Evaluating the Effect of Biocompatible Natural Additives on Thermal, Rheological and Filtration of Drilling Fluids

Filteration controlling of drilling fluid is one of the most important parameters in reducing drilling problems. For this purpose, additives are used, most of which are chemical and besides cost, they also have environmental damage. In this article, the effect of biocompatible natural additives has been studied on the rheological, thermal, and percolation properties of water-based drilling fluids. These additives including astragalus polymers and potato starch in concentrations of 1 to 6 grams per milliliter. As well as the performance of propesd additives is comparing with the hydrolyzed polyacrylamide as an industrial polymer in drilling. The experiments are conducted at 70 degrees Celsius temperature so that the results can be generalized to the real situation. In order to evaluate the effect of temperature on the changes in the thermal properties of the flower, the experiments were also carried out at a room temperature of 25 degrees Celsius. Since polymers have a chain and non-conductive structure, they create a reducing effect on heat transfer and the specific heat capacity of the drilling fluid, while these parameters have a direct effect on the cooling of the drill bit. Using the KD2 Pro apparatus, their thermal conductivity and specific heat capacity were measured. Experimental results show that astragalus polymer increases the viscosity of drilling fluid from 2.3 to 9 centipoise due to its two-part structure, soluble in water and swollen with water. Besides with the addition of astragalus polymer, the amount of mud waste has decreased by 65% compared to the base fluid. In addition, the thermal conductivity of the drilling fluid containing astragalus polymers, potato starch and hydrolyzed polyacrylamide is 7.5, 11 and 18.5% respectively and the specific heat capacity is 9.5, 14 and 23% respectively. The percentage decreased compared to the base drilling fluid. Therefore, Astragalus polymer has a lower reducing effect on the thermal properties of drilling fluid compared to other tested polymers. According to the results of the present article, astragalus polymer can be a suitable option for use in high temperature wells.