Crude Petroleum as it occurs in nature, is mainly a mixture of hydrocarbons belonging to the paraffin, benzene and naphthene series. Some varieties are viscous solids, some are liquid and others are gaseous. The great oil-fields of the world occur commonly in shallow water marine sediments. The exact nature of the original material which by slow distillation has given rise to the oil is a matter of dispute: land-plant residues, marine algae, phyto-plankton and remains of marine animals have been suggested. For the preservation of these, deficiency of oxygen at the site of deposition may be important. That which distinguishes petroleum from other sedimentary rocks is its powers of migration from the rocks in which it was formed to “reservoir rocks“. these, by reason of their open texture afford storage room. Such rocks are sandstones and cellular limestones. Where
these rocks are covered and sealed by relatively impervious beds such as shales, the petroleum may accumulate under great pressure due to the buoyant effect of ground water. When the covering rocks are pierced by the drill, the petroleum may rise to the surface. Channels of escape such as joints, faults, or the oil-bearing stratum itself at its outcrop, may be impregnated with solid bitumen representing the residue of the petroleum from which the lighter fractions have evaporated.
The first open reference to the possibility of exploration for the presence of petroleum reserves in Malta is given by C. Rizzo (1932) in the chapter “Prospecting for Mineral Oil and Natural Gas“. Here Rizzo points out the commercial interest of an American Oil Company, and suggests that the whole rock sequence and structure of the Maltese Islands do not rule out the possibility of petroleum accumulations. T.O. Morris (1952) also suggests that it is probable that should deep borings be made at suitable locations, supplies of mineral oil may be tapped along with highly saline water. Exploration activity in Malta was triggered by the discovery of oil in Triassic dolomites in 1953 at Ragusa in nearby SE Sicily. In 1953, a local company The national Oil Development Company (Malta) Ltd., financed by Maltese businessmen applied for a permit to start methodical prospecting. This attempt failed due to lack of capital. This was followed by an agreement with the D’Arcy Oil Exploration Company to co-ordinate deep boring and conduct detailed geological and geophysical surveying. In 1955 petroleum mining concessions were granted to BP Exploration Co. Ltd in respect of the whole of the land area of Malta. Between 1955 and 1959, the British Petroleum Co. Ltd. carried out three stratigraphic holes: Ghar Lapsi No.1 (929 feet), Naxxar No.1 (2000 feet), and Zabbar No.1 (1947 feet). A deep test well was carried out at Naxxar No.2 (10000 feet – 2999 m). The well reached the Cretaceous limestones but failed to reach the Triassic objective. Because of negative results, BP gave up its licences in 1959. In 1964, Shell Oil carried out and completed a gas explorer survey in the Malta offshore covering 700 km of lines. Following these attempts of exploration on the Islands, attention turned towards offshore exploration.
|YEAR||BLOCK/AREA||Blocks||OPERATOR||WELL||Year well drilled||Well status|
|1971||Offshore North Area 1||A||Shell||MS-A1||1972||Dry|
|1971||Offshore North Area 1||A||Shell||MS1B1||1973||Dry|
|1971||Offshore East||B||Home Oil||Home 1||1972||Oil shows|
|1971||Offshore SE Area 1||C||Aquitaine||Aualta 1||1971||Dry|
|1974||Medina Area 2||2,3,4 & 9||Texaco||Medina Bank 1||1980||Gas shows (suspended)|
|1974||Medina Area 2||10, 11 & 14||JOC *subsequently assigned
|1974||Medina Area 2||16||Aquitaine||–||–||–|
|1981||Area 3||3||IEOC||Alexia 2||1983||Oil & Gas shows|
|1981||Area 3||8||Reading and Bates||Gozo 1||1982||Dry (suspended)|
|1990||Area 3||2 & 3||Amoco/BHP||Valletta 1||1991||Dry|
|1990||Area 3||4 & 5||Texaco||–||–||–|
|1992||rea 4||3 & 4||Amoco/AGIP||Tama 1||1993||Oil Shows|
|1997||Offshore North Area 3||Part of Area 3||AGIP||–||–||–|
|1998||Onshore||Malta Government||Madonna taz-Zejt||1998||Gas shows|
|1998||Area 3||4 & 5||Hardman Resources||–|
|2002||Area 3||Part of Area 3||ENI||Lampuko 1||2002||Oil & Gas shows|
|2003||Area 3||4 & 5||RWE Des|
|2005||Area 3||2 & 3||Med Oil|
|2007||Area 2||Heritage Oil|
|2007||Area 7||Heritage Oil|
|2008||Area 4||4,5,6 & 7||Malta Oil|
|2014||Area 4||5 & 7||Mediterranean Oil and Gas and Genel Energy||Hagar Qim|
Malta oil exploration timeline
1954: First oil exploration licence in Malta granted to BP following the discovery of oil at Ragusa in 1953.
