Efficient Drilling of Ultra-HPHT Wells in the Gulf of Thailand | SLB

Efficient Drilling of Ultra-HPHT Wells in the Gulf of Thailand

Published: 05/05/2014

Schlumberger Oilfield Services

Development of gas fields in the Gulf of Thailand requires drilling and producing from reservoirs that are at static temperatures above 400 °F. Safe and economic production from these Ultra-HPHT fields is crucial to deliver on gas contracts that support the region’s economic activity. The operation limit of equipment used to drill these wells, such as measurement-while-drilling (MWD) and logging-while-drilling (LWD) tools, is 350 °F, with high temperatures bringing decreased reliability and the need for extensive time-consuming maintenance due to effects of exposure of electronics, elastomers, and sensors to these temperatures.

A technology that could enable MWD/LWD tools to operate reliably in this high-temperature environment would minimize the risk of drilling to the wrong target and potential well collisions by allowing directional trajectory control while confirming proper well placement with real-time downhole measurements.

We have developed and qualified technologies that enable electronics, sensors, and elastomers to operate in these HPHT environments, with the same level of reliability than that of current technology in normal temperature environments. An MWD tool has been designed based on these new technology developments. The tool can operate reliably at 400 °F and 30,000 psi while providing real-time direction and inclination surveys, azimuthal gamma ray, annular and internal pressure while drilling, and shock and vibration measurements.

An operator in the Gulf of Thailand used this new MWD technology to drill wells in these Ultra-HPHT reservoirs without the need to stop because of temperature limitations. Savings of 1/2 day per well have been achieved, and reliability and maintainability have been proved by executing four runs above 360 °F, with a maximum tool recorded operating temperature of 376 °F in more than 250 operating hours without the need for maintenance between runs. With 50 to 75 wells per year to be drilled above 350 °F, this operator now has access to a new workflow that can save 25 to 37 days of drilling per year which translates into considerable savings in rig spread rate and the ability to bring production online earlier.

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