TITLE 62: MINING
CHAPTER I: DEPARTMENT OF NATURAL RESOURCES
PART 240 THE ILLINOIS OIL AND GAS ACT
SECTION 240.455 HORIZONTAL DRILLING
Section 240.455 Horizontal Drilling
a) For purposes of this Subpart, a horizontal well is a wellbore that has an overall length within the reservoir of twice the thickness of the reservoir.
b) An oil or gas production well may be developed with one or more horizontal drainholes drilled from a single vertical wellbore and may be considered a single well and permitted in accordance with the provisions of Subpart B.
c) If the proposed horizontal well will be part of an enhanced oil recovery project, the spacing requirements for all portions of the horizontal drainholes shall comply with Section 240.430(b).
d) For a horizontal well:
1) the spacing requirements shall comply with Section 240.410; or
2) a horizontal drilling unit may be designated consisting of two or more drilling units of the same size, shape and location as that required for a well of the same depth in accordance with Section 240.410. The horizontal drilling unit may cross section lines.
e) For the horizontal wells described in subsection (d), all portions of the horizontal drainhole:
1) may travel in any direction or directions necessary for efficient production within the drilling unit;
2) shall be no less than 330 feet from the nearest lease boundary line except any boundary line located within a pooled unit; and
3) shall be no less than 330 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.
f) If a horizontal drilling unit configuration other than that allowed in subsection (d)is necessary because of geology or reservoir conditions, a modified or special drilling unit is required in compliance with Section 240.460 and/or Section 240.465.
(Source: Amended at 42 Ill. Reg. 5811, effective March 14, 2018)