COMPARATIVE STUDY OF CONTAMINANT EFFECT ON MUD SYSTEM AND DRILLING OPERATIONS.

The drilling for oil and gas is at high risk and challenging for the past decades. Irrespective of the uncertainly and the problem associated with the drilling operations, wells are being drilled every day. In order to overcome these problems, the drilling mud engineers must prepare for these challenges so as to meet the expected revenue and the time allocated for a particular drilling job. In this work, experimental tests were conducted at temperature of 120oF and atmospheric pressure to determine the contaminants effects of mud system and drilling operation on seawater and cement slurry of water-based mud (WBM) and oil-based mud (OBM) properties respectively. However, results obtained from the salt and cement contaminants have shown that filtration of different agents into mud system affects the rheological and chemical properties of both (WBM) and (OBM) respectively. The presence of other contaminants on the drilling mud reduces the properties as well and in turn affects the rate of penetration, its performance and poses serious drilling problems. Based on the results obtained, it is advisable that mud program should be properly designed which gives provision for correction of expected contaminant(s) beforehand. Basic knowledge of the drilling mud chemistry must be known so as to effectively supervise the contaminants control, and also mud must be properly treated in order to prevent the destruction of subsurface equipment. Keywords: Drilling fluids, contaminants, water base mud, oil base mud.