New Zealand’s Taranaki Basin is home to virtually all of New Zealand’s onshore oil and gas production. Development of this resource has been ongoing since the late 1950s and oil and gas discoveries continue to be made both onshore and offshore.
Amidst this activity, sometimes an operator comes across a well that is very difficult to drill successfully. Recently, an oil and gas exploration company faced such a challenge - a well that had stifled attempts by others - and was able to prevail using New Zealand’s first ever implementation of Newpark Drilling Fluids’ high-performance water-based EVOLUTION® system.
Grappling with a Tough Well
The drilling project was planned for a total depth (TD) of 4,863 meters, targeting the Eocene Kapuni sands. Understanding the challenges associated with drilling this difficult well upfront, the operator turned to Newpark to tackle the project.
The technical staffs of Houston and Perth set to work customizing a formulation using the EVOLUTION drilling fluid system that would overcome the wellbore stability issues attributed to drilling through thick coal sections in the Eocene-aged Mangahewa Formation. The system combined a polymeric viscosifier and shale stabilizer, with a drilling performance enhancer to deliver high penetration rates through hydraulics and lubricity optimization.
The drilling program initially called for a fluid density of 9.9 pounds-per-gallon (ppg). However, as drilling progressed through extensive coal sections in the production zone, wellbore stability proved troublesome. Newpark reformulated the drilling fluid to tackle the issue, supplementing the system with additives to seal coal micro-fractures and promote greater wellbore stability. Additionally, the fluid was weighted to 11.1 ppg (built slowly to TD). Using the reformulated EVOLUTION system, the operator was able to proceed effectively while maintaining wellbore stability through a geology that had previously proved very difficult.
Not only did this challenging well stand as the first one drilled in New Zealand using Newpark’s EVOLUTION drilling fluid, it also illustrated the performance of this innovative new system. Using Newpark’s high-performance water-based fluid, the operator was able to succeed where others had failed.
The debut of EVOLUTION in New Zealand is a game changer for operators who are looking for an environmentally friendly water-based drilling fluid that delivers performance meeting or exceeding that of non-aqueous alternatives. Beyond its proven performance, EVOLUTION also delivers added environmental benefits that make the remediation process much easier and delivers huge cost savings.