The use of changing-skin factors on gas well-testing interpreting

In gas well-testing interpreting, it is difficult and unreasonable to match pressure-history curve by using unchanged skin. Gas high speed flowing rate leads to the gas well additional pressure drop and additional skin. The more the flow rate is, the more skins are. Based on superposition and changing-skin theory, pressure whole history matching in unstable welt-testing has been carried using true extra,pie. And good matching is acquired. Using skin acquired by matching on different flowing period, we can acquire true-skin through line regression.