The Evaluation of Micronized Barite As a Weighting Material for Completing HPHT Wells

Abstract

Barite is one of the most common weighting materials for drilling and completion fluids. Its good properties (high density, less environmental impact, and low production cost) outperform the other weighting materials and make it a good candidate for drilling and completing oil and gas wells. However, some problems were encountered in the industry while using solid particles to increase fluid density, solids invasion which causes formation damage and permeability reduction in the vicinity of the wellbore, and the tendency of these solid particles to settle therefore, the loss of well control is likely. Moreover, an erosion to the surface facilities will result when these solid particles are produced. This study aims to investigate the effect of barite particle size on barite removal and completion fluids stability and how reducing barite particle size will help in resolving barite sag tendency and mitigating its effect. In this study, different samples of barite with different particle sizes were prepared using sieve analysis. Ball milling was used to reduce barite particle size to few microns. zeta potential and sag test were performed to evaluate the stability of micronized barite. Solubility test and high pressure high temperature filter press were used to study the effect of reducing barite particle size on barite removal. Solubility tests showed a good enhancement in barite removal as the particle size was reduced, with a difference of around 11 g/L (20 wt.%) between the largest and the micronized size of barite. HPHT Filtration test results confirmed the solubility results with 5 wt.% enhancement in filter cake removal efficiency. Micronized barite showed a moderate stability with zeta potential measurements for a pH range greater than 8, while sag test showed insignificant enhancement in fluid stability as barite particle size was reduced to the micronized size.

Development of a New Reservoir-Friendly Drilling Fluid for Higher Gas Production

“…Manganese tetroxide retains relatively high specific gravity and small particle size, which reduces particle settling and sagging in high mud weight formulations. Manganese tetroxide particles have a spherical shape of (4 µm) in size and specific gravity of (4.8 g/cm 3 ) which leads to lower contact in particle-to-particle interactions [11,12] . Field studies show that when Manganese tetroxide is used in oil-based drilling fluids, there was less formation damage and high amount of productivity.…”

Prevention of Barite Sag in Oil-Based Drilling Fluids Using a Mixture of Barite and Ilmenite as Weighting Material

“…In high-pressure high-temperature applications, a special drilling fluid formulation is required to meet the critical downhole conditions. In such cases, drilling fluids should have a high density to suppress the high formation pressure with good stability at that elevated temperatures [7].…”

“…However, solid particle settlement is a common issue while using barite-weighted drilling fluids, and this phenomenon is known as barite sag [16,17]. These settled particles will not contribute to the fluid density, leading to serious well control issues [18,19], and they interfere with drilling and production operations ( Figure 1) [7]. Moreover, the accumulated solid particles and drilled cuttings increase the possibility of pipe sticking and decrease the rate of penetration [20].…”

“…Sustainability 2019, 11, x FOR PEER REVIEW 2 of 14 downhole conditions. In such cases, drilling fluids should have a high density to suppress the high formation pressure with good stability at that elevated temperatures [7]. High-density weighting materials are introduced to the drilling fluid formulation to provide the required fluid density, such as barite, hematite, manganese tetraoxide, and ilmenite [8][9][10][11][12].…”

“…Some other research studies suggest playing with the weighting agent as a solution to the solids sag phenomenon. Mohamed et al [7] conducted a study on the effect of barite particle size on sag tendency in water-based drilling fluids. They found that reducing the particle size enhances drilling fluid stability and reduces sag tendency, whereas, it did not eliminate the problem.…”