New water mapping, oil extraction techniques by NGRI

Indian scientists are using electro magnetic signals from the earth to prepare water maps of various regions and decipher at what depth water is available. CSIR-National Geophysical Research Institute (NGRI) Hyderabad is working on the new technology called Transient Heliborne electro-magnetic survey. In this, a helicopter fitted with instruments measures the electro magnetic signals from the earth. Once the data is taken

and analyzed, the scientist can decipher the structures beneath the earth and can find out the conductive zones inside the earth. These also correspond to water zones. Therefore, scientist are able to prepare water maps of the regions and find out at what depth water is available. So far on pilot basis they have mapped six regions including the desert plains of Rajasthan, Gangetic plain in Uttar Pradesh and the rocky terrain in Tamil Nadu.

The results are very encouraging and NGRI which alone has this technology is now ready to take up mapping of the entire country with the assistance of Ministry of Water Resources. 

Dr N Purnachandra Rao, Chief Scientist and Professor (Seismology ), said that the government is very keen on pushing the study forward so that the whole country can be mapped in order to have the national aquifer map. 

This technology has been cross checked by putting drill holes and so far they have matched up with the Heliborne survey paving way for successful use of this procedure to decipher where ground water is available, at what level and how it can be maintained, he added. 

NGRI scientists are also are carrying out a research to use carbon dioxide to pump out any fuel left in used oil wells or oil reservoirs. Once the carbon dioxide pushes out the remaining oil then the carbon dioxide will be capped deep inside the excavation sites. 

The institute is carrying out research on the important topic of carbon dioxide sequestration in oil reserves which will help in enhancing oil recovery. The sequestration technique uses carbon dioxide from the atmosphere and injects it in used oil reservoirs to pump out the remaining oil. 

Rao explained that after extraction of oil from reservoirs some oil remains as it is difficult to extract completely. 

The process of extracting this remaining oil from these old oil reservoirs has remained difficult so far. But now a new technique has been developed using carbon dioxide from the atmosphere. 

With increased carbon dioxide levels in the atmosphere due to high levels of emissions from vehicles, industries etc, this procedure is beneficial. 

Rao said that the remaining oil from these reservoirs can be pumped out which hitherto was not possible and precious foreign exchange to some extent can be saved which is used to import oils. Research to refine this technique is going on. 

NGRI is using simulation techniques on computer called '4 D seismics' where the exact structure of the earth in that particular area is created and scientist find out the passage to the oil reservoir. 

Once the accuracy is developed they go to the next phase wherein it is seen how much carbon dioxide can be injected and how much oil can be extracted. 

He said research is going on in this 4 D Seismic modelling at NGRI and once successful oil companies can come forward and use this sequestration procedure. 

NGRI plans to tie up with oil companies to tap the oil oil fields where not so refined extraction techniques were used during the past and a lot of oil could still be present. 

The two major oil fields which have long been extracted include the Assam Digboy fields and the Bombay High. Similar oil fields are in Rajamundry and in Saurashtra.