1972: Offshore well yields oil shows, but no recoverable prospects.
1998: The Maltese government drills an oil well in Gozo, yielding gas shows but no usable reserves
2006: Malta and Tunisia sign agreement on joint oil exploration in zones of the continental shelf between the 2 countries.
In the early 70’s offshore licences were awarded to Shell, Aquitaine and Home Oil. Four dry wells were drilled between 1971 and 1973, AQ, HOM, MSA and MSB. The AQ and MSB had a Cretaceous objective whereas the other two had a Triassic one. Area No.1 was adequately explored, and the wells drilled there confirmed the presence of a carbonate sequence, but they did not reach the principle objective horizon productive in Sicily. It was recommended that when the technology of deep drilling improves, a well dug in Area No.1 deep enough to reach the Triassic strata may prove successful. In the first offshore area, the involved companies had drilled the following wells:
|1971||Aquitane||shallow well||5875ft||tertiary objective|
|1972||Home Oil||deep test||14452ft||Triassic objective|
|1972||Shell Oil||deep well||16444ft||Triassic objective|
|1973||Shell Oil||shallow well||2220m||tertiiary objective|
In 1974 the Medina Bank acreage was opened and Texaco were awarded four blocks, JOC three blocks and Aquitaine one. In 1980 Texaco spudded MB. Area No.2 is located between the first offshore exploration area and the Malta-Libya median line. The prospect covers the uplift which is an extension of the Tunisian shelf. The structure extends from Sfax to the east in the Medina Bank direction. The exploration of this area was received with a great deal of sensitivity from the Libyan quarters, and resulted in a number of political difficulties. but drilling was suspended because of a boundary dispute with Libya. This dispute was subsequently resolved at the ICJ in 1985.
In 1981 two awards were made in the north, one to IEOC and another one to Reading & Bates. By 1985 two wells were drilled, GOZ by Reading & Bates and ALX by IEOC. ALX tested good oil shows in the Triassic whereas GOZ was suspended in Cretaceous shales, short of the Triassic objective.
In 1990, two blocks in the north were awarded to Amoco-BHP and another two to Texaco. The former drilled VLT and encountered a dry Jurassic objective. In 1992 Amoco-Agip were awarded two blocks in the south. TAM was drilled in 1993 to a TD of 4064m in the Cretaceous after penetrating a dry Metlaoui objective. In 1993 Shell-Nimir were awarded Block 7 in the south. A 3-D survey was conducted but no wells were drilled. In 1997 an agreement was signed with AGIP for the exploration of an area to the north and another agreement was signed with ROC in 1998 for the exploration of Block 7 of Area 4. A similar agreement was signed with Hardman Resources et al. in 1998 for the exploration of Blocks 4 and 5 of Area 3.
In 2010 two companies, Heritage Oil and Malta oil, started conducting geological studies off Malta.
On Thursday 23 August 2012 Mediterranean Oil & Gas announced that its wholly owned subsidiary, Phoenicia Energy Company Limited had entered into a conditional farm-out agreement with Genel Energy Plcin for oil exploration in Area 4 Offshore Malta. Genel acquired 75% of PECL’s interest in its Area 4 Offshore Malta Production Sharing Contract for a US$10 million cash payment. It will also get 100% ‘carry on’ the first exploration well, which is planned to be drilled to a minimum depth of 2,500 metres, 100% carry on the second exploration well up to a maximum of US$30 million gross expenditure. At PECL’s option, should the costs of the second well exceed US$30 million, Genel is to provide a financing arrangement to fund PECL’s 25% share of any additional expenditure, at an interest rate equivalent to 3 Month Libor plus 400 bps. ECL is to remain as operator until completion of the first exploration well, at which time Genel can elect to become the operator, or at such later date as the parties may agree. Mediterranean oil and Gas has also signed an Area of Mutual Interest agreement with Genel to cooperate in acquiring exploration and production assets in the offshore basins of Libya, Tunisia and Malta for a minimum term of three years. The proposed Malta Transaction, targeted by the parties to be completed by the end of October 2012, is conditional upon receipt of approval by the Maltese Minister for Resources and Rural Affairs, together with the grant of a minimum one year extension of the first phase exploration period of the Malta Area 4 licence.
