What is lithological log?

What is lithological log?

1. An example lithologic log is included in Attachment A. Name of Sediment or Rock – In naming unconsolidated sediments, the logger shall describe the grain size, distribution, color, and moisture content, and determine the presence of fill materials.

What is lithological unit?

Lithostratigraphic units are bodies of rocks, bedded or unbedded, that are defined and characterized on the basis of their lithologic properties and their stratigraphic relations.

What does density log measure?

The density log measures electron density by detecting gamma rays that undergo Compton scattering. The intensity of scattered gamma rays is proportional to electron density. Electron density is the number of electrons in a volume of the formation.

What is lithological study?

Definition of lithology 1 : the study of rocks. 2 : the character of a rock formation also : a rock formation having a particular set of characteristics.

How does gamma ray tool work?

When a gamma ray strikes such a crystal, it may be absorbed. If it is, the crystal produces a flash of light. This light is “seen” by a photomultiplier staring into the end of the crystal. The photomultiplier shapes the light into an electrical pulse that is counted by the tool.

What does sonic log measure?

The sonic or acoustic log measures the travel time of an elastic wave through the formation. This information can also be used to derive the velocity of elastic waves through the formation. Its main use is to provide information to support and calibrate seismic data and to derive the porosity of a formation. velocity).

What is neutron logging?

The neutron log is sensitive mainly to the amount of hydrogen atoms in a formation. Its main use is in the determination of the porosity of a formation. The tool operates by bombarding the formation with high energy neutrons. The count rate of slow neutrons or capture gamma rays in the tool is therefore higher.

What is lithological mapping?

Abstract: Lithological mapping is important parameters for interpretation, identification and mapping of minerals. Lithological mapping in the study area defines the characteristics of nature of rock types and their association and formation.

What is cased hole logging?

Cased-hole logging is used to help operators obtain additional information from a well or reservoir that has already been completed. Cased-hole logging can be used to evaluate the formation and completion of the well, as well as determine the state of the cement, corrosion and perforation.

Why double detector is used in density log?

To overcome the problems of mudcake and hole irregularities, the new compensated formation density logging device employs two detectors spaced at different intervals from the source. The detector at the shorter spacing is particularly sensitive to the density of material immediately adjacent to the face of the pad.

How do you identify lithology?

Lithology is also determined from the logs, because each main reservoir lithology has characteristic responses. Frequently, lithologies are derived by pattern recognition of the GR-, density-, and neutron-log responses. Some subsequent delineation wells are likely to be cored over the entire of the reservoir interval.

What are the best logs for lithological purposes?

The best logs for lithological purposes are those that are (1) most influenced by rock properties and (2) least influenced by fluid properties. The most useful of the commonly available logs are (For more details on these logs, see Basic open hole tools. Also, Difficult lithologies covers logging tool response in sedimentary minerals.)

How do you interpret wireline logs for lithological purposes?

Lithological determination from wireline logs is often done by sophisticated computer programs, but basic quick-look interpretation can be made by visual inspection of appropriate logs. The best logs for lithological purposes are those that are (1) most influenced by rock properties and (2) least influenced by fluid properties.

What is the purpose of using lithology?

Lithology is the basis of subdividing rock sequences into individual lithostratigraphic units for the purposes of mapping and correlation between areas. In certain applications, such as site investigations, lithology is described using a standard terminology such as in the European geotechnical standard Eurocode 7 .

What are the lithological codes used for?

Lithological code identifying the dominant lithology in the logging interval. See the Lithological Codes on the Code Definitions page. Lithological code identifying the lithology of second abundance in the logging interval.