Section 1761 - Well Stimulation and Underground Injection Projects(a) The following definitions are applicable to this subchapter:(1) "Well stimulation treatment" means a treatment of a well designed to enhance oil and gas production or recovery by increasing the permeability of the formation. (A) Well stimulation is a short term and non-continual process for the purposes of opening and stimulating channels for the flow of hydrocarbons. Examples of well stimulation treatments include hydraulic fracturing, acid fracturing, and acid matrix stimulation. (i) Except for operations that meet the definition of "underground injection project" under Section 1761(a)(2), a treatment at pressure exceeding the formation fracture gradient shall be presumed to be a well stimulation treatment unless it is demonstrated to the Division's satisfaction that the treatment, as designed, does not enhance oil and gas production or recovery by increasing the permeability of the formation.(ii) Except for operations that meet the definition of "underground injection project" under Section 1761(a)(2), a treatment that involves emplacing acid in a well and that uses a volume of fluid equal to or greater than the Acid Volume Threshold for the operation shall be presumed to be a well stimulation treatment unless it is demonstrated to the Division's satisfaction that the treatment, as designed, does not enhance oil and gas production or recovery by increasing the permeability of the formation. For the purpose of determining whether a treatment is greater than the Acid Volume Threshold, the volume of fluid used in a treatment does not include the volume fluid used for a pre-flush that does not use acid or an overdisplacement that does not use acid.(iii) The searchable index maintained by the Division under Section 1777.4(e) will clearly indicate each submission for a treatment that exceeds the formation fracture gradient or emplaces acid in the well and exceeds the Acid Volume Threshold, and such submissions shall include the Division's determination that the treatment is not a well stimulation treatment and the basis for the determination.(B) Well stimulation treatment does not include routine well cleanout work; routine well maintenance; routine treatment for the purpose of removal of formation damage due to drilling; bottom hole pressure surveys; routine activities that do not affect the integrity of the well or the formation; the removal of scale or precipitate from the perforations, casing, or tubing; a gravel pack treatment that does not exceed the formation fracture gradient; or a treatment that involves emplacing acid in a well and that uses a volume of fluid that is less than the Acid Volume Threshold for the operation and is below the formation fracture gradient.(2) "Underground injection project" or "subsurface injection or disposal project" means sustained or continual injection into one or more wells over an extended period in order to add fluid to a zone for the purpose of enhanced oil recovery, disposal, or storage. Examples of underground injection projects include waterflood injection, steamflood injection, cyclic steam injection, injection disposal, and gas storage projects.(3) "Acid Volume Threshold" means a volume, in US gallons, per treated foot of well stimulation treatment, calculated as follows: (((Size of the drill bit diameter in inches that was used in the treated zone / 2 + 36 inches)2 - (bit diameter in inches / 2)2) x 3.14159 x 12 inches x treated formation porosity) / 231 (inches3/gallon).
The lowest calculated or measured porosity in the zone of treated formation shall be the treated formation porosity used for calculating the Acid Volume Threshold.
(b) Well stimulation treatments and underground injection projects are two distinct kinds of oil and gas production processes. Unless a regulation expressly addresses both well stimulation and underground injection projects,(1) Regulations regarding well stimulation treatments do not apply to underground injection projects; and(2) Regulations regarding underground injection projects do not apply to well stimulation.(3) If well stimulation treatment is done on a well that is part of an underground injection project, then regulations regarding well stimulation treatment apply to the well stimulation treatment and regulations regarding underground injection projects apply to the underground injection project operations.Cal. Code Regs. Tit. 14, § 1761
1. New section filed 12-30-2014; operative 7-1-2015 pursuant to Public Resources Code section 3161(a), as amended by SB 4, Stats. 2014, c. 313 (Register 2015, No. 1). For prior history, see Register 2014, No. 26.
2. Editorial correction of section heading and HISTORY 1 (Register 2017, No. 24). Note: Authority cited: Sections 3013 and 3160, Public Resources Code. Reference: Sections 3106, 3157 and 3160, Public Resources Code.
1. New section filed 12-30-2014; operative 7/1/2015 pursuant to Public Resources Code section 3161(a), as amended by SB 861, Stats. 2014, c. 35 (Register 2015, No. 1). For prior history, see Register 2014, No. 26.
2. Editorial correction of section heading and History 1 (Register 2017, No. 24).