Method for assessing ablation modulai of mudcakes to predict ease of mudcake removal or cleaning efficiency of cleaning/washing/spacer fluids

Abstract

Disclosed is a method and apparatus for determining an ablation modulus of a mudcake on a wellbore wall. According to various embodiments of the invention, the method includes preparing a mudcake, forming a mudcake assemblage comprising the prepared mudcake, screen, and a filter paper, and submerging and securing the mudcake assemblage in a container filled with a fluid. The fluid includes one of a native fluid and a foreign fluid to the mudcake. The method further includes agitating the fluid for a plurality of time intervals, removing the mudcake assemblage from the container after expiration of each time interval, and drying the mudcake assemblage. Further, the method includes weighing the mudcake assemblage to determine an interval weight for each time interval, and determining the ablation modulus of the mudcake on the wellbore wall by graphically correlating the determined interval weights of the remaining mudcake in the mudcake assemblage as a function of time. The ablation modulus of the mudcake is defined by a slope of a tangent of an initial portion of the graphical correlation between the determine interval weights and cumulative time.

Dependencies are inferred from the claim text.