Mitigation of downhole problems during well construction has entered a new dimension with the recent launch of engineered software that for the first time permits interactive, 3-D visualization of the inside of a virtual well bore using PCs and gamepads like those employed with today’s computer games.

Currently, the software package focuses on drilling hydraulics; however, there are countless

Figure 1. The 3-D visualization package incorporates concepts from six key technologies. (All images courtesy of M-I SWACO)
opportunities for 3-D visualization to facilitate engineering analysis and training efforts in other well construction, completion and workover operations. Stunning 3-D perspective rendering can show internal and side projections of well tortuosity, cuttings beds, drill string (including 3-D eccentricity), annular velocity profiles, formations (texture, rugosity and breakout), downhole engineering parameters (temperature, density, rheology, ECDs, etc.), and downhole tools, among others.

Hydraulics was targeted because it is central to the safe, economic and efficient drilling of all wells as well as being a principal concern for deepwater, high-temperature/high-pressure and highly directional wells. Plus, drilling personnel historically have had difficulty visualizing true downhole hydraulics behavior.

Measured values are used where possible, but most key data are provided by advanced hydraulics programs using steady-state, transient and real-time models. This makes the visualization software ideal for planning, analysis and optimization at the wellsite and for collaboration among multidisciplinary teams in onshore drilling centers.

Wide distribution of the visualization software with the hydraulics programs has created multiple case histories where it has been used to illustrate potential and experienced hydraulics-related problems. For example, the software was used in one well to visually demonstrate hole-cleaning issues caused by high angles, doglegs and inadequate flow rates. The problems were mitigated prior to a successful liner run. In other wells, it has been used to illustrate benefits of properly designed sweeps to avoid stuck pipe, to demonstrate why excessive sliding led to hole packoff, to illustrate skewed velocity profiles and their effects on cuttings transport and to explain increased stuck pipe potential due to key seats and hole spiraling.

Because of an ever-increasing focus on attracting new personnel, the system also has been used in school seminars to help students visualize the downhole drilling environment and expose them to high-tech opportunities in the oil industry.

Expanding 3-D visualization

Visualization involves the computer processing, transformation and graphical display of large
Figure 2. A screen shot displaying pertinent numerical data for the localized well interval in the four corners of the screen, illustrating lithology, well geometry and the current depth location of the virtual camera.
data sets to facilitate their interpretation. The oil industry has long employed this technology, which has now evolved into a significant tool for viewing and interpreting reservoir-related data. In drilling, it previously had been used for well placements in complex reservoirs, to control well tortuosity and avoid collisions on multi-well platforms.

Visualization of the inside of the well bore to improve drilling and completions operations, however, had previously not been considered. Furthermore, the power of 3-D visualization technology was not readily accessible to field personnel. These issues were addressed by incorporating concepts from these six technologies (Figure 1):
• 3-D Reservoir Visualization – interpretation of seismic data, 3-D logs, geocellular models, grids and horizons.
• Downhole Video Systems – mechanical inspection, fishing operations and problem investigation with transparent fluids where internal drill/work strings do not interfere with downhole camera operations.
• Flow-Loop Video – laboratory studies of hole cleaning, barite sag, sweeps and other flow-related processes.
• Non-Invasive Medicine – 3-D imaging from external measurements such as the “virtual” colonoscopy which assembles 2-D X-ray scans like slices in a loaf of bread.
• Engineering Modeling – hydraulics simulations based on finite-difference methods.
• Interactive Computer Games – graphics engines, accelerated video cards, computer hardware and innovative techniques for creating and manipulating interactive 3-D images.

Practically speaking, engineering modeling and computer-game graphics are the key supporting technologies for the 3-D wellbore visualization software. The modeling technology starts with measured data and leverages on proven methods to accurately simulate downhole conditions.

The 3-D graphics system is based on the graphics engine that drives more than 80% of the
Figure 3. The package is routinely used in offices for well planning.
world’s computer games. A keyboard, joystick or the ubiquitous gamepad manipulate a virtual downhole camera to display extraordinary views of the recreated downhole environment. Inside views of the wellbore simulate lowering of a live video camera, while side views provide 360° close-up and far-field panoramas.

At this point, the graphics technology clearly is far ahead of the engineering modeling, and it should remain so considering the extreme investments by the computer gaming industry. The graphics engine already is capable of rendering most of the wellbore parameters that can be measured or simulated. Combined with computer hardware advancements, this segment of the 3-D wellbore visualization process should continue to rapidly evolve and provide quality, flicker-free imaging far into the future.

3-D visualization, inside/out

Functional operation of the 3-D visualization software depends on whether the data are steady-state, transient or real-time. For steady-state data, a single dataset is generated by the hydraulics software as a snapshot of downhole profiles at a fixed point in time. The results are then rendered into “static” 3-D images ready for navigation. Unlike the well schematic typically drawn on a single sheet of paper, graphical representation of the virtual well bore immediately demonstrates the engineering required to drill a well, especially if it is deep and directionally drilled.

The display in Figure 2 shows pertinent numerical data for the localized well interval in the four corners of the screen, illustrating lithology, well geometry and the current depth location of the virtual camera. In the side view projection, a rainbow-colored velocity profile is displayed and represents the annular velocity distribution in the well bore. An annular flow regime distribution is rendered on the reverse side of this profile.

For transient data, a large collection of individual “frames” are recorded to a disk for subsequent Instant Replay playback using VCR-type controls that operate much like TiVo and DVRs for television. A notable enhancement permits interactive virtual camera movements while “recordings” are displayed, rewound and fast-forwarded.

Time-variant drilling, tripping and multiple-fluid displacement scenarios are modeled and critically evaluated in a look-ahead mode to generate the frames. Transient models are required to handle dynamic situations such as sliding cuttings beds and helical flow patterns of suspended cuttings. Special interpolation techniques are required to fill gaps in discrete data sets to target the aesthetic visual experience.

Requirements for the real-time visualization system are somewhat related to those of a transient system. In real-time mode, a wellsite equivalent circulating density (ECD) management system provides real-time datasets concurrently sent to the visualization system for processing. Multiple visualization computers can be connected to the server hosting the real-time ECD management system and allow simultaneous navigation while sharing the same dataset over a network. This design is well-suited for drilling centers and Internet applications, and supplemental traditional screens and displays are used to monitor well-construction operations remotely.

Several modules have been incorporated to help users analyze the virtual well bore and appreciate the more realistic aspect ratios, especially when transient data are involved. “Intelligence” is incorporated to direct the software to automatically find, display and visually inspect anomalies and potential hydraulics-related problems. For example, the software can automatically navigate to the first region of the well bore that satisfies user-selected criteria, such as poor hole cleaning, high viscosity, etc. A Heads-Up Display (HUD) activated by mouse position pinpoints and displays localized data, some of which may have been imported from external sources.

The future

Applications other than drilling hydraulics are natural extensions and already are under development. Among these are completion fluid displacements and interfaces, chemical and mechanical wellbore cleaning for removing residual mud films, and wellbore instabilities such as washouts and breakouts. While functional requirements are the same as for drilling hydraulics, engineering modeling requirements are different, as is the need to design the visualization to fit specific applications.

Advent of 3-D wellbore visualization already has had a positive impact on business and work-flow issues. It systematically is changing perception of the downhole environment for many non-drillers, experienced drillers, students and especially those generally unfamiliar with the oil field.

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