Washington Revised Code Title 78. Mines, Minerals, and Petroleum § 78.52.210. Development units--Size and shape

(1) The size and the shape of any development units shall be such as will result in the efficient and economical development of the pool as a whole, and the size shall not be smaller than the maximum area that can be efficiently and economically drained by one well as determined by competent geological, geophysical, engineering, drilling, or other scientific testimony, data, and evidence. The department shall fix a development unit of not more than one hundred sixty acres for any pool deemed by the department to be an oil reservoir, or of six hundred forty acres for any pool deemed by the department to be a gas reservoir, plus a ten percent tolerance in either case to allow for irregular sections. The department may, at its discretion, after notice and hearing, establish development units for oil and gas in variance of these limitations when competent geological, geophysical, engineering, drilling, or other scientific testimony, data, and evidence is presented and upon a finding that one well can efficiently and economically drain a larger or smaller area and is justified because of technical, economic, environmental, or safety considerations.

(2) The department may establish development units of different sizes or shapes for different parts of a pool or may grant exceptions to the size or shapes of any development unit or units. Where development units of different sizes or shapes exist in a pool, the department shall, if necessary, make such adjustments to the allowable production from the well or wells drilled thereon so that each operator in each development unit will have a reasonable opportunity to produce or receive his or her just and equitable share of the production.