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Optical fiber sensor for measuring downhole pressure

Abstract

The utility model relates to an optical fiber sensor for measuring downhole pressure, which is characterized by comprising a metal protective pipe, wherein one end of the metal protective pipe is a fixed end with a pressure inlet; the other end of the metal protective pipe is a sealed end with an optical fiber leading-out hole, and an outer-layer metal pipe is arranged in the metal protective pipe; an inner-layer metal pipe is arranged in the outer-layer metal pipe in a penetrating way, and one end of the outer-layer metal pipe and one end of the inner-layer metal pipe are connected with the fixed end; an intracavity of the inner-layer metal pipe is communicated with the pressure inlet, and the other end of the outer-layer metal pipe is provided with a pigtail fixing seat; a pigtail is fixed on the pigtail fixing seat, and a pressure cavity end plug is arranged at the other end of the inner-layer metal pipe; a signal transmission optical fiber is fixed on the pressure cavity end plug in the same horizontal line with the pigtail in a penetrating way, and a Fabry-Perot cavity is formed between the end part of the signal transmission optical fiber and the end part of the pigtail; an optical fiber outer armor is sleeved on the outer circumference of the other end of the signal transmission optical fiber, and the signal transmission optical fiber with the optical fiber outer armor penetrates through the optical fiber leading-out hole; and is connected with demodulation equipment after being tightened with the optical fiber leading-out hole through a sealing and tightening device.

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CN202001000U

China

Other languages
Chinese
Inventor
孙福街
黄正宇
曹砚锋
文进
靳勇
徐相涛
Current Assignee
BEIJING WEILANSHI TECHNOLOGY Co Ltd
China National Offshore Oil Corp CNOOC
CNOOC Research Center

Worldwide applications
2011 CN

Application CN2011200571620U events
2011-10-05
Application granted
Anticipated expiration
Expired - Lifetime

