Authority: IC 14-10-2-4; IC 14-37-3

Affected: IC 14-37

Sec. 1. (a) This section establishes additional requirements for the drilling of a well for oil and gas purposes in locations identified as karst prone areas. An owner or operator shall drill all wells drilled in an identified karst prone area in accordance with this rule.

(b) The owner or operator shall determine if the well for oil and gas will be drilled in an identified karst prone area from maps maintained by the division of reclamation.

(c) For wells drilled in karst prone areas an owner or operator shall do the following:

1. (1) Use a cable tool rig or a rotary drilling rig using air or water, without drilling mud, to circulate cuttings when drilling the interval between the surface and the depth where surface casing is to be set.

2. (2) Set surface casing in an impervious formation that:

   1. (A) is at least thirty (30) feet below the depth in which karst features or lost-circulation zones are likely to be encountered based on a review of local geology and oil, gas, and water well drilling records for wells previously drilled within one half (1/2) mile of the proposed well location; or
   2. (B) if previous drilling has not occurred within one-half (1/2) mile of the proposed well location, the minimum surface casing depth shall be into an impervious formation at least thirty (30) feet into the top of the Borden Group for karst developed upon Mississippian aged rocks or thirty (30) feet into the Maquoketa Group for karst developed upon Devonian and Silurian aged rocks.

(d) The driller shall note and record in the drillers log and the completion report the depth of any areas where voids or lost-circulation zones were encountered while drilling.

(e) Prior to cementing the surface casing, cement baskets shall be installed on the casing at the first joint above each area where voids or lost-circulation zones were encountered. Lost-circulation materials or commonly used cement additives shall also be used where practical to reduce cement loss into karst features.

(f) If voids or lost-circulation zones are encountered while drilling below the surface casing seat, the owner or operator shall take appropriate measures to minimize cement loss into karst features as follows:

1. (1) Set an intermediate casing string at least thirty (30) feet below the void or lost-circulation zone with a cement basket installed at the first casing joint above each area where a void or lost-circulation zone is encountered. If this method is used, care shall be taken to pump the minimum amount of cement necessary to fill the annulus up to the bottom of the void. Cement shall be placed from the surface by tremie pipe in the casing annulus to cement the interval above the cement basket.
2. (2) Use lost-circulation materials or cement additives alone or in combination with sufficient cement baskets installed at the first casing joint above each area where a void or lost circulation zone is encountered.

(Natural Resources Commission; 312 IAC 29-11-1; filed Dec 1, 2017, 10:35 a.m.: 20171227-IR-312160230FRA; readopted filed Jan 17, 2023, 1:53 p.m.: 20230215-IR-312220328RFA; errata filed Mar 18, 2026, 9:59 a.m.: 20260325-IR-312260094ACA)