Reservoir Pressure While Logging
Fast, accurate pressure and mobility
Perform reliable and efficient pressure measurement―in less than a minute.
The innovative tool architecture of PressureXpress-HT service provides the superior thermal stability of a quartz gauge and enables extended holding time: 14 h at 450 degF.
The dual-flask design protects the electronic components from high temperatures. The HPHT Quartzdyne gauge is in one of the flasked sections, which also isolates it from changes in borehole temperature. Because the flask eliminates the need for gauge thermal stabilization, the uncertainty that results from erratic pressure build-down behavior is avoided and pretests are completed in less time.
To measure the formation fluid and borehole temperatures, a flowline temperature sensor is positioned outside of the flask. A temperature sensor in the toolhead provides an additional borehole temperature measurement.
The dynamically controlled enhanced pretest system incorporated in PressureXpress-HT service gives you precise control of volume and drawdown rates across a wide mobility range.
A pressure limit can be set as necessary, and the pressure differential for drawdown is up to 8,000 psi. With the capability for ultrasmall pretest volumes and only a minimal flowline storage volume, you’ll be able to pressure test where conventional hydraulic technology cannot function―as shown by the scatter of the green points on the pressure plot.
Multiple pretests can be performed at a specified depth to verify measurement accuracy without having to cycle the tool, or they can be performed at multiple depths to produce a pressure-depth profile.
A reservoir pressure gradient can be established if the zone of interest is sufficiently thick, mud supercharging effects are not present, and flow from the formation is confirmed by diagnostic plots. The resulting profile can be converted directly to the density of the formation’s continuous fluid phase for use in defining fluid contacts. In extremely low-mobility formations, large-area packers can be used to effectively increase the probe’s exposure to the formation.
The extensive qualification process for PressureXpress-HT service was conducted at a system level for the entire tool, as well as testing of individual components and subassemblies. The mission profile is reliable tool operations under the full operational and environmental load, including high-temperature operations up to 450 degF. Even transportation conditions are included in the simulation of harshest situations that the equipment may experience during field operations:
Compatible with most openhole services, including the Platform Express integrated wireline logging tool and its foundational measurements for formation evaluation, PressureXpress service specifically conducts pressure and mobility testing. On the first logging run, a reservoir pressure survey can be quickly generated for connectivity analysis, along with the pressure gradient for fluid density and fluid contact information and fluid mobility determination to aid in sampling-point selection.
These data are the basis for accurate pressure profiles and mobility measurements that you can integrate with petrophysical, seismic, and conventional log data for a more complete reservoir picture. Our expert, multidisciplinary geoscientists and engineers work with you as needed to achieve an integrated interpretation, employing advanced workflows and software such as the Techlog wellbore software platform to maximize the value of your logging data and achieve the fullest possible understanding of your challenging reservoir environments.
Accurate pressure and mobility measurements are immune to thermal effects that distort conventional formation tester results, Gulf of Thailand.
Fast, accurate pressure and mobility measurements in high-temperature environments.
The PressureXpress-HT service from Schlumberger provides accurate formation pressure measurements under the most extreme conditions. Rated at 450 degF (232 degC) at 20,000 psi for at least 14 hours, the service allows acquisition of pressure and fluid mobility measurements in a fraction of the time required by multifunction formation tester tools.
Schlumberger's MDT Forte qualified rugged system and the MDT Forte-HT high-temperature version promise to deliver robust downhole-fluid analysis, fluid sampling, and transient testing to meet the challenges of oilfield operations.