Exhibit 99.1

Eclipse Resources Corporation Announces Second Quarter 2017 Results, a $325 Million Utica Shale Drilling Joint Venture Commitment Agreement and an increase in the Company’s Borrowing Base.

STATE COLLEGE, PA- August 2, 2017- (BUSINESS WIRE) - Eclipse Resources Corporation (NYSE:ECR) (the “Company” or “Eclipse Resources”) today announced its second quarter 2017 financial and operational results, along with updated guidance for the third quarter of 2017 and full year 2017. As discussed further below the Company has also entered into a commitment agreement with Sequel Energy Group LLC (“Sequel”) (an affiliate of GSO Capital Partners, or “GSO”) to establish a proposed drilling joint venture and has received an increase to its borrowing base on its senior secured revolving line of credit from its bank-lending group. In conjunction with this release, the Company has posted an updated investor presentation to its website at www.eclipseresources.com.

Second Quarter 2017 Highlights:

Subsequent to the end of the Second Quarter:

The Company’s proposed drilling joint venture with Sequel is subject to further negotiation, completion and execution of definitive agreements and other customary conditions. The commitment agreement provides that Eclipse and Sequel will negotiate in good faith for a period of time and use their commercially reasonable efforts to enter into mutually agreeable definitive documents relating to the proposed transaction, which the parties expect to complete by the end of the current quarter. Accordingly, there can be no assurance that the proposed transaction will be completed in the anticipated timeframe, if at all, and if consummated, what will be the final terms of such definitive agreement.

Benjamin W. Hulburt, Chairman, President and CEO, commented on the Company’s second quarter 2017 results, “Our continued focus on execution, innovation and efficiency resulted in the Company delivering another tremendous quarter with production above the top end of our guidance, operating expenses below the low end of our guidance and continued strong well performance in both the dry gas and condensate areas of our acreage.  This now marks the eleventh consecutive reporting period in which the Company has met or exceeded its production and operating expense guidance, which represents every single reporting period since our initial public offering in June of 2014.

We continue to strive to be a leader in innovation, not only in our region, but nationwide, with a significant amount of work we are doing today focused on new technology applications to improve productivity, reduce costs and maintain high returning wells as we develop our substantial drilling inventory.  This culture of innovation powers our well performance and we have seen that illustrated in our most recent set of Dry Gas wells.  These wells have incorporated a series of trials on numerous new techniques that will help us develop our “Gen4” well design.  Our seven well Moser pad, located in the Company’s Dry Gas acreage in eastern Monroe County, Ohio, was turned to sales in June and has produced at an average rate of approximately 19% above our recently increased Dry Gas type well expectation.  We are continuing to evaluate which of the new techniques may be the most impactful on future operations, but we are very encouraged with the results we are seeing on certain of the techniques we’ve tested.

We have continued our relentless pursuit for industry leading drilling innovation, and have set a new internal record on our most recent “super-lateral”, which we drilled to a total measured depth of 24,600 with a 15,600 foot completable lateral in our Utica Condensate area in 12 days from spud to TD.  Additionally, we are currently completing what we believe to be the longest onshore laterals ever drilled, the Great Scott 3H (19,100’ completable lateral) and Outlaw C11H (19,500’ completable lateral), located in our Utica Condensate area. We are approximately 70% done completing these laterals, which have treated as designed thus far.  We have two additional wells to complete on this pad before we will turn all four wells to sales, which we expect to occur in the fourth quarter of 2017.

We believe that the drilling joint venture commitment agreement we have recently entered into with Sequel, an affiliate of GSO, speaks to both the quality of our assets and our industry leading operational performance.  At today’s forward strip prices, Eclipse calculates that the present value of the carried interest and significant working interest reversion as outlined in the commitment agreement will equate to a meaningful valuation premium to both where we trade and where recent Utica asset transactions have taken place. Perhaps most importantly, as we see a significant amount of commodity volatility looking into 2018, the terms of this drilling joint venture will allow us to maintain, or even accelerate our current drilling pace, while scaling our company level capital expenditures based on the economic environment.  Additionally, prior to commencing each well program, under the terms proposed in the commitment agreement, Eclipse will have the ability to choose its working interest for such program within agreed upon bands.   We believe this structure allows us to maintain an efficient, two-rig operating program while providing flexibility to manage capital spending to a level that is appropriate depending on the strength of forward commodity curves.   We are extremely pleased with the proposed terms and structure as outlined by the commitment agreement with Sequel and the high degree of confidence that our partner has in our assets and operational capabilities.  We believe that the industry experience of the Sequel team combined with the scale and structuring capabilities of GSO make them the ideal drilling joint venture partners for Eclipse.

