The Qing Huang Dao oilfield, located in the Bohai Bay has been in production for more than 10 years. To achieve production targets, many directional wells and horizontal wells were initially drilled with conventional tools and measurements. However, at the end of 2012, as the oilfield matures, the field's average water cut had reached a high of 86.4%.
Following a multidisciplinary study on bypassed oil distribution in this field, a new horizontal well drilling program was launched in 2012. The study team highlighted challenges in identifying the oil water contact (OWC) while placing the trajectory within a very small target window close to the roof that the program needs to be overcome. Off a detailed technology review, advance azimuthal LWD, with the ability to map the distance to the multiple boundaries such as the OWC, the top and bottom of the reservoir structure in the remaining oil column, was selected as the fit-for-purpose application and to enhanced reservoir understanding. In combination, rotary steerable drilling system (RSS) was selected to improve drilling efficiency and deliver smooth trajectory control.
This new approach using innovative azimuthal LWD technology implementation proved value in its utility by achieving the ultimate objective of drilling productive horizontal wells in QHD oilfield. The application reduced drilling cost, avoided unnecessary trajectory adjustments and kept the lateral trajectory within a very small target window of 1m to 1.5m close to the reservoir cap. Production from these horizontal wells surpassed production by 31% with only 4% water cut. The integrated solution of innovative LWD, well placement and RSS optimized this mature oilfiled development. The authors believe this approach and techniques could effectively address other similar mature oilfields development.