A New Simplified Approach of Controlling Properties Of Invert Emulsion Drilling Fluids at the Well Site

American Institute of Mining, Metallurgical and Petroleum Engineers Inc. This paper was prepared for the 45th Annual Fall Meeting of the Society of Petroleum Engineers of AIME, to be held in Houston, Tex., Oct 4–7, 1970. Permission to copy is restricted to an abstract of not more than 300 words. Illustrations may not be copied. The abstract should contain conspicuous acknowledgment of where and by whom the paper is presented. Publication elsewhere after publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF PETROLEUM ENGINEERS JOURNAL is usually granted upon requested to the Editor of the appropriate journal, provided agreement to give proper credit is made. Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers office. Such discussions may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines. This paper points out some of the limitations of the present day testing procedures commonly in use and procedures commonly in use and describes a method used to obtain more meaningful data to control the properties of a fluid at a desired properties of a fluid at a desired optimum level with conventional equipment. The retort unit which measures the volumetric percentages of oil, water and solids in a mud has been found to be most useful. Experimental data obtained using this equipment fall within the experimental error range of the calculated volumetric percentages of oil, water and solids percentages of oil, water and solids for muds of different densities. As the oil-water ratio of an invert emulsion drilling fluid is increased, the density of the liquid phase (oil and water) decreases. The volume percent solid contribution from the percent solid contribution from the dissolved salt (NaCl) in the water phase to the total retorted solids phase to the total retorted solids percentage of the system also decreases. percentage of the system also decreases. Therefore, to maintain a constant mud density, additional amounts of barite are needed as the oil-water ratio is increased. Any change in the volume percent of salt caused by an alteration percent of salt caused by an alteration of the oil-water ratio is approximately balanced by a corresponding change in the volume percent of barite. Thus, a linear relationship between the volume percent solids and mud density is obtained which is practically independent of the amount practically independent of the amount of oil and water in the system. Representation of the above relationship in a graphical form has been proven to be of valuable assistance in controlling the properties of invert emulsion drilling fluid at the well site. It has been observed both in the laboratory and in the field that by maintaining the percentages of oil, water and solids within a specified range, all the measured properties (rheological, fluid loss and electrical stability) fall automatically within the desired range when measured under identical conditions.