Optimization of effective horizontal length utilizing underbalanced technique

Over the last two decades,horizontal wells are still more favorable over vertical ones because they maximize reservoir contact and increase productivity index. In addition, horizontal wells yield higher drainage area and reduce water coning impact. Many horizontal drilling patterns have been evaluated in terms of distance between wells and the length of horizontal section heel to tail. EHL (Effective Horizontal Length) has a great impact on EDA (Effective Drainage Area) of a horizontal well which can be used as indicator to evaluate the success of field development. Many data can be collected and extracted by remote real -time monitoring. These data can be used to estimate very important factors like reservoir permeability and drainage area at each foot of the horizontal section. This paper presents a new approach of investigating EHL by using UBD (underbalanced drilling) data. Simulation studies were conducted through the horizontal section trajectory of the well to determine the reservoir drainage area along the length of the horizontal section. Eventually, the evaluated EDA summed up to produce the total productivity of the well using nodal analysis for each section separately. Results of this study showed very promising potential for actual field applications.