Harvest Natural Resources Announces
2013 First Quarter Results

HOUSTON, June 5, 2013 — Harvest Natural Resources, Inc. (NYSE: HNR) today announced 2013 first quarter earnings and provided an operational update.

Harvest reported first quarter net income of approximately $36.1 million, or $0.91 per diluted share, compared to a net loss of $1.0 million, or $0.03 per diluted share, for the same period last year. The first quarter results included exploration charges of $1.9 million, or $0.05 per diluted share and unrealized gain on warrant derivative of $3.8 million, or $.10 per diluted share.

Petrodelta reported earnings during the first quarter of $187.7 million, $60.1 million net to Harvest’s 32 percent interest, under International Financial Reporting Standards (IFRS). Included in Petrodelta’s IFRS first quarter earnings is a gain on exchange rate resulting from a revaluation of assets and liabilities recorded by Petrodelta due to the Venezuela Bolivar/U.S. Dollar currency exchange rate devaluation announced by the Venezuelan government on February 8, 2013. After adjustments to Petrodelta’s IFRS earnings, primarily to conform to accounting principles generally accepted in the United States (GAAP), Harvest’s 32 percent share of Petrodelta’s earnings was $39.6 million.

Excluding the effects of the Venezuelan devaluation, exploration charges and unrealized gain on warrant derivatives, we estimate net income for the first quarter of 2013 would have been approximately $4.3 million, or $0.11 per diluted share.

Highlights for the first quarter of 2013 include:

Venezuela

Indonesia

VENEZUELA

During the three months ended March 31, 2013, Petrodelta sold approximately 3.36 MMBO for a daily average of 37,346 BOPD, an increase of 13 percent over the same period in 2012 and remaining at the same level over the previous quarter. Petrodelta also sold 0.78 billion cubic feet (BCF) of natural gas for a daily average of 8.6 million cubic feet per day (MMCFD). Petrodelta’s current production rate is approximately 40,000 BOPD.

During the first quarter of 2013, Petrodelta drilled and completed one development well in the Isleño Field and one development well in the El Salto Field. Currently, Petrodelta is operating five drilling rigs and two workover rigs and is continuing with infrastructure enhancement projects in the El Salto and Temblador Fields.

Petrodelta’s production target for the year 2013 is projected to be approximately 42,000 BOPD. The 2013 Petrodelta capital budget is expected to be approximately $210.0 million. Petrodelta expects to drill 31 oil wells and 2 water injector wells during 2013.

On February 8, 2013, the Venezuelan government published in the Official Gazette the Exchange Agreement No. 14 which establishes new exchange rates for the Bolivar/U.S. Dollar currencies that became effective February 9, 2013. The exchange rate established in the Agreement is 6.30 Bolivars per U.S. Dollar. The Exchange Agreement also announced the elimination of the Sistema de Transacciones con Títulos en Moneda Extranjera (“SITME”) effective February 8, 2013. All exchanges of Bolivars must now transact through the Central Bank. As a result of the February 8, 2013 devaluation, in the three months ended March 31, 2013, Harvest Vinccler recorded a $0.1 million gain on revaluation of its assets and liabilities, and Petrodelta recorded a $186.7 million gain on revaluation of its assets and liabilities.

In March 2013, PDVSA requested an exemption from MENPET for the Windfall Profits Tax under the provision in the April 2011 Windfall Profits Tax law. The exemption was applied to several oil development projects, including Petrodelta. The exemption is allowable under the April 2011 Windfall Profits Tax law; however, MENPET has neither publicly defined the projects qualifying for exemption, nor the guidance to be used in calculating the exemption. PDVSA issued to Petrodelta its share of the exemption credit, $55.2 million ($36.4 million net of tax) ($17.7 million net to our 32 percent interest, $11.6 million net of tax net to our 32 percent interest) based on PDVSA’s calculation and projects PDVSA deemed to qualify for the exemption. Neither Petrodelta nor Harvest have been provided with supporting documentation indicating the properties have been appropriately qualified by MENPET, the specific details for the exemption credit, such as which fields, production period or production, or the supporting calculations. Until MENPET either issues guidance on the exemption provision in the April 2011 Windfall Profits Tax law or issues payment forms including the exemption credit, or written approval from MENPET for this exemption credit is received by Petrodelta, Harvest has and will continue to exclude the exemption credit from our equity earnings in Petrodelta.

The average sale price for crude oil produced during the quarter was approximately $94.41 per barrel.

EXPLORATION AND OTHER ACTIVITIES

Dussafu Project — Gabon (Dussafu PSC)

Operational activities during the three months ended March 31, 2013 included completion of drilling activities on the Dussafu Tortue Marin-1 exploration well (DTM-1), and appraisal sidetrack (DTM-1ST1). On January 4, 2013, Harvest announced that DTM-1 had reached a vertical depth of 11,260 feet within the Dentale Formation. Log evaluation and pressure data indicate that the Company has an oil discovery of approximately 42 feet of pay in a 72 foot column within the Gamba Formation and 123 feet of pay in stacked reservoirs within the Dentale Formation. DTM-1ST1 was drilled to a total depth of 11,385 feet in the Dentale Formation, approximately 1,800 feet from DTM-1 wellbore and found 65 feet of pay in the primary Dentale reservoir.