We believe that our proven operational performance, continued gain in efficiency and financial flexibility leave us well positioned to deliver upon the production guidance that we have provided. We remain highly focused on returns and excited for continued operational improvement. We believe that these attributes will drive significant value enhancements from our assets and generate long-term shareholder value.”

Operational Discussion

The Company’s production for the three and six months ended June 30, 2017 and 2016 is set forth in the following table:

Market Conditions

Prices for various quantities of natural gas, NGLs and oil that we produce significantly impact our revenues and cash flows. Prices for commodities, such as hydrocarbons, are inherently volatile. The following table lists average daily, high, low and average monthly settled NYMEX Henry Hub prices for natural gas and NYMEX WTI prices for oil for the three and six months ended June 30, 2017 and 2016:

Financial Discussion

Revenue for the second quarter of 2017 totaled $86.2 million, compared to $47.1 million for the second quarter of 2016.  Adjusted Revenue³, which includes the impact of cash settled derivatives and excludes brokered natural gas and marketing revenue, totaled $83.6 million for the second quarter of 2017 compared to $58.8 million for the second quarter of 2016.  Net Income (Loss) for the second quarter of 2017 was $11.5 million, or $0.04 per share compared to $(73.2) million or $(0.33) per share for the second quarter of 2016. Adjusted Net Income (Loss) ³ for the second quarter of 2017 was $(2.8) million, or $(0.01) per share, compared to $(24.1) million, or $(0.11) per share for the second quarter of 2016. Adjusted EBITDAX³ was $39.6 million for the second quarter of 2017, compared to $16.9 million for the second quarter of 2016.

Revenue for the six months ended June 30, 2017 totaled $188.1 million, compared to $96.7 million for the six months ended June 30, 2016.  Adjusted Revenue³, which includes the impact of cash settled derivatives and excludes brokered natural gas and marketing revenue, totaled $179.0 million for the six months ended June 30, 2017 compared to $117.6 million for the six months ended June 30, 2016.  Net Income (Loss) for the six months ended June 30, 2017 was $38.3 million, or $0.15 per share compared to $(118.7) million or $(0.53) per share for the six months ended June 30, 2016.  Adjusted Net Income (Loss)³ for the six months ended June 30, 2017 was $2.1 million, or $0.01 per share, compared to $(39.2) million, or $(0.18) per share for the six months ended June 30, 2016.  Adjusted EBITDAX³ was $89.8 million for the six months ended June 30, 2017, compared to $37.3 million for the six months ended June 30, 2016.

Average realized price calculations for the three and six months ended June 30, 2017 and 2016 are set forth in the table below:

The Company’s operating expenses per Mcfe for the second quarter of 2017 decreased by 8% compared to the prior year’s quarter and are shown in the table below.  Per unit cash production costs (includes lease operating, transportation, gathering and compression, production and ad valorem taxes) were $1.36 per Mcfe for the second quarter 2017 and includes $0.35 per Mcfe of firm transportation expenses.

Capital Expenditures

Second quarter 2017 capital expenditures were $98.5 million. These expenditures included $80.2 million for drilling and completions, $0.7 million for midstream expenditures, $17.3 million for land-related expenditures, and $0.3 million for corporate-related expenditures.

During the second quarter of 2017, the Company drilled 9 gross (8.6 net) operated Utica Shale wells.  In addition, the Company completed 6 gross (5.8 net) operated wells and turned to sales 9 gross (9.0 net) operated wells.  

