mounting core plug assembly,, one group of supporting positive cover is set between intubate lower end and middle part and shaft in wall in order to improve the accuracy of contraposition; When the intubate lower end is provided with supporting positive cover, correspondingly then sets up one and set upright block set at the cylinder lumen of assembly connection chamber upper end.
The present invention has been owing to adopted the cone plug type seal arrangement high pressure air has been sealed, the employing of device cylindrical shell and pit shaft and singly with valve equal diameter and the Placement identical with the conventional well cylindrical shell be tightly connected, its integrity and good airproof performance; Earlier cylindrical shell and pit shaft and one-way valve are assembled into one during installation and hang in the shaft bottom in the lump and adopt intubate technology grouting well cementation back, utilize the intubate at scene that core plug assembly is lifted in the cavity of seal arrangement again, and tighten the seal by gland.Thereby have good airproof performance to pressurized gas, be used for the shaft bottom sealing and can effectively avoid the gas storage loss of high-pressure gas, guarantee its safe operation; Install in two steps, neither overslaugh grouting well cementation, have again easy for installation, reliability is high, and has overcome well cementation of conventional high-tension gas storage well and the characteristics such as drawback of shaft bottom difficult sealing to take into account mutually very dexterously.
Description of drawings:
Fig. 1, for gas-tight sealing structure of the present invention and with one-way valve annexation schematic representation;
Fig. 2, be gas-tight sealing and pit shaft body and one-way valve mutual alignment relation and core plug assembly scheme of installation.
Among the figure: 1, cylindrical shell, 1～1 is set upright block set, and 2, the core plug, 3, the spill thread bush, 4, trapezoidal nut, 5, pressure spring, 6, gland, 6～1 installing technological holes; 7, one-way valve, 7～1 spherical valve cores, 8, pit shaft, 9, intubate, 10, supporting positive cover, 11, head is installed, 12, basic well.
With effective gas storage well depth 150m, pit shaft external diameter is 7 " (time) high-pressure gas storage well be example with the bottom seal arrangement;
The external diameter of cylindrical shell 1, high 543mm, external diameter and pit shaft 8 is identical, be 7 ", the taper pipe thread that upper and lower end is connected with pit shaft 8 and one-way valve 7 respectively is that standard oil pipe thread, the axial height of thread section are 121mm; Set upright block set 1～1 internal diameter φ 130mm, axial high 30mm, the axial high 246mm of cavity that cylinder lumen stage casing and core plug assembly are supporting, this section cavity top and gland 6 cooperation place screw threads are standard 4 " tubing round thread (left-handed), axial high 65mm; middle part internal diameter φ 98mm, its upper end diameter of the annular conical surface core obturating plug φ 98mm, lower end diameter φ 86mm, the axial high 21mm that cooperate with core plug 2; The spherical radius of spherical valve core 7～1 cooperation places of this section cavity bottom and one-way valve 7 is SR50mm; Core plug 2 axial high 74mm, the high 21mm of bottom cone, upper end diameter φ 98mm, lower end diameter φ 89mm, the middle part cooperates the high 19mm of cylinder, diameter phi 40mm, top to cooperate with trapezoidal nut 4 with spill thread bush 3 screw column is M24 * 1.5mm, high 34mm; With it the trapezoidal nut 4 of Pei Heing, wherein, lower outer diameter is respectively φ 61mm and φ 75mm, height is respectively 10mm and 6mm, top is 6 jiaos of nuts of standard, high 18mm; Pressure spring 5 its large and small footpaths are respectively φ 69mm and φ 4mm, free high 51mm; Spill thread bush 3 high 37mm bottom thick 5mm, center hole φ 41mm, external diameter φ 92mm, internal thread is M85 * 3mm; Gland 6 lower cavity internal diameter φ 70mm, high 51mm, the outside thread that cooperates with spill thread bush 3 also are M85 * 3mm, the high 35mm of helical thread portion, the axially dark 64mm of installing technological hole 6～1, bottom and installation 11 cooperation place are 2 " dextrorotation tubing round thread; both are 42mm by the helical thread portion height, top pilot hole internal diameter φ 68mm.A 11 height overall 180mm, top employing 2 are installed
2" tubing round thread is connected with intubate 9, and intubate 9 also is 2
2" standard oil pipe; Supporting positive cover 10 internal diameter φ 61mm, external diameter 130mm, thick 30mm.
The installation method of present embodiment gas-tight sealing is:
At first the cylindrical shell in the seal arrangement 1 being fastened and connected with one-way valve 7 and pit shaft 8 is integral, and by the background technique mode it is hung in back in the basic well, the intubate of will be in the milk 9 then and inserts the spherical valve core 7～1 that the goes directly well cementation of being in the milk; Well cementation back, hang out intubate 9 and with supporting positive cover 10 and 11 bottoms that are loaded on intubate 9 are installed, again with core plug assembly by installing technological hole 6～1 with install 11 fixing and screw with instrument after, hang in that the inner chamber of cylindrical shell 1 is inserted with core plug assembly in the shaft bottom and by intubate 9 rotations (left-handed), gland 6 is screwed in the screw of cylindrical shells 1 and then with core plug 2 be pressed into the core obturating plug; After gland 6 puts in place, intubate continues left-handedly can to withdraw from installing technological hole 6～1 with installing 11, at last intubate 9 is hung out pit shaft 8.