High-temperature, water-based fluid system helps operator save $349K

Overview

Drilling through hard rock formations is a standard challenge in Oman’s deep gas wells, where abrasive sandstone, siltstone, and shale formations are encountered. These difficult conditions often result in a slow rate of penetration (ROP) and average 5 m per hour during the drilling of the 6-in. interval. Halliburton introduced BaraXtreme®, a low-rheology, near solid-free drilling fluid enhanced with nano sealant particulates. The solution optimized bit hydraulic efficiency and reduced equivalent circulating density (ECD) with the creation of a turbulent flow regime throughout the wellbore. The fluid also controlled fluid loss into the formation and exhibited good stability under elevated bottom hole static temperatures (BHST) up to 148°C.

Challenge

Six-inch wellbore sections face significant drilling challenges, including abrasive hard rock formations, high differential pressure (1,600 psi), and elevated bottom hole temperatures (148°C). The main objective is to enhance the ROP to achieve faster drilling and reduce wellbore construction time.

Solution

Our BaraXtreme® drilling fluid system, with the advanced additives BaraFLC® Nano-1 and BaraVis® W-637, was designed to help mitigate differential sticking risk and control fluid invasion into the formation. Extensive laboratory testing that simulated downhole pressure and temperature conditions validated the fluid’s performance under operational scenarios. The team used proprietary hydraulic modeling software (DFGTM drill-ahead and hydraulics) to optimize wellbore flow regimes and ensure maximum hydraulic horsepower delivery and a turbulent flow regime. This is essential for effective hole cleaning and bit performance.

Results

The 6-in. interval was successfully drilled without wellbore stability issues. A turbulent flow regime ensured exceptional hole cleaning efficiency without noticeable increases in torque or drag during drilling or tripping. Controlled PPT/HPHT minimized differential sticking risk and produced a slick, thin mud cake that prevented washouts. This optimized strategy increased the drilling rate by approximately 47% compared to previous fluids used in offset main holes. The section was completed 6.98 days ahead of schedule (AFE), saving the client an estimated $349,000.