How to Design Well -OIl and Gas drilling

Summary

In this educational video, Isabelle RFRA, a lecturer at IFP School, guides viewers through the complexities of well drilling in oil and gas exploration. She explains the importance of understanding subsurface characteristics, such as pore and fracture pressure, and how these factors influence the design of the drilling mud to prevent blowouts. The video also covers the different phases of well construction, from exploration to production, and the technical aspects of the drilling process, including the use of drilling mud, casing, and blowout preventers to ensure safety and efficiency.

Takeaways

• 📚 Isabelle RFRA is a lecturer at the IFP School's Center for Exploration and Production, focusing on field development scenarios and well treatment strategies.
• 🚧 The lesson aims to explain how to describe subsurface characteristics for well design and define the drilling phases, including the use of drilling systems and safety management.
• 🔍 During the exploration phase, wells are necessary for confirming hydrocarbon presence and delineation, with the reservoir model guiding the development strategy and well placement.
• 💰 Wells are expensive and require careful planning; the well preparation phase involves coordination between Geoscience and drilling completion engineers to set up a drilling program.
• 📍 Accurate knowledge of subsurface characteristics, such as pore pressure and fracture pressure, is crucial for well planning and to ensure a good connection between the well and the reservoir.
• 🛠 Pore pressure is the pressure within the rock's grains, influenced by depth and rock nature, while fracture pressure is the minimum pressure needed to create fractures in the rock during drilling.
• 💡 The drilling mud's pressure must be carefully managed to be higher than the pore pressure to prevent blowouts but lower than the fracture pressure to avoid fracturing the rock.
• 🔑 The 'mud window' is the interval between pore and fracture pressures where the mud pressure should be maintained to ensure safe and effective drilling.
• 🏗️ Well design involves multiple phases, each with a specific casing to protect the well and isolate the reservoir, with the design becoming more complex for exploration wells due to data uncertainties.
• 📈 Pressure profiles for wells can vary significantly between exploration and development wells, with the latter benefiting from surrounding well data to reduce uncertainties.
• 🔨 The drilling process involves a combination of mechanical force and rotation applied to the bit, with the driller controlling parameters to optimize penetration rate and prevent blowouts using a blowout preventer system.

Q & A

What is the role of Isabelle RFRA in the script?

Isabelle RFRA is a lecturer at the Center for Exploration and Production at IFP School, teaching about field development scenarios and well treatment strategies.

What is the purpose of describing subsurface characteristics in well design?

Describing subsurface characteristics is essential for planning the design of future wells and defining the phases of the drilling job, ensuring good connection between the well and the reservoir.

Why are appraisal wells needed in the exploration phase?

Appraisal wells are needed to confirm the presence of oil and gas in the reservoir and to delineate the field for further development.

What is the importance of the reservoir model in field development?

The reservoir model defines how to develop the field, particularly where to drill the wells and the contribution of each well to the production plateau.

What are the two key characteristics of a formation that need to be known accurately for drilling?

The two key characteristics are pore pressure and fracture pressure, which are crucial for maintaining the integrity of the well and avoiding blowouts.

What is pore pressure and why is it important during drilling?

Pore pressure is the pressure of the fluid within the grain of the rock, which depends on the depth and nature of the formation. It is important to avoid blowouts and ensure the well's stability.

What is fracture pressure and how does it relate to drilling?

Fracture pressure is the minimum pressure needed to generate fractures in the rock when drilling. It is important to prevent the mud from entering fractures instead of flowing up to the surface.

What is the mud window and why is it significant in well drilling?

The mud window is the interval between the pore pressure and the fracture pressure where the mud pressure should be maintained. It is significant for preventing blowouts and rock fractures during drilling.

What is the purpose of casing in well design and what are the different types mentioned in the script?

Casing is installed and cemented to protect the well from the formation already drilled and to finalize the well walls. The types mentioned are conductor pipe, surface casing, intermediate casing, and production casing.

How does the drilling process differ between exploration and development wells?

Exploration wells face more uncertainties due to a lack of measurements and information, making mud window determination more difficult. Development wells benefit from data from surrounding wells, reducing uncertainties.

What are the factors that affect the rate of penetration during drilling?

Factors affecting the rate of penetration include the weight on bit, the rotation per minute provided by the rotary table, the type of rock being drilled, and the regulation of the mud flow.

What is the role of a blowout preventer in the drilling process?

A blowout preventer is installed to close the well in case of an emergency, such as a blowout, to prevent uncontrolled release of well fluids and protect the drilling rig and personnel.