Reservoir Pressure While Logging
Fast, accurate pressure and mobility
Perform reliable and efficient pressure measurement―in less than a minute.
PressureXpress-HT
High-temperature reservoir pressure service
Fast, accurate pressure and mobility measurements in high-temperature environments
The performance of the HPHT Quartzdyne gauge (red) in the PressureXpress-HT service shows no build-down behavior compared with an unflasked conventional gauge (blue).
Superior thermal stability for extended surveys with no measurement degradation
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.
Precise control = accurate pressure measurements
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.
Pressure profiling for fluid density
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 accuracy of PressureXpress-HT service measurements that results from precise control over both the pretest volume and drawdown rate makes it possible to determine a valid pressure gradient and establish the fluid contact. The measurements from a conventional tool (green) are influenced by transient temperature effects. By using a flasked design to eliminate the need for gauge thermal stabilization, the PressureXpress-HT service does not experience build-down effects.
Extensively qualified operating confidence at extreme temperatures
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:
- shock
- pressure-temperature cycling of sonde and electronics: more than 600 h of testing
- thermal cycling: –15 to 400 degF for sondes, –15 to 350 degF for electronics cartridges
- thermal aging
- cold storage: –15 degF
- low- and high-temperature operations: –15 to 450 degF
- high-temperature life for 400 h: sonde at 400 degF, electronics at 350 degF
- shock transmissibility.
Defined preventive maintenance
To sustain quantified operating confidence in each tool, preventive maintenance procedures and steps have been defined for field operations implementation, providing the most reliable tool each and every job.Interpretation
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.
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