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  • 标题:Is scientific visualization a gimmick or a useful tool?
  • 作者:W. Wright
  • 期刊名称:World Oil Magazine
  • 出版年度:2001
  • 卷号:March 2001
  • 出版社:Gulf Publishing Co.

Is scientific visualization a gimmick or a useful tool?

W. Wright

Many regard visualization technologies as hype that, although possibly useful in the geoscience domain, has no place in the well-construction arena--that perspective is rapidly changing

What value does visualization bring, particularly to well construction? Visualization allows complicated geometric and computational models to be simply represented; wells can be more easily linked to the larger picture of the field. No longer is there a need to use terms that confuse all but the individual-discipline experts; a 3-D picture is now available. This speeds and facilitates communication and mutual understanding of problems and potential solutions. Experts can look for creative solutions suggested from their extra-discipline peers. Small, subtle changes are much more easily dealt with, and the exercise becomes a shared learning experience.

Teams start to appreciate what is involved in the collaborators' disciplines, thereby facilitating future teamwork. Visualization enables a common language to be established for future communication amongst a multi-disciplinary team. Mutual understanding and appreciation of problems can greatly enhance team performance. This article discusses the many diverse benefits realized so far with 3-D visualization, as well as future, potentially rich areas to exploit within the well-construction arena.

INTRODUCTION

Large-scale visualization has only recently started to come of age. For most oilfield people, it is associated with the geological and geophysical (G&G) business. Extensive mapping of fields and key geological surfaces, viewed simply and easily in an integrated environment, has become commonplace. In drilling, viewing complex directional plans in a multi-well environment is becoming routine. In some cases, drilling progress can be monitored in real time. [1]

In and of themselves, the applications discussed briefly in this paper are of significant value, but they pale compared to their use to provide mutual understanding in a multi-disciplinary team. One analogy can be found in the film industry.

Movies are probably the most visual of all media. One of the largest factors in the demise of 3-D movies was cost. Many theater owners were reluctant to equip the cinemas with the proper equipment. However, there has been a recent resurgence in using 3-D movies for instruction, and while the entertainment business will continue to employ a range of tactics to shock, surprise and entertain (e.g., the marriage of rides with 3-D visuals at Disneyland and Universal Studios), 3-D movies are used today to inform.

A prime example has been the combination of IMAX technology and 3-D for movies, such as the ascent of Everest and the exploration of undersea worlds, with realism that a 2-D projection could only hint at. This is exactly what must be achieved among the various domain experts that make up multi-disciplinary oilfield teams.

One must reflect that sound and color were once dismissed as gimmicks when they initially appeared. Indeed, in 1927 one of the founders of Warner Brothers said "Who the hell wants to hear actors talking?" They are now an essential part of the viewing experience.

In the next few years, 3-D visualization of drilling data in the context of a complex framework model of the subsurface will soon be viewed as an essential tool. Eventually, no one will even pause to consider how anyone worked without it.

CURRENT VISUALIZATION TECHNIQUES

What follows are some common uses of visualization that illustrate how they are most powerful when combined and shared.

Visualizing directional drilling.

Directional drilling (DD) has traditionally been considered more of an art than a science. A skilled directional driller knows his particular subsurface location better than any 3-D seismic could reveal, and can navigate within that environment accordingly. However, in the types of developments occuring today, using continuous direction and inclination measurements has allowed wellbore trajectories that can be more precisely geosteered and managed; this ensures optimal use of bit/BHA combinations and downhole tools. [2]

It is essential to identify and assess the severity of undulations occurring between conventional survey points; this enables a true determination of wellbore tortuosity, as well as any remedial action. This inter-survey visualization needs to be performed in a 3-D environment, since the well is 3-D. The directional driller needs to determine when a change in operating parameters or BHA configuration is necessary to reduce tortuosity, if it is becoming prohibitive to further operations such as running casing.

There is also a clear need to enable visualizing complex trajectories in 3-D in a manner completely independent of the earth-model framework in which they are placed, purely from a directional-drilling perspective.

Some multiwell platforms require careful planning and drilling to avoid collisions in the uppermost well sections. Traditional drilling-planning centers have evolved to become true drilling-engineering centers, where wells can first be "drilled on paper." Multiple contingency plans can be evaluated and appropriate information fed back to personnel who can make a decision.

Fig. 1 shows a typical 3-D horizontal well. As more wells are drilled from this platform, it is clear that anticollision policies and procedures will be crucial to development success. When the final development is seen, it is a complex tangle of trajectories. Navigation within this environment is difficult; it requires skill and coordination at both the planning/engineering center and directional-driller levels.