Description

The Fibre Optical Sensor of measuring well downforce
Technical field
The utility model relates to a kind of sensor, particularly is placed on the down-hole about a kind of for a long time in the production logging of oil gas well, is used for the Fibre Optical Sensor of measuring well downforce.
Background technology
Smart well is exactly that sensor, the data transmission system that can the obtain down-hole oil gas production information control appliance of unifying has been installed in well, and can carry out that data are collected and the well of decision analysis on ground.Can carry out Long-distance Control by smart well, reach the purpose of optimizing production capacity.Use smart well technology and can carry out Long-distance Control, the cross flow one of avoiding different reservoir pressures to bring to the inflow and the outflow of a plurality of reservoir fluids by a bite well.Adopt for heavy wool is laminated, the application of intelligent completion allows alternately to exploit the upper and lower payzone, has accelerated the speed of production of whole well, has also improved the net present value (NPV) of oil well.The telemanagement of oil reservoir makes that the operating personnel need not well is carried out physical interventions, has reduced the cost of potential workover treatment.Under the condition of rig time (especially in deep water or seabed) cost costliness, the reduction of workover cost can bring significant benefit, has also remedied the output of losing owing to well workover simultaneously.In addition, the injection well of using intelligent completion can carry out water filling control better, improves the ultimate recovery of oil well.Simultaneously, using the smart well system also can reduce the surface based construction and execute cost.The purpose of smart well technology is to improve the oil mining rate, improves the oil field automation controlling level, reduces oilfield operations cost and equipment cost, thereby realizes long-range economic benefit.
Pressure measxurement for the oil gas down-hole, need be able to realize the pressure measxurement that 100Mpa is above, and raising along with the oil and gas exploitation technology, the degree of depth of oil-gas mining constantly increases, the temperature, pressure of oil gas down-hole constantly increases, the pressure-temperature sensor of electronic type can't adapt to present mining environment, the work drifting problem under hot environment occurred, can't long-term work and technical barrier that can't duplex measurement.Fibre Optical Sensor with high temperature resistant, anti-electromagnetic interference, long-time stability do not strike sparks well, safe in utilization, volume is little etc., and advantage has extensively been approved; during but Fibre Optical Sensor is worked under this mal-condition in down-hole; owing to vibrate, the effect of factors such as corrosive fluid is corroded or is destroyed through regular meeting.Such mal-condition can cause the precise decreasing of sensor itself to make sensor failure even.Contact with liquid in the environment so need prevent sensor, avoid corrosion or the destruction of fluid to be measured the kernel approach handkerchief cavity segment of sensor.Need in addition to prevent that the friction that produces between each member in the sensor construction itself from returning the influence that stagnates to what sensor brought, cause the deviation between data that sensor is surveyed and the real data.
Summary of the invention
At the problems referred to above, the purpose of this utility model provides a kind of simple in structure, can adapt to the down-hole mal-condition, and survey data is accurate, is used for the Fibre Optical Sensor of measuring well downforce.
For achieving the above object, the utility model is taked following technical scheme: a kind of Fibre Optical Sensor of measuring well downforce, it is characterized in that: it comprises a protection metal pipe, one end of described protection metal pipe is a fixed end, it is provided with a pressure entrance, the other end of described protection metal pipe is a sealed end, and it is provided with an optical fiber fairlead; Be provided with an outer layer metal tube in the described protection metal pipe, be equipped with an inner layer metal pipe in the described outer layer metal tube, one end of described outer layer metal tube and inner layer metal pipe all is connected described fixed end, and the inner chamber of described inner layer metal pipe is communicated with described pressure entrance; The other end of described outer layer metal tube is provided with the tail optical fiber holder, wears on the described tail optical fiber holder and is fixed with a tail optical fiber; It is stifled that the other end of described inner layer metal pipe is provided with pressure cavity end, wear in same horizontal position on described pressure cavity end is stifled, with described tail optical fiber and be fixed with a signal transmission fiber, have certain distance between the end of described signal transmission fiber and the end of described tail optical fiber, form a method handkerchief chamber; The other end periphery of described signal transmission fiber is arranged with the outer armour of optical cable, and the signal transmission fiber with the outer armour of described optical cable passes described optical fiber fairlead, and by sealing fastening device and the sealing of described optical fiber fairlead fastening after, the connection demodulated equipment.
Described optical fiber fairlead is tapered, described sealing fastening device comprises and is arranged in the described optical fiber fairlead, is set in cutting ferrule before the outer circumferential taper of the outer armour of described optical cable, the awl tip seal of cutting ferrule is pressed on the annular space between described optical fiber fairlead awl tip and the outer armour of described optical cable before described, the other end of cutting ferrule connects the back cutting ferrule before described, it is circumferential outward that described back cutting ferrule other end adapter sleeve is located at the outer armour of described optical cable, and screw thread compresses the hold-down bolt that is connected in described optical fiber fairlead the other end.
Distance range between the end of described signal transmission fiber and the end of described tail optical fiber is 100~200nm.
Described protection metal pipe, fixed end, inner layer metal pipe, pressure cavity end are stifled, outer layer metal tube, tail optical fiber holder and sealing fastening device adopt a kind of material in stainless steel material and the high nickel-base alloy-steel to make.
