Drilling and Completion

PURPOSE: One of the important functions of the council is to prevent the contamination of the waters of the state. In Missouri, an underground source of drinking water may occur either above or below an oil and gas reservoir. This groundwater is commonly the only source of water for irrigation and animal and human consumption. This rule provides procedures for protecting all waters of the state and to create acceptable safety standards for wells and surface installations. Plugging of wells when they are abandoned is consistent with a statewide effort to prevent contamination of waters of the state and additionally is important in areas proven to be productive using enhanced recovery methods. (1) During the drilling of any well, surface casing shall be set as follows, except as otherwise required or approved by the state geologist as indicated on the approved permit to drill, deepen, plug-back, or recomplete: (A) Through all unconsolidated material plus twenty feet (20') into the underlying competent bedrock; or (B) In areas where underground sources of drinking water are present above the production or injection zone(s), at a point at least fifty feet (50') below the base of the deepest known underground source of drinking water penetrated. (2) All casing materials shall be steel or other material of equal or greater strength approved by the state geologist and able to withstand collapse and burst pressures that the well might encounter. (3) All wells drilled shall be completed with tubing, packer, and a string(s) of casing which are properly cemented at sufficient depths to protect all water, oil, or gas bearing strata and prevents their contents from passing into other strata. For wells drilled to producing strata at a depth of no greater than one thousand five hundred feet (1500'), an operator may set a single casing string with no tubing or packer, if the well is cemented from the bottom of the casing to the surface to seal off and protect any underground source of drinking water. The state geologist may approve other methods of cementing casing in a well. (4) Cement shall, except as otherwise modified or approved by the state geologist— (A) Be used in setting all casing or sealing off producing strata, underground porosity gas storage strata, or underground sources of drinking water; (B) Be installed from the bottom to the top of the casing in one (1) continuous operation using pressure grouting techniques; (C) Be placed in a minimum one inch (1") annulus between strings of casing or the casing and borehole; (D) Be maintained at surface level; and (E) Be in place for at least eight (8) hours and reach a compressive strength of three hundred (300) pounds per square inch before the bottom plug is drilled or before tests are initiated, and before further operations begin. (5) Multiple-completed wells. Operators may produce from more than one (1) pool through the same wellbore if separation of each pool is maintained and after application to, and approval by, the state geologist. Multiplecompleted injection and production wells may be permitted if, in addition to the requirements above, all of the following conditions are met: (A) Any offsetting production will not be adversely affected; (B) Underground sources of drinking water will not be endangered; (C) The well is continuously cemented across the injection and producing intervals; and (D) The well demonstrates mechanical integrity. (6) The state geologist may require specific casing and cementing requirements for injection wells based on the following: (A) The depth of the underground source(s) of drinking water; (B) The nature of the injected fluids; or (C) The hydraulic relationship between the injection zone and the underground source(s) of drinking water. (7) Each operator of a permitted injection well shall comply with the following requirements: (A) Equip the wellhead with a pressure observation valve and maintain equipment necessary to obtain injection pressure measurements upon inspection by an authorized representative(s) of the state geologist. For injection wells completed prior to March 30, 2016, add the pressure observation valve prior to testing for mechanical integrity, or upon request of the state geologist; (B) Tubing and packer requirements. 1. Each well permitted shall meet one (1) of the following requirements: A. Equip the well to inject through tubing below a packer; B. Set a packer run on the tubing in casing opposite a cemented interval at a point immediately above the uppermost perforation or openhole interval. Fill the annulus between the tubing and the casing with a corrosion-inhibiting fluid or hydrocarbon liquid. All wells using wellhead pressure to inject fluids must follow the tubing and packer requirements set in this subparagraph; or C. Construct a packerless or tubingless completion for injection wells drilled to no greater than one thousand five hundred feet (1500') pursuant to paragraph (7)(B)2. or 3. of this regulation. 2. Injection through tubing without a packer is authorized if all of the following requirements are met: A. Run the tubing to a depth not shallower than forty feet (40') above the uppermost perforation or open hole of the injection interval; B. Equip each wellhead with a pressure observation valve on the tubing and the tubing-casing annulus; and C. Maintain the well so that the mechanical integrity tests can be performed as specified in 10 CSR 50-2.055(12). 3. Injection without tubing is authorized if all of the following requirements are continuously met during the life of the well: A. The casing is cemented continuously from setting depth to surface; B. Surface wellhead injection pressure is recorded monthly and kept by the operator for five (5) years; C. All pressure readings recorded are taken during actual injection operations; and D. The operator of the tubingless completion maintains the well so that the mechanical integrity tests can be performed as specified in 10 CSR 50-2.055(12). (8) In existing wells to be converted to other use, including but not limited to injection, all additional casing or recompletion shall be constructed as specified in sections (1) through (7). (9) All points at which a well is in physical contact with a pool shall meet all minimum distance requirements as specified in 10 CSR 50. For horizontal wells, submit a directional survey with the well completion or recompletion report to verify points at which the well is in contact with the pool. (10) Any well not constructed in compliance with requirements of this regulation shall be shut in, according to 10 CSR 50-2.060 until compliance is achieved. (11) All stratigraphic test wells that are not converted to another type of well must be permanently plugged according to 10 CSR 50-2.060(3) within ninety (90) calendar days of the spud date. A single thirty (30) calendar day extension period may be granted upon written request to the state geologist. If conversion is to take place, submit a permit modification to the state geologist as detailed in 10 CSR 50-2.030(9) or 10 CSR 50-2.060(4) prior to conversion. The well will then be subject to all completion and location requirements for the type of well to which it is being converted. (12) Permanent signage must be posted within ninety (90) calendar days of spud date at each well site indicating the well name, well number, and API number. Stratigraphic test wells and non-commercial gas wells are exempt from signage posting. AUTHORITY: section 259.070, RSMo 2016.* Original rule filed Oct. 11, 1966, effective Oct. 21, 1966. Amended: Filed Sept. 12, 1973, effective Sept. 22, 1973. Amended: Filed Oct. 14, 1981, effective Feb. 11, 1982. Amended: Filed Aug. 11, 1986, effective Oct. 27, 1986. Amended: Filed Sept. 16, 2015, effective March 30, 2016. Amended: Filed June 27, 2018, effective Feb. 28, 2019. *Original authority: 259.070, RSMo 1965, amended 1972, 1983, 1987, 1993, 1995, 2012, 2015.