Kiumars Kamalyar - SPE, Petroleum University of Technology, Ahwaz, Iran; Mohammad Mesbah, SPE, Petroleum University of Technology, Ahwaz, Iran.

The fluid used in rotary drilling, once regarded only as a means of bringing rock cuttings to the surface, is now recognized as one of the major factors involved in the success or failure of the drilling operation. In addition to lifting the cuttings, the drilling fluid must perform other, equally important functions directed toward the efficient, economical, and safe completion of the drilling operation. For this reason, the compositions of the drilling fluid and its resulting properties have become the subject of much study and analysis.The sample which is selected for conducting the experiments is a kind of soil which uses as additive materials in ceramic factories. Two types of this Sample were used as drilling additives which are mentioned as Sample-A and Sample-B. The base mud used in the experiments was a water base mud including 20gr Bentonite per 350 cc water. For each type five samples with different concentrations were prepared and properties of the mud such as fluid loss of the mud, filter cake thickness, apparent viscosity, plastic viscosity, yield point, 10-sec and 10-min gel strength, and mud weight are determined.

Drilling Mud, Physical Properties of Mud, Drilling Additive