The utility model is owing to take above technical scheme; it has the following advantages: 1, the utility model is owing to be provided with protection metal pipe; be provided with the inner layer metal pipe and the outer layer metal tube of coaxial line in the protection metal pipe; the fiber fixed frame of forming sensor; therefore, be beneficial to method handkerchief chamber and control chamber, method handkerchief chamber long value are set between two sections optical fiber, sensor has excellent sealing performance in addition; stop hydrogen loss greatly, prolonged the application life of sensor.2, it is stifled that the utility model is provided with pressure cavity end in the end of inner layer metal pipe, be set with signal transmission fiber on pressure cavity end is stifled, when fluid or gas enter in the inner layer metal pipe from pressure entrance, can intercept continuing to flow into of gas or liquid, make the inner layer metal pipe be subjected to the pressure effect of fluid or gas, and can pass through signal transmission fiber transmission pressure value.3, the utility model since the outside of signal transmission fiber is arranged with one deck optical cable outside armour, therefore, draw connection during demodulated equipment from protection metal pipe when signal transmission fiber, can be used for optical fiber is carried out the protection of mechanical strength aspect.4, the utility model is owing to the sealed end at protection metal pipe is provided with the optical fiber fairlead; optical fiber passes the optical fiber fairlead; and armour outside optical fiber is outside equipped with optical cable; the outer armour of optical cable circumferentially is arranged with preceding cutting ferrule, back cutting ferrule and hold-down bolt outward, the outer armour sealing of optical cable can be fastened on the optical fiber fairlead by preceding cutting ferrule, back cutting ferrule and hold-down bolt.The utility model structure is provided with simply, can not produce friction between each member, and can Protection Code handkerchief cavity segment not corroded or destroys, and can adapt to abominable conditions down-hole, and survey data is accurate, therefore, can be widely used in the oil gas underground survey process.
Description of drawings
Fig. 1 is the utility model sensor section schematic diagram
Fig. 2 is the utility model sealing fastening device enlarged diagram
The specific embodiment
Below in conjunction with drawings and Examples the utility model is described in detail.
As shown in Figure 1; the utility model comprises a protection metal pipe 1, and an end of protection metal pipe 1 is a fixed end 2, and fixed end 2 is provided with one and is communicated with protection metal pipe 1 pressure inside inlet 3; the other end of protection metal pipe 1 is a sealed end, and it is provided with the optical fiber fairlead 4 of a taper.Be provided with an inner layer metal pipe 5 in the protection metal pipe 1, an end of inner layer metal pipe 5 is connected and fixed end 2, and the other end is provided with pressure cavity end and blocks up 6, and the inner chamber of inner layer metal pipe 5 is communicated with pressure entrance 3 and forms a pressure cavity 7.The outer outer layer metal tube 8 that circumferentially is arranged with of inner layer metal pipe 5, an end of outer layer metal tube 8 are connected and fixed end 2, and are provided with tail optical fiber holder 9 at this end, wear on the tail optical fiber holder 9 and are fixed with a tail optical fiber 10.Wear on the pressure cavity end of inner layer metal pipe 5 ends stifled 6 and be fixed with a signal transmission fiber 11, signal transmission fiber 11 and tail optical fiber 10 are on same horizon, and has certain distance between the end of the end of signal transmission fiber 11 and tail optical fiber 10, get 100~200nm in the utility model (only as example, but be not limited thereto), form a method handkerchief chamber 12.The optical fiber fairlead 4 that the other end of signal transmission fiber 11 passes protection metal pipe 1 sealed end connects demodulated equipment.Be positioned at the outer outer armour 13 of optical cable that circumferentially is arranged with of the signal transmission fiber 11 of optical fiber fairlead 4 and protection metal pipe 1 outside, the outer armour 13 of optical cable is fastened on the optical fiber fairlead 4 of protection metal pipe 1 by the sealing fastening device sealing.
As shown in Figure 2, sealing fastening device comprises and is arranged in the optical fiber fairlead 4, is set in the outer armour 13 outer circumferential preceding cutting ferrules 14 of optical cable, the one end sealing of preceding cutting ferrule 14 is pressed on the annular space between optical fiber fairlead 4 and the outer armour 13 of optical cable, the other end connects back cutting ferrule 15, back cutting ferrule 15 other end adapter sleeves are located at outside the outer armour 13 of optical cable circumferential, and screw thread compresses the hold-down bolt 16 that is connected in optical fiber fairlead 4 ends.Seal when fastening; compress double-screw bolt 16 extruding back cutting ferrules 15; cutting ferrule 14 before back cutting ferrule 15 extruding; because optical cable fairlead 4 places of protection metal tube 1 are cone structure; when being compressed double-screw bolt 16 extruding; before cutting ferrule 14 awl mouthful most advanced and sophisticated material will fill up in the external diameter and the slit between optical cable fairlead 4 internal diameters of the outer armour 13 of optical cable into, reach the purpose of metallic seal.
Pressure measurement method of the present utility model is: when the pressure of gas or liquid when pressure entrance 3 enters the pressure cavity 7 of inner layer metal pipe 5, pressure cavity end stifled 6 can effectively intercept continuing to flow into of gas or liquid, make inner layer metal pipe 5 be subjected to the pressure effect of fluid or gas, because signal transmission fiber 11 is fixed on the pressure cavity end stifled 6, pressure cavity end stifled 6 is fixed on the inner layer metal pipe 5, tail optical fiber 10 is fixed on the outer layer metal tube 8 by tail optical fiber holder 9, form a method handkerchief chamber 12 between signal transmission fiber 11 and the tail optical fiber 10, therefore, when the pressure that enters pressure entrance 3 changes, corresponding change will take place in the length of inner layer metal pipe 5, this method handkerchief chamber 12 that has also just caused forming between signal transmission fiber 11 and the tail optical fiber 10 changes, pressure increases, the chamber length in method handkerchief chamber 12 will increase thereupon, otherwise, pressure reduces, the chamber in method handkerchief chamber 12 is long also can be reduced thereupon, just formed the relation of a direct ratio like this between the pressure at the chamber long value in method handkerchief chamber 12 and pressure entrance 3 places, after demarcation is finished, by this chamber long value, just can extrapolate current force value, reach the purpose of the utility model pressure measurement with this.
In the foregoing description; resistant materials such as protection metal pipe 1, fixed end 2, inner layer metal pipe 5, pressure cavity end are stifled 6, outer layer metal tube 8, tail optical fiber holder 9 and all preferred stainless steel material of sealing fastening device, high nickel-base alloy-steel are made, but are not limited to this different materials.
The various embodiments described above only are used to illustrate the utility model; wherein the structure of each parts, connected mode etc. all can change to some extent; every equivalents of carrying out on the basis of technical solutions of the utility model and improvement all should not got rid of outside protection domain of the present utility model.

