Technical Discussion of Surface Casing Issues
Statewide Rule 13 requires that surface casing be set and cemented from the depth of the deepest usable quality groundwater to ground surface. Rule 13 also stipulates the minimum quality of cement required through the groundwater zone.
Rule 13 provides alternative methods of protecting groundwater. The most common alternative is to drill a shallow well without setting surface casing and then cementing production casing from total depth back to ground surface.
As a matter of policy, a well being drilled for injection or disposal must set surface casing through the entire groundwater zone. UIC will not administratively approve an application to permit a well to be drilled without full surface casing protection. The rationale for this policy is that injection wells carry inherently higher risk to groundwater and should have the maximum level of groundwater protection required by Rule 13.
A common scenario affecting the permitting of existing wells to be converted to injection or disposal is that the surface casing set at the time of drilling did not extend through the current groundwater protection depth. UIC may administratively approve an application for an injection/disposal permit for an existing well without full surface casing protection, if: 1) the well has a majority of usable quality groundwater protected by surface casing or the long string/production casing is cemented through the entire groundwater zone, and 2) provided the permit requires increased testing and/or monitoring to counterbalance the inadequate groundwater protection.
If the well does not have a majority of the groundwater covered by surface casing (critically short surface casing) and the long string/production casing is not cemented through the entire groundwater zone, then the application will be administratively denied. As with any administrative denial, the applicant has the option to request a hearing before the Commission to present his case.
The technical staff may suggest remedial methods to increase the level of groundwater protection to allow administrative permit approval. The most common option is to perforate the production casing 50' below the deepest groundwater and circulate cement back to ground surface. Please note that this option is not viable if the production casing cement top is already inside the usable quality groundwater zone. A less common option is to cement a liner from the injection zone back to ground surface.