An Evolutionary Account of Seismic Technology

Louis D. Brandeis said, “There are no shortcuts in evolution,” and rightly so. Oil and Gas industry has observed a paradigm shift with the advent of technology and one of the significant ones is the incorporation of Seismic Technology in the exploration and production processes.

It has traversed, the Oil & Gas industry, a long way from using the 2-D seismic which was much popular in the 1980s and then advancing to 3-D seismic which enhanced the results by providing larger ‘acquisition foot-print’. And, as years rolled by and engineers unraveled other potential technologies which gave birth to Depth Imaging and AVO/AVA/Inversion.

A closer look into the past: Conventional Exploration Methods

World Wars led to the facilitation of too many ambitious projects and in 1924, one such project was commissioned and first exploration discovery to use seismic was made in the U.S. But it came to be of practical use in the 1980s with subsequent technological advancements.

One of the methods used to extract oil was drilling. After a well was drilled, oil and gas were extracted by natural pressure from the wells and pumping stations. As technology progressed different methods were incorporated to increase production.

Read how digital oil rig can revolutionize the exploration process in the industry

Seismic technology which was first devised by a German mine surveyor, Ludger Mintrop in 1914 in an attempt to predict salt domes, came to the rescue. However, it was the 1950-1980s when Oil replaced Coal and consequently, the process of practically feasible exploration spearheaded. Still one of the widely used conventional methods for exploration remained seismic imaging. Seismic imaging uses the sound waves which bounce back from a possible crude oil or natural gas bearing formation.

The conventional exploration geophysics involves the seismic reflection which presents the contrast of impedance which is the product of seismic velocity and density. Mapping structure and depth to ground were the common applicability of the same technology back then.

A stride ahead from conventional methods

There has been a substantial progress in the seismic technology. It evolved from being two dimensional and took various shapes, be it 3D or 4D imaging or Controlled Source Electromagnetic (CSEM) which is a coupling of Electromagnetics (EM) & Seismic Reflection.

Seismic technology’s ability to fine tune the exploration is one of the major factors for its wide popularity and usage in exploration. Seismic surveys help provide an idea about the structural characteristics, fault pattern and sediment velocity. It helps to create a conceptual model of the site which facilitates in better chances of discovery. Let us discuss some of the new seismic methods:

1. Seismic Imaging (3D & 4D Surveying): In an attempt to explore a more detailed data in exploration researchers are using 3-D seismic imaging. In this large and obvious traps are mapped basis which survey lines are marked and closer to each other which increases the quality of data. And, hence, it succeeds the 2-D imaging but it is costly at the same time. A more advance feature of 3-D is the Time-Lapse 3-D or 4-D seismic surveying. In this 3-D imaging is carried out at different intervals to produce more detailed, precise information through acquisition, integration and interpretation basis which can help them predict the possible exploration areas.
2. CSEM: Seismic technology is more sensitive to rocks; it doesn’t take into account fluids during exploration. And if we can incorporate CSEM technology which is more sensitive to fluids than the results can be improved. It is observed that the discovery rate is 25% without using EM. So, the results can be enhanced if we can couple the two technologies. This method is extremely useful in the areas where there is poor seismic performance and probability of a possible site of exploration. Augmenting these two technologies can produce a considerable amount of data which can be integrated to analyze the possible location of oil site.
3. Geochemical Methods: This exploration method for searching petroleum is done on the premise that hydrocarbons might migrate upward from subsurface accumulations. There are two types of techniques followed in this, direct and indirect. The main advantage of this method is that the exploration is not limited due to the type of the trap of the hydrocarbon.

New & Unexplored technologies

One of the recently used technologies for marine exploration is to use very intense shots or pulses produced by releasing air under extremely high pressure.  These shots are used by industry during seismic surveys to find oil and gas deposit in the bottom of the sea and oceans. As very loud noise can be very disturbing to the environment, Marine Vibroseis (MV) which has been used successfully for inland exploration is a much viable and less noisy alternative. These are called alternative quieter technologies.

The best contender amongst the upcoming technology in the field of exploration is Drones which fall in the category of Unmanned Aerial Vehicles (UAVs) and are probably the uncontested next big thing in the Oil & Gas industry. One of the most important advantages of such a system is that it is extremely cost effective in comparison to giant mechanical machineries used by the O&G industry. It [Drones] can be used for vigilance purpose and mapping the field for a long time; it is free from human fatigue and the data captured can be archived for future analysis.

If, in the future, we invest in such technologies and try to incorporate amendments in the same by performing various experiments we can arrive at new and advanced technologies for oil and natural gas explorations.