Oil and gas bearingness and structural elements of Adriatic islands and peninsulas (Outer Dinarides) with special review of anhydrite – carbonate Mesozoic complex and diapiric belt

Abstract

Već dugi niz godina evaporitne naslage mezozojske starosti na području jadranskih otoka i poluotoka (vanjski Dinaridi) zaokupljaju pažnju geologa istraživača. Ovim radom su prikazani naftno-geološki podaci, koji omogućuju veću sigurnost kako bi se moglo točnije nego dosad planirati istraživačke radove u cilju lociranja novih, vrlo dubokih istraživačkih bušotina na pojedinim dijelovima jadranskih otoka i poluotoka (slike l, 2, 3, 4 i 5). To je područje anhidritno-karbonatnog kompleksa, a naročito u području južnootočkog mezozojskog bazena, gdje su bušotinom Brač-lß određene pojave ugljikovodika od C1-C5, te izmjeren tlak od 1 100 bara. Time se potvrđuju ranija saznanja, da naslage s anhidritnim pokrivačem (izolator) predstavljaju zatvorene naftno-geološke cjeline s visokim tlakom i temperaturom, te ekonomski značajnim količinama ugljikovodika. Dano je mišljenje o pojavama sumporovodika u anhidritno-karbonatnom kompleksu i njegovom lošem djelovanju na ljudski organizam, a također i na razornu izmjenu kristalne rešetke u čeliku. Prikazani su i dijapiri na južnom rubu južnootočkog mezozojskog bazena, njihov utjecaj na formiranje pojedinih otoka i mogući utjecaj na nafto-plinonosne odnose u tom bazenu (slika 5).Evaporite deposits of Mesozoic age in the area of Adriatic islands and peninsulas (Outer Dinarides) have been attracting attention of exploration geologists for many years. This paper presents petroleum geological data that provide more certainty for more accurate planning of exploration operations that would result in location of new, very deep exploration wells in certain parts of Adriatic islands and peninsulas (Figures l, 2, 3, 4 and 5). This is the area of anhydrite-carbonate complex, especially in the part of Mesozoic basin where certain hydrocarbon shows of C1-C5 were acquired in Brač-1 ß well and where the pressure of 1 100 bar (15 954 psi) was measured. This confirms the previous knowledge that deposits with anhydrite seal represent closed petroleum geological units with high pressure and temperature and commercially significant hydrocarbon quantities. The opinion is presented on hydrogen sulfide shows in anhydrite-carbonate complex and its bad impact on human health and on destructive alteration of crystal lattice in steel. The paper also presents diapirs on the southern edge of Mesozoic basin in the area of southern islands, their impact on formation of certain islands and possible impact on oil and gas bearing relations within this basin (Figure 5)