Electric pulse method of drilling wells in the rocks.
Electric pulse method of drilling wells in the rocks is a fundamentally new method of rock breaking and drilling. This method has a high efficiency of conversion of electrical energy into mechanical energy and high speed drilling. For example, 2 m/h when drilling wells with a diameter of 380-400 mm in the granite. Electric pulse method can be destroyed almost all the rocks.
Electric pulse method of drilling wells in the rocks is a fundamentally new method of rock breaking and drilling wells with a diameter greater than 300 mm.
When exposed to a pulsed high voltage microsecond duration on the rock, located in an insulating liquid (including water), the introduction of the channel of electric discharge in rock. Later in this channel during the time of 10-6 – 10-5 with the allocated electric energy stored in the external high-voltage pulse generator voltage (GIN). When this occurs, the electrical blast in the rock. Working body (tool) that Deplete the rock, is the plasma of the discharge channel, which does not change its characteristics from digit to digit, i.e. wear and tear of aging.
Electric pulse method can be destroyed almost all the rocks, except in breeds with very high (metallic) conductivity.
The conversion of electrical energy into mechanical work of destruction takes place directly in the rock without the intermediate steps of transformation. Destruction of rock by cleavage. This ensures a high efficiency of transfer of energy storage in a work of destruction, low power consumption and high performance for blasting of rock at the well bottom.
Feature electric pulse method of drilling is a substantial increase in the efficiency of drilling by increasing the diameter of the borehole (drill bit) in the condition of optimization of drilling mode.
Electric pulse method of drilling allows us to drill wells with coring, it is possible to drill wells of any shape. It was virtually completed the drilling of wells square, ellipsoidal cross-sections. A priori there can be effective curvature of the wells and multilateral drilling.
Schema of washing of wells with electric pulse drilling is not significantly different from the traditional mechanical methods of drilling. The wellhead is equipped with a conductor. The liquid circulation is ensured by pump. The removal of the sludge the liquid, which is the destruction of rocks on the bottom of the well. The sludge precipitated in the settling tanks or is removed by the cyclones. As the drilling fluid are different fluids oil-based. Possible drilling on technical water and water-based solutions.
– high drilling speed and its weak dependence on the strength of rocks (e.g., 2 m/h when drilling wells with a diameter of 380-400 mm in the sample of granite),
– low cost of drill bits and small wear of its electrodes, which are made of ordinary steel,
– no rotating drill string (as a working tool for use electric spark),
– high performance drilling of wells by reducing the number of tripping operations,
– electropulse drilling method has a high efficiency of conversion of electrical energy into mechanical energy,
– low energy consumption,
– high performance blasting of rock at the well bottom and in the development of its diameter,
– design of the electrode system provides automatic control of the sequence of development of the well bottom and the development of its diameter, which eliminates the need for rotation of the drill bit and other types of mechanical loads,
– wear of the drill bit is negligible, which allows to take hundreds of meters of wells without changing the drill bit. All this allows to produce the elements of the drill string out of the ordinary steels,
– electric pulse method of drilling provides the drilling of wells of different shapes, including core sampling,
– there can be effective curvature of the wells and multilateral drilling.
Simplified technological scheme of the electro pulse drilling includes an external sourcegenerator pulsed high voltage, drilling Assembly, tripping device, the flushing system of the well.
Drilling Assembly comprises a drill bit, drill stem and high-voltage input.
The transmission of pulses of high voltage from an external high voltage generator of impulse voltages to the drill tip by using high voltage input on the Central conductor located coaxially in the drill pipe, which is fixed inside the column by using insulators.
The drill bit consists of a set of high-voltage (1) and grounded (2) electrodes combined in a single structure, but electrically isolated from each other.
|the diameter of wells, mm||80 – 1100|
|drilling depth, m||270|
|the energy stored in the high-voltage source pulse, kJ||Of 0.1 – 20|
|the average drilling speed during the pulse repetition rate of 10 pulse/s:|
|borehole diameter, mm||breed||average speed, m/hour|
|250||permafrost with boulders and layers of ice||14,6|