Double-layer continuous pipe double-gradient drilling system

Abstract

The invention discloses a double-layer continuous pipe double-gradient drilling system. On the basis of conventional drilling equipment, the double-layer continuous pipe double-gradient drilling system includes a double-layer continuous pipe system, isolation fluid, a downhole lifting pump system, a throttle control system and a data monitoring system; power fluid is injected by a drilling pump package, passes through a conversion joint and enters a double-layer pipe annulus, passes through a downhole lifting pump, enters a double-layer continuous pipe inner pipe through a bridge type channel,and then passes through a power drill tool and a drill bit and enters a bottom hole; and return fluid passes through a recovery hole and enters an annulus channel of a double-layer continuous pipe, then enters the double-layer continuous pipe inner pipe through the bridge type channel and enters the downhole lifting pump, and then passes through the conversion joint and the throttle control system successively and enters a solid control system. According to the double-layer continuous pipe double-gradient drilling system, a drill pipe does not need to be connected, the drilling time is saved,through monitoring of the isolation fluid and adjustment and control of the drilling pump package, the bottom hole pressure gradient is adjusted and controlled, the problem of narrow safety drillingdensity windows is solved, the advantages of lowering the drilling cost, reducing the drilling risk, and improving the efficiency are achieved, and the practicability is high.

Description

technical field [0001] The invention relates to the field of deep water drilling, in particular to a double-layer continuous tubing double-gradient drilling system. Background technique [0002] At present, the global energy problem is becoming more and more serious, and the oil and gas resources in land and shallow sea areas are far from meeting the needs of human beings. The exploration and development of deep-water oil and gas resources has become a current development hotspot. However, when drilling in deep sea areas, there are problems such as narrow safety pressure window, weak cementation of the seabed formation, difficulty in wellbore pressure control, and poor wellbore stability, resulting in high drilling safety risks and high costs. [0003] Therefore, in order to promote the exploration and development of deep-water offshore oil and gas, how to address the problems of easy-to-leak production layers, poor drilling safety in loose seabed surface layers, low format...

AI Technical Summary

Problems solved by technology

However, when drilling in deep sea areas, there are problems such as narrow safety pressure window, weak cementation of the seabed formation, difficulty in wellbore pressure control and poor wellbore stability, resulting in high drilling safety risks and high costs

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