Optimum Selection of H₂S Scavenger in Light-Weight and Heavy-Weight Water-Based Drilling Fluids

Abstract

During hydrocarbon drilling operations, the presence of hydrogen sulfide (H2S) gas could cause serious health and safety issues. Scavenging this gas and eliminating its impact are essential requirements for a safe drilling operation. This study investigated the impact of three H2S scavenger additives (copper nitrate, iron gluconate, and potassium permanganate) on water-based drilling fluids (WBDFs). The additives were tested on two actual field drilling mud samples that differ mainly in their weight. The scavengers’ impact on drilling muds was investigated by measuring their scavenging capacity and their effect on rheology, fluid loss, and pH. Potassium permanganate outperformed the other scavengers when added to the lighter (lower density) WBDF. However, it did not impact the scavenging capacity of the heavier mud system. Copper nitrate outperformed the other scavengers in the heavier drilling mud system. Also, the addition of copper nitrate in the lighter mud system increased its H2S-scavenging capacity greatly, while for iron gluconate, it did not perform very well. Overall, all the scavenger-containing drilling muds did not have any significant harmful impact on the plastic viscosity or the fluid loss properties of the drilling muds. Furthermore, all the tested drilling mud samples showed an excellent ability to clean wellbores and suspend drill cuttings evident by the high carrying capacity with the exception of iron gluconate or potassium permanganate with the heavy mud system.

Investigation of Using Various Quantities of Steelmaking Waste for Scavenging Hydrogen Sulfide in Drilling Fluids

“…When the scavenger is entirely consumed (i.e., saturation is reached), the following equation [30] can be used to estimate the scavenging capacity (in mg H 2 S/l mud) of each mud sample.…”

“…Hydrogen peroxide is a nonselective reactant that causes an uncontrollable scavenging process, making it inappropriate for use in drilling fluid [3,19,28,29]. Potassium permanganate has a better mud rheological effect, but it is ineffective with heavy mud weight [30][31][32][33][34].…”

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

“…The H 2 S-scavenging capacity (in mg H 2 S/l mud) by each mud formulation when the scavenger was fully consumed (i.e., saturation was attained) was calculated using the following equation 45 where ρ is the H 2 S density (1.391 mg/cm 3 ), t s is the saturation time in minutes at the outlet H 2 S concentration of 100 ppm, and C out is the H 2 S concentration at the outlet gas stream.…”

“…The H 2 S-scavenging capacity (in mg H 2 S/l mud) by each mud formulation when the scavenger was fully consumed (i.e., saturation was attained) was calculated using the following equation 45 C t saturation capacity (mg/L) 150 10 (100…”

Experimental Investigation of Using Manganese Monoxide as a Hydrogen Sulfide Scavenger for Aqueous Drilling Fluids

“…Nevertheless, hydrogen peroxide displays instability at elevated pH levels and acts as a nonselective reactant, thereby exhibiting high reactivity with other mud components. ,, On the other hand, potassium permanganate demonstrates a more effective scavenging performance, accompanied by improved rheological properties. However, it proves ineffective when dealing with heavy mud. , …”