Combined multi-stage pressure control method and device

Abstract

The invention discloses a combined multi-stage pressure control method, which is applied in petroleum and natural gas drilling pressure control. In the invention, a rough adjustment throttling control system and a fine adjustment throttling control system are connected in series to control the circulating pressure loss of drilling fluid and adjust a bottom-hole pressure. The rough adjustment throttling control system consists of a plurality of rough adjustment throttling channels and a straight flow channel, which are connected in parallel; and each rough adjustment throttling channel is formed by connecting a self-control flat valve and a throttling short connector in series, and the self-control flat valves as well as the throttling short connectors of all rough adjustment throttling channels are the same. The method has the advantages that: the mode of connecting various throttling channels in parallel or series is adopted, so the control range of the throttling pressure differenceof a throttling short connector is kept in a certain range; the circulating pressure of the drilling fluid is adjusted roughly to approach or reach a bottom-hole pressure control range; and the fine adjustment throttling control system finely adjust the circulating pressure of the drilling fluid to meet the requirements for high-precision bottom-hole pressure control.

Description

technical field [0001] The invention relates to the field of oil and natural gas drilling pressure control equipment, in particular to oil and gas well pressure control drilling technology, and is a combined multi-stage pressure control method and device. Background technique [0002] Oil and gas well engineering includes three basic drilling methods, namely underbalanced drilling, near balanced drilling and overbalanced drilling. Among them, the bottom hole pressure is lower than the formation pressure during underbalanced drilling, the bottom hole pressure is close to the bottom hole pressure during near balance drilling, and the bottom hole pressure is greater than the formation pressure during overbalanced drilling. The application fields of the three drilling methods are different. Overbalanced drilling is relatively conservative, which is not conducive to improving drilling speed and reservoir protection, and the application range will gradually narrow; The performanc...

AI Technical Summary

Problems solved by technology

The application fields of the three drilling methods are different. Overbalanced drilling is relatively conservative, which is not conducive to improving drilling speed and reservoir protection, and the application range will gradually narrow; The performance requirements are high, and the application range is limited; the application range of near-balanced drilling is not limited, which is helpful for the increase of drilling speed and reservoir protection, but requires precise bottom hole pressure control

[0004] The traditional well control and throttling system can only control the bottom hole pressure with aggravated drilling fluid, the control accuracy is low, and it takes a long time to establish equilibrium, which cannot meet the requirements of controlled pressure drilling. A new pressure control system must be developed to meet the development requirements of controlled pressure drilling.

The pressure control systems of international well-known companies such as Halliburton and Shell all use a single high-performance throttle valve for throttling, which can perform precise pressure control for a long time under large pressure difference and large flow, but the cost is very expensive. Although the cost of the throttle valve is low, its wear resistance and impact resistance are poor, and it cannot meet the requirements of long-term and continuous pressure control under the condition of large pressure difference

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