Exhibit 99.1

ENERGEN’S GEN 3 WELLS CONTINUE TO DELIVER OUTSTANDING RESULTS

3Q17 Production Beats Guidance by 9%; All Commodities Exceed Expectations

4Q17 Production Guidance Raised 5%

Per-Unit LOE and SG&A Decrease Substantially Again in 3Q17

****NOTE: 3Q17 conference call slides available at www.energen.com****

BIRMINGHAM, Alabama – Energen Corporation (NYSE: EGN) (“Energen” or the “company”) today announced financial and operating results for the third quarter ended September 30, 2017.

FINANCIAL AND OPERATING HIGHLIGHTS

PRODUCTION

EARNINGS AND EXPENSES

CAPITAL EXPENDITURES

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3Q17 WELL RESULTS

Comments from the CEO

“Energen’s execution and operational success continued in the third quarter of 2017,” said Energen Chief Executive Officer James McManus. “Once again, we delivered on our drilling and development plans; we exceeded our expectations for oil and total production; and we further reduced our LOE and G&A.

“Our Gen 3 wells continue to perform at or above our highest EUR type curves and at or above wells completed by other operators. Importantly, we expect our Gen 3 multi-zone pattern wells to continue driving production growth as we move forward. We have increased our guidance for 4^th quarter production in all commodities, with estimated total production up 5 percent; and we now expect year-over-year production growth in 2017 to be 34 percent.

“During the 3^rd quarter, we continued to execute on our bolt-on acquisition program, which we believe has created significant value for Energen. Over the last 21 months, we have added approximately 20,300 net acres in prime Delaware and Midland basin locations for an average price of about $17,500 an acre,” McManus said.

“We are extremely pleased with our performance this quarter and very excited about our future prospects as we successfully implement our 2017 drilling and development program and plan for 2018. We are confident that Energen is well-positioned to continue delivering strong results and creating shareholder value now and in the future.”

Operations Update

In the third quarter of 2017, Energen turned to production 17 gross (16 net) wells in the Midland Basin and 9 gross (9 net) wells in the Delaware Basin; 77 percent are multi-zone pattern wells completed in batches. The company is currently operating six horizontal drilling rigs and two frac crews.

2017 First Production/Flow back (Operated Horizontal Wells – Gross/Net)

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3Q17 Wells Turned to Production

For 80 Gen 3 wells drilled to date (78 percent of which were multi-zone pattern wells completed in batches), the average cumulative production uplift of wells in each formation group (normalized to 10,000’) is performing at or above the highest EUR type curve – and significantly outperforming the midpoint EUR type curve – identified for wells in that group completed with pre-Gen 3 frac designs. These are key measures of success for Energen’s latest frac design.

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Relative to the midpoint EUR type curve, the average cumulative production uplift of the Gen 3 wells normalized to 10,000’ is:

In another assessment of success, the average cumulative production of Energen’s Midland Basin Gen 3 multi-zone pattern wells completed in batches continues to outperform other operators’ pattern wells, and the average cumulative production of Energen’s Gen 3 wells (pattern and stand-alone) in the Midland and Delaware basins is outperforming other operators’ wells with proppant loads of 1,700-2,500 pounds per foot; Energen’s average proppant loading is near the low end of this range at approximately 1,800 pounds in the Midland Basin and 1,900 pounds in the Delaware Basin.

The company attributes this outperformance to completing the wells in multi-zone batches instead of completing them as offset pattern wells. Utilizing simultaneous, multi-zone pattern development allows all wells to be completed at the original reservoir pressure, which should maximize reservoir productivity. In offset pattern well development, the original stand-alone well causes the reservoir pressure to drop and reduces the productivity of all subsequent wells drilled.

Bolt-on Lease Acquisitions Continue

During 3Q17, Energen closed on an additional 1,300 net acres of unproved leasehold in the Permian Basin for approximately $20 million. Year to date, Energen has acquired more than 11,000 net acres for approximately $235 million, or an average price of some $21,400 per acre. The company also has purchased 690 net mineral acres primarily in the Delaware Basin in the first nine months of 2017 for approximately $20 million.

Over the last 21 months (CY16 and YTD17), Energen’s bolt-on acquisition program has added approximately 20,300 net lease acres in prime Delaware and Midland basin locations for some $355 million, or an average price of less than $17,500 per acre.

2017 Capital Overview

Energen’s estimate of capital spending for drilling and development in 2017 remains unchanged at $850-$900 million.

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Liquidity and Leverage Update

The fall redetermination cycle is under way. While Energen estimates that its borrowing base will increase from $1.4 billion to $1.7 billion, the company expects its aggregate commitment under the credit facility will remain unchanged at $1.05 billion. At September 30, 2017, Energen had cash of $0.3 million, long-term debt of $527.8 million, and $238.0 million drawn on its $1.05 billion line of credit. The company estimates that net debt-to-adjusted EBITDAX at year-end 2017 will range from 1.2x-1.3x.

