Reaching HPHT Reservoirs

Overview Library

Endurance and reliability in HPHT conditions

Elastomer seals and the lubricating material of a standard 300 degF-rated drill bit quickly degrade under HPHT conditions, causing bearing failure. Proprietary compounds provide a solution with Kaldera high-temperature drill bits. Schlumberger also manufactures HPHT-rated directional drilling, LWD, and MWD tools, which continue to perform reliably when exposed to the shocks and vibrations associated with drilling operations.

Maintain well balance with stable, noncorrosive fluids

While drilling HPHT wells, engineers frequently encounter overpressured formations, weak zones, and reactive shales. Acceptable fluid-density range is often small, requiring careful control of equivalent circulating density. The fluid must also be chemically stable and noncorrosive.

Ensure long-term zonal isolation in harsh environments

Well cements are permanently exposed to downhole conditions. Above about 110 degC [230 degF], the commonly used Portland cement may shrink, lose strength, and gain permeability. This deterioration can be minimized or even prevented by adding at least 35% silica by using cements engineered for the HPHT environment.

Even if zonal isolation is initially adequate, changes in downhole temperature and pressure can crack or even shatter the cement sheath; radial pressure/temperature fluctuations can create a microannulus. These concerns are particularly significant in deep, hot wells and thermal-recovery wells. FlexSTONE HT advanced high-temperature flexible cement technology has a lower Young’s modulus for improved flexibility and a significantly higher expansion after setting to ensure firm contact with the casing and formation.

High-Pressure, High-Temperature Drilling

HPHT Drilling Fluids

FlexSTONE Advanced Flexible Cement Technology

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High-Temperature Drilling Operations Technology

HPHT Drilling Catalog
Directional drilling tools to put the HPHT well in the right spot, and pressure and sampling tools to deliver accurate results and samples at 30,000 psi are but a few of the technologies routinely used in the anything-but-routine environment of HPHT. Download High-Temperature Drilling Operations brochure

High-Temperature Fluids

HPHT Envirotherma NT
Envirotherm NT environmentally friendly water-base drilling fluid is rated for HT operations up to 450 degF.
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