On Friday 24 August 2012 a spat developed between entrepreneur David Lenigas, chairman of Leni Gas & Oil and Mediterranean Oil and Gas (MOG) over a stake in oil exploration rights in Maltese acreage. According to the London Evening Standard, Leni Gas said it was “surprised” by Mediterranean Oil & Gas’s deal with Genel in Malta and said it “is seeking immediate advice” from its litigation lawyers, Mishcon de Reya. The source of the dispute is thought to centre around Leni Gas’s sale of its 10% interest in Malta oil exploration rights to a subsidiary of MOG. MOG had agreed a multi-million dollar deal to sell a 75% stake in these wells to Genel.
Mediterranean Oil and Gas aims to start drilling at Malta before the end of the year, the company’s chief executive said on Friday 12 October 2012 Upstream, an international oil and gas news source, reported that Genel Energy’s Area 4 off Malta holds 260 million stock tank barrels of prospective resources, according to an independent analysis commissioned by MOG, a junior partner. The license is wholly owned by MOG but Genel Energy has bought 75 per cent of play under a $10 million farm-in, that was the subject of controversy and legal threats from Leni Gas & Oil. Leni sold its 10 per cent share of the play to MOG for $1 weeks beforehand.
“If proven by drilling, the prospects identified at the Eocene/Palaeocene can be economically viable on a stand-alone basis,” MOG chief executive Bill Higgs said. He said that the company aimed to see drilling on the first prospect before the end of 2013 pending approval of the Genel Energy farm-in.
On 24 July 2013 the Times of Malta reported:
Ħaġar Qim is a magnificent example of megalithic architecture but shortly the prehistoric temple will lend its name to an oil well. Situated out at sea, about 150 kilometres southward of the ancient site, the drilling of the deepwater oil well is expected to start in the final three months of this year. The exact location of Ħaġar Qim 1, as the oil well will be known, will be determined after data from a seabed survey concluded last month is analysed. In a recent operational update, Mediterranean Oil and Gas said the data would assist the operational team to determine the “most suitable location” for the well. Mediterranean Oil and Gas is a minority shareholder in the company licensed by the Government to look for oil in Area 4, where a dispute over the offshore boundary with Libya was settled in the 1980s. The oil rig tasked to drill the exploration well, the Paul Romano, will shortly start making its journey towards the site after undergoing maintenance work at the Palumbo shipyard.
On Tuesday 4th November 2013 Infrastructure Minister Joe Mizzi told Parliament that all geological and economic studies carried out to date had shown that the projected oil well called Hagar Qim shows more promise than the one named Tarxien, and will therefore be the one to be drilled first.
Mr Mizzi also said that the contractor was bound to drill an oil well in the first phase of exploration, and would be obliged to drill more if he chose to pursue the exploration with other oil wells.
Mediterranean Oil and Gas and Genel Energy should start drilling the first well in the first quarter of 2014.
The minister explained that before the Government entered into a production sharing agreement with an oil company, it must ascertain that the company would technically and financially be in a position to satisfy the obligations on contract.
The contract also specified that the contractor must undertake the exploration for, and exploitation of, oil on the Government’s behalf, and must exclusively assume all risks and expenses.
Besides their own studies, the two companies had chosen to appoint an independent company to give its own technical opinion.
Hagar Qim is located about 150 kilometres south of Malta in Area Four.
Area 4 has largely been overlooked in Malta’s oil exploration history. In 1993, Amoco had drilled Tama-1 and although the well gave indications that oil was present, it was not in commercially viable quantities.
Tama-1 was drilled in Block 3, to the west of blocks licensed to Mediterranean Oil and Gas, which will drill in unexplored zones.
26 March 2014 – Following January’s 2014 declaration by Mediterranean Oil and Gas (MOG) that preparations for a marine seismic acquisition campaign in offshore Malta were underway, the Maltese Parliament announced that a seismic survey ship was due to arrive in Malta in late March 2014. The vessel owner was MOG as MOG’s subsidiary company Melita Exploration Co. Ltd had a 40% share in Area 3 blocks 1, 2 and 3 in partnership with oil company Capricorn Malta Limited, a subsidiary of oil and gas giant Cairn Energy. MOG’s original intention was to acquire circa 1,500 km (932 mi) of broadband 2D seismic during the first half of 2014. Results of the drilling at the site about 130 kilometers (81 miles) south of Malta were expected in July 2014.
In July 2014 Genel Energy plugged and abandoned an exploratory oil well it had been drilling south of Malta after finding no indication of hydocarbons. The Hagar Qim-1 well on the Area 4 licence offshore Malta was drilled to the Eocene (rock level) and plugged and abandoned with no indication of hydrocarbons, the company announced in July 2014. The Noble Paul Romano rig moved on to drill the Nour prospect on the Sidi Moussa (Genel 60% working interest) block offshore Morocco.
