Louden, L.R., and Lawson, G.W., Members AIME, Oilfield Products Group, Dresser Industries, Inc.
Discussion of this paper is invited. Three copied of any discussion should be sent to the Society of Petroleum Engineers office. Such discussion may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines.
A review of the role of sedimentation as applies to oilfield equipment for solids control is presented. By remembering that most all solid removal oilfield equipment except the screen function on an accelerated gravity principle, a proper understanding and use of the available equipment can be principle, a proper understanding and use of the available equipment can be obtained.
In many processes it becomes necessary at some stage to separate one liquid from another, or solids from a liquid, or both — problems that have traditionally been solved by filtration or gravity sedimentation. Equipment presently in use in the oilfield for removing solids from mud for plastic viscosity and yield strength control is all based on sedimentation plastic viscosity and yield strength control is all based on sedimentation in one form or another, with one exception. Block diagram in Fig. 1 shows how oilfield equipment may be classified.
This exception, and it is important, is the vibrating screen, a sort of continuous filtration operation, to remove continuously the particles which would form the filter cake. Ironically, the vibrating screen is capable of removing a greater weight of drilled solids per dollar spent than any other piece of rig equipment. Yet it is probably misused and misunderstood by most people.
The remainder of the devices in common use all depend upon the sedimentation operation, and except for settling pits and ditches, these devices are based on enhancing the gravimetric forces to do this job faster, more efficiently, more economically, and in less space.
Often the term separation is used to describe an operation which is not separation at all. (The authors have fallen into this trap in this paper.) When the term separation is used in this paper, it means paper.) When the term separation is used in this paper, it means concentration of one phase or the other to acceptable limits.