the seismic method

United Geophysical's ability to design 3D surveys using "state of the art" 3D design software ensures our clients obtain the very best results at the most economical price with the minimum disturbance to local communities and the environment.

Ensuring the success of important client projects requires strategy and the exceptional management skills of United Geophysical team leaders.

Detailed land, air surveys and reconnoiter reveal every aspect of the prospect to be surveyed and are examined by high resolution satellite imagery.

Profiling of local cultures and social make up are detailed, the local people advised and informed of the company operations. People's parliaments are held regularly with a forum for the local communities to voice any concerns they may have regarding the United Geophysical operations.

Importantly, United Geophysical make every provision to restrict environmental and population disruption to a minimum working along side local dignitaries.

Comprehensive mobilisation and work strategies are planned in the greatest of detail to ensure compliance with all the legal, environmental, contractual and technical requirements of the company and its clients.

Transport and logistical management procedure manuals are refined and tailored for every prospect.

Detailed community relations, safety, health and environment plans and procedures to deal with every contingency are put in place greatly assisting local communities.

Each and every phase of operations are covered by total quality assurance policies.

External audits and close monitoring by senior management personnel and consultants ensure compliance.

Explosives are used in the majority of surveys. These provide the seismic energy pulse that travels through the earth and is reflected back to the surface by subsurface geological features. The pulse is then recorded at the surface by sophisticated electronic equipment to provide the data from which a seismic image of the subsurface geology can be formed. The explosives are loaded into drilled holes to ensure safety and that maximum energy is transmitted into the ground. In an average month a seismic crew will use twenty tonnes of explosives for this purpose.

The company also has non-explosive sources for use in areas where explosives cannot be used. For example Airgun barges which are positioned in real time by satellite positioning. An airgun creates a seismic energy pulse by the sudden release of compressed air and the subsequent collapse of the bubble formed.

In seismic operations energy source holes are drilled by a variety of methods, as in water jetting through lightweight steel casings or by manual augers. It would not be unusual in a 3D seismic project to drill over 100,000 source points per month (400,000 metres of drilling).

The seismic signal is detected by geophones. This signal is then converted from analog to digital in electronic station units deployed at each geophone station, then transmitted by cable (or sometimes radio) to a central recording unit.

Each seismic record could contain the output from at least 13,000 geophones, the signal digitised in 720 Field Units, over 43 megabytes of data per individual seismic record. On a typical day a seismic project will record between 300 and 400 records or 17,000 megabytes of seismic data.

The continuous data from a field unit representing the output from a group of geophones is called a "trace". Each of these 300,000 "traces" of data recorded each day are rigorously checked for quality on our in field processing system to ensure the clients requirements are met.

The final stage is the reduction of all the seismic and topographic data into a S.P.S. (Seismic Processing Software) data file. This data file specifies the exact geometry of every shot point and seismic record and their exact position on the surface of the Earth. This SPS data is used at the main data processing centre to assist in the further processing of the data to a subsurface map or image of the earth.

The final product after processing is a cube of data, a 3 dimensional model of the Earth's subsurface to a depth of 10km or more.

Survey Crew

LAUX and Husky

LAUX Deployment

Line Scouts

LAUX and Battery

Drilling Operations Flushing Method

Shot Monitor Record

Observer in RT