Optimizing oil recovery using new inflow-control devices (ICDs) skin equation

Inflow-control devices (ICDs) were developed to avoid coning problems in long horizontal wells mainly in heterogenous formations, but cause some additional drawdown which does not contribute to rate increase. This rate reduction is seen to be impairment to the productivity of horizontal wells. Therefore, horizontal wells that are equipped with ICDs require a pre-quantification of their productivity by determining skin caused by each ICD nozzle size. This will help prevent additional expenditure that will be spent for a corrective horizontal well intervention.  Many authors have proposed equations that can be used to estimate skin due to damage, partial completion, slanted well and perforation. No author has provided a skin equation that can be used to estimate recoverable and productivity loss that may result from the use of inflow control devices. In this work, a 3D numerical model which includes inflow control devices along horizontal wells was used to investigate reservoir and production performances of various ICD nozzle sizes. Different productivity losses from different nozzle sizes were seen as skin and a 0.002ft2 ICD nozzle flow area estimated to have a zero skin. Consequently, a simple equation for calculating this skin due to restricted fluid entry through ICD nozzles was derived. The derived equation which shows insignificant deviation from skin equation is then used for selecting the right nozzle size for production and recovery optimization from horizontal wells. Key words: Inflow control device