Section 240.430  Drilling Unit Exceptions

a)         In the case of irregular sections containing more or less than 640 acres, in those areas where the United States Government has not made an official survey, in areas covered by the old French Surveys and Grants, in meandered lands, in government lots, and in subdivisions thereof where the acreage in quarter-quarter-quarter sections and quarter-quarter sections do not conform to the requirements of Section 240.410, the Department shall establish drilling units for wells such that drilling units will not cause a greater well density than would be encountered in regular official surveys  relative to the distance between wells and the external drilling unit boundary lines specified in Section 240.410.

b)         If the proposed oil wells will be part of an enhanced oil recovery project, spacing requirements for oil or gas production wells are as follows:

1)         Except as provided in subsection (b)(2), the drilling unit and well location requirements of Section 240.410 do not apply to an oil well that is part of an enhanced oil recovery project.  For purposes of this Subpart, an enhanced oil recovery project is a lease, or a unit composed of a group of leases operating under an agreement that provides for the sharing of production by all of the owners within the unit, which has one or more enhanced oil recovery injection wells permitted and in operation at the time an application for a permit to drill and operate an oil well is filed.  The enhanced oil recovery injection wells in operation must be injecting into the reservoir that will be produced in order for the project to be classified as an enhanced oil recovery project.

2)         Oil wells permitted and drilled in accordance with this Section must be located no less than 330 feet from the nearest lease boundary line or unit boundary, except that, if, at the time of application, a lease immediately adjacent to the proposed well has producing wells located less than 330 feet from the common boundary line, then the proposed well may be located at a distance closer than 330 feet, but no closer than the distance to the common boundary line of the immediately offsetting well.

c)         If the proposed well is to be a post-primary recovery well:

1)         The spacing requirements shall comply with Section 240.410; or

2)         A new drilling unit may be designated consisting of two or more drilling units of the same size, shape and location as that required in Section 240.410 and located in the same reservoir.  At least one-half of the drilling units used to make up the new drilling unit are required to contain at least one plugged or non-producing well.  The new drilling unit shall not contain any drilling unit of a well actively producing from the same individual reservoir.  The new drilling unit may cross section lines.  In a reservoir in which the top lies less than 4,000 feet beneath the surface, the well shall be no less than 330 feet from the nearest external boundary lines of the new drilling unit nor less than 660 feet from the nearest location of a producing well, a well being drilled, or a well for which a permit has previously been issued (but under which the well has not yet been drilled) using the same individual reservoir.  In a reservoir in which the top lies at or below 4,000 feet beneath the surface, the well shall be no less than 330 feet from the nearest external boundary lines of the new drilling unit nor less than 900 feet from the nearest location of a producing well, a well being drilled, or a well for which a permit has previously been issued (but under which the well has not yet been drilled) using the same individual reservoir.

(Source:  Amended at 35 Ill. Reg. 13281, effective July 26, 2011)