8.7 (a) Three beds of equal cross section have permeabilities of 50 md, 500 md, and 200 and lengths of 10 ft, 40 ft, and 75 ft, respectively. What is the average permeability of the beds placed in series? (b) What are the ratios of the pressure drops across the individual beds for liquid flow? Problems 285 (c) For gas flow, will the overall pressure drop through beds in series be the same for flow in either direction? Will the individual pressure drops be the same? (d) The gas flow constant for a given linear system is 900, so that p² - P = 900L/k. If the upstream pressure is 500 psia, calculate the pressure drops in each of two beds for series flow in both directions. The one bed is 10 ft long and 100 md; the second is 70 ft and 900 md. (e) A producing formation from top to bottom consists of 10 ft of 350 md sand, 4 in. of 0.5 md shale, 4 ft of 1230 md sand, 2 in. of 2.4 md shale, and 8 ft of 520 md sand. What is the average vertical permeability? (f) If the 8 ft of 520 md sand is in the lower part of the formation and carries water, what well completion technique will you use to keep the water-oil ratio low for the well? Discuss the effect of the magnitude of the lateral extent of the shale breaks on the well production.