Novel Drilling Fluids Enable Record High-Temperature Well Offshore Malaysia
Authors: Wilson Adam 
Published: October 2016

This article, written by Special Publications Editor Adam Wilson, contains highlights of paper SPE 170557, “Novel Drilling Fluids Enable Record High-Temperature, Deep- Gas Exploration Well Offshore Peninsula of Malaysia,” by A. Witthayapanyanon, SPE, Baker Hughes; K.A. Nasrudin, F. Wahid, M.M. Pepple, SPE, and M. Abshar, Petronas; and A.B. Dollah, K. Chandramouleeswaran, A. Kongsawast, SPE, R.G. Bland, and D.K. Clapper, SPE, Baker Hughes, prepared for the 2014 SPE/IADC Asia Pacific Drilling Technology Conference and Exhibition, Bangkok, Thailand, 25–27 August. The paper has not been peer reviewed.

Despite hostile wellbore conditions, an operations team overcame challenges of drilling-fluid design and management to drill the first ultrahigh-pressure/ high-temperature (HP/HT), deep-gas well offshore Malay Peninsula. With a bottomhole temperature (BHT) of 488°F, the well reached the highest temperature ever recorded in Southeast Asia. Thorough planning and advanced drilling-fluid technology resulted in drilling fluids with extreme temperature stability. Designing, planning, and deploying a thermally stable drilling fluid for this high-temperature environment helped reduce the time required for circulating or conditioning, thus reducing rig time and mud treatment cost.

Introduction

Because of extreme wellbore conditions, HP/HT drilling and exploration involve engineering expertise, competent well design, and enabling HP/HT technologies. Among enabling technologies, thermally stable drilling-fluid systems remain one of the key components for successful HP/HT drilling operations. As a result of fluid-engineering design and extensive testing, a suitable ultra-HP/HT drilling fluid was formulated with a maximum mud density of 18 lbm/gal and thermal stability of 455°F. The successful drilling of this first ultra-HP/HT gas well set a new benchmark for the operator in designing, planning, and managing drilling fluid. The effort underlines the importance of high-temperature drilling-fluid technology, which led to reduced cost and time in the operation.

Well Background and Operational Goal. The well was the operator’s first ultra-HP/HT, deep-gas exploration well in the south Malay basin. It was a straighthole, vertical well with a water depth of 251 ft. The well was drilled to a total depth of 14,380 ft, where it reached a pressure of 14,282 psi and maximum bottomhole static temperature (BHST) of 488°F. The operational goal of the well was the evaluation of the hydrocarbon potential in the Group M sandstone, where the reservoir pressure and temperature are greater than 14,000 psi and 450°F, respectively.

Ultra-HP/HT Drilling-Fluid Design.

The key objectives for drilling-fluid performance include

Zero nonproductive time (NPT) associated with drilling fluids

Thermally stable, high-density fluid with desirable low rheological properties with no barite sag under static or circulating conditions

No excessive equivalent circulating density (ECD) associated with drilling fluid at bottomhole circulating temperature

Controlled HP/HT fluid loss under wellbore conditions