TY - JOUR TI - Gas reservoir evaluation for underbalanced horizontal drilling AU - Li Gao AU - Meng Ying-Feng AU - Wei Na AU - Xu Zhao-Yang AU - Li Hong-Tao AU - Xiao Gui-Lin AU - Zhang Yu-Rui JN - Thermal Science PY - 2014 VL - 18 IS - 5 SP - 1691 EP - 1694 PT - Article AB - A set of surface equipment for monitoring the parameters of fluid and pressure while drilling was developed, and mathematical models for gas reservoir seepage and wellbore two-phase flow were established. Based on drilling operation parameters, well structure and monitored parameters, the wellbore pressure and the gas reservoir permeability could be predicted theoretically for underbalanced horizontal drilling. Based on the monitored gas production along the well depth, the gas reservoir type could be identified.