Esempi di
applicazioni
Using WinWedge and GPS to Search
for natural resources under the ocean floor
Austin Exploration Inc.,
headquartered in Houston, Texas, conducts GPS-based high-resolution
land and marine gravity and magnetic surveys throughout the world.
Their surveys and associated interpretations have proven to be
invaluable to the oil and gas industries worldwide. Austin
Exploration’s surveys are also beneficial to the mining industry in
its search for gold, silver, iron, zinc, lead and diamonds.
Austin Exploration has conducted
nonexclusive regional land studies in the United States, beginning
in the Cordilleran Hingeline Thrust Belt in Utah. Other nonexclusive
areas of study include the Appalachian area, the Ouachita Trend in
Arkansas, Oklahoma, Texas, Mississippi and Louisiana. Nonexclusive
marine projects include most of the Gulf of Mexico and offshore
Alaska, east and west coasts of North America, Sulawesi, Indonesia,
Timor Sea and several surveys offshore United Kingdom.
Austin Exploration began their land
survey operations in 1976, and in 1979 expanded their operations to
include marine services. Shipboard systems have been employed in
offshore South America, Africa, Pacific Rim countries, Europe, the
coastal regions of North America, Indonesia, Malaysia, Korea,
Vietnam and Burma.
Marine Surveys
To perform underwater gravity surveys
and locate oil and gas beneath the floor of the ocean, Austin
Exploration uses a ship equipped with advanced instrumentation to
check below the ocean floor for minute differences in the earth’s
gravitational field. These changes in the earth’s gravitational
field indicate a change in density in the subsurface, and
correspondingly, the presence of various structures including salt
domes, anticlines (folds with layers of sedimentary rock sloping
downward on both sides from a common crest), reefs, etc. By
rigorously analyzing these changes in gravitational field,
structures are precisely located implying the existence of oil
fields.
Austin Exploration makes use of the
most advanced marine surveying instrumentation including Digital
Marine Gravity Meters and GPS Receivers, both with RS232 output. The
marine gravity field meters are the latest in shipboard gravity
technology manufactured by LaCoste and Romberg Laboratories, out of
Austin, TX. The series 4000 GPS Receiver is manufactured by Trimble,
from Sunnyvale, CA (800-827-8000, www.trimble.com). Since both
instruments offer RS232 output, they are easily connected directly
to a PC with a serial cable. Connecting the instruments to a PC
offers complete automation of the survey data.
PC Configuration
The gravity information is recorded
along with the GPS-based navigational information to accurately map
density changes in the substructure beneath the ocean floor. To
accomplish this the gravity information is fed into the PC over the
PCs serial port 2 while a GPS Receiver is hooked up to serial port
3. The GPS Receiver accurately tracks the ship’s location relative
to satellites in orbit around the earth.
Hence exact location and gravity
information, from com 3 and com 2, must be simultaneously plotted
into a Microsoft Excel spreadsheet. This is achieved using the
WinWedge for Windows Pro v3.0 (or WinWedge Pro) from TALtech
(800-722-6004, www.taltech.com). This software interfaces both the
gravity meter and the GPS Receiver simultaneously and parses and
filters the data and sends it to the correct locations in a
Microsoft Excel (v7.0) spreadsheet. The spreadsheet then
automatically graphs the information.
At present both these instruments
are connected to a Pentium 100 with 16 megabytes of RAM running
Windows 95. The researchers are considering moving to Windows NT in
the future. They are using an add-in 4 channel serial port board (Digiboard
PC 4) by Digi International (800-344-4273) to allow for connection
to additional serial ports.
Before they discovered WinWedge,
researchers at Austin Exploration were using ProComm to simply dump
the incoming serial data from the navigation equipment to a disk
file. WinWedge allowed them more control over parsing, filtering and
formatting their serial data and sending it in real time to their
Excel spreadsheet. WinWedge also allowed them to collect data
simultaneously from different instruments on different serial ports.
The digital marine gravity meters
outputs binary serial data that is converted to decimal in the
WinWedge before it is transferred to Excel. The GPS Receiver
transmits serial ASCII data. As this is already decimal form, it can
be easily transferred by WinWedge into Excel.
Benefits
- Simultaneous data collection
from two different instruments (GPS Receiver and Gravity Meter).
- Ability to plot real-time
location versus gravity data in Excel to locate natural resources
below the ocean floor.
- Cost effective
- Very Easy to set up and use
- Ensures complete data accuracy
Conclusion
The results, which are collected in
Excel in real time, help define subsurface structures believed to be
prospective hydrocarbon accumulations (i.e. oil). Automating the
collection of the survey data provides 100% accuracy and quality
control of the data while at sea.
|