Financial Position and Liquidity

As of June 30, 2017, the Company’s liquidity was $238.5 million, consisting of $97.1 million in cash and cash equivalents and $141.4 million in available borrowing capacity under the Company’s revolving credit facility (after giving effect to outstanding letters of credit issued by the Company of $33.6 million).

Subsequent to the end of the second quarter, 2017, the Company completed its semi-annual borrowing base redetermination of its revolving credit facility, which resulted in an increase in its borrowing base from $175 million to $225 million. The Company remains undrawn on its revolving credit facility, other than for letters of credit.

Matthew R. DeNezza, Executive Vice President and Chief Financial Officer, commented, “At quarter end and pro-forma for the recent borrowing base redetermination, which resulted in a borrowing base increase of approximately 29%, our liquidity would have been approximately $288 million.  We remain highly focused on the strength of our balance sheet with the objective of keeping our leverage ratios low.  We believe this strong liquidity position coupled with our proposed drilling joint venture will allow us the flexibility to navigate the current commodity price volatility with a focus on the future. Finally, we believe we possess a well-balanced hedge book through the end of the fiscal year 2018, which will provide additional certainty of cash flows as we look toward the future.”

Commodity Derivatives

The Company engages in a number of different commodity trading program strategies as a risk management tool to attempt to mitigate the potential negative impact on cash flows caused by price fluctuations in natural gas, NGL and oil prices. Below is a table that illustrates the Company’s hedging activities as of June 30, 2017:

Natural Gas Derivatives

Oil Derivatives

NGL Derivatives

Subsequent to June 30, 2017, the Company entered into the following derivative instruments:

Guidance

The Company issued the following third quarter and full year 2017 guidance in the table below:

Conference Call

A conference call to review the Company’s financial second quarter 2017 earnings is scheduled for Thursday, August 3, 2017, at 10:00 a.m. (Eastern). To participate in the call, please dial 877-709-8150, or 201-689-8354 for international callers, and reference Eclipse Resources Second Quarter Earnings Call. A replay of the call will be available through October 4, 2017. To access the phone replay dial 877-660-6853 or 201-612-7415 for international callers. The conference ID is 13667027. A live webcast of the call may be accessed through the “Investors” section of the Company’s website at www.eclipseresources.com.

ECLIPSE RESOURCES CORPORATION

CONDENSED CONSOLIDATED BALANCE SHEETS

(In thousands, except share and per share amounts)

(Unaudited)

ECLIPSE RESOURCES CORPORATION

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS

(In thousands, except per share data)

(Unaudited)

Adjusted Revenue

Adjusted revenue is a non-GAAP financial measure.  The Company defines Adjusted revenue as follows: total revenues plus net cash receipts or payments on settled derivative instruments less brokered natural gas and marketing revenue.  The Company believes Adjusted revenue provides investors with helpful information with respect to the performance of the Company's operations and management uses Adjusted revenue to evaluate its ongoing operations and for internal planning and forecasting purposes. See the table below, which reconciles Adjusted revenue and total revenues.

Adjusted Net Income (Loss)

Adjusted net income (loss) represents income (loss) before income taxes adjusted for certain non-cash items as set forth in the table below. We believe Adjusted net income (loss) is used by many investors and published research in making investment decisions and evaluating operational trends of the Company and its performance relative to other oil and gas producing companies.  Adjusted net income (loss) is not a measure of net income (loss) as determined by GAAP.  See the table below for a reconciliation of Adjusted net income (loss) and net income (loss).

Adjusted EBITDAX

Adjusted EBITDAX is a supplemental non-GAAP measure that is used by the Company to evaluate its financial results. The Company defines Adjusted EBITDAX as net income or loss before interest expense; income taxes; impairments; depreciation,

depletion and amortization (“DD&A”); gain (loss) on derivative instruments, net cash receipts (payments on settled derivative instruments, and premiums (paid) received on options that settled during the period); non-cash compensation expense; gain or loss from sale of interest in gas properties; exploration expenses; and other unusual or infrequent items set forth in the table below. Adjusted EBITDAX is not a measure of net income or loss as determined by GAAP.  See the table below for a reconciliation of Adjusted EBITDAX to net income or net loss.