Claims (5)
Hide Dependent

1. the Fibre Optical Sensor of a measuring well downforce, it is characterized in that: it comprises a protection metal pipe, and an end of described protection metal pipe is a fixed end, and it is provided with a pressure entrance, the other end of described protection metal pipe is a sealed end, and it is provided with an optical fiber fairlead; Be provided with an outer layer metal tube in the described protection metal pipe, be equipped with an inner layer metal pipe in the described outer layer metal tube, one end of described outer layer metal tube and inner layer metal pipe all is connected described fixed end, and the inner chamber of described inner layer metal pipe is communicated with described pressure entrance; The other end of described outer layer metal tube is provided with the tail optical fiber holder, wears on the described tail optical fiber holder and is fixed with a tail optical fiber; It is stifled that the other end of described inner layer metal pipe is provided with pressure cavity end, wear in same horizontal position on described pressure cavity end is stifled, with described tail optical fiber and be fixed with a signal transmission fiber, have certain distance between the end of described signal transmission fiber and the end of described tail optical fiber, form a method handkerchief chamber; The other end periphery of described signal transmission fiber is arranged with the outer armour of optical cable, and the signal transmission fiber with the outer armour of described optical cable passes described optical fiber fairlead, and by sealing fastening device and the sealing of described optical fiber fairlead fastening after, the connection demodulated equipment.
2. the Fibre Optical Sensor of measuring well downforce as claimed in claim 1, it is characterized in that: described optical fiber fairlead is tapered, described sealing fastening device comprises and being arranged in the described optical fiber fairlead, be set in the preceding cutting ferrule of the outer circumferential taper of the outer armour of described optical cable, the awl tip seal of cutting ferrule is pressed on the annular space between described optical fiber fairlead awl tip and the outer armour of described optical cable before described, the other end of cutting ferrule connects the back cutting ferrule before described, it is circumferential outward that described back cutting ferrule other end adapter sleeve is located at the outer armour of described optical cable, and screw thread compresses the hold-down bolt that is connected in described optical fiber fairlead the other end.
3. the Fibre Optical Sensor of measuring well downforce as claimed in claim 1 is characterized in that: the distance range between the end of described signal transmission fiber and the end of described tail optical fiber is 100~200nm.
4. the Fibre Optical Sensor of measuring well downforce as claimed in claim 2 is characterized in that: the distance range between the end of described signal transmission fiber and the end of described tail optical fiber is 100~200nm.
5. as claim 1 or 2 or the Fibre Optical Sensor of 3 or 4 described measuring well downforce, it is characterized in that: described protection metal pipe, fixed end, inner layer metal pipe, pressure cavity end are stifled, outer layer metal tube, tail optical fiber holder and sealing fastening device adopt a kind of material in stainless steel material and the high nickel-base alloy-steel to make.