DTM-1 and DTM-1ST1 are suspended pending future appraisal and development activities. The drilling rig was demobilized and released on February 21, 2013.

A program of subsurface and conceptual engineering studies commenced with the objective of evaluating the commerciality of Tortue and the other oil discoveries to determine the optimum development options for the Dussafu block.

In other parts of the block, activities during the first quarter of 2013 included the continuation of the Pre-Stack Depth processing and reprocessing of the new Central 3-D together with the 2005 Inboard 3-D seismic, approximately 1,300 square kilometers, which commenced in June 2012. The Pre-Stack Depth processing of the merged 3-D project is expected to be completed in July 2013.

Harvest is moving forward with the development plans for the resources discovered to date, and is also planning the acquisition of 3D seismic over the outboard portion of the Dussafu block to better define the exploration prospects that have been identified on existing 2D seismic.

Harvest has engaged Tudor, Pickering, Holt & Co. to manage a competitive process to farmout a significant portion of its interest in the Dussafu block. This process is expected to be concluded in the third quarter 2013.

Budong-Budong PSC — Indonesia

In December 2012, we signed a farm-out agreement with the operator of the Budong PSC to acquire an additional 7.1 percent participating interest and to become operator of the Budong PSC. The assignment of interest was approved by the Government of Indonesia on April 9, 2013. Approval of the transfer of operatorship was received from SKK Migas, the Special Task Force for oil and gas upstream sector, on March 25, 2013.

Operational activities during the three months ended March 31, 2013 included continued work on an exploration program targeting the Pliocene and Miocene targets encountered in the previous two wells. Land acquisition, tender prequalification and environmental studies are on-going.

Non-GAAP Financial Measures

These measures are included due to the significant nature of Petrodelta’s earnings to Harvest. In this press release, Petrodelta’s adjusted EBITDA disclosure is not presented in accordance with accounting principles generally accepted in the United States (GAAP) and Petrodelta’s financials are not intended to be used in lieu of GAAP presentations of net income or cash flows from operating activities. Adjusted EBITDA is presented because we believe it provides additional information with respect to both the performance of our fundamental business activities as well as our ability to internally fund our future capital expenditures and working capital requirements. We also believe that financial analysts commonly use adjusted EBITDA to analyze Petrodelta’s performance.

The Company defines adjusted EBITDA as net income (loss) before interest expense, investment earnings, current income taxes and certain non-cash items in the Company’s statements of operations, including depreciation, depletion and amortization, accretion of asset retirement obligations, deferred income taxes, certain employee compensation charges and gains or losses from foreign exchange. Although we present selected items that we consider in evaluating our performance, you should also be aware that the items presented do not represent all items that affect comparability between the periods presented. Variations in our operating results are also caused by changes in volumes, prices, exchange rates and numerous other factors. These types of variations are not separately identified in this release, but are discussed, as applicable, in management’s discussion and analysis of operating results in our Annual Report on Form 10-K for the year ended December 31, 2012.

A reconciliation of adjusted EBITDA to net income and cash flows from operating activities for the periods presented is included in the tables attached to this release.

Conference Call

Harvest will hold a conference call at 10:00 a.m. Central Daylight Time on Wednesday, June 5, 2013, during which management will discuss Harvest’s 2013 first quarter results. The conference leader will be James A. Edmiston, President and Chief Executive Officer. To access the conference call, dial 888-455-2263 or 719-325-2463, five to ten minutes prior to the start time. At that time you will be asked to provide the conference number, which is 7050198. A recording of the conference call will also be available for replay at 719-457-0820, passcode 7050198, through September 4, 2013.

The conference call will also be transmitted over the internet through the Company’s website at www.harvestnr.com. To listen to the live webcast, enter the website fifteen minutes before the call to register, download and install any necessary audio software. For those who cannot listen to the live broadcast, a replay of the webcast will be available beginning shortly after the call and will remain on the website for approximately 90 days.

About Harvest Natural Resources:

Harvest Natural Resources, Inc., headquartered in Houston, Texas, is an independent energy company with principal operations in Venezuela, exploration assets in Indonesia, West Africa, and China and business development offices in Singapore and the United Kingdom. For more information visit the Company’s website at www.harvestnr.com.

CONTACT:

Stephen C. Haynes

Vice President, Chief Financial Officer

(281) 899-5716

This press release may contain projections and other forward-looking statements within the meaning of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934. They include estimates and timing of expected oil and gas production, oil and gas reserve projections of future oil pricing, future expenses, planned capital expenditures, anticipated cash flow and our business strategy. All statements other than statements of historical facts may constitute forward-looking statements. Although Harvest believes that the expectations reflected in such forward-looking statements are reasonable, it can give no assurance that such expectations will prove to have been correct. Actual results may differ materially from Harvest’s expectations as a result of factors discussed in Harvest’s 2012 Annual Report on Form 10-K and other public filings.

Harvest may use certain terms such as resource base, contingent resources, prospective resources, probable reserves, possible reserves, non-proved reserves or other descriptions of volumes of reserves. These estimates are by their nature more speculative than estimates of proved reserves and accordingly, are subject to substantially greater risk of being actually realized by the Company.