Prediction method of actual pressure-on-bit at the bottom of static push-by rotary steerable drilling tool

Abstract

The invention discloses a method for predicting the shaft bottom actual bit pressure of a static pushing type rotary guide drilling tool, and belongs to the fields of research and application of a rotary guide drilling technology. The method mainly comprises a shaft bottom bit pressure and minimal nominal bit pressure calculation method in the process of drilling a large-section homogeneous formation (the well wall does not have steps) and soft and hard staggered formation (the well wall has steps), as well as a chamfer upper limit value calculation method capable of avoiding self locking of a wing rib front chamfer surface. The implementation mode of the method as well as an influence ruler of nominal bit pressure, a guide wing rib pushing force and well wall friction coefficient on the shaft bottom actual bit pressure are provided by combining the embodiments. By the method, the shaft bottom actual bit pressure can be predicted, regulated and controlled accurately, the drilling efficiency of an SRS drilling tool is improved, and the drilling time and the drilling cost are saved; and technical support is provided for the guide wing rib front chamfer design of the SRS drilling tool.

Description

technical field [0001] The invention relates to the field of petroleum drilling engineering, in particular to the field of research and application of rotary steerable drilling technology, in particular to a method for predicting the actual pressure-on-bit at the bottom of a static pushing type rotary steerable drilling tool. Background technique [0002] Rotary Steerable Drilling System (rotary steerable system, referred to as "RSS") is a steerable drilling system that completes the steering function in real time while drilling under the condition of drill string rotation. Since the 1990s, rotary steerable drilling technology has gradually matured and been popularized, and directional drilling technology has made a qualitative leap. At present, relatively mature RSS systems mainly include the AutoTrak drilling system of Baker Hughes Company, the PowerDrive drilling system of Schlumberger Company, and the Geo-Pilot drilling system of Halliburton Company. Drill type. Among ...

AI Technical Summary

Problems solved by technology

However, the non-rotating sliding sleeve of the SRS drilling tool hardly rotates with the drill string during normal drilling, and there is a large friction force between the guide rib and the well wall, resulting in the actual drilling pressure at the bottom and the nominal drilling weight obtained by releasing the hook hanging weight. There is a large difference in drilling pressure, and the selection of nominal drilling pressure based on experience at the drilling site often results in the actual drilling pressure at the bottom of the well not meeting the predetermined requirements, which not only affects the drilling speed, but also makes it difficult to give full play to the advantages of rotary steerable drilling technology

Especially when drilling in soft and hard formations, there are often small steps at the formation interface, which has a greater impact on the WOB transmission efficiency; once the front chamfer of the guide rib is not designed properly, the chamfer surface may self-lock with the well wall , it will be difficult for SRS drilling tools to pass through the steps of the well wall, and it will be difficult to maintain normal drilling work

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