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Towering Inferno

ONGC engages US experts to cap the Mandapeta blow-out

Towering Inferno
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EVEN before they could recover from the shock of the November 1996 hurricane, the people of the paddy-rich East Godavari district are yet again faced with a disaster, this time a man-made one. The February 19 blow-out in the Manda-peta ONGC well, near Devarapalli village, found officials and district administrators ill prepared for emergency measures. Immediately after the blow-out, the district administration evacuated 400 families. Says Hari Shankar Brahma, the state relief commissioner: "We acted before people fell prey to the possible gas leak from the well, rather than the fire, which rose to a height of almost 70 ft." Adds M. Rangarajan, general manager (projects) of the Krishna-Godavari basin: "Yes, the situation is grim. But we are confident of coping with it." However, as has happened in the past, the blow-out at Mandapeta seems to be causing complications in the ONGC's Crisis Management Team (CMT). Suspected leak of hydrocarbons at various stages in the subsurface, known as an internal or inwell blow-out, is also putting brakes on the CMT's action plan.

ONGC sources say the well may collapse because its mouth is bigger than normal (12 inches) and no casing has been done on it. The well mouth developed cracks around 11.30 am on February 19 and smoke emanated from the leak. Sensing trouble, the drilling workers dumped mud into the well. But despite these and other such safety measures, the ONGC staff could not control the flow. Muddy water followed by gas and condensate gushed out. The well caught fire and an hour later the 125-ft-high rig came down with a crash. The Devarapalli well had more oil reserves, with limited gas levels.

The KG basin, where the ONGC has so far drilled more than 120 wells, has suffered as many as 10 blow-outs of which two besides the recent one were major (Kom-arada, March 19, 1993, and Pasarlapudi, January 8, 1995). What's worrying officials is that the blow-outs are occurring with dangerous frequency—three during the last four years.

This, say ONGC officials, is still fewer than those in other countries. Claims a senior ONGC official: "While there were 43 blow-outs for every 10,000 wells drilled in either the Gulf or Mexico, it is only 39 blow-outs per 10,000 in India." Statistics show that the US had 293 blow-outs from 1960 to 1980. But India had only 30 blowouts in the three-and-half decades ending 1995.

Blow-outs are said to be far more serious in on-shore drilling for exploration of hydro-carbons. Of the 4,750 on-shore wells and 1,280 off-shore drilled by the ONGC till last year, only seven blow-outs occurred in the off-shore wells. The blowouts have mostly occurred while drilling. And failure of the surface equipment was found to be the root cause in half a dozen cases. There are several similarities between the Mandapeta and the Pasarlapudi blow-outs.

Both occurred only after reaching a depth of 2,750 ft. Although the ONGC officials are tight-lipped over the recent blow-out, where 10 employees had a providential escape, the needle of suspicion once again points towards the complacency that has crept into those engaged in drilling. The Pasarlapudi well capping had taken over 60 days and the ONGC had to depend heavily on Red Adair of the US. The intensity was then much more—the flames from the oil well touched a height of 200 m, while in the present case it was 70 ft.

Options of digging a parallel well, while using water umbrellas to cool down the flames, are not ruled out, say officials. Says Rangarajan: "Unlike in the past, we are confident of capping the well soon." The CMT is awaiting the arrival of American experts to chalk out the strategies for capping of the well, if, of course, it does not collapse in the meantime.

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