Monitoring method of annulus displacement efficiency in simulated cementing engineering

Abstract

The invention discloses a method for monitoring the annular space displacement efficiency of simulated cementing engineering. The method includes respectively injecting displaced liquid and displacing liquid with different electric conductivities into annular spaces of measurement sections of simulated pit shafts; creating sensitivity fields in regions of the annular spaces of the measurement sections of the simulated pit shafts and acquiring voltage signals; computing information of electric conductivities of various points in the sensitivity fields to obtain the occupied volumes of the displaced liquid with the electric conductivities C1 and the displacing liquid with the electric conductivities C2 in the annular spaces of the measurement sections of the simulated pit shafts in different periods; acquiring the displacement efficiency of the displacing liquid for the displaced liquid in a certain period according to the total volumes of the annular spaces of the measurement sections of the simulated pit shafts and the occupied volumes of the displacing liquid in the annular spaces of the measurement sections of the simulated pit shafts in the different periods; drawing displacement efficiency curve graphs by the aid of the acquired displacement efficiency and comprehensively analyzing the displacement efficiency of the displacing liquid for the displaced liquid in the annular spaces of the integral simulated pit shafts. The occupied volumes of the displacing liquid in the annular spaces of the measurement sections of the simulated pit shafts in the different period are acquired by means of analysis and identification. The method has the advantage that displacement flowing conditions of real cementing liquid in annular spaces can be effectively monitored by the aid of the method.

Description

technical field [0001] The invention relates to an efficiency monitoring method, in particular to a monitoring method for annulus displacement efficiency of simulated cementing engineering. Background technique [0002] Cementing engineering is a systematic project that inserts casing into the well and injects cement into the annular space between the wellbore and the casing or between the casing and the casing. The main purpose is to achieve good interlayer isolation and fix the casing. The cementing operation needs to inject flushing fluid, spacer fluid, cement slurry and other fluids into the annular space, which is a complex multiphase flow displacement process. Due to various reasons such as the complexity of drilling fluid, the replacement efficiency of drilling fluid in the annular space during the cementing process is greatly reduced, resulting in low replacement efficiency of cement slurry in the annular space, serious drilling fluid channeling, and poor interface c...

AI Technical Summary

Problems solved by technology

However, at present, in the cementing engineering annular multiphase flow test, there are many methods for monitoring the displacement efficiency at home and abroad, but they all have obvious shortcomings: the waiting coagulation section method needs to wait for the cement slurry in the annular space to solidify and then cut the wellbore , observing the distribution of cement in the annular space to infer the displacement efficiency, but this method is complex to operate, takes a long time to experiment, and cannot measure the displacement efficiency in the flow, which is not conducive to in-depth research; the laser velocimetry method can monitor the real multiphase flow in the annular space Flow state, measuring displacement efficiency, but because the measurement liquid is required to have good light transmission, it is impossible to measure real cement slurry and other on-site experiments with slurry, resulting in a large gap between the experimental results and the actual site; the temperature measurement method can measure real cement The flow of slurry, drilling fluid, etc. in the annular space, but the temperature sensor needs to be immersed in the annular flow field during the measurement, so it will interfere with the flow field and affect the experimental results. In addition, the heat loss during the flow process is large, and the experimental error is large.

[0004] To sum up, the existing methods for monitoring the displacement efficiency of the annulus in simulated cementing engineering have obvious defects, and cannot accurately measure the displacement flow process of real cement slurry and drilling fluid in the annulus. Simulation and research needs

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