Investigation of Water-Coning Phenomenon in Iranian Carbonate Fractured Reservoirs

摘要

The water coning caused by the imbalance between gravity and viscous forces is the most important reason for water production in different fractured reservoirs.There are various controllable and uncontrollable parameters affecting this phenomenon.In this study different dynamic models were constructed to search for the key parameters affecting the coning process in both single-well and Cartesian multi-well models.It has been determined that oil layer thickness,perforation thickness,fracture permeability and its orientation,especially horizontal not vertical fracture permeability,production rate,mobility ratio,and fracture storativity have the major role in water coning phenomenon.Also it has been determined that fracture spacing,aquifer strength and skin factor have insignificant effect on water coning in fractured reservoirs.The variation of water breakthrough time respect to each effective parameter has also been studied.We concluded that for any production program or adjusting the wells location,the parameter study is very important.Multi-well studies using an Iranian fractured reservoir data show that the trend of dependency of water coning on each parameter is similar to the single-well model.However,in field scale,it is necessary to have all reservoir data including well location,and production history for a successful water coning simulation because a small pressure drawdown exerted by a far well will affect the cone shape and its breakthrough time.