Even more gas than previously thought is likely lurking in the Levant basin, following a Wednesday announcement of a small but significant additional prospect just next to the Tamar reservoir.

The new reservoir, called Tamar Southwest, is expected to contain about 0.7 trillion cubic feet, or about 19 billion cubic meters, of natural gas, Delek Drilling and its Tamar exploration partners reported to the Tel Aviv Stock Exchange that day.

In addition, international oil and gas consulting firm Netherland Sewell and Associates Inc. (NSAI) has deemed the likelihood of success at Tamar Southwest to be higher than 70 percent, the TASE report said.

While it is still too early to reveal an investment decision for gas production on the new reservoir, the discovery increases the amount of proven gas in the Israeli market, the partners stressed.

Tamar Southwest, as its name indicates, is located southwest of the much larger, 282-billioncu.m. Tamar reservoir and southeast of the even larger, roughly 535-billion-cu.m. Leviathan reservoir.

As the Tamar Southwest gas field is located mostly within the Tamar license block, but also overlaps with the Eran license block – the block sandwiched between the Tamar and Leviathan gas fields – Tamar partners will own an 80% share of Tamar Southwest, while the Leviathan partners will hold a 20% share.

At Tamar, Houston-based Noble Energy holds 36%, Delek Drilling and Avner Oil Exploration – both subsidiaries of the Delek Group – each own 15.625%, while Isramco owns 28.75% and Dor Gas owns 4%.

At Leviathan, Noble Energy owns 39.66%, Delek Drilling and Avner Oil Exploration each own 22.67% and Ratio Oil Exploration holds 15%.

According to pre-drilling data presented in the report to the TASE, the significant risks – if any – involved with drilling at Tamar Southwest would mainly be technical and operational ones. Later on in the drilling process used for commercial extractions, there could be a risk that the permeability of the reservoir rock is not high enough to allow for sufficient gas flow to achieve commercial significance, the report stated.

So far, the partners are unable to provide an estimated probability that the reservoir will reach the level of commercial production, the document said. However, the partners wrote, a study of the resources has indicated that based on the development of similar gas fields, the reservoir has a reasonable chance of becoming commercial.

Meanwhile Wednesday, Delek Drilling, Avner Oil Exploration and Noble Energy announced that they would soon begin production tests on the Aphrodite A2 reservoir located in Cyprus’s Block 12, according to another report the partners submitted to the TASE.

Noble Energy holds a 70% share of this Cypriot reservoir, while Delek Drilling and Avner Oil Exploration each hold 15%.

The production tests will begin soon and will last for about a month, during which the partners will be using an ENSCO 5006 rig to withdraw up to about 60 million cubic feet per day, the report said.

The total estimated budget for the production tests is expected to be about $64 million, the report added.

Also Wednesday, both Delek Drilling and Avner Oil Exploration reported the results of their 2013 first-half and second- quarter earnings, indicating significant improvement due to the ongoing production at the Tamar reservoir.

“The production from the Tamar reservoir is a very significant growth engine for the Israeli economy,” said Delek Drilling CEO Yossi Abu. “The production is unequivocally improving the financial results of the partners in the Tamar project, and in addition will lead to significant reductions in energy costs for all of Israeli industry, will contribute to the creation of new jobs and will significantly improve the environment.”

In the first half of 2013, Delek Drilling’s net earnings amounted to $18.2m., as opposed to $8.7m. during the same period last year. Avner Oil Exploration’s net earnings for the first half of 2013 were $11.8m., compared with $5.5m. during the same period last year, according to the companies.

These figures constitute a leap of 109% and 114%, respectively.

“We will continue our activities in the exploration and in the production of oil and gas in order to realize the potential for the benefit of the Israeli economy and the partnerships,” said Gideon Tadmor, chairman of Delek Drilling and CEO of Avner Oil Exploration.