Dynamic seal pressing method and device for improving complex perforation pressing crack effect

Abstract

The invention relates to dynamic seal pressing method and device for improving complex perforation pressing crack effect in petroleum development. High-energy gas generated by complex perforation can be sealed in a perforating section, effective pressure action time can be prolonged and capability for doing work on stratum pressing crack can be strengthen. In the dynamic seal pressing method, shafts at the upper end and the lower end of the perforating section of a composite perforating gun are sealed by gas generated by explosive explosion and gunpowder detonation when the composite perforating gun carries out pressing crack. The dynamic seal pressing device comprises a tubular body which is connected with the end part of the perforating gun, wherein a pressure relief hole with a plug piece is arranged on the tubular body; an inner cavity of the tubular body is provided with an explosive column, first-class explosive and second-class explosive; the first-class explosive is packaged outside the explosive column; the second-class explosive is isolated from the explosive column; and an explosion isolating plate with a sieve mesh is arranged between the second-class explosive and the first-class explosive. After the explosive column is exploded, the first-class explosive is ignited, and the first-class explosive ignites the second-class explosive. The periphery of the shaft near the dynamic seal pressing device is full of the generated high-pressure gas.

Description

technical field [0001] The invention belongs to the field of petroleum exploration and development, and relates to a dynamic sealing pressure method and device for improving the effect of composite perforation and fracturing, and is especially suitable for composite perforation operations of cable or oil pipe transmission and other processes. Background technique [0002] In the field of exploration and development of oil and gas wells, compound perforation, as an effective stimulation method for perforating and completing oil and gas wells, has been widely used in oil and gas well exploration and development. The technical principle of compound perforation is to assemble the perforating bullets arranged according to certain hole density and phase rules into the perforating gun, and evenly distribute and load a certain amount of powder column in the gun. When perforating, the energy-gathering jet generated by the explosion of the perforating bullet first penetrates the casin...

AI Technical Summary

Problems solved by technology

However, for different well conditions, formation conditions and different perforation techniques, the effect of compound perforation operation is different. The pressure difference relative to the wellbore pressure is very large (for example, in a 1000-meter well, the liquid column pressure is about 10MPa, while the peak gas pressure of compound perforation is generally 50-60MPa, and the pressure difference reaches 40-50MPa), the large pressure difference will cause the high-pressure gas to The axial high-speed flow at the wellhead or the low-pressure area at the bottom of the well with the least resistance, the loss of energy causes the gas pressure in the perforation section to drop rapidly, the energy entering the formation is reduced, the action time is short, and the fracturing efficiency is reduced

For wells with low permeability, dense rock and high formation pressure, the formation resistance is large, and the gas pressure cannot quickly enter the formation, so that the wellbore pressure increases, the pressure difference increases, and the energy will also flow to the wellhead and bottom-hole low-pressure area with low resistance. High-speed release causes pressure loss and reduces fracturing efficiency

Different perforation techniques will also affect the fracturing efficiency. For example, for cable transmission, the perforation section length generally does not exceed 4 meters. From the curve obtained by the downhole p-T tester, it can be known that the effective pressure duration of the 4-meter gun is 1 2 to 3 times that of the meter gun, the shorter the distance between the central area of ​​the perforating section and the gun head and tail of the perforating gun, the faster the pressure drop in the central area of ​​the perforating gun, and the worse the fracturing effect

Up to now, there are no reports on the solutions to these problems both at home and abroad.

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