Accurate real-time characterization of complex channel sand reservoir is very critical for horizontal well drilling and production improvement. CB block located in the southwest part of Bohai Bay which is the main offshore block for SINOPEC Sheng Li. This block is featured by braided river and fluvial deposition environment. The operator faced challenges during horizontal drilling, such as thin sand channels, inner-beds development, severe lateral change, unstable sand structure and low sand connectivity.
A horizontal well drilling campaign was launched in 2021. Through considerable data assessment and feasibility study, the new generation of Ultra-High-Definition multilayer mapping-while-drilling service and rotary steerable system (RSS) as an integrated solution package was deployed to this project to overcome above challenges. Without any a-priori assumptions, the new generation service doubles depth of detection (DOD) range compared with previous bed-boundary detection services, delivers clearer boundary delineation, and is capable of remotely identifying the quantitative subsurface features, including layers’ numbers, resistivity and anisotropy distribution, thickness, and dip etc. Meanwhile, the truly hybrid RSS with near bit measurements ensures accurate and smooth trajectory control and reduces the drilling risk in the soft formation.
The pilot project was successfully completed. With the help from real-time measurements combined with seismic data, and by utilizing the advanced inversion advantage, this technology could depict whole individual sand bodies and their mutual lateral contact relationship clearly, which not only can optimize the reservoir exposure rate but also provide a better way for detailed reservoir characterization. Four wells were geosteered for a total of1026m with 96.1% reservoir exposure rate. Primary production from these 4 horizontal wells exceeded the expected production by 40% with only 10% water cut.
This innovative solution demonstrates its advantage on optimizing a complex channel sand drilling and development. The authors believe that the fit-for-purpose solution could be expanded to other similar projects by showcasing the distinctive case studies in this paper.