Geology workstation

Development Geology Reference Manual
Series	Methods in Exploration
Part	Integrated computer methods
Chapter	A development geology workstation
Author	Tom C. Anderson
Link	Web page
Store	AAPG Store

While the basic methods of development geology have changed little in recent years, the tools available to the geologist for applying those methods have evolved dramatically. This facet of our work is changing so rapidly that this part of the Manual is likely to become dated faster than any other. Nevertheless, it is worthwhile to summarize the current state of computer applications and identify the key components of a workstation.

Three main approaches have been used in providing computer tools for the geologist. The first was a centrally located mainframe attended by white-coated operators and fed by keypunched card decks, or later, remote video terminals. These have largely been superseded by one or both of the other methods, although mainframes still have their place in certain applications. The second method was fostered by the advent of mini-computers and could best be termed distributed computing, where the computing power was placed in operating regional offices. These computers were often networked together within a company to provide for data sharing and some central databases. The third approach has been the explosion in personal computers, or PCs, over the past decade. Initially only offering what could be termed business applications, there are now numerous geoscience applications available, and a useable development geology workstation can be built solely around a PC.

Today, the geologist is likely to have a hybrid of any or all of the above, often with everything from PC to mainframe networked together, and each computer platform filling its appropriate role in the total system. The mainframe is best at managing large databases and providing certain computer-intensive applications such as reservoir simulation. Minicomputers offer local peripheral sharing of plotters and digitizers, file serving to local area networks, and scientific applications such as map gridding and contouring. The PC may overlap significantly with the mini-computer in providing geoscience applications, but it is still the work horse in general purpose applications such as word processing and spreadsheet calculations. In addition, it has become the best platform for graphics-oriented programs.

All of these elements are illustrated in Figure 1, except for the remote mainframe, which may not be present at all. Great variability is seen among various installations; for example, laser printers can be connected to a dedicated print server on the network rather than directly to the PC, and digitizing can be done directly into the PC. In some cases, color graphics terminals directly connected to the minicomputer are still in vogue, but these are largely being supplanted by PCs running terminal emulation programs instead.

Integration

Figure 1 Principal components of a development geology workstation.

The time-honored sequence for computing is

${\mbox{Data input}}\rightarrow {\mbox{processing}}\rightarrow {\mbox{Output}}$

Unfortunately, development of specific programs, whether by commercial software vendors or “in-house,” has followed this model independently for each major task and ignored the potential for data sharing or interfacing with other programs. As a result, we have programs that cannot talk to one another, or if they can talk, one program will say “I'll talk to you as long as you speak my language, not yours.” Thus, much time is spent transferring and/or reformatting data among applications. Rather than having to be concerned with these roadblocks, a more desirable situation would be to have all the data a user wants directly available and usable by any application desired. A requirement of this ideal is universally accepted standards, which is discussed later.

The database

Data to the development geologist means many things. First, it means well data, including, but not limited to, well locations, header information (such as operator, year, total depth, status, elevation, and API gravity), deviation surveys, formation tops, fault cuts, results of drill stem tests and production tests, core data, and a host of calculated values such as isochore, true vertical depth, true stratigraphic thickness, and so on. Equal in importance is log information, including curves or traces, logging parameters such as mud type and resistivity, and analysis parameters such as formation water resistivity or cementation and saturation exponents. In some projects, surface geology is of great importance, consisting of bed attitudes and surface expression of contacts and faults. Seismic data can be critical, including time cross sections with interpreted horizons that need to be tied to the well control using an accurate interval velocity model. The geologist may also deal with periodic or cumulative production data by well, lease, or field. Also, the interpretation process generates new data elements, including zone average porosity, net pay, and hydrocarbon pore feet.

These data types are stored in some form of a database, which can range from a simple spreadsheet or application-specific custom files to powerful relational database management systems. The data are entered into the database by one of four methods: (1) direct keyboard entry of text or numerical values; (2) digitizing from a map, seismic section, or log print; (3) extracting or downloading from another computer system followed by reformatting (if necessary) and direct entry as digital data; or (4) as derived or computed data stored back into the database by an application program. The more powerful databases provide utilities for search and retrieval, sorting, reporting and statistical analysis, and interfaces into applications.

