Synergistic Effect of Nanoinhibitive Drilling Fluid on the Shale Swelling Performance at High Temperature and High Pressure

Borehole stability is one of the crucial success elements of the drilling operation, which is partially dependent upon the chemistry of the drilling fluid. Nanoparticles are emerging as one of the most significant additives for improving the major properties of drilling fluids. Thus, SiO2/KCl/xanthan nanocomposites (NCs) was synthesized from Euphorbia condylocarpa extract in an eco-friendly and environmentally friendly way. The synthesized NCs was used to prepare nanoinhibitive drilling fluids (NIDFs) at different concentrations to improve the rheological, filtration, and inhibition properties of the drilling fluid. All of the required experimental tests related to the rheology, filtration, and swelling measurements were performed at the ambient and high temperature and high pressure (HTHP) conditions. The obtaining results revealed that the rheological properties of the drilling fluids (plastic viscosity, yield point, and gel strength) were improved from 4 cP, 10 lb/100 ft(2), and 27 lb/100 ft(2) to 19 cP, 17 lb/100 ft(2), and 46 lb/100 ft(2) (with adding 4000 ppm of KCl) and 19 cP, 62 lb/100 ft(2), and 54 lb/100 ft(2) (with adding 4000 ppm of synthesized NCs), respectively. In addition, the filtration properties of the base drilling fluid were increased by adding 4000 ppm of KCl at HTHP (fluid loss from 25.85 to 36.38 mL and thickness of the filter cake from 3.4 to 5.1 mm), while the synthesized NCs was more effective in lowering the fluid loss and filter cake thickness from 25.85 mL and 3.5 mm to 2.5 mL and 0.33 mm, respectively. Moreover, NIDFs were favorable in decreasing shale swelling that was 52.2%, but conventional inhibitive drilling fluids could lower shale swelling by 41%. It can be stated that NIDFs are highly applicable toward the successful drilling operation as a result of their abilities in reducing shale swelling, improving rheological properties, and decreasing the filtration properties.