Low Frequency Seismic (LFS) is a DHI (Direct Hydrocarbon Indicator) methodology that is easily applicable, cost effective, environmentally friendly and a robust alternative to find untapped oil-gas deposits from matured or brown fields. In addition, it can be implemented in situations, where conventional practices would not be an option, either due to block size, active seismic waves energy penetration issues, budget limitations, accessibility and/or environmental restrictions.

LFS utilizes a natural sources of low-frequency 1-6 Hz vertically oriented P-waves. An accumulated pre-processed spectrum of the ambient microseismic signal is considered as the resultant of filtering by the geological media i.e. amplitude- frequency curve (AFC) of media. Due to the mechanics of fluid-saturated, fractured and porous media, oil and gas reservoirs have high dispersion of velocity and high attenuation at low frequencies. Thin layer of oil/gas reservoir with high attenuation amply reflects the low-frequency P-waves that is why, it transforms AFC of the media under observation point on the ground surface.

LFS has already been applied extensively to several geological and geographical situations in Russia, Ecuador and India, wherein the success ratio in finding additional hydrocarbons is about 86%. All three wells confirmed our forecast on pilot project In Gandhar Field of Cambay Basin in India. In other words, it defines productive and non-productive zones at reservoir-scale of under-developed, developed and matured fields within the limited-time and budget.

The advantages include:
(a) ecological cleanliness (without explosives, chemicals and drilling);

(b) efficiency (surveys in an area of 30 km2, with 300-400 measurement points, can be processed in two months’ time i.e. 1 month for data acquisition and 1 month for processing, interpretation and delivery of a report);

(c) mobility (conducting of operations in regions difficult to access).