Wellbore Trajectories Database Service - Case Study
Bin Malik, Sulaiman S.*1
(1) Saudi Aramco, Dhahran, Saudi Arabia.
Measurement While Drilling (MWD) logging tools are capable of taking directional surveys in real-time. MWD readings provide directional data such as wellbore inclination and azimuth at intervals from every 30ft to every 500ft. MWD readings are generally not taken on the vertical portion of a wellbore. This results in directional surveys not including all the points from surface to total depth. While many applications have software that simulates the wellbore trajectories and can provide 3D plotting from this raw directional surveys data, most applications do not have the capability to calculate subsurface trajectory and offsets from the wellhead dynamically.
This case study details how Saudi Aramco enabled building a 3D model of borehole trajectories for every foot drilled. It takes the existing directional surveys and then calculates the Measured Depth (MD), True Vertical Depth (TVD), Subsea Depth (SSD), Offsets and Universal Transverse Mercator (UTM) coordinates for every foot, drilled in a well. It covers wellbore trajectory for surveyed points received from drilling operations, and non-surveyed footage by using standard interpolation and extrapolation methods.
The approach provides complete and consistent coverage for all wellbores from surface to Total Depth (TD). Data is pre-packaged and ready for use by applications. It is automatically updated when any changes occur such as well location and TD updates. Petroleum engineers and geoscientists use the wellbore trajectories data and get a smooth line from surface to TD. Everyone gets the same information. It extends the benefits of data available to 3rd party tools and supports any 2D and 3D mapping application and wells can be shown in full 3D, properly located in real space. This 3D model can easily be modified to include any data item that can be assigned by depth in a well, such as the formation that the wellbore is in at that particular depth.
AAPG Search and Discovery Article #90141©2012, GEO-2012, 10th Middle East Geosciences Conference and Exhibition, 4-7 March 2012, Manama, Bahrain