Land sinking in K-G Basin may have caused explosion

By SNV Sudhir

Visakhapatnam, June 27, 2014:  While the reasons like, corrosion and usage of substandard material are being pointed  at the gas pipeline leak which led to a blast that killed at least 15 persons in East Godavari, experts are also pointing at the possibility of land subsidience also one of the reasons for the pipe leak.

Retired professor of Andhra University’s geology department DR G Krishna Rao, who  has done many studies on KG Basin and other sites of gas exploration near Kakinada, observed that about 60pc of the gas pipeline failures are said to be due to excavations in their vicinity while 20pc accounts for corrosion problem.

“Similar to excavation situation arises in the K-G Basin where land subsidence or sinking is taking place. Thereby, the pipeline loses its base support which was laid about 20 to 25 years back. In such places, the ground below the pipeline has to be grouted with soil or elevated with supports to restore horizontal alignment of the pipeline. There are also reports of pipe line breakages due to land subsidence in some countries,” he added.

Prof Krishna Rao, further observed that While attending to the causes like mechanical problems in pipeline fittings, quality of pipes and corrosion, the major problem in oil and gas fields related to land stability and subsidence should be thoroughly investigated through surveying of the land for its elevation changes and areas prone to pipeline failures should be identified and remedial measures should be taken where necessary to avoid future pipeline breakages.

Land Subsidence is the major disaster in the production of natural gas from semi-consolidated sandstone reservoir rocks. As this parameter has been ignored in the earlier production activities in the KG Basin, he added.

An EIA report submitted by ONGC on expansion of Odalarevu Onshore Terminal in East Godavari district last year, the ONGC have quoted some lines from the report submitted in October, 2009 by a Sub-Committee,  constituted by the MOEF on the direction of High Court to look in to land subsidence. The sub-Committee clearly written in their recommendations that oil and gas extraction has led to land subsidence in many parts of the world and therefore this factor is to be taken in to consideration while taking up any project. The committee suggested to get this KG Basin investigated by an expert Central Institute on existing or likely land subsidence in the region. It seems this suggestion has not yet been complied with, he added.