Filed by Newfield Exploration Company

pursuant to Rule 425 under the Securities Act of 1933

and deemed filed pursuant to Rule 14a-12

under the Securities Exchange Act of 1934

Subject Company: Newfield Exploration Company

Commission File No. 001-12534

Date: November 12, 2018

Newfield Exploration Provides Supplemental Information Regarding its

Strategic Combination with Encana Corporation

The Woodlands, Texas – November 12, 2018—Newfield Exploration Company (NYSE: NFX) today provided a slide deck with supplemental information regarding its previously announced combination with Encana Corporation. The slides can be found on the Company’s website at http://www.newfield.com.

Newfield Exploration Company is an independent energy company engaged in the exploration, development and production of crude oil, natural gas and natural gas liquids. Our U.S. operations are onshore and focus primarily on large scale, liquids-rich resource plays in the Anadarko and Arkoma basins of Oklahoma, the Williston Basin of North Dakota and the Uinta Basin of Utah. In addition, we have a producing oil field offshore China.

Forward-Looking Statements

This communication includes certain statements that constitutes “forward-looking statements” within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended. Such forward-looking statements involve known and unknown risks, uncertainties and other factors which may cause the actual results, performance or achievements of Newfield Exploration Company (the “Company”) to be materially different from any future results, performance or achievements expressed or implied by such forward-looking statements. Statements preceded by, followed by or that otherwise include the words “believes,” “expects,” “anticipates,” “intends,” “projects,” “estimates,” “plans,” “may increase,” “may fluctuate,” “will,” “should,” “would,” “may” and “could” or similar words or expressions are generally forward-looking in nature and not historical facts. Any statements that refer to outlook, expectations or other characterizations of future events, circumstances or results are also forward-looking statements. Important risks, assumptions and other important factors that could cause future results to differ materially from those expressed in the forward-looking statements are specified in Newfield Exploration Company’s Annual Report on Form 10-K for the year ended December 31, 2017 and its Quarterly Reports on Form 10-Q for any subsequent periods under headings such as “Forward-Looking Statements”, “Risk Factors” and “Management’s Discussion and Analysis of Financial Condition and Results of Operations” and in other filings and furnishings made by the Company with the Securities and Exchange Commission from time to time. The Company undertakes no obligation to release publicly any revisions to any forward-looking statements, to report events or to report the occurrence of unanticipated events.

Important Additional Information Regarding the Transaction Will Be Filed With the SEC

In connection with the proposed transaction, Encana Corporation (“Encana”) will file a registration on Form S-4 that will include a joint proxy statement of the Company and Encana. The definitive joint proxy statement/prospectus will be sent to the stockholders of the Company and Encana. Encana and the Company may also file other documents with the SEC regarding the proposed transaction. INVESTORS AND SECURITY HOLDERS OF THE COMPANY ARE ADVISED TO CAREFULLY READ THE JOINT PROXY STATEMENT AND ANY REGISTRATION STATEMENT/PROSPECTUS (INCLUDING ALL AMENDMENTS AND SUPPLEMENTS THERETO) WHEN THEY BECOME AVAILABLE BECAUSE THEY WILL CONTAIN IMPORTANT INFORMATION ABOUT THE TRANSACTION, THE PARTIES TO THE TRANSACTION AND THE RISKS ASSOCIATED WITH THE TRANSACTION. A definitive joint proxy statement and any registration statement/prospectus, as applicable, will be sent to security holders of the Company in connection with the Company’s shareholder meetings. Investors and security holders may obtain a free copy of the joint proxy statement (when available), any registration statement/prospectus, and other relevant documents filed by the Company with the Securities and Exchange Commission (“SEC”) from the SEC’s website at www.sec.gov. Security holders and other interested parties will also be able to obtain, without charge, a copy of the joint proxy statement, any registration statement/prospectus, and other relevant documents (when available) by directing a request by mail or telephone to Investor Relations, Newfield Exploration Company, 4 Waterway Square Place, Suite 100, The Woodlands, Texas 77380. Copies of the documents filed by the Company with the SEC will be available free of charge on the Company’s website at ir.newfield.com.

Participants in the Solicitation

The Company and its directors, executive officers and certain other members of management may be deemed to be participants in the solicitation of proxies from its security holders with respect to the transaction. Information about these persons is set forth in the Company’s proxy statement relating to its 2018 Annual Meeting of Stockholders, as filed with the SEC on March 29, 2018 and subsequent statements of changes in beneficial ownership on file with the SEC. Security holders and investors may obtain additional information regarding the interests of such persons, which may be different than those of the Company’s security holders generally, by reading the joint proxy statement, any registration statement and other relevant documents regarding the transaction, which will be filed with the SEC.

No Offer or Solicitation

This document is not intended to and does not constitute an offer to sell or the solicitation of an offer to subscribe for or buy or an invitation to purchase or subscribe for any securities or the solicitation of any vote in any jurisdiction pursuant to the proposed transaction or otherwise, nor shall there be any sale, issuance or transfer of securities in any jurisdiction in contravention of applicable law. Subject to certain exceptions to be approved by the relevant regulators or certain facts to be ascertained, the public offer will not be made directly or indirectly, in or into any jurisdiction where to do so would constitute a violation of the laws of such jurisdiction, or by use of the mails or by any means or instrumentality (including without limitation, facsimile transmission, telephone and the internet) of interstate or foreign commerce, or any facility of a national securities exchange, of any such jurisdiction.