What is a 4D seismic survey?
4D seismic survey is a three-dimensional (3D) seismic data acquired at different times over the same area to assess changes in a producing hydrocarbon reservoir with time. Changes may be observed in fluid movement and saturation, pressure, and temperature.
What is 3D seismic survey?
In three-dimensional (3D) reflection seismic surveying the sound detectors (numbering up to a thousand or more) are spread out over an area and the sound source is moved from location to location through the area. 3D seismic programs are generally a uniform and evenly spaced grid of lines.
When was the first 3D seismic survey?
The first commercial 3D survey was recorded in 1975 in the North Sea and was interpreted in the same year. 3D seismic data quickly evolved from a research idea to cost-effective methods that have substantially boosted the efficiency of finding and recovering hydrocarbons.
What is bin size in 3D seismic survey?
A bin is a subdivision of a seismic survey. The area of a three-dimensional survey is divided into bins, which are commonly on the order of 25 m [82 ft] long and 25 m wide; traces are assigned to specific bins according to the midpoint between the source and the receiver, reflection point, or conversion point.
What is a 2D seismic survey?
A two dimensional (2D) seismic survey is an exploration method used to create a map of the structures beneath Earth’s surface (see image below). The different rock formations then reflect the waves back to the surface, where they are recorded over a period of time and converted into a seismic image.
How is a seismic survey done?
Seismic survey is a method used during the exploration phase of oil and gas development. The reflected and refracted seismic waves are recorded by a receiver (geophone or hydrophones in water) and give the first image of the subsurface.
Who invented 3d seismic?
Modern 3-D seismic exploration can be traced to February 1963, when Whit Mounce of Humble’s Geophysics Research Department proposed a 3-D seismic system. By May 1964, Jack Ball’s Long Range Seismic team had developed a field technique, built recordingcompleted an initial test of the concept.
What is nominal fold?
The nominal fold (or full fold) of a 3D survey is the fold for the maximum offset. The majority of the bins is filled by the nominal fold.
What is offshore seismic survey?
Marine seismic surveys use sound energy to map geological structures under the seabed. These sound waves bounce back to the ocean surface where receivers, called hydrophones, record the strength and return time of each sound wave. From this data, maps of the geology below the seabed are developed.
What is a 3-D seismic survey?
Most 3-D surveys are aimed at detailed delineation of already discovered oil and gas fields. Additionally, 3-D surveys are repeated over the same area at appropriate intervals, say every few years, to monitor changes in fluid saturation which may be inferred from changes in seismic amplitudes.
What is the 4-D seismic method?
Seismic monitoring of oil and gas reservoirs by using time-lapsed 3-D surveys has come to be called the 4-D seismic method ( 4-D seismic method ). The basic principles of 2-D seismic data processing still apply to 3-D processing.
What is “geometry” in seismic processing?
Like so many other terms in seismic processing, “geometry” carries a slightly different meaning in that it describes the relationship between geophysical data (e.g. shot records) and coordinate information (the specific position on the Earth where that shot took place).
What is the difference between 2D and 3D seismic data processing?
In 2-D seismic data processing, traces are collected into common-midpoint (CMP) gathers to create a CMP stack. In 3-D data processing, traces are collected into common-cell gathers (bins) to create common-cell stacks. A common-cell gather coincides with a CMP gather for swath shooting.