Experimental Investigation of Local Thinners (Wheat Straw and Pomegranate Peel Powder) in Water-Based Drilling Fluid

Abstract

Drilling fluid is a vital element for safe and optimum drilling operations. A proper selection of drilling fluid can perform its essential functions during well construction. However, more uncertainties in planning the drilling fluid properties meant that operators faced more drilling challenges with inexplicable differences between the used and the required fluid properties. Flocculation of clay solids is one of the most common challenges at certain drilling conditions, and thus many drilling processes are exposed. To overcome this challenge, on the other hand, chemical thinners such as tannins and lignosulphonate can be used to naturalize the ability of the clay platelets to be linked together. A major issue with these additives is that they are not locally available, and they are expensive. This study investigates two local materials as thinners to increase the efficiency of the fluid system. These materials are wheat straw (SW) and pomegranate peel powder (PPP). Seeing how the fluid rheological properties are sensitive to the proposed thinners, four rheological properties were investigated in this study which are plastic viscosity, yield point, mud filtration, and gel strength. To figure out whether the drilling fluid gelation will be affected by different concentrations of thinners, three times of mud gelation (10 sec, 5 mins, and 10 mins) were checked. The chemical analysis of this study supports the evidence that the presented thinners contain acceptable percentages of lignin which can control the fluid rheological properties. The results reveal that increasing the thinners concentrations leads to a decreasing in the yield point, plastic viscosity, and effective viscosity. Although the results of both wheat straw (SW) and pomegranate peel powder (PPP) resemble to be closely, the PPP was more conservative in controlling the fluid rheological properties than SW. This study presents cost-effective local thinners for future well planning in Iraqi oil fields.

Keywords: Drilling fluids; thinners; wheat straw; pomegranate peel powder