Major advancements have been made in the past decades to determine the effects from particle additions to drilling fluids. These additions affect wellbore stability, hole cleaning, sag stability, formation damage and back-production capabilities. Furthermore, optimum drilling fluid performance is strongly dependent on knowing the properties of the formation such that correct selections of drilling fluid additives can be made. Likewise, it is important to know if produced solids are drilled cuttings or cavings originating from unstable holes.

In field applications, there has been reluctance towards trusting solids control equipment as the only method for controlling the particle size distribution (PSD) and particle content of the drilling fluid system, since no real-time monitoring equipment has been available to produce the necessary measurements. The present paper describes a technique based on image analysis, which makes it possible to obtain such information in real-time. The method also provides valuable information for characterizing drilled cuttings, creating the basis for caving logs. A method for obtaining mineralogical data from the formation by analyzing the drilled cuttings by using Raman spectroscopy is also described. Field tests and laboratory studies demonstrate the potential of the techniques for improved drilling process control by continuously monitoring the particles in the system while drilling. Some of the elements in a drilling fluid process which are affected by the presence of particles are also described.

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