Feasibility Study of Rice and Bread Waste as Sustainable Fluid Loss Additives in Water-Based Drilling Fluids

Drilling fluids are essential in oil and gas operations for wellbore stability, cuttings transport, pressure control, and fluid-loss reduction. Water-based drilling fluids (WBDFs) are widely used because of their cost-effectiveness and lower environmental impact compared with oil-based systems; however, they often suffer from fluid loss into the formation and lower rheological performance. This laboratory-scale study investigates the feasibility of using rice and bread waste powders as bio-based additives for WBDFs to mitigate fluid loss. The collected food wastes were dried, milled, and sieved into three particle sizes of fine (150 µm), very fine (75 µm), and ultrafine (45 µm). The prepared powders were characterized using Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX). A total of 18 drilling-fluid formulations were prepared using rice and bread powders at concentrations of 1 wt%, 2 wt%, and 3 wt%. Filtration tests were conducted under low-pressure low-temperature (LPLT) conditions of 100 psi and 25 °C and high-pressure high-temperature (HPHT) conditions of 1500 psi and 70 °C, while rheological properties were measured using a rotational viscometer. The results showed that additive type, particle size, and concentration strongly influenced WBDF performance. The best-performing formulation was WBDF with added rice powder at 45 µm and 3 wt% (RC45-3), which reduced fluid loss from 19.5 mL to 6.1 mL, corresponding to a reduction of approximately 68.7% at LPLT. Under HPHT conditions, the same formulation reduced fluid loss from 36.5 mL to 11.4 mL, corresponding to a reduction of approximately 68.8%. RC45-3 also produced the thinnest measured filter cake, reducing filter-cake thickness from 5.0 mm for the base mud to 0.52 mm. The formulation maintained shear-thinning behavior and produced suitable gel strength values, indicating improved suspension capacity. The improved performance of rice powder is attributed to its fine particle size, favorable morphology, and ability to form a compact, low-permeability filter cake. Overall, the findings indicate that processed rice waste powder has potential as a low-cost, bio-based fluid-loss-control agent for WBDFs, although further testing in field-representative mud systems is required before practical application.