Within 30 days following the completion of each well in any pool whether such well produces oil or gas or both, the owner of such well shall make a subsurface pressure test on such well and shall report the results thereof to the board on Form No. 11 within 20 days after such test is made. Each such well shall remain completely shut in for at least 24 hours prior to the test. The subsurface determination shall be obtained as close as reasonably possibly to the midpoint of the productive section of the reservoir. Further, the board will require periodic subsurface pressure measurements on a sufficient number of wells in any pool to provide adequate data for establishing maximum efficient rates of production (M.E.R.) .