Portfolio Update - Gulf of Mexico

LENI GAS & OIL PLC

("LGO" or "The Company")

06 April, 2010

PORTFOLIO UPDATE - GULF OF MEXICO

Leni Gas & Oil plc (LGO), the AIM listed international Oil and Gas Exploration, Development and Production Company, today announces an update to its interests in the United States Gulf of Mexico and Gulf Coast ("GoM"). Further updates on the other countries of operation within the portfolio including Spain, Trinidad and Malta shall be issued shortly.

Highlights

·; LGO retains rights within sixteen blocks in the GoM from its investment in Byron Energy LLC ("Byron") in 2008. As announced on 25 January 2010, an agreement was completed to convert the Byron investment into direct working interests and exercise options in GoM acreage.

·; The sixteen blocks in the GoM encompass interests in leases West Cameron, South Marsh Island, Eugene Island, Ship Shoal, Grand Isle and Main Pass, with the Company currently retaining direct working interests in Eugene Island and Ship Shoal leases with exercise options in the remainder.

·; LGO net reserves across all existing GoM interests are 1.33mmboe proved, 0.28mmboe probable, 1.96 mmboe possible, and 0.04mmboe prospective resources, in accordance with the competent person's report of March 2009 and the Petroleum Resources Management System ("PRMS"). The competent person's report is scheduled for the next annual update in June 2010.

·; Unaudited potential incremental reserves and resources assuming all current exercise options are completed are 0.33 mmboe proved, 0.65 mmboe probable, 1.65 mmboe possible and 3 mmboe of prospective resources.

·; The Eugene Island production asset reported gross production of 1,616 boepd at 31 December 2009 with some well performance issues restricting production. A higher-capacity natural gas compressor was successfully installed boosting production from the low pressure wells and well interventions are currently in preparation to recomplete behind pipe reserves in the higher producers.

·; The first Ship Shoal development well was successful drilled and evaluated in early March 2010 at a restricted rate of 2,153 boepd (20% oil, 80% gas) after encountering 65 feet of true vertical thickness pay. Commencement of production is expected to occur during Q2 2010.

·; LGO exercised its rights in February 2010 on the South Marsh Island development (block Eugene Island 177). The remaining block on the development, South Marsh Island block 8, remains to be exercised and is scheduled for September 2010 after further geological interpretation.

·; LGO retains exercise options to acquire a 7.25% direct working interest in Grand Isle blocks 95 and 100, South Marsh Island block 8, West Cameron block 106 and Main Pass block 115. These are planned for late 2010 and 2011.

·; LGO also retains exercise options to acquire up to a 20% direct working interest in other properties held directly by Byron. These properties include West Cameron blocks 476 and 477, South Marsh Island block 6 and Ship Shoal block 180. These options are currently being evaluated by the Company.

Existing Producing and Development Interests

The Company's existing interests in the GoM include the Eugene Island producing field, the Ship Shoal development and the South Marsh Island development.

The Eugene Island Field is located 50 miles offshore Louisiana in approximately 80 feet of water, and is operated by Leed Petroleum plc ("LDP") on behalf of the joint venture with Byron and LGO. Current production in the field comes from the Tex X2, Tex X3, T-1 and Mid Tex sands at depths ranging from 12,000 to 15,000 feet.

As announced on 25 January 2010, LGO is now a direct party to the joint venture with LDP and Byron in the Eugene Island production asset which spans blocks 172, 183 and 184. LGO retains a 7.25% direct working interest in Eugene Island blocks 183 and 184 south, a 3.625% direct working interest in block 184 north and a 3.00649% direct working interest in block 172. Net revenue interests range from 2.50540% to 6.04167%.

As of the March 2009 competent persons report, gross reserves are proved of 4.48 mmbo and 26.23 bcf (8.852 mmboe), probable of 2.10 mmbo and 14.87 bcf (4.58 mmboe), possible of 7.05 mmbo and prospective resources of 131.65 bcf (28.99 mmboe).

The Eugene Island field reported gross production of 1,616 boepd at 31 December 2009 with some well performance issues restricting production. Higher capacity compression facilities were successfully installed to increase production from the low pressure wells. Various workovers are planned on the three main producers. The A6 well experienced mechanical failure and various plans are being finalised to return the well to producing status. The A7 well depleted after recovering more reserves than initially forecast with remaining behind pipe reserves identified for completion. The A8 well continues to produce from the MidTex sands with a workover provisionally planned in Q2 2010 to recomplete the well into a more prolific sand once the current sands have economically depleted.

The Ship Shoal development encompasses blocks 197, 201 and 202 and is located 125 miles offshore Louisiana in approximately 100 feet of water. Under terms of the LDP and Byron Scouting Agreement ("Scouting Agreement"), LGO exercised in February 2010 its rights on the Ship Shoal development, with completed interests in block 197 (direct working interest 7.25%, net revenue interest 5.7819%) and block 202 (direct working interest 7.25%, net revenue interest 6.0417%) with an overriding royalty in block 201 (0.4714%).

Several material opportunities have been identified across the Ship Shoal blocks with total proved reserves of 4.79 bcf and 0.15 mmbo (0.94 mmboe), probable of 8.08 bcf and 0.25 mmbo (1.59 mmboe), possible of 28.8 bcf and 0.54 mmbo (5.34 mmboe), and prospective resources of 6.08 bcf and 0.1 mmbo (1.11 mmboe) as reported in the March 2009 competent persons report.