The company had started drilling the well, called Hagar Qim, in May 2014 some 130km south of Malta. It was the 11th well to be drilled offshore Malta and the first exploration well since 2002. But the chances of striking oil were never high.
Four distinct Upper Triassic-Jurassic paleaogeographic domains can be recognized in offshore Malta, a strongly subsiding one characterised by basinal facies of the Noto, Streppenosa, Modica, Buccheri, Chiaramonte, Hybla and Amerillo Formations, a stable one characterised by shallow open to restriced water facies of the Siracusa and Naxxar Formations, an intermadiate domain characterised by open marine facies of the Siracusa-Buccheri combination and an evaporitic domain of the Krachoua Formation.
Proven source rocks of Upper Triassic and Lower Jurassic Noto and Streppenosa Formations were deposited in the basins. These formations are known to source the oil in the Ragusa Basin which extends into Blocks 1,
2, 3, 4 and 5 of Area 3 in the north.
A similar situation is inferred in the south-eastern parts of Area 4 where Jurassic faulting is observed along a NNW-SSE trend cutting through Blocks 5 and 7. Facies differentiation culminated in the Late Cretaceous. Three similar domains developed in regions covered by Area 4 and to the west of it: a platform domain characterised by a monotonic sequence of dolomites and limestones of the Zebbag and Halk el Menzel Formations drilled in Tama-1, an intermediate domain with rudist buildups observed on the shelf edge of the Melita Rise drilled offshore Tunisia (Isis field), and a third domain characterised by Zebbag dolomites overlain by a thick sequence of organic rich shales and limestones of the Fahdene, Bahloul, Aleg el Haria and Bou Dabbous Formation.
Transitional Cretaceous facies are present in GOZ and AQ indicating the Malta Platform limit to be close to these wells. GOZ which was suspended in the Early Cretaceous encountered a thick section of Hybla shales overlain by chalks which are reminiscent of the Abiod Formation in Tunisia. These chalks have also been encountered in AQ. Beds of porous, intertidal dolomite and shelf-edge calcarenite, altering with impermeable marl, mudstone and shale, are inferred to occur in the Cretaceous transition zone, providing good reservoirs and seal potential. Rudist-reef reservoirs, present in offshore Tunisia may extend into parts of Area 4. Cretaceous source rocks, equivalent to the Bahloul and Fahdene are also inferred to be present in this zone.
A very striking fourth domain is recognised in the western half west of Area 4. Geological and geophysical data indicate that the tectono-sedimentary history of the area followed the same pattern observed in nearby basins with important local salt movements. One observes on seismic sections a central broad structural high with thinning of the overlying Late Cretaceous sedimentary sequence as well as a rim syncline also of Late Cretaceous age. Towards the end of the Cretaceous salt activity appears to have been damped and basin inversion occurred. Palaeocene and Lower Eocene Metlaoui reservoirs of offshore Tunisia may also be present in Area 4 and to the west of it. A shelf-edge carbonate build-up recognized on seismic sections in west of Area 4 is interpreted in this sense. An equivalent of the Bou Dabbous Formation, source rock to nearby Ashtart and Bouri fields, should be present. Post-Eocene age Lower Coralline Limestone, Globigerina Limestone, Blue Clay and Upper Coralline Limestone are widespread. They have been encountered in all wells including MB and TAM.
Mudstone and claystone with abundant planktonic foraminiferids of Pliocene-Quaternary age, encountered in AQ, are present in the troughs of the Sicily-Channel rift complex and other subsiding areas. The thickness of these sediments is controlled by post-Miocene rifting, about 340m at the downthrown AQ and one metre at the upthrown MB. As much as 2,000m are estimated to be present in the deep troughs.
click on diagram for an enlarged version
Tectonic reconstruction shows Late Triassic-Early Jurassic pull-apart basis in parts of offshore Malta. Here, Triassic carbonates of the Gela Formation (Gela, Ragusa) are a potential play but may be too deep to be
Jurassic carbonates of the Siracusa (Vega, Perla) and Nara Formations (El Biban) are expected on the flanks of the Ragusa Basin in Area 3 and the Melita-Medina Basin in Area 4.
Cretaceous shelf-basin transition zone stratigraphic plays in reefal facies of the Zebbag Formation (Isis, Miskar) are likely to be widespread in Area 4 and to the west of it.
Metlaoui nummulitic bank facies (Ashtart, Bouri) of Tertiary age are also likely to be present in Area 4 and to the west of it, therefore appearing in places to be conformable with Cretaceous plays, making multiple play objectives likely.
Plays associated with halokinesis are also evident in the west of Area 4.