Roadmap to Unlock Light, Tight and Highly Laminated Oil Resources in South Oman

Abstract

Field "A" produces from a mixed-wet formation comprising of fine grained silicilite. The field is a sour light tight oil reservoir with permeability range from 0.001 – 0.1 mD, the only way to flow the existing vertical wells is through hydraulic fracs. Historically the wells have been fracced using water based frac fluids, which have caused severe negative consequences related to well integrity and reduced productivity. With a recovery factor of <1% after 15 years of production, the main challenge and objective lies in enhancing productivity and unlocking the huge volumes of this reservoir through optimizing the field development concept, completion, frac design and execution. A study was conducted with a recommendation to develop the field by drilling slanted wells with ~10 – 15 frac stages. The frac design in itself is unconventional or hybrid where the targeted frac half length is 5x more than the existing conventional ones. The use of oil based frac fluid instead of water is an opportunity actively pursued to enhance productivity and eliminate issues related to scale and corrosion that in the past have resulted in a loss of production. Findings of the study have clearly indicated that developing the field with several slanted multi frac wells is economically attractive; with an increase in Net Present Value (NPV) by ~60% and decrease in Unit Technical Cost (UTC) by ~30% compared to developing the field conventionally with vertical wells.