RHELIANT PLUS Innovation for faster drilling and lower costs in challenging downhole environments
Globally, operators face a dilemma. They need invert fluids for deepwater and extended reach drilling (ERD) but face complications from shifting wellbore temperatures where increased temperature conditions downhole coexist with near freezing temperatures at sea bottom. In deepwater, poor hole cleaning, barite sag and other costly problems can arise from reducing surface rheology to compensate for increasing Equivalent Circulating Density (ECD) in cold riser temperatures.
Next generation drilling fluid provides excellent hole cleaning and rheological stability
Features
Flat rheology profile over wide temperature range
Uses single rheological modifier
Enhanced gel structure
Organophillic clay as a viscosifier
Temperature stability up to 350°F
Tolerant to solids
Benefits
Improved well construction costs
Reduced gel strength progression
Reduced hydraulic fluctuations from surge/swab
Reduced sag potential
Easier to engineer
Reduced whole mud losses
The next generation RHELIANT PLUS? drilling fluid system from M-I SWACO,
a Schlumberger company, provides operators thermal stability, consistent rheological properties, and protection from barite sag in deep water and ERD drilling operations, despite significant temperature fluctuations in the formation and riser.
An advancement from the M-I SWACO RHELIANT drilling fluid system deployed successfully in deepwater globally, the RHELIANT PLUS drilling fluid system allows for excellent hole cleaning. It also provides reduced operating costs through improved tripping speeds and reduced potential for loss of circulation in all types of well profiles: deepwater, directional and ERD.
The RHELIANT PLUS drilling fluid system maintains constant properties independent of temperature and pressure. This oil-base drilling fluid system retains nearly constant 150°F low shear rates viscosities even when encountering temperatures as low as 40°F (4.4°C). Its consistent rheological properties and gel structure allow drilling and break circulation pressures with lower ECDs, contributing to fewer problems while drilling and successfully avoiding the loss of whole drilling fluid.
The RHELIANT PLUS fluid system also reduces wellbore stresses because it is more tolerant of solids contamination than other systems and provides ECD management for enhanced ERD operations. The robust formulationis easily adaptable to changing well conditions with a minimal number of components, thus reducing storage requirements and simplifying engineering.
Compared to the field-proven RHELIANT drilling fluid system, the RHELIANT PLUS drilling fluid system assures improved cement operations with improved cement bonding from the low gel structure and higher temperature stability in drilling operations. At the same time, the new RHELIANT PLUS drilling fluid system provides the same flat rheological property profile.
Superior rheological properties outperform competing fluids
The RHELIANT PLUS drilling fluid system allows a higher clay content（>50%） while delivering lower gel progression.
It minimizes additives that contribute to ‘polymer viscosity.’ Instead, clay chemistry is manipulated by the primary additives. The gel strengths structure of the RHELIANT PLUS drilling fluid system is essential to minimizing sag, suspension of cuttings and hole cleaning.
Simple formulation for superior results
The RHELIANT PLUS drilling fluid system is a robust, three-component formulation that is easily adaptable to changing well conditions, making it easy and quick to maintain and control on location while reducing the amount of fluid wasteand associated costs. The all-in-one SUREMUL PLUS? emulsifier, the all-in-one RHEFLAT PLUS rheology modifier and VG PLUS? , a single type of organophilic clay, are the key components of the RHELIANT PLUS drilling fluid system.
The SUREMUL PLUS emulsifier is the primary emulsifier and combined wetting agent in the RHELIANT PLUS drilling fluid system. It delivers excellent emulsion stability, preferential wetting of solids by the continuous oil-phase, filtration control and stability at high temperatures. Additionally, the SUREMUL PLUS emulsifier is tolerant to solid contaminants and changes in the oil-water ratio (OWR).
Initial treatment is 8-12 ppb (22.8 – 34.2 kg/m3) depending on density, oil-water ratio and required temperature stability
The RHEFLAT PLUS? rheology modifier is a gellant and rheological modifier specifically designed to increase the low-shear viscosity, improve sag control and provide the flat rheology of the RHELIANT PLUS drilling fluid system.
The RHELIANT PLUS drilling fluid system works in conjunction with VG-PLUS and/ or VG-SUPREME? organophilic claysand is effective at temperatures up to 300°F (149°C). If temperatures above 300°F (149°C) are expected, usage of the VERSAGEL HT? viscosifier is recommended. Initial treatment is 0.6 lb/bbl to 1.5 lb/bbl (1.7 – 4.3 kg/m3) depending on the base fluid, the drilling fluid density, and the oil-water ratio. Maintenance treatment is 0.05 lb/bbl to 1.0 lb/bbl (0.15 -2.85 kg/m3).
Next generation conversion with no operations changes
The RHELIANT PLUS and RHELIANT drilling fluid systems are fully compatible. Converting to the RHELIANT PLUS drilling fluid system does not require changes in operation and can be effectively carried out from a wide range of NAF fluids.
The next generation RHELIANT PLUS offers additional performance benefits that include reduced gel strength progression, lower break-circulation pressures and associated break-circulation ECD, reduced hydraulic fluctuations from surge/swab, simpler formulation in the field, and greater temperature stability.
It generates shorter tripping times than the RHELIANT drilling fluid system or reduced surge/swab effect at the same tripping times. In hole cleaning, the RHELIANT PLUS drilling fluid system shows a slight edge in large ID holes. Swab effect is reduced with the RHELIANT PLUS drilling fluid system, resulting in the ability to pull out of hole (POOH) faster, especially in deeper or ERD sections where time savings are amplified.
The RHELIANT PLUS drilling fluid system is stable to approximately 330-350°F. The RHELIANT PLUS drilling fluid system has been run in HPHT conditions in the southern GOM, including 17 ppg / 350°F BHST.
Current RHELIANT drilling fluid system chemicals such as the SUREWET? fluid additive, the RHEBUILD? viscosifier, and the RHEDUCE? dispersant are all compatible with the RHELIANT PLUS drilling fluid system and will be maintained for any potential specialty requirement until they are deemed unnecessary
Angola: The RHELIANT PLUS drilling fluid system performs above the client’s expectations in Deepwater Angola
The Situation
A deepwater operator in Angola wanted to improve drilling performance and avoid higher costs by using only the RHELIANT PLUS drilling fluid system for its large diameter deviated hole section where hole cleaning and mud conditioning for cementing casing previously required extra rig time.
The Solution
A plant provided 90,000 barrels of the new RHELIANT PLUS drilling fluid system. Plant’s fluid ECDs in 12.25-in. and 8.5-in. sections were reduced 30-50 percent compared to a historical comparison of competitive systems.
The RHELIANT PLUS drilling fluid system’s organophilic clay, provided rheological properties of approximately 60 percent compared to historical offsets while exhibiting no sag tendencies.
The Results
The operator drilled and completed the first well with the RHELIANT PLUS drilling fluid system, significantly lowering rheology in 70-85 degree deviations while delivering improved hole cleaning.
The operator was able to pull out on elevators for the first time in six years without back-reaming the 17.5-in. and 12.25-in. sections. Extremely flat gel strength progression was observed in both paraffin and Low Toxicity Mineral oil formulations.
石油圈