Using nudge bins to facilitate long-term directional planning and mitigate anticollision concerns in complex multiwell platforms revealed the sensitivity of the trajectories. Subtle changes to trajectories were needed in the near-surface locations to reduce casing wear over the drilled life of the well, and to enable all planned wells to be completed without significantly compromising directional designs. [3]

One factor that can complicate analysis is positional uncertainty due to survey uncertainty. The 3-D environment is one of the most useful ways to visualize such uncertainties, particularly how they relate to uncertainties in other planned and drilled wells. Fig. 2 adds the survey tool error-ellipse-of-uncertainty to the line trajectories. Being able to view potential collisions from multiple angles in this framework can enable rapid replanning, as well as aiding the selection of BHA components and stabilizer configurations.

Indeed, 3-D visualization in DD should not be viewed as replacing conventional techniques, but as complementing traditional spider maps and traveling-cylinder plots. Visualization can bring additional benefits above and beyond straightforward well-proximity warnings, highlighting not only targets and hazards, but uncertainties associated with their position and an indication of the hazard type and potential severity.

In addition to visualizing well trajectories, one can start to ideatify potential hazards: for example, regions of lost circulation, kicks or poor cleaning. Visualization in this case is a facilitator, bringing the drilling engineer, wellsite engineer and directional driller closer together in their common goal of drilling a successful, trouble-free well.

In the G&G world, the engineer is typically looking for formation tops or targets. This can be in highly faulted locations or near salt domes, etc. Visualization can enable different types of "virtual" surfaces to be displayed. These surfaces could be the events described above, such as a surface of lost circulation that may be located near various faults, or regions where differential sticking might be experienced. With such visualization, well engineers (no longer called just planners) can optimize wellbore placement--a key part of the well-construction process--and enable drilling the well in the most efficient manner.

Toward a shared earth model.

For a model to be a shared earth model, it must involve all users, whatever their discipline. Each contributor must obtain value from using it, and it must be simple enough for fast understanding. A shared earth model must thus be a balance between enough information to facilitate understanding and too much detail, which causes confusion. In fact, if constructed correctly, an outwardly simple model can be interrogated to obtain detail, should it be required.

A complex, multilayer framework model is shown in Fig. 3. Each surface is important in its own right, but not every surface is displayed all the time. Surfaces must be easily displayed when needed and be removable when no longer of interest. In this way one avoids a situation where there may be too much detail for a critical well-construction phase. A typical scenario is the need to set a casing shoe as close as possible to a particular surface. Once this is done and casing is set, the intervening layers now behind casing are no longer critical to the well-construction phase, at least for the current well. Therefore, they should be removed from the display.

Fig. 4 shows the same model reduced to a couple of crucial surfaces and well trajectories with a limited number of (what were initially regarded as) key faults. In this particular North Sea example, the wells have also been shaded to represent problems that each well encountered. This provides a simple representation of important information without overcomplicating the complete field picture.

Each along-trajectory color represents a type of drilling problem; severity of the problem is depicted by cylinder diameter, while the cylinder length illustrates the well section over which the problems occured. Further, the cylinders can be interrogated to provide detail by simply clicking on them. This directs the user to a simple event database that provides details of the environment in which the event took place, problems encountered and actions taken to solve the problems etc.

In this case study, it became clear that greater fault interpretation was needed to further improve the well-construction process. What was more surprising was that, as a function of the drilling groups' greater appreciation of the cause of problems, it was they who insisted on the need for additional interpretation. In fact, the area above the two key surfaces shown in Fig. 4 contained no less than 159 faults. These faults are depicted in Fig. 5, and it is clear that, as interpreted, they do not provide any clarity to the driller. Actually, they probably serve to confuse, and do not provide a simple aid in well design.

However, if we now take these faults into the context of our shared earth model and take both vertical and horizontal cuts through them, they can be greatly demystified as the local stresses become evident, even to those who do not hold a PhD in rock mechanics, Figs. 6 and 7. Well engineers can intuitively see where not to place wells if drilling surprises are to be avoided. When wells are planned in this manner, more wells can be effectively placed more accurately and in less time. [4]

So, what has been achieved in this case? Inputs have been taken from a number of domain experts and translated into information from which a driller can make faster, better-informed decisions. The next step is that the driller needs access to some of this information while drilling the well.

Sharing the shared earth model.

Historically, various control-room environments that interface with the wellsite have failed because they have disempowered wellsite personnel. It is therefore of upmost importance that wellsite personnel remain empowered. Wellsite visualization must be seen as aiding the decision process rather than adding additional hierarchy. It should be viewed as a vital part of large-scale visualization, since it allows wellsite personnel to interface with other experts and understand their thinking. Hence, the ability to synchronize onshore and offshore-based models at the appropriate frequency is required.

Wellsite communications have improved greatly in recent years and-- in the best cases--are fiber optic links to permanent installations, allowing fast and continuous communication. Sharing between two sites need not necessarily be between wellsite and town. The increasing shortage of skilled personnel means that, in many cases, it will be important for two locations to collaborate on the same model. This situation occurs today when companies have so-called "split assets." Experts may reside in headquarters that support multiple operations, while operational personnel are in the country where the well is under construction.

