Permitting Support for the Closure of Deep CO2 Wells

M&A provided a technical basis for regulators to waive the requirement for compliance monitoring and to approve the clean closure of wells that had previously undergone testing using hydraulic fracturing methods to assess their ability to produce CO2. ADEQ agreed that the activities conducted at these wells posed no threat to the overlying aquifer. The wells were abandoned in accordance with State regulations.

Overview

The initial goal of the St. Johns CO2 Source Field Project was to develop a CO2 wellfield on the St. Johns Dome, located between the towns of St. Johns and Springerville. The CO2 produced from this wellfield would have been piped to the Permian Basin in west Texas for use in enhanced oil recovery. As part of an earlier phase of the project, hydraulic fracturing had been used to test CO2 recovery from deep zones that were isolated from the overlying aquifer by hundreds of feet of consolidated rock. Although the CO2 project is not moving forward at this time, the client decided to close the 10 test wells that had been stimulated using hydraulic fracturing methods.

Services

M&A provided services to obtain the required permit through the Arizona Aquifer Protection Permit (APP) program for clean closure of the test wells. M&A’s scope of work changed as the focus of the project evolved. Initially, the permitting effort was to cover both test well closure and operation of an injection well that would have been used to dispose of brine streams generated through the separation process during CO2 production. When Kinder Morgan decided to discontinue the CO2 Source Field project, the permit was modified to only include the well closure. During the course of the project, M&A conducted the following tasks:

  • Analyzed hydrogeologic and water quality data to assess the requirements of test well closure and disposal well permitting
  • Developed Aquifer Water Quality Standard (AWQS) demonstrations at points of compliance (POCs)
  • Developed analyses to support the definition of pollutant management and discharge impact areas
  • Prepared closure and post-closure plans
  • Prepared a hydrogeologic study and other components of the permit application
  • Met with regulatory staff to review technical requirements and additional information requests
  • Analyzed data, developed strategies, and prepared submittals in response to regulatory requests
  • Developed technical analyses that successful demonstrated aquifer isolation, leading to a waiver for POC monitoring