Enhancing Hematite-Based Invert Emulsion Mud Stability at High-Pressure High-Temperature Wells

Abstract

Drilling fluids have a crucial continued role in drilling a successful well; however, most of the drilling technical and operational challenges are incorporated with the drilling mud stability and properties. The solid particles settling in drilling mud that deteriorates its stability is a common issue encountered in high-pressure high-temperature (HPHT) conditions. This issue, known as solids sagging, may eventually result in stuck pipes, wellbore instability, and loss of circulation. The objective of this work is to introduce garamite to enhance the stability of hematite-based invert emulsion mud under HPHT situations. The used garamite and hematite weighting material were analyzed using X-ray fluorescence, scanning electron microscopy, and particle size distribution to identify their compositions, morphologies, and particle sizes. The effects of adding different concentrations of garamite (0.5, 1.0, 1.25, and 1.5 g) to the field formula of hematite-based invert emulsion mud were investigated. The mud density, stability, sagging tendency, rheology, viscoelasticity, and filtration properties were studied to formulate a stabilized and distinguished-performance drilling mud. The obtained results indicated that garamite did not change the mud density while enhancing the emulsion stability by increasing the electrical stability proportionally with the added garamite quantity. The sagging experiments showed that adding 1.25 g of garamite is sufficient to prevent the sagging problem in both static and dynamic conditions as it was enough to enforce the sag parameters into the safe range of sag performance indicators. This 1.25 g of garamite improved the yield point by 152% from 19 to 48 lb./100 ft 2 with a slight increase in plastic viscosity from 14 cP for base mud to 18 cP and significant increase in the gelling strength and viscoelastic properties. Adding 1.25 g of garamite showed a slight enhancement in the filtration properties as the filtrate volume was reduced by 8% from 3.7 to 3.4 cm 3 and the filter cake thickness has 16% reduction from 2.69 to 2.26 mm. As a result, a mud with distinguished performance, in terms of rheology, suspension, sag performance, and stability, was obtained. Hence, a basis for safely drilling the HPHT formations was delivered, which reduces the drilling cost by minimizing the nonproductive time.

Improvement of Hydrogen Sulfide Scavenging via the Addition of Monoethanolamine to Water-Based Drilling Fluids

“…Two commercial H 2 S scavengers (i.e., triazine and SourScav), supplied by a drilling fluid services company, were used as references for comparison with the proposed scavenger. The obtained triazine is in the liquid phase with a density of 1.073 g/ cm 3 , pH of 10.5, and average concentration of 60 vol %. While SourScav is an iron gluconate-based powder that is soluble in water and has a density of 0.7 g/cm 3 , pH of 4.5, and average concentration of 60 vol %.…”

Ilmenite Inclusion: A Solution towards Solid Sagging for Hematite-Based Invert Emulsion Mud

“…The relatively high abrasiveness of hematite is reduced by micronizing its particles [27], which helps in improving the filtration and rheology performance as well [28][29][30][31][32][33][34][35][36][37]. However, hematite sagging was still encountered in HP/HT wells [24,[38][39][40][41].…”

Utilization of Vermiculite for Solving Hematite Sagging in Water-Based Drilling Fluids

“…Different solutions are proposed to mitigate the hematite sagging at both water-and oil-based drilling fluids and experimentally investigated. Some of these solutions used anti-sagging materials such as garamite, laponite, and perlite [11,17,18], while others proposed combining different weighting materials [19][20][21][22]. The research is continued to develop more feasible solutions for the hematite sagging issue.…”