Shared earth models used in this way also provide for a much simpler peer-review process, whether remote or not. In short, a functioning, shared earth model not only provides for better, more informed decision making, but it also can become an intuitive repository of prior knowledge and experience, thus facilitating working in today's interconnected world.

CONCLUSIONS

What then does visualization provide?

* It allows complicated terminology to be turned into pictures, transforming the abstract into a reality.

* It facilitates mutual understanding in a multi-disciplinary team.

* Subtlety of both problems and solutions can be much more easily conveyed.

* It allows for varying detail that can be accessed when required.

* "Out of the box" solutions can be proposed by extra-discipline experts.

* It greatly enhances communication of distributed/virtual teams via a shared picture or model.

* A shared 3-D model that contains data from all disciplines can become the historical repository for all information about a field, and it can be more intuitively accessed.

The authors believe that 3-D visualization is truly a paradigm changer; something that will become an everyday tool for all multi-disciplinary teams. Perhaps its greatest, often-overlooked attribute is its ability to bring people together and improve team dynamics by providing clarity in the face of the ever-increasing data that forms the modern well-construction process.

ACKNOWLEDGMENT

The authors would like to thank Richard Hammersley, Violeta Ivanova, Laura Murphy and John Fuller of Schlumberger, and Lorraine Beacom for their contributions to the images and text. This article is derived from SPE/IADC Paper 67754, presented at the Drilling Conference held at Amsterdam, the Netherlands, February 27-March 1, 2001, and is used with permission.

THE AUTHORS

Bill Wright has worked in management and technical positions across all of the Schlumberger companies throughout the world for 23 years. For the last five years, he has been seconded to Amoco, subsequently BP-Amoco and BP on various drilling related, applied R&D projects. He is currently Drilling Solutions project manager for Schlumberger worldwide.

Iain Rezmer-Cooper is currently the Product development manager for Drilling Engineering and Planning for Schlumberger, based in Sugarland, Texas. Previously, he was manager for drilling interpretation, where his group developed real-time leak-off test processes, as well as predictive software to facilitate extended-reach drilling and enable advanced well-control simulation. He has conducted research on real-time kick monitoring and control.

Christoph Ramshorn is a research scientist at Schlumberger Oilfield Services Research in Cambridge, England. His interests include networked virtual environments, high-performance visualization, and geometric modeling. Before joining Schlumberger Austin Research in 1993, Ramshorn worked for two years on sedimentary process modeling and visualization at Stanford University. He holds a PhD in Geology from Freiburg University, Germany

Jonathan Halt manages the "no drilling surprises" technology project at BP, presently based in Aberdeen, Scotland. He joined BP in 1983 and worked in exploration and appraisal drilling operations in the UKCS until 1990. He worked in Houston for five years on drilling and facilities-related projects for Pompano Phase 1 and 2. Previously, he was involved in managing development-drilling operations on Bruce Western area development, UKCS. Jonathan earned a BS degree from Heriot-Watt University Edinburgh, Scotland.

Reginald C. Minton joined BP in 1976 and worked in drilling fluids before moving to Anchor Drilling Fluids in 1983 as technical director and then UK operations manager. He returned to BP in 1986 and has held a series of drilling engineering, R&D project management and exploration-drilling, operations-management posts. In June 2000, he became technology theme leader for BP, managing the company's drilling R&D portfolio and is presently based in Aberdeen, Scotland. Reginald earned a BS from Hatfield Polytechnic, Hertfordshire, England, and a PhD from the University of Aberdeen, Scotland. He has been an SPE Distinguished Lecturer and received the Stavanger SPE Engineer of the Year award in 1997.

LITERATURE CITED

(1.) Marshall, G., et al., "Relevant time update of an earth model with logging while drilling data," Paper SPE 62528, presented at the SPE/AAPG Western Regional Meeting, Long Bench, California, June 19-23, 2000.

(2.) Lesso, W. G., I. M. Rezmer-Cooper and M. Chau, "Continuous direction and inclination measurements revolutionize real-time directional drilling decision-making," Paper SPE 67752, presented at the IADC/SPE Drilling Conference, Amsterdam, the Netherlands, February 27-March 1, 2001.

(3.) Rezmer-Cooper, I. M. et al., "Field data supports the use of stiffness and tortuosity in solving complex well design problems," Paper SPE 52819, presented at the SPE/IADC Drilling Conference, Amsterdam, the Netherlands, March 9-11, 1999.

(4.) Holt, J., et al., "Mungo field: Improved communication through 3D visualization of drilling problems," Paper SPE 62528, presented at the SPE/AAPG Western Regional Meeting, Long Beach, California, June 19-23, 2000.

COPYRIGHT 2001 Gulf Publishing Co.
COPYRIGHT 2001 Gale Group

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