Research and application of quantitative model for optimal well trajectory selection.

Area of Science:

• Petroleum Engineering
• Geological Engineering
• Drilling Engineering

Background:

• Wellbore trajectory selection is critical for geological objectives and operational efficiency.
• Current methods focus on feasibility and target safety, neglecting factors like cost and drill string integrity.
• Existing optimization lacks comprehensive scientific quantification, limiting effective assessment based on experience.

Purpose of the Study:

• To develop a quantitative method for wellbore trajectory selection.
• To incorporate key indicators like trajectory difficulty, drill string stress, wellbore cleanliness, drilling cycle, and cost.
• To provide a theoretical basis for oilfield trajectory and wellhead layout selection.

Main Methods:

• Introduced the concept of a trajectory difficulty coefficient.
• Optimized and scientifically quantified trajectory selection evaluation indicators.
• Established a trajectory optimization quantification method.
• Applied the method to an oilfield case study (A oilfield).

Main Results:

• Scheme 4 was identified as the optimal trajectory in the A oilfield case study.
• The optimal trajectory demonstrated minimum difficulty, favorable drill string stress, and good wellbore cleaning.
• The chosen trajectory resulted in the shortest footage and lowest drilling cost.
• Directional wells showed advantages in construction costs and overall drilling cycle compared to vertical wells.

Conclusions:

• The developed comprehensive wellbore trajectory selection method provides theoretical support for optimal trajectory decisions.
• The new method enables more scientific and comprehensive assessment of wellbore trajectories.
• This approach leads to reduced drilling costs and improved operational efficiency in oilfield development.