UltraFLO direct flowback solids-free drilling fluid technology is specifically designed to address reservoir protection and sand carrying challenges during open-hole completion of horizontal wells. By utilizing a unique solids-free weak gel system, this technology ensures efficient sand carrying, reservoir protection, and direct flowback after completion, significantly simplifying the completion process and enhancing drilling efficiency.

Features

1. Solids-Free Weak Gel System: The UltraFLO drilling fluid employs a solids-free design to avoid potential reservoir damage caused by solid particles in traditional drilling fluids.      The rapidly forming weak gel offers unique rheological properties, maintaining suitable viscosity under low shear rates for effective suspension and transport of drill cuttings.

2. Moderate Viscosity at Low  Shear Rates: At a shear rate of 0.3 r/min, the viscosity of UltraFLO drilling fluid is controlled between 15,000 and 30,000 mPa·s. This characteristic helps balance fracture pressure and flowback pressure during drilling, ensuring the fluid doesn’t easily invade the reservoir      and facilitates easy flowback.

3. Environmentally Degradable: All additives are derived from natural biological materials, which are non-toxic and biodegradable, meeting environmental requirements. This      characteristic gives UltraFLO an advantage in both marine and land  oilfield applications.

4. Efficient Reservoir Protection: The fluid achieves a mud cake acidification rate of over 90%, enabling direct  induced flowback without the need for gel breaking, thereby maximizing reservoir protection while effectively controlling the invasion depth of solids and fluids.

Advantages

1. Increased Drilling Efficiency: The excellent sand-carrying ability and rheology of UltraFLO drilling fluid help minimize cuttings bed formation and borehole blockage issues,      enhancing drilling speed and efficiency.

2. Simplified Completion Operations: Post-drilling, the fluid can automatically liquefy and flow back directly, eliminating the need for complex gel breaking and mud cake removal steps, greatly simplifying the completion procedure.

3. Reservoir Productivity Protection: Its high-efficiency reservoir protection minimizes drilling-induced damage, safeguarding long-term reservoir productivity.

4. Environmental Safety: Utilizes non-toxic, biodegradable natural biological materials as treatment agents, reducing potential environmental and personnel hazards.

Applications

1. Complex Geological Formations: Particularly suited for geologically complex formations with developed fractures and intersecting faults. Its solids-free weak gel system      effectively controls fluid loss, reducing formation damage and facilitating smooth drilling operations.

2. High Temperature and High Pressure Formations: With heat and pressure-resistant additives, UltraFLO maintains stable rheological and sand-carrying performance under      extreme conditions, preventing issues like stuck pipe and wellbore collapse.

3. Sensitive Reservoirs: Low solids content and ease of flowback minimize reservoir damage and protect productivity. It can be enhanced with specific inhibitors to reduce      sensitivity to drilling fluids.

4. Horizontal and High-Angle  Wells: Superior sand-carrying capability and rheology prevent cuttings bed formation and keep the borehole open. The fluid's rheological properties      can be adjusted to suit various inclination angles.

5. Long Open-Hole Sections: Retains stable performance over extended periods, reducing drilling incidents and formation damage due to fluid degradation.

6. Offshore Oilfields: Environmentally friendly and highly protective in offshore applications, UltraFLO is widely used in offshore oilfield development.

In summary, UltraFLO direct flowback solids-free drilling fluid technology is effective in a range of challenging scenarios, including complex formations, high-temperature and high-pressure environments, sensitive reservoirs, and various well types. Its unique performance advantages and broad applicability make it a valuable technology in the oil drilling sector.

Complementary Additives

• STARFLO Filtrate Reducer: A critical component of the UltraFLO system, this polymer-based additive controls filtrate loss, protects wellbore stability, and optimizes drilling efficiency.

• BIOVIS Rheology Adjuster

Key Additive: STARFLO Filtrate Reducer

As an essential component of UltraFLO’s solids-free system, STARFLO Filtrate Reducer is designed to control filtrate loss during drilling, protect the wellbore, and optimize operational efficiency. This high-molecular-weight compound plays a pivotal role within the fluid system.

Functions:

1. Reduce Filtrate Loss: Effectively minimizes fluid invasion into formations, safeguarding reservoirs and preventing damage.

2. Wellbore Stabilization: Forms low-permeability, high-quality filter cakes, aiding in shale stability and reducing collapse risks, enhancing safety.

3. Enhanced Drilling Efficiency: Reduces filtration and instability issues, such as differential sticking, thereby boosting efficiency and lowering costs.

Applicable Range:

1. Temperature: Suitable for use in environments up to 163°C.

2. System: Incorporated within UltraFLO direct flowback solids-free drilling fluid system, especially effective in complex drilling scenarios such as open-hole horizontal completions.

Case Study

At the eastern South China Sea, the common drilling fluid system used is the PRD system, known for overcoming sand-carrying challenges in horizontal or high-angle wells. However, it has shown areas requiring optimization, particularly its low-shear viscosity exceeding 40,000 mPa·s, which, while reducing fluid invasion damage, poses gel breaking and return flow challenges that affect progress.

In response, a rapid weak gel drilling fluid system was developed, controlling LSRV (Low Shear Rate Viscosity) between 15,000-30,000 and utilizing specific particulates for effective temporary plugging, minimizing invasion and ensuring ease of flowback. This system, requiring no gel breaking, shortens operational cycles and costs, demonstrating significant initial flowback efficiency.

Successfully deployed in wells such as LF13-1-28 and LF13-1-11, this technology has seen widespread application across oilfields, enhancing output, reducing fluid loss, and minimizing post-drilling fluid recovery, having a profound impact on completion strategies. The system's simplified additive profile aids safer transport and aligns with offshore hazard management requirements.