Solids-Conveyance Dynamics and Shaker Performance

Abstract

Summary No comprehensive mathematical models are available that can predict solids conveyance and shaker fluid handling capacity for arbitrary solids in a specified drilling fluid. This paper addresses the solids loading problem and presents an analytical approach to the design of shale shakers, based on a dynamic model for solids conveyance off the screen and fluid flow through the screen. First, the solids loading is derived as a function of shaker geometry, solids-conveying speed, bit penetration rate, hole size, drilling fluid flow rate, particle size distribution of drilled solids, and screen opening size. Second, the solids-conveyance model is developed, based on the physics of the problem, accounting for the adhesive forces resulting from wet solids. The effect of various parameters, such as vibration pattern and normal acceleration on solids conveyance, is discussed. The solids-conveyance model can give the optimum set of shaker design parameters for efficient solids conveyance off the screen. For a given shaker, the solids conveying speed predicted by the model can also be used to obtain the flow capacity of the shaker in the presence of solids. Experimental and field results relevant to this study are also discussed.