Horizontal wells are being a common practice in offshore field development in Bohai Bay recently. Maintaining well trajectory in sweep spot while drilling is one of the key factors to optimize horizontal well’s productivity. However, great challenges are often faced in Bohai Bay area including survey uncertainties while drilling and reservoir geology variation. On the one hand, successful placement of a horizontal well requires accurate landing of the well in the right position and orientation in the reservoir. On the other hand, the trajectory is optimized based on structural geobody variation resulted from the uncertainty of parameters governing the static behavior of the field. Therefore, the ability to update geosteering model in timely manner and to proactively adjust well trajectory in real time are required.
This paper presents an innovative method in Bohai Bay by applying the technology of integrated seismic volume and reservoir geosteering model while drilling to achieve very promising productivity. That is to say, the new geosteering method includes seismic inversion of checkshot calibrating, single/multi-wells reservoir model updating, conventional logging while drilling, and mud logging etc. How to develop new horizontal well steering methodology and software integrated seismic volume of time (or depth) domain, logging while drilling, reservoir modeling result to optimize well planning and placement for high productivity?
Results from lower Neogene Minghuazhen formation tests executed in SuiZhong 36-1, Bozhong oilfield of Bohai Bay clearly demonstrate the following capabilities of the technology.
Reduction of the steering need for the tools of distance to boundary included Directional and deep well placement tool.
A bridge from three-dimensional geology model to two-dimensional geosteering model before drilling; vice versa, 2D geosteering model update 3D geological model after drilling.
More People grasp the systematical methodology of integrated reservoir geosteering model and trajectory optimizing while drilling which provide a higher degree of confidence in the drilling process.