PROBLEM 2 The initial volume of gas in place in the P Sand reservoir of the Holden Field is calculated from electric log and core data to be 200 MMM SCF underlying 2250 productive acres, at an initial pressure of 3500 psia and 140°F. The pressure-production history is Pressure, psia Production MMM SCF Gas Deviation Factor at 140ºF 3500 (initial) 2500 0.0 75.0 0.85 0.82 (a) What is the initial volume of gas in place as calculated from the pressure production history, assuming no water influx? (b) Assuming uniform sand thickness, porosity, and connate water, if the volume of gas in place from pressure-production data is believed to be correct, how many acres of extension to the present limits of the P Sand are predicted? PGE 403 Natural Gas Engineering HW-7 Due Date: 17.11.2019 by flippedlearning environment... (c) If, on the other hand, the gas in place calculated from the log and core data is believed to be correct, how much water influx must have occurred during the 75 MMM SCF of production to make the two figures agree? PROBLEM 3 Explain why initial calculations of gas in place are likely to be in greater error during the early life of depletion reservoirs. Will these factors make the predictions high or low? Explain.