A Test Method for Settling Drag Coefficient of Drilling Particles

Abstract

The invention discloses a test device for the sedimentation drag coefficients of drilling cutting particles. The test device comprises a simulated wellhole, a high speed camera, a data collector and acomputer. In addition, the test method comprises the following steps: step A, carrying out experimental preparation work, sorting experimental settlement drilling cuttings by using a screening net, injecting prepared liquid in a simulated wellhole, and carrying out standing to prevent bubble generation; step B, aligning the camera at the simulated wellhole, placing different mesh numbers of sorted drilling cutting particles in a liquid level slightly one by one, observing a sedimentation experiment of the drilling cutting particles in liquid, and collecting object sedimentation images; step C, processing the collected images and acquiring sedimentation speeds of the drilling cutting particles by using a frame difference method; step D, calculating a sedimentation drag coefficient based onthe sedimentation speeds obtained by the experiment; and step E, constructing a new shape description factor to obtain a new sedimentation drag coefficient empirical model. Therefore, the sedimentation drag coefficients of rock debris particles with different shapes can be analyzed deeply; and thus the prediction accuracy is improved.

Description

technical field [0001] The invention belongs to the technical field of oil and gas field development, in particular to a test method for the settling drag coefficient of drill cuttings particles. Background technique [0002] During the drilling process, wellbore cleaning is one of the main issues affecting efficient and safe drilling. The drilling cuttings in the wellbore are distributed in the drilling fluid in the form of particles. The drilling fluid is a continuous phase and the cuttings are a discontinuous phase, and the cuttings are carried out of the wellbore by the drilling fluid. When the drilling fluid is not enough to provide enough energy to move the cuttings, a cuttings bed will be formed at the bottom of the well. The formation of the cuttings bed will increase the annular pressure loss, which will easily cause high torque and high resistance of the drill string. Adhesion sticking causes problems such as difficulty in running casing and cementing, heavy wear...

AI Technical Summary

Problems solved by technology

Ganser (1993) proposed a method to predict the settlement drag coefficient of spherical and non-spherical, but did not consider the problem of settlement directionality

Gholamhossein Bagheri (2016) proposed a settling drag coefficient prediction model considering regular and irregular non-spherical particles, but the calculation of the shape description factor has the problem that the particle shape cannot be finely distinguished

Although Xianzhi Song (2017) considers the problem of settlement direction, there are oversimplification problems in the calculation of projected area and the use of shape description factors

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