In early March 2010, the first Ship Shoal development well was successfully drilled and tested on block 201 at a restricted rate of 10.4 mmscfd and 423 bopd (a combined rate of 2,153 boepd). The well reached a total depth of 13,341 feet with logs confirming the well encountered 65 feet of true vertical thickness pay in its primary objective.

The well was drilled from the Ship Shoal 202 "A" platform which will enable the rapid commencement of production, expected to occur during Q2 2010.

The South Marsh Island development encompasses South Marsh Island block 8 and Eugene Island block 177. The development is located 90 miles offshore Louisiana in approximately 60 feet of water, was initially developed by Chevron and produced from numerous sands from 10,000 to 15,000 feet.

As of March 2009, gross proved reserves of 0.69 mmbo and 6.61 bcf (1.79 mmboe), probable of 1.87 mmbo and 12.29 bcf (3.92 mmboe), possible of 1.85 mmboe and 9.99 bcf (3.51 mmboe) and prospective resources of 0.66 mmbo and 1.93 bcf (0.98 mmboe).

Under terms of the LDP Byron Scouting Agreement, LGO exercised its rights in February 2010 on the South Marsh Island development (block Eugene Island 177). The remaining block on the development, South Marsh Island block 8, remains to be exercised and is scheduled for September 2010 after further geological interpretation to refine the drilling plan.

The competent person's report of all GoM reserves and resources is scheduled for update in June 2010, and the results of this report, incorporating the performance of the Eugene Island and Ship Shoal wells, and new geological interpretations, will be issued in due course.

Exercise Option Development Interests

The Grand Isle development encompasses blocks 95 and 100 and is located 100 miles offshore Louisiana in approximately 200 feet of water having been initially discovered by ExxonMobil in 1974. The field is located on the up-thrown side of a large counter-regional fault which trends northeast-southwest with hydrocarbons being trapped in over twenty pay intervals identified from 4,000 to 18,000 feet. Gross proved reserves of 22.67 bcf (3.78 mmboe) are estimated to remain as of 01 March 2009 with probable of 41.52 bcf (6.92 mmboe) and possible of 129.17 bcf (21.53 mmboe).

The Main Pass development includes block 115 and is located 83 miles offshore Louisiana in approximately 50 feet of water. Several material opportunities have been identified in the block with total possible reserves of 10.85 bcf (1.81 mmboe) estimated to remain as of 01 March 2009.

The West Cameron development includes block 106 and has gross prospective resources of 39.93 bcf (6.66 mmboe).

Reserves and resources of all exercise options are as per the competent persons report of March 2009.

Under terms of the LDP Byron Scouting Agreement, LGO retains an exercise option to acquire 29% of Byron's interests in these developments, equivalent to a direct 7.25% direct working interest, with net revenue interests between 5.8906% and 6.0417%.

Outwith of the LDP Byron Scouting Agreement, LGO also retains a Strategic Scouting Agreement with Byron for exercise options to acquire up to a 20% direct working interest in all other developments held directly by Byron. These developments include West Cameron blocks 476 and 477, South Marsh Island block 6 and Ship Shoal block 180. The Company is currently assessing these blocks for potential exercising of the options.

David Lenigas, Executive Chairman, commented:

"We are extremely pleased with the substantive progress of our interests in the GoM. The recent conversion to direct working interests provides the Company with both reporting and forecasting advantages and a fuller participation in the management of these interests."

"We anticipate 2010 shall return the Eugene Island assets to near original production capacity, are encouraged by the recent Ship Shoal well results and look forward to the next stage of development of these high potential assets."

Competent Person's Statement:

The information contained in this announcement has been reviewed and approved by Fraser S Pritchard, Executive Director for Leni Gas & Oil Plc (member of the SPE) who has over 20 years relevant experience in the oil industry.

Enquiries:

Leni Gas & Oil plc

David Lenigas, Executive Chairman

Fraser Pritchard, Executive Director

Tel +44 (0) 20 7016 5103

Beaumont Cornish Limited

Roland Cornish / Rosalind Hill Abrahams

Tel +44 (0) 20 7628 3396

Mirabaud Securities Limited

Rory Scott

Tel +44 (0) 20 7878 3360

Pelham Bell Pottinger 

Mark Antelme / Henry Lerwill

Tel + 44 (0)20 7337 1500

NOTES TO EDITORS

Leni Gas & Oil Plc is an international oil and gas exploration, development and production company headquartered in London, trading on the London Stock Exchange's AIM index. LGO's strategy is to acquire projects and businesses within the oil and gas sector that contain a development premium which can be unlocked through a combination of financial, commercial, and technical expertise.

LGO operates a low risk portfolio of production expansion assets in the US Gulf of Mexico, Spain, Trinidad and Malta with significant play upside using similar strategies to leverage technologies and proven production enhancement techniques. LGO specifically targets near term production with upside exploitation potential and manages its portfolio to ensure all assets have accelerated incremental reserves and production enhancement programs.

All reserves and resources were determined by pore-volume and performance analysis and undertaken by the competent person, Collarini Associates of Texas, and reported to partners on 18 May 2009 with an effective validity date of 01 March 2009.

All reserves and resources definitions are per the Petroleum Resources Management System.

GLOSSARY

bcf = billion standard cubic feet of gas

boe = barrels of oil equivalent calculated on the basis of six thousand cubic feet of gas equals one barrel of oil

bo = barrels of oil

bopd = barrels of oil per day

Byron = Byron Energy LLC

LDP = Leed Petroleum plc

LGO = Leni Gas & Oil plc

mm = million

PRMS = Petroleum Resources Management System

scf = standard cubic feet of gas

scfd = scf per day

SPE = Society of Petroleum Engineers