Section 250.413 - What must my description of well drilling design criteria address?Your description of well drilling design criteria must address:
(b) Formation fracture gradients, adjusted for water depth;(c) Potential lost circulation zones;(d) Drilling fluid weights;(e) Casing setting depths;(f) Maximum anticipated surface pressures. For this section, maximum anticipated surface pressures are the pressures that you reasonably expect to be exerted upon a casing string and its related wellhead equipment. In calculating maximum anticipated surface pressures, you must consider: drilling, completion, and producing conditions; drilling fluid densities to be used below various casing strings; fracture gradients of the exposed formations; casing setting depths; total well depth; formation fluid types; safety margins; and other pertinent conditions. You must include the calculations used to determine the pressures for the drilling and the completion phases, including the anticipated surface pressure used for designing the production string;(g) A single plot containing curves for estimated pore pressures, formation fracture gradients, proposed drilling fluid weights (surface and downhole), planned safe drilling margin, and casing setting depths in true vertical measurements;(h) A summary report of the shallow hazards site survey that describes the geological and manmade conditions if not previously submitted; and(i) Permafrost zones, if applicable. 76 FR 64462 , Oct. 18, 2011, as amended at 81 FR 26017 , Apr. 29, 2016; 84 FR 21973 , May 15, 2019