RU2060383C1 - Generator of ac current to supply self-contained well instrumentation in the process of core drilling a well of small diameter - Google Patents

Abstract

FIELD: well drilling, power supply to well self-contained instrumentation and metering devices in the process of core drilling wells of small diameter. SUBSTANCE: generator design provide placing electric magnets instead of permanent magnets in the first detachable part of case of two ones. The case is used as rotor. Small-size power sources are placed in the second part of the case. Electromotive force of high value is possible to increase magnetic field intensity inside generator . This in turn results in power increase. Mechanical key is provided to switch on small-size power sources in the process of drill casing rotation only. Small-size power sources are insulated from impact of aggressive media in the process of drilling. EFFECT: high reliability. 6 dwg

Description

 The invention relates to drilling, in particular to energy converters of the flow of flushing fluid circulating in the well into electrical energy and devices designed to supply electricity to downhole autonomous measuring and control elements and devices.

Small-sized chemical current sources are known that are used to power pipe devices, measurement and control systems during drilling. But their size, low energy consumption and other parameters do not always satisfy the requirements for them [1]
Alternators are also known for these purposes, which consist of a rotor mounted on a drive shaft and a fixed stator. The design of these alternators is closest to the one proposed and adopted by us as a prototype [2]
The widespread use of these alternators for powering autonomous equipment in the process of core drilling of small diameter wells is mainly hindered by the fact that they have a relatively low power. The low pressure of the flushing fluid does not allow a large number of revolutions per unit time of the rotor and thereby limits the increase in the magnitude of the electromotive force of the induction at the outlet, and the small diameter of the well limits the use of permanent magnets with a high magnetic field strength, which depends on the external dimensions of the permanent magnets, t. e. limits the increase in EMF induction, and ultimately limits the increase in generator power.

 The purpose of the invention is to increase the power of an alternating current generator to power autonomous downhole equipment during core drilling of small diameter wells by increasing the magnitude of the magnetic field, which causes the occurrence of EMF induction, and the outer diameter of the structure should not undergo this increase.

 The goal is achieved by using electromagnets located in the housing of the proposed design instead of permanent magnets and power sources for them. Figure 1-6 shows the proposed generator.

 The design of the generator consists of a housing 1, which serves as a rotor, since it is connected to the shaft of a hydraulic turbine, a fixed stator 2 with windings and a collector 3.

 The stator axis 4 is planted at opposite ends in bearings 5 and 6, which are pressed into flanges 7 and 8. The housing consists of two parts: metal 9 and plastic 10. In the metal part, holes 11 for electromagnets are provided (they can be instead of holes depending on the design of the electromagnets grooves) and grooves 12 for their conclusions, and in a plastic groove 13 for small-sized power supplies of electromagnets and grooves 14 for their conclusions, as well as groove 16 for a mechanical key, which is designed to turn on small-sized sources power supply only during the rotation of the column. Instead of plastic, metal can also be used for the second part of the casing, but then in order to prevent short circuits, small-sized power supplies should be installed in the casing. The fastening between the parts of the housing is threaded, and holes 16 serve for their locking with screws.

 The power sources in this case are connected in series in a row, but the rows are connected in parallel with each other and the corresponding conclusions 17 and 18 through the mechanical key are routed to contacts 19 and 20. The leads 21 and 22 of the electromagnets are connected to this using contacts 23 and 24. To close the contacts 19 and 23, 20 and 24 use spring plates.

 The electromagnets consist of a frame 25 or 26, the shape of which can be different, made of a material with a high magnetic permeability μ (for this case μ 2000), which provides a magnetic field with a higher intensity H, and several balls of copper wire wound around it 27.

 The inputs and outputs of the electromagnets with DC sources are connected so that there are different poles of the magnetic field on the diametrically opposite sides of the case, and the same along the rotor, that is, if the input of the first row of electromagnets that are connected in parallel is connected to the plus of the power source, then the input is diametrically the opposite row is connected to the minus of the source. To turn on power sources only during rotation of the drill string, frequency sensors or mechanical keys are used. The key consists of contacts 29, 30, springs 31 placed in a lockable container 28, with a load 32, which are able to freely move along the rod 33.

 The absence of permanent magnets makes it possible to increase the thickness h of the housing of the proposed generator compared with the thickness of the prototype, and this, in turn, makes it possible to increase the number of turns in an electromagnet, i.e. ultimately increase the generator power.

 In order to prevent exposure to a corrosive environment, electromagnets, small-sized power supplies, a mechanical key, and all leads on the case are filled with epoxy.

 The stator design of the proposed generator practically does not differ from the design of the prototype anchor.

 The connection between the generator housing 1 and the flexible coupling 34, mounted on the shaft 35 of the turbine, is made using screws, for which holes 36 are provided. Rotating the turbine, the circulating flow of washing fluid rotates the rotor of the generator. The resulting centrifugal force changes the length of the spring 31, thereby closing the contacts 29 and 30, including the power sources, and the resulting field in the rotating coils of the electromagnets induces the appearance of alternating current in the stator windings, which, using the terminals 37 from the collector, is supplied to the downhole monitoring devices or drilling process control.

 A significant difference in the proposed design of a generator of increased alternating current power for feeding downhole equipment during the drilling of small diameter wells is that in order to increase power without increasing the external diameter, the rotor is equipped with electromagnets, a small-sized electromagnet power source and a mechanical key, and is made in the form of a housing, consisting of two detachable parts, in one of which electromagnets are placed in rows, and in the second also small-sized current sources electricity, and a small-sized power supply source is isolated from the influence of a corrosive medium and interconnected in parallel, and their conclusions and the corresponding conclusions of electromagnets are interconnected through the contacts of a mechanical key.

 In this design of the generator, without increasing the size of the outer diameter, the magnetic field strength causing the appearance of induction EMF is several times greater, and therefore, more power than in the prototype (in this case, more than 5 times).

 Indeed, the method of calculating the magnetic fields of strip permanent magnets according to Scott and nomograms according to this method show that strip magnets with a maximum magnetic induction of several tens of millites are applied to alternating current generators with a small diameter. But, according to the law of Bio-Savard-Laplace, electromagnets for the same purpose with a current strength of 0.012 A can form magnetic fields by induction an order of magnitude higher than 0.5 T. This explains the feasibility of using the proposed generator design.

 Technical and economic efficiency of using the proposed generator design lies in the simplicity of manufacture, the use of standard small-sized power sources.

 The use of this proposed design, which is simple in manufacturing, will allow us to increase and expand the range of both the quality of control and the quality of drilling process control due to the possibility of using more powerful devices.

Claims (1)

 An alternating current generator for supplying autonomous borehole equipment during core drilling of small diameter wells, including a rotor fixed to the drive shaft, a stator and a collector, characterized in that the rotor is equipped with electromagnets, small-sized sources of electromagnet power supply and a mechanical key and is made in the form of a housing, consisting of two detachable parts, in one of which electromagnets are placed in rows, and in the other also small-sized power sources and mechanical spanner, and compact power sources are isolated from current exposure to the corrosive environment and connected in series in a row, rows of AC power sources connected in parallel, and their findings and conclusions corresponding electromagnets are interconnected through the contacts of the mechanical key.

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