Schlumberger

uHPHT Single-Shot Reservoir Testing Systems

Simple, rugged, reliable test strings rated to ultrahigh reservoir temperatures and pressures

Schlumberger uHPHT single-shot strings are designed to operate in hostile downhole conditions with a special seal package developed and tested for ultrahigh temperatures and pressures. The single-shot-tools-based uHPHT strings reliably perform with a simple, rugged design that can handle the most extreme testing environments. The strings can reliably operate in downhole temperatures to 500 degF, differential pressures to 17,500 psi, and annular pressures to 25,000 psi for the J-String and 30,000 psi for the K-String.

Rigorous qualification testing in extreme conditions

In 1998, the J-String underwent qualification testing that combined maximum pressure of 25,000 psi with maximum temperature of 500 degF. The J-String uses proprietary Schlumberger sealing technology that has been tested and proven in fields worldwide with the biggest activity occurring in India and the North Sea.

The single-shot K-String, introduced in 2013, increases the maximum annulus pressure to 30,000 psi. A dual-action valve (DAV) can be used in the K-String to provide extra flexibility in test design by enabling a second buildup while adhering to the same reliable single-shot principle.

Robust, simplified string with reliable components

The uHPHT strings include two tubing tester valves (TTVs). The TTV at the lower end of the string pressure-tests the BHA and is set to automatically open at a preset hydrostatic pressure while running in hole. Subsequent pressure-testing of the string is done against the other TTV located at the upper end of the string. A pump-through flapper safety valve (PFSV) automatically shuts in the well downhole in case of a sudden increase in annulus pressure resulting from a tubing leak. The valve also provides a downhole shut-in at the conclusion of the test. For redundancy, two single-shot reversing valves, positioned above the PFSV, are set to operate at the same pressure.

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Global HPHT Conditions

Global HPHT Conditions
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