Egypt Nile delta gas plays take off

G. Alan Petzet
Exploration Editor

Amoco Nile Delta Discoveries [37198 bytes]

Exploration since about 1992 is establishing Egypt's Nile delta as a major gas/condensate prov- ince.

The delta was estimated to have produced about 1 tcf as of Jan. 1, 1992. At that time reserves were estimated at almost 7 tcf.

Only a few fields are yet on production. Reserve estimates for the delta appear to be at least several times what they were in 1992. Many blocks are still to be explored by the drill. Lack of comprehensive source rock studies is complicating resource estimates.

The pace of discoveries has picked up the past 2 years, and operators have assured Egyptian authorities that sufficient gas has been found to support domestic and export projects. Liquefied natural gas export feasibility is under early study.

The delta's gas reserves seem poised to dominate Egypt's overall gas reserves, estimated at 22.3 tcf as of Jan. 1, 1996. Most of that resides in the Western Desert and Gulf of Suez.

Offshore discoveries in the Mediterranean Sea are overtaking the Nile delta onshore gas fields in stature. Pay zones at most discoveries have been of Miocene age, but lately a Pliocene play has become significant.

Most of the delta is under concession. Key operators are Amoco, AGIP SpA's International Egyptian Oil Co. affiliate, and British Gas. Egyptian General Petroleum Corp., Shell, Marathon, Edison Gas, and Repsol also have holdings (Fig. 1 [78167 bytes]).

Most of the delta gas is earmarked for use in Egypt, but the government has been negotiating all year for sales through a planned pipeline to Israel, Jordan, and Palestine.

What's on production

IEOC started up production in mid-1996 from Wakar and Port Fouad gas fields. The fields, on the North Port Said concession that dates to the early 1980s, are producing about 70 MMcfd through a subsea pipeline with landfall near Port Said.

The only other offshore production is from Abu Qir field, operated by EGPC's General Petroleum Co. unit. Phillips Petroleum Co. discovered Abu Qir in 1969.

Belayim Petroleum Co. is producing from Egypt's first gas field, Abu Madi onshore, a 1967 discovery.

IEOC/Amoco plan to place several fields on production soon. First is likely to be Baltim South by yearend 1997, the other Baltim fields by 1999, and a combination of fields on the Temsah and Ras el Barr concessions by 2000.

Egypt's gas pipeline grid is mainly developed in populated areas around Alexandria, Cairo, Port Said, and Suez. The grid does not extend to the Sinai, most of northern Egypt, or southern Egypt.

Tentative plans are to lay a pipeline from the Nile delta across Sinai to serve Israel, Jordan, and Palestine by about 2000. Intended sales volumes are 250 MMcfd each to Israel and Jordan and 50 MMcfd to Palestinian settlements (OGJ, Jan. 8, 1996, Newsletter).

Israel burns no gas but intends to generate electricity. Egypt's gas consumption, mainly for electricity, was 1.3 bcfd in 1995.

Egypt's first private pipeline company, Egypt Trans Gas Co., was formed this year to construct the export pipeline if negotiations succeed. Ownership is the Egyptian government through Egypt Gas 34% and Amoco and IEOC each 33%.

Drilling steady

Drilling has perked up in the delta since Egypt began allowing contractors to develop gas in the late 1980s and issued gas concessions in the early 1990s.

Amoco has about 4 million net acres or 34% of the acreage in the delta. Tracts in which it owns interests cover about two thirds of the delta, eight offshore and one onshore.

Since 1993 Amoco has been involved in about 23 delineation and exploratory wells in the delta, including three 100% owned wells and the rest owned 50-50. All but one of the 50-50 wells was with IEOC.

Baltim, Ras el Barr, and Temsah are the most active concessions offshore. Here are the results:

Baltim concession, IEOC operator, eight wells drilled with three discoveries, Baltim South, East, and North fields.
Ras el Barr concession, Amoco operator, three wells drilled with three discoveries, Ha'py, Akhen, and Seth, and one well drilling on a fourth feature.
Temsah concession, IEOC operator, 10 wells drilled with three discoveries, Temsah, Denise, and Denise South, and one well drilling.

Amoco said Temsah field is quite large, at least 20 km long and 4-6 km wide, and will require much delineation drilling.

An AGIP-Amoco task force in Milan is working on development schemes for the companies' fields. With all in less than 300 ft of water, conventional hardware is likely. Some wells should come on at 40-50 MMcfd.

Condensate may go to Egypt and export markets. The deepest gases in Temsah and Middle Miocene have 40-50 bbl/MMcf, while Late Miocene Abu Madi and deeper Pliocene zones contain 17-25 bbl/MMcf. Shallower Pliocene zones contain almost dry gas.

Delta subsurface

The Nile delta province stretches from just north of Cairo to 70-100 km offshore in the Mediterranean.

The delta is about 250 km wide at the shoreline. Water depths are 400-500 ft in the southern part of the two northerly deep marine concessions and 4,000-4,500 ft in their northern parts along the basin edge.

Three reservoirs have been found gas productive in the offshore Nile delta, said Denis Mascardelli, vice-president of exploration, Amoco Egypt (Fig. 2 [74732 bytes]).

The oldest are Serravallian (Middle Miocene) sands. Temsah field and the Akhen discovery are examples. The sands have porosities of 20% to more than 30% with excellent permeabilities. DSTs of 30-40 MMcfd on 5/8 in. chokes are common. These sands are at about 4,000 m.

Reservoir characteristics are also excellent in the Baltim fields, which produce from the Abu Madi formation of Upper Messinian, latest Miocene. These sands are at 3,300-3,500 m.

The third play is Pliocene age sands in the Kafr el Sheikh formation. The Nile delta, a continental margin in Miocene, becomes a true delta in Pliocene with largely focused sediments with sand from an integrated river, Mascardelli said.

Wells encounter Pliocene sediments at 500-3,300 m. Well costs are $3-4 million to shallowest Pliocene reservoirs at 1,500-1,800 m and about $10 million to Serravallian reservoirs at 4,000 m.

Pliocene play

Pliocene will be a significant play in the delta, Mascardelli said.

The Amoco/AGIP Ak- hen-1 well encountered 170 ft of gross gas pay of Miocene and Pliocene age at 11,540-14,466 ft. A test of a 39 ft Miocene zone at 14,427-466 ft flowed 36 MMcfd of gas and 2,075 b/d of 42° gravity condensate on a 3/4 in. choke. The well is in 289 ft of water 50 km offshore.

There were major differences in the producing reservoirs from those seen in previous wells in the area. The Miocene sands were of a different age from those found in Temsah field to the east, indicating that a new gas bearing trend may exist in the area, Amoco said. The company said the Pliocene gas bearing sands were the deepest encountered to date and may open up a new, high pressured Pliocene gas trend.

In addition to the two main zones in the Akhen well, a small gas column was also present in the formation tested in the Ha'py-1 discovery well announced in March 1996. This confirms an upside potential for gas reserves in that Pliocene discovery.

The next well on the Ras el Barr concession, Osiris East-1, is to test the area between the Akhen discovery and Temsah field.

The delta's deepest well may be one Mobil drilled years ago toward a Cretaceous objective. It went to 4,200-4,300 m.

Drilling is not easy in the delta, Mascardelli said. Pliocene Kafr el Sheikh contains much sediment deposited very quickly. Deeper Pliocene has severe overpressuring with gradients of 0.8 psi/ft. Miocene Abu Madi is normally pressured, while deeper Temsah is overpressured at 0.6 psi/ft. Multiple casing strings to control pressures are common, and the lowermost portion of the Akhen discovery is a 6 in. hole.