This paper presents solutions and analysis of mathematical model of skins due to completions in gravel packed oil and gas wells. The models can be divided into three cases: (1) Open Hole gravel packed well (2) Cased-hole perforated gravel packed well (3) Collapsed perforation tunnel gravel packed well. The skins due to completion include damaged skin, restricted entry skin, liner skin, gravel packed sand skin, slanted well skin, perforation geometry skin, crushed zone skin, non-darcy skin and the skin in the perforation tunnel.
The results obtained from the calculation in open hole gravel packed show that the skin in damaged zone decreases as the damaged zone permeability increases. For the cased-hole perforated gravel packed oil and gas well, the results show that increasing the perforation radius, perforation length and crushed zone permeability result in the decrease of crushed zone skin for both darcy and non-darcy flow, the perforation geometry skin and skin in the perforation tunnel for both darcy, and non-darcy flow for a given shot density. For the collapsed perforation tunnel gravel packed oil and gas well, the results show that the increasing perforation radius results in the decrease of hemispherical flow geometry skin and skin in the perforation tunnel for both darcy and non-darcy flow for a given shot density.
The solutions of each gravel packed skin model is used to analyze field and experimental data in order to estimate the skins and the decrease or Increase in productivity ratio due to completions in gravel packed wells.