RU2147664C1 - Method of well drilling - Google Patents

Abstract

FIELD: oil-and-gas producing industry. SUBSTANCE: method may be used in production of oil, gas, etc., in exploration of oil and gas fields, and in earth drilling for investigation purposes. Distinguishing feature of the method is the fact that joining of drill pipes to one another and their disconnection in the course of drilling are carried out for one revolution by one laser beam tool and without interruption of drilling process. EFFECT: higher productivity and reliability of drilling equipment. 2 cl, 2 dwg

Description

 The present invention relates to the field of well drilling and can be used in the production of oil, gas, etc., in the exploration of oil and gas, as well as in the drilling of land for research purposes.

 Traditional drilling methods involve sequential drilling into the rock with a drill, which is located at the end of the drill pipe. Drilled rock is brought to the surface by a continuous stream of clay solution (see, for example, [1]). As the drill and the first drill pipe sink into the ground, a new drill pipe connects to the first. To connect drill pipes to each other, use [2], either through a sleeve with two internal threads at both ends (over-bit pipes), or with an internal thread at one end and an external thread at the other (intermediate pipes), or with drill joints. Alloy pipes with steel lightweight drill joints also have standard threads at the ends.

 Each time a drill with a drill pipe system sinks to a depth equal to the length of one drill pipe, a new pipe is attached (screwed or coupled).

 After completing the drilling of the well to a predetermined depth, the drill with the drill pipes connecting to each other is subsequently taken to the surface. As soon as the interconnected drill pipes (drill string) are pulled out to the length of one pipe, the upper pipe is unscrewed. Next, the drill string rises and unscrews the next pipe and so on until the drill reaches the surface.

The disadvantages of the traditional method of drilling wells are:
1. Low productivity of the entire drilling process of the well, due to the fact that usually the drilling depth is quite large compared to the length of the used drill pipes. Therefore, a sufficiently large number of pipes are used for drilling a well, and each of them has two threads that must be screwed together directly or through a coupler when drilling the well and unscrewed when pulling the drill out of the well, which is time consuming.

 2. For screwing pipes together or screwing through a sleeve, it is necessary to rotate one of them, which requires appropriate mechanisms.

 3. The strength of the threaded joint is lower than the strength of the base metal of the drill pipe. Failure of a threaded joint leads to a halt in the process of drilling a well and the loss of an expensive drill.

 4. In order to increase the resistance of the threaded connection to alternating bending, unloading threaded grooves are created with a roller running in the profile and surface cavities. To increase the fatigue endurance of a threaded connection, there are unloading grooves that extend along the outer diameter of the pipe on both sides of the connection.

 All these measures sharply increase the cost of work and, in addition, the strength of the threaded joint after them increases, but does not reach the strength of the base metal of the drill pipe.

 5. In case the pipes are connected by external and internal threads, the length of the drill string is reduced by 2 lengths of the cut sections of the pipes to be connected. Therefore, an additional number of pipes is required.

 6. In the field, it is necessary to carefully protect the pipe threads from impacts against foreign objects and against each other, and make sure that dirt, precipitation, etc. do not get into the threaded connections.

 7. On each of the used drill pipes it is necessary to cut two threads, which increases the cost of tooling.

 8. If the drill pipe is connected to each other without a threaded connection, using a sleeve, then the strength of such a connection will still be lower than the strength of the base metal of the pipes and breakage is most likely to occur in this place.

 The above-mentioned disadvantages of the analogue methods are partially or completely eliminated by using the tool joint of drill pipes (rods) [3], which contains a nipple and a sleeve with an annular cavity filled with solder, the inner walls of which are parallel to the vertical axis of the joint, and for the purpose of irreversible and non-orientational joining and of the pipe undocking, the annular cavity of the coupling is made with lateral grooves evenly spaced around the circumference, and on the outer surface of the nipple grooves are made with longitudinal slots up to end face.

 The method of connecting pipes (rods), which is implemented using lock joints [3], we took as a prototype as the closest technical solution to the claimed invention.

 According to this method, one-piece connection of drill pipes (rods) is realized by melting the solder located in the annular cavity of the coupling, the flow of this solder into the vertical slots of the nipple, solidification of the solder, which provides one-piece connection with the possibility of transmitting torque from one rod (pipe) to another.

The disadvantages of the prototype method are:
1. Low productivity of the process of connecting one pipe (rod) to another. To ensure a one-piece connection, it is necessary to heat the coupling with the solder in it to the melting point of the solder, then additional time is required for the solder to flow into the nipple grooves and to cool the solder to a temperature that guarantees the necessary strength of the connection.

 2. Relatively low joint strength, since the strength of the solder is usually much lower than the strength of the metal of the nipple and the coupling, in addition, the cross section of the hardened solder nipple in the grooves is much smaller than the cross section of the pipe.

