Springer Iranian Journal of Science 2731-8095 Articles in Press 2016 03 09 Prediction of subsidence over oil and gas fields with use of influence functions (case study: South Pars gas field, Iran) 3621 10.22099/ijsts.2016.3621 EN Mohammad Hossein Taherynia PhD candidate in engineering geology at Kharazmi University Seyed Mahmoud Fatemi Aghda Department of Geology, Faculty of Sciences, Kharazmi University Akbar Ghazifard Department of Geology, Faculty of Sciences, University of Isfahan, Isfahan, Iran Eslam Moradi Kharazmi University, Faculty of Mathematical Sciences & Computer, Tehran, Iran Journal Article 2014 04 23 Withdrawal of oil and gas from reservoirs causes a decrease in pore pressure and an increase in effective stress which cause reservoir compaction. Reservoir compaction will result in surface subsidence through the elastic response of the subsurface. In order to determine the subsidence above a hydrocarbon field, the reservoir compaction must first be calculated and then the effect of this compaction on the surface be modeled. The use of the uniaxial compaction theory is more prevalent and accepted method for determining the amount of reservoir compaction. Surface deformations above compacting reservoirs can be efficiently modeled using influence functions. In this paper used Knothe and Geertsma influence functions in a simple approach for subsidence modeling of the South Pars gas field. In this approach we used circular network, called as influence network, for determining the whole reservoir compaction effect on the field surface. Also semi-analytical modeling of subsidence with use of the AEsubs software is presented for comparing the results of modeling using the influence functions.