Laboratory Evaluation of Weighting Materials for Ultra-High Density Oil-Based Drilling Fluids in Ultra-HPHT Wellbore Applications

Abstract

Global energy demand has driven the petroleum industry to develop hydrocarbon resources from extremely harsh formations which contain ultra-high pressure and temperature (HPHT) reservoirs. Ultra-high density drilling fluids are critical to successful drilling and completion practices in all of these wells. In this paper, potential weighting materials were systematically evaluated and screened to accomplish an ultra-high density oil-based drilling fluid system (19.62 to 22.12lb/gal) aimed to utilize in ultra HPHT conditions (>30000psi and >410°F). Several potential high-density weighting materials were evaluated in the laboratory conditions. Basic properties (pure density, particle size/distribution, surface area etc.) were evaluated and compared. Special treatments were conducted to optimize the properties of weighting materials. HPHT filtration tests under static and dynamic conditions were conducted at higher than 410°F and 300 psi. Real cores with an average porosity of 19% and an average permeability of 50 mD were used in the filtration tests. Rheological properties, sag tendency, the volume of filtrate, and the filtrate cake characterization of oil-based drilling fluids were measured before and after heating at 410°F for 16 hours. Results revealed that ultra-micro manganese and ilmenite complex after suitable surface treatment could act as an ideal weighting material than ultra-pure barite or other materials, which could fail in rheology and sag controlling measurement with such high temperature and density. The viscosity and filtration analysis confirmed the stability and reliability of this novel ultra-high density oil-based drilling fluid. This study developed a challenged drilling fluid system under critical testing states, as well as established a systematical laboratory evaluation and screening procedure of weighting materials for ultra-deep wells and contributed recommendations on how to utilize it in the fields.

Application of High-Density Brines in Drilling and Completion Fluids: Current Insights and Future Perspectives

“…The key features of Mn 3 O 4 were exploited by combining with ilmenite to get ultrahigh-density drilling fluid with a density of 22.12 lb/gal. The testing of a Mn 3 O 4 and ilmenite mixture under drastic field conditions of 410 °F and 300 psi proved their stability . Later on, another research group did a similar study with Mn 3 O 4 and ilmenite and supported the outcomes of previous research outcomes .…”

“…The testing of a Mn 3 O 4 and ilmenite mixture under drastic field conditions of 410 °F and 300 psi proved their stability. 116 Later on, another research group did a similar study with Mn 3 O 4 and ilmenite and supported the outcomes of previous research outcomes. 117 The comparison of ultrafine barite, Mn 3 O 4 , barite, and ilmenite as weighing agents proved the most effective role of ilmenite in drilling fluid rheology and fluid loss control as shown in Figure 5.…”

The Role of Drilled Formation in Filter Cake Properties Utilizing Different Weighting Materials

“…Many materials were used as weighting agents over the years, and researchers are still looking for new materials and ways to improve the existing ones. Examples of common weighting materials include barite, calcium carbonate, ilmenite, hematite, manganese tetroxide (Micromax), galena, stibnite, and potash. − One potential method to improve the weighting material performance is by reducing its particle size; this introduced more options such as micronized barite, micronized ilmenite, and micronized manganese tetroxide as weighting materials. − Furthermore, other researchers used a mixture of several weighting materials with the aim of mitigating drilling instability issues such as barite sagging and of improving the drilling mud properties. , Also, nanoparticles were investigated as weighting agents by several studies that showed a general improvement in the drilling fluid properties. ,− Accordingly, selecting the right weighting material is not a trivial task and it depends on many factors including the cost, the required properties (i.e., density), and its solubility in conventional filter cake removal treatments since it affects approximately 70–80% of the filter cake structure …”

Application of Anhydrous Calcium Sulfate as a Weighting Agent in Oil-Based Drilling Fluids

“…8−10 Commonly used weighting materials are calcium carbonate, barium sulfate or barite, hematite, manganese tetroxide, and ilmenite. 11,12 During the drilling operation, the drilling fluids impair the permeability of the formation upon their invasion into the formation. The invaded particles block the pore throat and lead to a loss of permeability of the produced formation by building a filter cake on the wall of the permeable formation.…”