Multilateral well drilling technologies have evolved significantly since being pioneered in the Bashkiria fields in Russia in 1953. Today, the diversity of drill string and bottom hole assembly designs combined with the ever-increasing volumes of subsurface data allow operators to more accurately understand geological conditions, identify risks, and plan and drill multilateral wells to maximize recovery.
Geology and Geophysics Guide Drilling Technology
Data integration and visualization software, such as CoViz 4D, by Dynamic Graphics, Inc., designed for the petroleum industry provides well planners and drilling engineers with detailed 3D models of the subsurface environment. When used in conjunction with advanced directional drilling packages, such as WellArchitect, also by Dynamic Graphics, 3D models allow drilling teams to assess the reservoir at the macro level, showing formations, faults, horizons, salt domes, and share layers. The 3D models also allow teams to explore properties such as lithology, porosity, permeability, and saturation along proposed multilateral well paths.
In developed fields, 3D models can depict existing nearby wells and well data to help well planners avoid encroachment and gain a better understanding of local geologic and geophysical properties. A detailed 3D model of the geologic and geophysical characteristics of a reservoir gives well planners relevant information to:
- Accurately identify targets.
- Identify geologic risks such as faults or salt domes, or thin sand zones and thin layer formations that demand accurate entry and placement of laterals.
- Plan the preliminary distribution of the laterals through the reservoir—multi-branched, forked, stacked, dual-opposing, or variations of each.
- Locate wellbore and laterals within the geology to maximize reservoir coverage and exposure to fractures.
Well planners can also create 3D cross-sections “on-the-fly” to explore any specific area in detail. A detailed understanding of geologic and geophysical characteristics sets the initial stage for determining drilling methods, lateral drilling sequence, casing and completion strategy, and frac stages.
Plan Well Trajectories in Context of the Geology
- Identify and avoid geologic features that may compromise borehole stability.
- Plan multilateral well trajectories from KOPs to targets, selecting specific points in the geologic model, allowing software to calculate curves.
- Be alerted when a planned trajectory intersects a horizon or fault at an angle that could deflect the BHA.
- Determine minimum allowable separation distance (MASD) from a reference wellpath, using collision avoidance rules.
- Examine and compare several multilateral trajectory design options to determine the preferred design with respect to drilling costs and risks.
- Review geology, plans, drilling logs, production data, etc. of nearby multilaterals and apply insights to current multilateral design.
Geology Also Determines Multilateral Well Drilling Technology
- Determine the sequence for drilling laterals.
- Specify bit and BHA configuration for the main wellbore and laterals.
- Decide the appropriate Technology Advancement of Multilaterals (TAML) junctions to provide required hydraulic integrity.
- Specify the window milling techniques and components (whipstock, milling assembly, or pre-milled window casings) for each lateral branch.
- Plan frac stages in adjacent multilaterals using a “wine rack” view.
The Added Value of WITSML Technology
- Show lateral and current bottom hole location and automatically use ahead-of-bit calculations to avoid collisions and ensure the trajectory remains on-target relative to zones.
- Visualize as well as analyze lateral drilling progress in the context of nearby wells to ensure the lateral does not encroach on offset wells.
- Monitor drilling performance—rotational speed, vibration, torque, downhole temperature, and mudflow—to ensure BHA components are operating within their technical limits.
Data Drives Multilateral Well Drilling Technology
CoViz 4D and WellArchitect, data visualization analytics and well planning software from Dynamic Graphics, Inc., are essential technologies for multilateral well planning and drilling. Extensive data integration capabilities, powerful 3D visualization of geologic data, and the ability to plan wells within the geologic context allow drilling engineers to determine the appropriate multilateral well drilling technologies to reduce drilling risk and improve drilling efficiency. To learn more about CoViz 4D and WellArchitect, contact our team.