User interface

The geologist interacts with the computer and its programs through the user interface. This is the appearance or “look and feel” of the system to the user. Well-designed user interfaces are called user friendly and are successful in guiding the novice through a maze of choices to reach the final results. There are generally two classes of user interfaces: command driven and menu driven. A command-driven system presents an often cryptic prompt to the user and expects him or her to learn a set of commands to tell the computer program what to do next. These are very flexible but more difficult for the beginner to learn, and they are largely being replaced by the second method.

A menu-driven system presents the user with a series of menus containing choices that can be made at that step and often have “context-sensitive” help available to further define each choice if needed. Menu systems are much easier to learn, but they can become cumbersome as the user becomes more proficient. Sometimes the best of both systems is available by the provision for native commands that can bypass wordy menus and add flexibility for the experienced user.

An enhancement to the menu approach is the graphical user interface, which combines text menus with graphical objects or icons to represent choices. Inherent with this method is consistency of design, so that the same type of function, such as editing, is always presented in the same place and the same way in all applications using the interface. These applications are also designed to share data, both text and graphics, among themselves. Also featured are standard methods for moving about within the data using scroll bars and consistent keyboard commands. Because of the graphical approach, even text-oriented applications such word processing present a what-you-see-is-what-you-get (WYSIWYG) display, incorporating font selections, character sizes, and even integrated graphics such as symbols and pictures.

The previous discussion has essentially described the evolution of user interfaces from primitive to modern, and it appears that all applications are moving toward incorporation of a standard graphical user interface in the future. Another desirable feature usually provided by these systems is multitasking, which is the ability to do more than one thing at one time, with each process resident in its own window that can be arranged on the screen like papers on a desktop. Coupled with standardized data sharing, these systems go a long way toward achieving the integration goals described previously.

Applications

What does the development geologist want to do with the computer? Certainly he or she has the same needs as any other worker for general purpose business applications (word processing, spreadsheets, and so on), and these are not discussed here. In addition to these, numerous geoscience applications have been developed to make the geologist's job easier, and these are summarized in the following list:

Selected geoscience computer applications

• Mapping
  • Base maps
  • Contours
  • Geological
  • Topographic
• Log analysis
• Basin and maturation modeling
• Digitizing (logs, seismic, maps)
• Potential methods modeling
• Decline curve analysis
• Plate reconstruction
• Log plotting
• Cross section plotting
• Three-dimensional modeling
• Statistics plotting
• Synthetic seismograms
• Seismic two-dimensional modeling (stratigraphy)
• Geostatistics and fractals
• Utilities
  •  Apparent dip to true dip
  •  Three-point problems
  •  TVD, TVT, and TST
  •  Coordinate conversions
  •  Map projections
  •  Well deviation plotting
• Stereonet plotting
• Ternary diagrams
• Rose diagrams
• Geochemical analysis and plotting
• Hydrology
• Stratigraphic column plotting
• Core description
• Strip logs
• Section balancing
• Expert systems
• Economic analysis

The major task of the geologist has always been to make maps, and this is where the first computer applications were developed and where the greatest progress has been made in refining techniques (see Contouring geological data with a computer). Computer-assisted map making can be merely posting values from the database on a basemap for hand contouring, or it can make use of one of the many specialized algorithms to compute a grid and contour that grid automatically. An intermediate approach is to digitize hand-drawn contours and compute a grid that exactly models the geologist's interpretation. The gridding step is desirable because it allows mathematical operations between surfaces (such as computing an isopach from two structure grids), volumetric reserve calculations, and three-dimensional perspective views of the surfaces, which are practically impossible to do by hand.

Second to mapping, but closely tied to it, is log analysis (see Log analysis applications). The computer can help by plotting multiple runs, curve types, and text information onto a composite log, or it can compute water saturation curves from input curves using the Archie equation or more complex variants of it. Crossplots of any curve against any other curve (such as a Pickett plot) can be generated. These types of analyses are not restricted to a single well. With the proper application program, an entire field study can be processed, complete with field-wide crossplots by zone. Often the output data from the log analysis process is imported into the mapping package to be contoured.

Geophysical applications round out the big three (see Introduction to geophysical methods). A basic tool in the kit is generation of synthetic seismograms from input sonic and density log data (which should be integrated with the log analysis database). Interpretation workstations for two-dimensional and three-dimensional seismic data make the geoscientist's job easier by displaying the raw data in flexible views, assisting the picking of horizons and storing the interpretations in a common database for mapping. Seismic modeling in one, two, or three dimensions can help test hypotheses of structural or stratigraphic interpretations. There are also applications for potential fields modeling, including gravity, magnetics, and electrical methods.

