New Sequential Formation Tester for Log Analysis
Fred Jay Lazor, David Wayne Hampton, Gary Baird, Gregory N. Gilbert
The Formation Tester is a new tool developed for wireline logging operations. The tool has many novel innovations that make it ideal for both pressure tests and taking fluid samples in many difficult areas of the world.
The new Formation Tester has a quartz pressure transducer. The quartz transducer has excellent repeatability, high resolution, and greater accuracy than a Bourdon tube strain gauge. Example logs illustrate the improved qualities of the quartz pressure transducer.
The Formation Tester operates on a pad pressure priority system.
The tool monitors the pad pressure and responds to changes in it. An example log illustrates the advantages of the pad pressure priority system.
The Formation Tester is interfaced with a computerized logging unit. Displays of data that include operation times, hydraulic pressure, formation pressure, drawdown pressures, and buildup pressures on a CRT screen can be obtained. The screen may also display drawdown and buildup permeability calculations.
There have been numerous changes in downhole tool electronics. The new Formation Tester now incorporates digital uplink and downlink telemetry. Solid-state switching has replaced mechanical switching relays and the original wiring connectors have been replaced with a more reliable connector.
AAPG Search and Discovery Article #91035©1988 AAPG-SEPM-SEG Pacific Sections and SPWLA Annual Convention, Santa Barbara, California, 17-19 April 1988.