Self-feedback two-phase system drilling fluid mixing system and method of mixing drilling fluid

Abstract

The invention relates to a self-feedback two-phase system drilling fluid mixing system. The self-feedback two-phase system drilling fluid mixing system comprises a mixer, a sea water pool and a base slurry pool; the sea water pool is connected to the mixer through a first pipeline, and the base slurry pool is connected to the mixer through a second pipeline. The sea water pool contains sea water and used for providing a sea water raw material for the first pipeline; the base slurry pool contains base slurry and used for providing a base slurry raw material for the second pipeline; the sea water and the base slurry enter a slurry pool or a slurry pump manifold through a density self-feedback module after being mixed in the mixer. Compared with the prior art, the self-feedback two-phase system drilling fluid mixing system is provided with the density self-feedback module which can not only make the density of mixed liquid more precise, but also calibrate a flowmeter by detecting the density and setting or designing density comparison, an overflow valve added between a pump and the flowmeter can make the system mix materials of various proportions in the state that the power of the pump is not controlled, and mixing is more efficient.

Description

technical field [0001] The invention belongs to the technical field of drilling, and in particular relates to a self-feedback two-phase system drilling fluid mixing system and a drilling fluid mixing method. Background technique [0002] Drilling fluid balanced drilling is currently a mature drilling technology in the world. In deep water drilling, balanced drilling technology uses the static pressure of seawater and drilling fluid to balance the underlying pressure to ensure normal drilling. However, drilling in deep water and shallow formations faces the risks of shallow geological disasters such as shallow flow and shallow gas, as well as drilling difficulties such as narrow pressure windows caused by weak formations: [0003] 1. The safe density window is narrow, the design of the well body structure is difficult, and the casing cannot be lowered to the predetermined depth. In deepwater drilling, the overburden pressure exerted by seawater is much lower than that exerte...

AI Technical Summary

Problems solved by technology

Therefore, since the fracture pressure gradient of deep-sea formations is smaller than that of land formations with the same well depth, the safety margin between the formation pressure gradient and the fracture pressure gradient is very small, and the safety density window becomes narrower as the water depth increases. It is more difficult, and the casing cannot be lowered to the predetermined depth

[0004] 2. Drilling encountered high-pressure shallow flow, it is difficult to effectively implement well control

[0006] There is no self-feedback device in the prior art, and it is impossible to re-test and adjust the mixed liquid that does not meet the requirements. The long-term use of the system will lead to deviations in the readings of the flowmeter, which will cause the ratio of the base slurry and seawater to be different from the preset parameters or design. Deviations in the parameters will eventually lead to the failure of the mixed fluid density to meet the requirements, which is very fatal in the implementation of this technology; there is no pump pressure protection device in the prior art, and it is impossible to realize the mixing of various mixing ratios , or the safety and reliability of the pump cannot be guaranteed; the high-viscosity base slurry phase is pumped by a shear pump, which can destroy the network structure of the high-viscosity fluid and is more conducive to the mutual mixing of the base slurry and seawater, making the mixing more efficient

Images