Many of the remaining items listed in Table 1 are simply programs to display specific geological data types in traditional forms expected by the geologist. A rapidly growing area is geological modeling, which includes basin and maturation modeling, plate tectonic reconstruction, and cross section reconstruction and balancing. Certainly the list will grow as new ways are found for the computer to assist the geologist.

Direction and standards

In the future, we should expect the geologist's workstation to evolve toward greater integration of databases and applications and toward greater ease of use through incorporation of a graphical user interface. Adoption of standards by industry and software vendors will become essential. Table 1 lists a number of possible standards in use at this time. Several of these are de facto standards that have gained acceptance from widespread use or the lack of an alternative. Others have been proposed as official standards by various organizations but may have not yet received acceptance. A recent development is the formation of the Petrotechnical Open Software Corporation (POSC), which has the goal of establishing and promoting petroleum industry standards for software. The ideal standard should be nonproprietary, free to all users, widely accepted, and policed by some professional organization. It is beyond the scope of this overview to discuss these standards in detail, but some definition of terms is desirable.

Table 1 Standards in computer industry

Application	Standard
File formats
Well data	AAPG-B
Log curves	LAS or LIS-II
Seismic traces	SEGY
Shotpoint locations	SEGP1 or UKOOA
Wellsite	WITS
Databases
Model	Relational (RDBMS)
Query language	SQL
User interface	X-Windows & MOTIF
Workstation
Operation system	UNIX
Central processing unit	RISC
Network	OSI/FDDI

The AAPG Computer Applications Committee has proposed the AAPG-B data exchange format for general purpose data transfers among computer systems, applications software, and companies. For log curves, the Schlumberger LIS (log information standard) has become a de facto standard, and extensions to it have been proposed. Another log data format called LAS, for log ASCII standard, has been proposed by the Canadian Well Logging Society, which may supplant LIS. The Society of Exploration Geophysicists oversees several standards for seismic data formats, the most common being SEGY for seismic trace data and SEGP1 for location data. A de facto standard for offshore shotpoint location (also called navigation) data is the UKOOA format, from the United Kingdom Offshore Operators Association. A format for transferring wellsite data called WITS, for wellsite information transfer standard, has been proposed by the International Association of Drilling Contractors (IADC).

While database standards are still evolving, most users prefer a full function relational database management system (RDBMS). A standard query language, called SQL for Structured Query Language, is receiving acceptance from all quarters. Several commercial database products are available that support SQL. It thus becomes unimportant which product is used since applications can interact with the database via this standard interface. Direct retrievals from the database are available to users who learn SQL, but because many users do not wish to learn a command language, other products are available that build SQL statements from “fill-in-the-blanks” forms or example prompts. Some of these operate within a graphical user interface, letting users point and click their selections with a mouse. Most of the commercial databases offer or plan to offer a distributed database method, in which the actual database spans numerous computers in a network. The user will be able to store and access local data locally, yet still access other needed data from halfway around the world and not be concerned with the difference.

The graphical user interface standard being adopted by most players is X-Windows, from MIT, with an associated window manager called MOTIF, proposed by the Open Software Foundation (OSF). PC users will recognize the strong resemblance it bears to the Macintosh user interface and Windows on IBM-compatible computers.

The trends in hardware platforms, operating systems, and network connections are toward standards as well. The UNIX operating system presents advantages in running on computers from many vendors, thus making software portable across platforms. The newer, high performance workstations use a central processing unit (CPU) that employs RISC, which stands for reduced instruction set computing. This makes the processor operate at much faster effective speeds. Finally, network connections will likely move away from the de facto Ethernet standard of today toward FDDI, for fiber optic distributed data interchange, using OSI (Open Systems Interconnect) protocols. The benefits will be a ten-fold improvement in network transport speed.

What this alphabet soup of buzz words means for the development geology workstation is that in the future, applications software will have the same “look and feel,” will run on computers from many hardware vendors, will share data among themselves, and will be able to access a common database. The end users will not need to be concerned with data transfers and reformatting, the computer itself or its operating system, or where the data are located.

See also

• Introduction to integrated computer methods
• Using and improving surface models built by computer
• Log analysis applications
• Introduction to contouring geological data with a computer
• Two-dimensional geophysical workstation interpretation: Generic problems and solutions

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