Cash General and Administrative Expenses

Cash General and Administrative Expenses is a non-GAAP financial measure used by the Company in the Guidance Table to provide a measure of administrative expenses used by many investors and published research in making investment decisions and evaluating operational trends of the Company. See the table below for a reconciliation of Cash General and Administrative Expenses and General and Administrative Expenses.

About Eclipse Resources

Eclipse Resources is an independent exploration and production company engaged in the acquisition and development of oil and natural gas properties in the Appalachian Basin, including the Utica and Marcellus Shales. For more information, please visit the Company’s website at www.eclipseresources.com.

Forward-Looking Statements

This press release contains “forward-looking statements” within the meaning of Section 27A of the Securities Act of 1933, as amended (the “Securities Act”) and Section 21E of the Securities Exchange Act of 1934, as amended (the “Exchange Act”). All statements, other than statements of historical fact included in this press release, regarding Eclipse Resources’ strategy, future operations, financial position, estimated revenues and income/losses, projected costs and capital expenditures, prospects, plans and objectives of management are forward-looking statements. When used in this press release, the words “plan,” “endeavor,” “will,” “would,” “could,” “believe,” “anticipate,” “intend,” “estimate,” “expect,” “project” and similar expressions are intended to identify forward-looking statements, although not all forward-looking statements contain such identifying words. These forward-looking statements are based on Eclipse Resources’ current expectations and assumptions about future events and are based on

currently available information as to the outcome and timing of future events. When considering forward-looking statements, you should keep in mind the risk factors and other cautionary statements described under the heading “Risk Factors” in Eclipse Resources’ Annual Report on Form 10-K filed with the Securities Exchange Commission on March 3, 2017 (the “2016 Annual Report”), and in “Item 1A. Risk Factors” of Eclipse Resources’ Quarterly Reports on Form 10-Q.

Forward-looking statements may include statements about Eclipse Resources’ business strategy; reserves; our proposed drilling joint venture with Sequel; general economic conditions; financial strategy, liquidity and capital required for developing its properties and timing related thereto; realized natural gas, NGLs and oil prices; timing and amount of future production of natural gas, NGLs and oil; its hedging strategy and results; future drilling plans; competition and government regulations, including those related to hydraulic fracturing; the anticipated benefits under its commercial agreements; pending legal matters relating to its leases; marketing of natural gas, NGLs and oil; leasehold and business acquisitions; the costs, terms and availability of gathering, processing, fractionation and other midstream services; general economic conditions; credit markets; uncertainty regarding its future operating results, including initial production rates and liquid yields in its type curve areas; and plans, objectives, expectations and intentions contained in this press release that are not historical.

Eclipse Resources cautions you that these forward-looking statements are subject to all of the risks and uncertainties, most of which are difficult to predict and many of which are beyond its control, incident to the exploration for and development, production, gathering and sale of natural gas, NGLs and oil. These risks include, but are not limited to; legal and environmental risks, drilling and other operating risks, regulatory changes, commodity price volatility and the recent significant decline of the price of natural gas, NGLs, and oil, inflation, lack of availability of drilling, production and processing equipment and services, our inability to successfully negotiate or enter into definitive agreements and satisfy other conditions precedent for our proposed joint venture drilling transaction with Sequel,  and to effectively implement that transaction, counterparty credit risk, the uncertainty inherent in estimating natural gas, NGLs and oil reserves and in projecting future rates of production, cash flow and access to capital, the timing of development expenditures, and the other risks described under the heading “Risk Factors” in the 2016 Annual Report and in “Item 1A. Risk Factors” of Eclipse Resources’ Quarterly Reports on Form 10-Q.

All forward-looking statements, expressed or implied, included in this press release are expressly qualified in their entirety by this cautionary statement. This cautionary statement should also be considered in connection with any subsequent written or oral forward-looking statements that Eclipse Resources or persons acting on the Company’s behalf may issue.

Contact:

Eclipse Resources Corporation

Douglas Kris, Investor Relations

814-325-2059

dkris@eclipseresources.com