 3. The high cost of the connection, associated with the complexity of the design of the rods (pipes), including the nipple and couplings of complex shape, requiring complex equipment for their manufacture.

 The problems solved by the invention are to increase the productivity and reliability of the drilling process, as well as its cost.

 The above tasks are realized by the fact that the permanent connection of drill pipes during drilling is carried out by laser welding, and the separation of drill pipes when drilling the drill to the surface is carried out by laser cutting.

 Connection by laser welding and separation by laser cutting lead in one pass.

 Connection by laser welding and separation by laser cutting are carried out by rotation of the drill pipe with a non-rotating laser.

 The connection of drill pipes together is one-piece.

 The connection and disconnection of drill pipes can be carried out both in one place and in different places of the pipe. The cut pieces of the pipe can be longer than the welded ones. Longer pipe pieces are easier to reuse than shorter ones.

 The invention is illustrated in FIG. 1 and FIG. 2.

 In FIG. 1 shows a General diagram of the implementation of the method of drilling wells.

 In FIG. 2 shows a section along AA in FIG. 1.

 The method is implemented as follows (Fig. 1).

 In the process of drilling a well, a drill pipe 1 with a drill 2 fixed at its end from the surface of the earth 3, rotating around its own axis, sequentially drops down. As soon as the main part of the drill pipe goes down to the ground, a new drill pipe 4 is installed on its upper end face 4. Laser radiation (not shown in Fig. 2) supplied to the joint 5 of the drill pipes being welded. The rotation of the pipes around its axis provides welding of the annular seam. In the case when laser welding is carried out simultaneously with drilling, the laser beam is lowered as the drill string is lowered.

 The manipulators of the optical focusing systems of the laser can be performed in various ways and are not considered in the framework of this application.

 After the laser beam has welded the pipes, the drilling process will continue.

 The welded pipe will constantly move down until the moment when its upper end gets into the place of welding. The next pipe is installed on the pipe and the next laser welding is performed and so on.

 After the desired drilling depth is reached, the process of excavating the drill and drill string from the well is carried out. Using hoisting mechanisms, drill pipes welded together with the drill fixed to the last of them are removed from the well.

 The drill string is cut into individual pipes by a laser beam at the welding site in one pass using the same laser beam manipulators as in welding.

 To ensure maximum productivity of the well drilling process, the drilling process is carried out without stopping to connect the pipes. To do this, the rotation of the drill pipe is used as a working movement in laser welding. In this case, using additional mechanical units, the laser beam, following the pipe junction point to which it is directed, is lowered down by a distance equal to the distance that the drill drills with one revolution of the drill string.

Thus, the use of the invention will allow:
1. Significantly increase the productivity of drilling due to the abandonment of the operation of making and unscrewing pipes or in comparison with the prototype due to the rejection of their connection with the coupling and the time required to melt the solder, flowing it into the grooves of the nipple and cooling the solder.

 2. To increase the reliability of the working equipment due to the fact that the pipes welded together are a single unit, and the screwed ones are not, and breakages are possible at the places of the thread or other places where the pipes are connected. In addition, the mechanical properties of the weld metal welded with a laser beam are equal to or higher than the characteristics of the metal of the main material of the pipe.

 3. Significantly simplify the drilling process and reduce the cost of its rigging through the use of pipes without threads at their ends or without structurally complex joints such as the coupling - nipple. Pre-cutting pipe ends before laser welding is not required. Since laser cutting provides a sufficiently good quality of the edges of the cut, for the secondary use of the pipes does not require additional processing of the ends.

 4. Laser welding and laser cutting ensure that the entire length of the pipe is used in the drilling process, while the traditional method uses part of the pipe (total length minus 2 lengths of thread at both ends or total length minus nipple or coupling, as in the prototype).

 5. There are no mechanisms for turning and screwing the pipe.

 List of references.

 1. The Great Soviet Encyclopedia, M., 1951, g. 6, p. 306.

 2. A. G. Kalitin et al. "Profiles of directional wells and layout of the bottom of the drill string", M., "Nedra", 1995, pp. 245-252.

 3. Copyright certificate SU N 570691, “Lock connection”, IPC E 21 V 17/046, F 16 V 17/00. A.A. Petrosyan et al., Publ. BI N 32, 09/13/77.

Claims (2)

 1. A method of drilling wells, in which the consecutive one-piece connection of drill pipes to the drill string is carried out as the drill goes deeper and the drill pipes are sequentially disconnected from the drill string when the drill is brought to the surface after drilling, characterized in that the drill pipe is connected by laser welding, and disconnection is carried out by laser cutting in one pass, and laser welding of drill pipes is carried out simultaneously with drilling, while the drill pipes are rotated helically around their own axis, and the laser beam is lowered during welding as the drill string is lowered.  2. The method of drilling wells according to claim 1, characterized in that the cutting of the drill string by laser cutting is carried out into pieces of greater length than the original drill pipe.

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