3Q17 Financial Results

For the 3 months ended September 30, 2017, Energen reported a GAAP net loss from all operations of $(18.5 million), or $(0.19) per diluted share. Adjusting for a non-cash loss on mark-to-market derivatives of $(40.2 million) and other miscellaneous items totaling $2.5 million, Energen had adjusted net income in 3Q17 of $19.2 million, or $0.20 per diluted share. This compares with an adjusted loss in 3Q16 of $(21.4 million), or $(0.22) per diluted share. [See “Non-GAAP Financial Measures” beginning on pp 8 for more information and reconciliation.]

Energen’s adjusted 3Q17 net income of $19.2 million exceeded internal expectations by $6.6 million largely due to better-than-expected performance of wells completed with Gen 3 fracs, less-than-expected lease operating expense (LOE) and net salaries and general and administrative expense (SG&A), and higher realized oil prices. Partially offsetting these gains was increased depreciation, depletion, and amortization expense (DD&A) largely due to increased production.

Energen’s adjusted EBITDAX totaled $174.0 million in the 3rd quarter of 2017, increased 22 percent from the second quarter, and exceeded internal expectations by 14 percent. In the same period a year ago, Energen’s adjusted EBITDAX totaled $84.8 million. [See “Non-GAAP Financial Measures” beginning on pp 8 for more information and reconciliation.]

3Q17 Production (mboepd)

Note: Totals in production tables above may not sum due to rounding.

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3Q17 Expenses

3Q17 Average Realized Prices

CY17 Guidance

Energen today raised its production guidance for 2017 by 4 percent to 73.2 mboepd to reflect the company’s strong 3Q17 performance as well as a 5 percent increase in its estimated 4Q17 production. Energen now expects 4Q17 volumes to reach 85.7 mboepd for an increase of 60 percent from the same period a year ago. On the strength of its Generation 3 frac design, Energen sees YOY production growth in 2017 of 34 percent, up from the prior estimate of 29 percent.

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Production (mboepd)

Note: Totals in production tables above may not sum due to rounding.

Operating Expenses

LOE per boe in CY17 is estimated to range from $4.95-$5.25 in the Delaware Basin, $5.50-$5.80 in the Midland Basin, and $18.20-$18.50 in the Central Basin Platform. Production and ad valorem taxes in CY17, as a percent of revenues excluding hedges, are estimated to be 6.2 percent in the Delaware Basin, 6.2 percent in the Midland Basin, and 7.3 percent in the Central Basin Platform. SG&A per boe in CY17 is estimated to be comprised of cash and other of $2.55-$2.65 per boe and non-cash, equity-based compensation of $0.45-$0.65 per boe.

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Hedges

Energen recently added some 1.1 mmbo of 2018 WTI Midland to WTI Cushing (sweet oil) differential hedges at an average price of $(0.60) per barrel. The company also has initiated hedging for its estimated 2019 oil production and Midland to Cushing sweet oil differential.

For the last three months of 2017, 64 percent of the company’s estimated oil production of 5.0 mmbo is hedged. Swaps for 2.0 mmbo have an average NYMEX price of $50.68 per barrel, and 3-way collars for 1.2 mmbo have average call, put, and short put prices of $62.18, $45.00, and $35.00 per barrel, respectively. Approximately 36 percent of Energen’s estimated NGL production is hedged at an average price of $0.57 per gallon, and 47 percent of its estimated gas production is hedged at an average NYMEX-equivalent price of $3.36 per Mcf. Energen also has hedged the WTI Midland to WTI Cushing (sweet oil) differential for 3.0 million barrels at an average price of $(0.68) per barrel; approximately 88 percent of Energen’s oil production for the remainder of the year is estimated to be sweet.

Basis Differentials

Energen’s average realized prices in the last three months of CY17 will reflect commodity and basis hedges, oil transportation charges of approximately $1.97 per barrel, NGL T&F fees of approximately $0.13 per gallon, and basis differentials applicable to unhedged production. Natural gas and NGL production also is subject to a percent of proceeds contract of approximately 85%.

The assumed gas basis for all open contracts for November-December 2017 is $(0.45) per Mcf, and assumed prices for unhedged Midland to Cushing basis differentials for sweet and sour oil (November-December) are $(1.00) and $(1.30), respectively. Energen’s assumed commodity prices for unhedged production are approximately $51.46 per barrel of oil (October-December), $0.76 per gallon of NGL (October-December), and $2.93 per Mcf of gas (November-December).

Estimated Price Realizations (pre-hedge):

2018 Hedges

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Energen also has hedged the Midland to Cushing differential on 10.8 million barrels of its estimated 2018 sweet oil production at an average price of $(1.01).

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2019 Hedges

Energen also has hedged the Midland to Cushing differential on 1.4 million barrels of its estimated 2019 sweet oil production at an average price of $(0.53).

Conference Call

3Q17 slides associated with Energen’s quarterly release and conference call are available at www.energen.com. Energen will hold its quarterly conference call Wednesday, November 8, at 8:30 a.m. EDT. Investment community members may participate by calling 1-877-407-8289 (reference Energen earnings call). A live audio Webcast of the program as well as a replay may be accessed via www.energen.com.

Energen Corporation is an oil-focused exploration and production company with operations in the Permian Basin in west Texas and New Mexico. For more information, go to www.energen.com.

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Financial, operating, and support data pertaining to all reporting periods included in this release are

unaudited and subject to revision.

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