Enhancing Drilling Efficiency in Soft and Plastic Formation: A Field Trial of Hyperbolic Diamond Element (HDE) Bits in Eastern Offshore Basin and Assam-Arakan Basin, India

Abstract

In the ever-evolving landscape of the oil and gas industry, infill drilling plays a crucial role in maximizing reservoir recovery. It involves drilling additional wells within an existing field to efficiently extract remaining hydrocarbon resources. While infill drilling itself is vital, the speed at which it is conducted becomes equally significant. A larger number of wells drilled in a year will in turn ensure higher production by tapping into the small leftover patches of oil and gas in any mature field. Assam-Arakan Basin, Cambay Basin, and Eastern Offshore Basin are three such similar mature fields in India where the operator drills a huge number of infill wells to meet production targets. Accelerated infill drilling also contributes to improved field development, enhanced reservoir management, and mitigated reservoir risks. The economic viability of infill projects is significantly enhanced by reducing drilling cycle times and achieving cost savings. As the industry strives to unlock the full potential of existing fields, faster infill drilling serves as a key enabler for sustainable and profitable hydrocarbon extraction in an evolving energy landscape. The Assam-Arakan Basin in northeastern part of India is the oldest oilfield in India and has been in production since 1901. The field reached its plateau of production around 1970–1990 and has been on a declining curve lately. This basin has some unique challenges in terms of lithology being drilled; soft and sticky Girujan clay formation, abrasive Tipam sand, and problematic Kopili formation. While the Tipam sand causes a lot of wear and damage on the PDC bits, pipe sticking challenge is of primary concern in the Kopili formation. Girujan clay formation on the other hand, even after being very soft and easy to drill, causes the bulk of challenges in terms of low penetration rate and multiple trips in the tophole section due to bit balling issue. The Cambay Basin in western India is also an aging field that has been in production since 1960s and drills a huge number of infill wells each year to meet production targets. The Cambay Basin exhibits a complex geological structure, characterized by faulted and folded formations. These structural complexities pose challenges in wellbore stability and can lead to difficulties in drilling and maintaining wellbore integrity. Lithology wise however the tophole sections do not pose a significant challenge for drill bit design. The major flat time while drilling however comes from the directional requirement of these wells where a single bit cannot drill vertical and build sections.