2 Colo. Code Regs. § 404-1-1312

Current through Register Vol. 47, No. 20, October 25, 2024

Section 2 CCR 404-1-1312 - GEOTHERMAL INJECTION

a. An Operator cannot operate a Geothermal Injection Well without authorization to inject from the relevant authority pursuant to the Safe Drinking Water Act, an approved Form 4 pursuant to Rule 1312.d, and an approved Form 2 for the Geothermal Injection Well.

b. For Deep Geothermal Operations utilizing Geothermal Injection Wells, the Operator will comply with Rule 805, and Rule 806.a. and b.

c.Geophysical Logs. Operators will run openhole gamma ray, electrical resistivity, and neutron/density logs from total depth to the bottom of the surface casing on all Geothermal Injection Wells, in addition to any other logging requirements of Rule 408.r., unless otherwise specified as a condition of approval on the Form 2.

d.Form 4, Authorization to Inject. After a Geothermal Injection Well is completed, recompleted, or after Injection Zones are temporarily abandoned, the Deep Geothermal Operator will file a Form 4, Authorization to Inject. The Form 4, Authorization to Inject will include the following as-constructed details:

(1)Wellbore Diagram. A final schematic drawing showing all casing strings with cement volumes and tops, plug back total depth, isolation devices, depth of any existing open or squeezed perforations, setting depths of any bridge plugs, formation tops, perforations in the Injection Zone, tubing and packer size, and setting depths.

(2)Casing and Cementing. Documentation of the final casing and cement in the Geothermal Injection Well, any existing remedial cement confirmed during the work, and remedial cement placed during the work.

(3)Cement Bond Log. Unless already provided to the Commission, to determine if the cement has been placed to adequately isolate the Injection Zone, production zones, and Groundwater, a cement bond or other cement evaluation Log will be run and provided with this report as a means of verifying cementing records.

(4)Mechanical Integrity Testing Requirement. Before the Director or Commission approve the authorization to inject, the proposed Geothermal Injection Well will satisfactorily pass a mechanical integrity test pursuant to Rule 417 and be witnessed by the Director.

e.Maximum Allowable Injection Rate and Surface Injection Pressure. The Director will set the maximum allowable injection rate and surface injection pressure in the approved Form 4, Authorization to Inject. Except during Hydraulic Fracturing Treatment, the maximum allowable injection pressure will be set below the fracture gradient of the injection zone, as determined by a step-rate injection test in the Geothermal Injection Well, a step rate injection test in an offset well completed in the same injection zone, or other test acceptable to the Director. The maximum allowable injection pressure will assure that the pressure in the injection zone during injection does not initiate new fractures or propagate existing fractures. Until a step-rate injection test is performed, the maximum allowable injection pressure will be set consistent with a formation pressure gradient of 0.6 pounds per square inch ("psi") per total vertical foot from surface to the uppermost injection perforation.

f. Deep Geothermal Operators utilizing Geothermal Injection Wells will perform continuous seismic monitoring if:

(1) The Director determines it necessary to protect public health, safety, and welfare, including protection of the environment and wildlife resources;

(2) The Operator plans to inject at a rate exceeding 40,000 bbl/day; or

(3) If injection is to occur within any Precambrian basement formation or within 300 feet in the vertical dimension of any Precambrian basement formation.

g. For Deep Geothermal Operations that are subject to Rule 1312.f, the Operator will provide seismic monitoring data to the Director upon request, and a traffic light protocol for seismicity associated with injection activities may be applied as a condition of approval.

h. Geothermal Injection Wells may only inject the following types of Fluids:

(1) Geothermal Fluids from the same geothermal reservoir, including any Geothermal Fluids produced during flow testing;

(2) Fresh or recycled water used for the makeup of minor system losses; or

(3) Other Fluids with prior approval from the Director or other relevant authority.

i. When an Operator proposes to inject any Fluid other than Geothermal Fluids or fresh or recycled water, pursuant to Rule 1312.h.(3), the Operator will comply with Rule 803.g.(5).C. and D.

2 CCR 404-1-1312

47 CR 17, September 10, 2024, effective 9/30/2024