Oil Exploration History In Israel

In all, around 410 petroleum wells have been drilled in Israel (including about 95 appraisal and development wells) since exploration commenced in the 1940's. The majority of early exploration efforts were in the coastal plain, Negev, Dead Sea areas and later offshore Mediterranean coast. Most of these earlier wells were located on limited seismic of inferior quality or poorly processed and were mainly targeted at shallower horizons or at the Triassic or Permian in a southern Negev region interpreted by Givot Olam to be of low prospectivity. The few Triassic wells drilled in the northern prospective region were located on single line anomalies totally off structure and could only be used for stratigraphic information.

The first exploration drilling was carried out in 1947 on a gravity nose in the Heletz area south of Ashkelon. Almost ten years later, the Heletz oilfield was discovered at that location by the deepening of the original well. Shortly after, the Zohar gas field was discovered in the northeast corner of the Negev. During the 1960's,with substantial government financial support, a large amount of seismic was acquired along with many geological studies and geochemical surveys, predominantly in the areas around the Heletz and Zohar fields although some regional data was acquired at that time also. Following the 1967 war, less governmental support was provided for exploration within the earlier areas of exploration and efforts were focused on the recently accessible Gulf of Suez fields. Around this time, an American consortium drilled six offshore wells along the Mediterranean coast without making a commercial discovery despite several good shows.

The oil price crisis of 1973 shifted the exploration focus to large structures in deeper unexplored sediments. Oil shows were encountered in Lower Jurassic limestones to the north of Jerusalem, Triassic and Paleozoic in the northern Negev were explored and the Jurassic near Zohar gas field produced oil at low rates for a short time. In this period a large effort was spent on the Sinai which resulted in the discovery of the Alma oil field and Sadot gas field in the northern Sinai and encouraging oil shows offshore. Exploration continued in the coastal plain area and resulted in the discovery of the small Shiqma gas field in Neogene and Ashdod oil field in Jurassic sediments.

Exploration in the Sinai terminated abruptly with the signing of the Egypt Israel peace treaty in 1979 and exploration efforts reduced due to low oil prices. Moderate levels of exploration continued in the Dead Sea area with seismic acquisition, shallow drilling and deepening of some existing wells which resulted in a live oil recovery from Triassic in one deepened well but no commercial discoveries. Additional drilling took place around the Ashdod area for Jurassic carbonate reservoirs which resulted in one small oil discovery.

At the end of 1985, OEIL ( later called INOC, Israel National Oil Company-a government owned entity ) suspended all drilling operations in order to carry out a comprehensive basin analysis study over all of Israel. Only limited exploration work continued by private operators including the drilling of two Jurassic wells in the northwestern part of the Negev which gave oil shows but no discoveries. INOC recommenced exploration around the Dead Sea area where a large amount of asphalt oil shows encouraged continued exploration without resulting in any commercial discoveries.

Substantial drilling occurred to test Triassic and Permian plays in the Negev region without success. Seismic clearly shows the Mesozoic thinning southwards onto the platform and therefore the Negev area does not have the same Triassic or Permian potential as in the central and northern area of Israel. Various Triassic shows were encountered in the Hakanaim and Massada wells in the Negev region. INOC recently made a small discovery at the Zuk Tamrur field near the Dead Sea which is producing at 150-200 bbls/day from the base Triassic, Raaf Fm in an extended production test. The Emunah-1 well recently tested 39° API oil from the Permian Saad Fm before watering out and flowed 800 bbls per day of 31° API oil from the Lower Triassic Yamin Fm. The area of these recent discoveries includes Massada, Gurim, Hakanaim and other small discoveries which have produced small amounts of varying API gravity oils from Permian, Triassic and Jurassic levels. The Dead Sea area, unlike the Rosh Ha'Ayin area, was exposed to active fresh water flushing probably from Early Cretaceous time. The oil found in the Dead Sea area was probably generated very recently from poor Triassic (Jurassic?, Cretaceous?) source rocks, but in very limited amounts.

In addition, three wells were drilled during the early 1990's offshore Israel and two of these tested oil. The Yam-2 well, drilled due west of Gaash-2, is reported to have tested 500 bbls/day of oil from the Jurassic. The other well, Yam-1 to the south, is reported to have tested 800 bbls/day and is likely to be appraised by drilling in the future.

Only a few Triassic tests have been drilled in the northern or central part of Israel, none of which, until Meged-2, were within the boundaries of L-244. Most of the previous 410 wells drilled were in the western coastal area, the eastern Dead Sea area or the southern Negev area. The first four wells to reach Triassic in central and northern Israel, Ramallah-1, Deborah-2A, Gaash-2 and Atlit-1, were drilled almost entirely without the aid of seismic. The Ramallah-1 well was drilled to the east and the Gaash-2 well was drilled to the west of the Rosh Ha'Ayin structure. Both wells were drilled to test the Jurassic and were deepened to the Triassic for stratigraphic information.

The Triassic and Permian potential in central and northern Israel associated with the extension of the Palmyra Rift where several large oil and gas fields were discovered in Syria in the Triassic during the 1980's, was more completely developed and understood by Givot Olam in the early 90's.

a) Givot Olam's Meged-2 well which recovered oil from the Mohilla Fm in L-244 and

b) the David-1 well to the southwest of Rosh Ha'Ayin, reached T.D. at 6,000m. The well had a strong gas show at the Base Permian Saad Fm but was not tested due to mechanical problems.

Since 1981, some 775 km of seismic lines have been acquired over the Rosh Ha'Ayin area and several studies by independent consultants confirmed the potential for both structure and prospective carbonate facies. In the early 90's Givot Olam reprocessed almost all of the existing seismic lines ( around 1150 kms, which is now available on work station ) and totally reworked the play. The results of the Meged-2 and David-1 wells have much enhanced the prospectivity of the area and the chance to find commercial oil and gas accumulations.

Exploration expenditure on the Rosh Ha'Ayin area can be split into two phases with around US $10.0 million being spent by Givot Olam on drilling the Meged-2 well, seismic acquisition, reprocessing and various studies between 1992 and the present and around US $30 million being spent by INOC ( and its predecessors ) on approximately 1000 km of seismic lines and two wells, Ramallah-1 and Gaash-2, drilled on the flanks of the Rosh Ha'Ayin structure prior to 1983.