Downhole Pressure Measurement

DESCRIPTION

For high precision downhole pressure measurement, we use Sondex quartz pressure gauge tool, employing an industry standard quartz crystal pressure transducer. The tool provides both pressure and gauge temperature outputs.

OPERATING PRINCIPLE

Fluid pressure applied to the quartz tension member changes the resonant frequency of the quartz crystal. Thermal compensation of the sensor and measurement of its temperature allows the calculation of very accurate, high-resolution downhole pressures.

Pressure readings are digitized to 24-bit resolution and gauge temperature to 16 bits and transmitted on one channel of the telemetry system simultaneously with other logging signals. In surface readout applications two pressure tools can be used with output from both tools transmitted in a single digital channel.

SPECIFICATIONS

	Memory	Wireline
Supply Voltage	+12V DC	+60V DC
Power / Current	5 mA	50 mA

Max. Pressure	15,000 psia
Max. Temp.	350⁰ F (177⁰ C)
Drift	Less than 3 psi per year

Tool Length

12.25" (311mm)

22.5" (572mm)

Measure Point	2.9" (74mm)
Tool Diameter	1-1/2" (38mm)

Weight

4.85 lb (2.2kg)

6.5 lb (3kg)

Range	0-15,000 psia
Linearity	≤ 0.01 % FS
Resolution	0.008 psi
Repeatability	≤ 0.01 % FS
Hysterisis	≤ 0.01 % FS
Materials	Corrosion resistant throughout

Benefits:

Downhole pressure gradient measurement.
Evaluating the multiphase production profile.
Draw down and build up pressure transient analysis
Data for productivity index and Nodal Analysis.
It could be used in horizontal or highly deviated Wells

The study of hydrodynamic characteristics is one of the most important methods to monitor production life of reservoir. It consists of:

Reservoir pressure monitoring helps in optimizing primary production regime and enhanced production regime. In addition reservoir pressure is to be used in reserves assessment by material balance
Evaluation of reservoir permeability and skin effect of region around the wellbore. The can then be used to determine the technical solution such as acidizing fracturing works
Determination of present oil-water contact.