ULTRA Universal Logging Tool Response Analysis

ULTRA is one of the most famous software in petrophysical analysis. It is a very powerful, useful and effective program. This program is a set of software modules, designed to process wireline logs. ULTRA program is based on an optimization approach, computing the most probable parameters from the set of logs and local knowledge of the logging environment.

This is a weighted-least-squares error minimization technique which provides the analyst extensive flexibility to choose parameters, log measurements, and interpretive models. The affects of trace minerals, such as pyrite or ankerite, can be accurately evaluated with the ULTRA program. The analyst can also incorporate core results and other petrophysical data into ULTRA analysis to enhance the interpretation.

Tool response equations are available for the following: SP, Gamma Ray, Natural Spectroscopy Gamma Ray, Bulk Density, Photoelectric, Sidewall Neutron, Sonic Log, Pulsed Neutron/TMD/Neutron Lifetime, Dielectric Constant/EPT.

The following Log Analysis Models are built in: Shaly Sand, Sand-Lime-Dolomite with up to six other minerals and clay, Sand-Lime-Dolomite with up to six other minerals and shale represented as a mixture of clay and silt, Lime-Dolomite with up to six additional minerals and clay, Igneous and metamorphic reservoir model. Core data are used quantitatively in the minimization process.

Fracture and secondary porosity may be determined in one of two possible ways:

As the difference of porosity from the sonic log and the porosity from the weighted least squares error optimization process.

From the cementation factor which can be declared to be unknown and computed at each level along with all other unknowns in the weighted least squares error minimization process.

Vietsovpetro and L&TD have selected ULTRA program because it is the best log interpretation software available

Easy to use
Flexible
Powerful
Intelligent

Adaptable – for operation on a variety of systems, including but not limited to Vax, HP, IBM and Apollo

This program has been popular in L&TD for sedimentary and basement rock evaluation.

Figures 1 & 2 show results of ULTRA processing for two sedimentary models. The Sand-Lime-Dolomite with other mineral and clay (Fig.1) and Shaly Sand with another minerals (Fig.2) had been chosen for use with porosity, clay volume, sand volume, water saturation, flushed zone saturation, hydrocarbon density, lime volume, dolomite volume and another mineral volumes as the unknowns.

Figure 3 shows a result of ULTRA processing for a basement model. The unknowns are porosity, quartz volume, kali-feldspar volume, plagioclase volume, and another mineral volume.