Design and Life Cycle Considerations for Unconventional Reservoir Wells

Abstract

Abstract This paper provides an overview of design and life cycle considerations for certain unconventional reservoir wells. An overview of unconventional reservoir definitions is provided. Well design and life cycle considerations are addressed from three aspects including up-front reservoir development, initial well completion, and well life and long-term considerations. Up-front reservoir development issues discussed include well spacing, well orientation, reservoir stress orientations, and tubular metallurgy. Initial well completion issues include maximum treatment pressures and rates, treatment diversion, treatment staging, flowback and clean-up, and dewatering needs. Well life and long-term discussions include liquid loading, corrosion, refracturing and associated fracture reorientation, and the cost of abandonment. These design considerations are evaluated using case studies for five unconventional reservoir types including shale gas (Barnett shale), tight gas (Jonah Field), tight oil (Bakken play), coalbed methane (San Juan basin), and tight heavy oil (Lost Hills Field). In evaluating the life cycle and design of unconventional reservoir wells, "one size" definitely does not fit all and valuable knowledge and a shortening of the learning curve can be achieved for new developments by studying similar, more mature fields.