Exhibit 99.1

IN THE UNITED STATES BANKRUPTCY COURT

FOR THE SOUTHERN DISTRICT OF TEXAS

HOUSTON DIVISION

NOTICE OF (I) ENTRY OF ORDER APPROVING THE DEBTORS’

DISCLOSURE STATEMENT FOR, AND CONFIRMING, THE DEBTORS’ JOINT

PREPACKAGED CHAPTER 11 PLAN OF REORGANIZATION AND (II) THE

OCCURRENCE OF THE EFFECTIVE DATE

PLEASE TAKE NOTICE that on May 11, 2020, the Honorable David R. Jones, United States Bankruptcy Judge for the United States Bankruptcy Court for the Southern District of Texas (the “Bankruptcy Court”), entered the Findings of Fact, Conclusions of Law, and Order Approving the Debtors’ Disclosure Statement and Confirming the Debtors’ Joint Prepackaged Chapter 11 Plan of Reorganization [Docket No. 331] (the “Confirmation Order”) confirming the Plan² [Docket No. 16] and approving the Disclosure Statement [Docket No. 16] of the above-captioned debtors and debtors in possession (the “Debtors”).

PLEASE TAKE FURTHER NOTICE that the Effective Date of the Plan occurred on May 29, 2020.

PLEASE TAKE FURTHER NOTICE that copies of the Confirmation Order, the Plan, and the related documents are available for inspection. If you would like to obtain a copy of the Confirmation Order or the Plan, you may contact Epiq Corporate Restructuring, LLC, the voting and claims agent (the “Notice and Claims Agent”) retained by the Debtors in these Chapter 11 Cases, by: (i) accessing the Debtors’ restructuring website at https://dm.epiq11.com/pioneerenergy, (ii) calling the Notice and Claims Agent at 1-833-991-0977 (Domestic Toll-Free) or 1-503-597-7679 (International); or (ii) emailing the Notice and Claims Agent at PioneerEnergy@epiqglobal.com. Parties may also obtain any documents filed in the Chapter 11 Cases via PACER at https://www.pacer.gov/.

PLEASE TAKE FURTHER NOTICE that the Bankruptcy Court has approved certain discharge, release, exculpation, injunction, and related provisions in Article VIII of the Plan.

PLEASE TAKE FURTHER NOTICE that pursuant to Article V of the Plan, all (a) requests for payment of Cure Claims that differ from the amounts paid or proposed to be paid by the Debtors or the Reorganized Debtors to a counterparty must be filed with the Reorganized Debtors and the Notice and Claims Agent on or before thirty (30) days after the Effective Date and/or (b) proofs of claim with respect to Claims arising from the rejection of Executory Contracts and Unexpired Leases, if any, must be filed with the Bankruptcy Court within thirty (30) day after the date of the order of the Court approving such rejection (including the Confirmation Order). Any such request that is not timely filed shall be disallowed and forever barred, estopped, and enjoined from assertion, and shall not be enforceable against any Debtor or Reorganized Debtor, as applicable, without the need for any objection by the Debtors, Reorganized Debtors or any other party in interest or any further notice to or action, order, or approval of the Court.

PLEASE TAKE FURTHER NOTICE that the Plan and its provisions are binding on the Debtors, the Reorganized Debtors, and any Holder of a Claim or Interest and such Holders’ respective successors and assigns, whether or not the Claim or Interest of such Holder is Impaired under the Plan, and whether or not such Holder voted to accept the Plan.

PLEASE TAKE FURTHER NOTICE that the Plan and the Confirmation Order contain other provisions that may affect your rights. You are encouraged to review the Plan and the Confirmation Order in their entirety.

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