The case of “Giovanna” platform, in the province of Teramo, where Eni-Agip operated in the ’90. How to extract gas “fracturing” the sea floor and using seawater. Volumes trebled, costs cut down. Also because of advantageous permits.
“Until 1992 in my stretch of sea, enough far from the shore, it was so beautiful to fishing. But, when Giovanna arrived, I ceased, because the water was not the same after that”. With these words, Aldino is looking backwards when he was a former fisherman. He coughed, stopped for a while, put the receiver on the table, left away, and then came back over the phone telling that “the sea in front of the stretch of shore among Montesilvano, Silvi Marina and Giulianova today is not the same as well. I don’t like it anymore”.
“Giovanna” platform in the Adriatic Sea / Photo by Unmig website
We are in the Middle Adriatic Sea, in the Abruzzi – Teramo Province – where the many gas platforms (one, two-casing, and network ones) have changed fishermen practice. Even though, until 2002 (year during which an ordinance by the Pescara Harbor Office Authority became effective, publisher’s note) fishing near to methane gas platforms was almost a routine. One of these is the “Giovanna” platform (as per above photo) realized in 1992, and located a little farther than 23 miles from coastline; a 37, 38 kilometres from land. The “Giovanna” natural gas field was found out by Agip and Deutsche Shell in 1988, 6 years after that the “Emma” gas field went into production, with a platform having the same name. Both of them are within the “B.C 10.AS” exploitation permit, awarded on December the 16th 1980, and which the two companies were charged for with an annual rent of 867,400 lire. 40 lire per hectare. In 1993, Edison Gas took over Shell, in 1998 Eni took the place of Agip, and in 2010 Adriatica idrocarburi S.p.A. bought Eni shareholder out, joining to Edison. According to the latest data the Ministry for Economic Development provided for, in the last year the average production has been of about 255 million cubic metres of natural gas, and the productive wells are 12, even though there have been drilled at least a total of about fourty.
Mr Aldino, though asserting that “the water was not the same
”, could not having been told that the “Giovanna” field – besides of presumably changing his plans as fisherman – would had been the object of a special testing for hydraulic fracturing (also known as fracking). Informing us about that, there is a scientific article published on July the 17th 2000 on the Oil&Gas Journal, whose title is “Seawater streamlines polymer-free fracturing
”. The study was focused on a period going from 1994 to 1999, and involved the drilling workover of the 6, 12 and 20 wells. The first one still productive. The second and the third ones yet productive, but delivering no more.
“A novel seawater-based, polymer-free fluid improved the operational efficiency of 23 frac packs in Ani Agip’s Giovanna field, off Italy in the Adriatic Sea. The treatments were part of a three-well, multizone workover program, requiring large-sized fracture stimulation. These were the first successful treatments for Eni Agip that included seawater as the base fluid for Schlumberger’s ClearFrac system, a polymer-free, viscoelastic surfactant (VES) fracturing fluid”. This is the document’s beginning. Essentially, seawater “has been used as a base fluid to reduce offshore fracturing costs in various parts of the world, but the treatment results have been mixed” […] “Recent offshore fracturing operations in the Adriatic Sea have demonstrated that seawater is an effective base” […] “Seawater also reduced costs by increasing operational efficiency and saving rig and process time”.
Practically, before successfully establishing the mining and extractive industry applied geology operations, the natural gas extractions through hydraulic fracturing were processed using a HEC (hydroxyethylcellulose) polymer fluid. On the contrary, in that case, Eni-Agip engineers operating in the Giovanna field area wells, have tested a viscoelastic surfactant fluid, precisely the VES. Through chemical analysis, they have demonstrated this kind of fluid was more functional than the HEC one, because it could operate as polymer-free, and, not as a thing of minor importance, exclusively using seawater.
By this hydraulic fracturing testing, a workover for exhausted or poor yielding wells – extracting as much as possible hydrocarbons (gas, in that case) – tripling their produced material, and an effective cuts in volume expenditure and of production downtime have been made possible. And that is precisely the case of “Giovanna” field area, characterized by shale layers, and containing “much dirtier, lower permeability formations with clay content as high as 50%”. A successful testing, so as to have been repeated some years later, further north, in the sea in front of Falconara Marittima coastline, in the “Barbara” field. A huge gas exploitation offshore field, in which there have been drilled more than 100 wells since ’70 up today – most of them directional-like – and fixed 11 platforms up. Some of the article authors, after a past in Eni, now they are working for Halliburton, the first company commercially using this fields stimulation technique.
This is not, however, the first time the Adriatic Sea is used as a test bench. For example – further south than Giovanna platform – in front of Vasto coastline in “Rospo Mare” oil field permit, Elf Italiana drilled one of the former directional wells in Europe, the “Rospo Mare 6 dir”. It was 1982, and its story is written into an excerpt of the same company