What is down hole logging?

Downhole logs are used to determine the physical, chemical, and structural properties of formations penetrated by drilling and to complement discrete core measurements. Where core recovery is incomplete, logging data may serve as a proxy for lab data for sedimentological and physical properties.

What is well logging techniques?

• Well Logging is the technique of making. petrophysical measurements in the sub-surface earth formations through the drilled borehole in order to determine both the physical and chemical properties of rocks and the fluids they contain.

What is the component at the very bottom of a wireline string *?

Wireline logs The logging tool, also called a sonde, is located at the bottom of the wireline. The measurements are taken by lowering the wireline to the prescribed depth and then raising it out of the well.

Why formation evaluation is important?

In petroleum exploration and development, formation evaluation is used to determine the ability of a borehole to produce petroleum. Modern rotary drilling usually uses a heavy mud as a lubricant and as a means of producing a confining pressure against the formation face in the borehole, preventing blowouts.

What is geophysical well logging?

Geophysical well logging (borehole logging,) is a set of borehole investigation methods that are based on special logging tools. First developed in the beginning of the 20th century, well logging comprises today several tens of methods that involve measurements of natural or induced physical fields in the borehole.

What is sonde in geophysics?

1. n. [Formation Evaluation] The section of a logging tool that contains the measurement sensors, as distinct from the cartridge, which contains the electronics and power supplies.

What is wildcat drilling?

Wildcat drilling is a form of exploratory drilling in the oil & gas exploration and production process that seeks to exploit unproven or high-risk areas. A wildcat driller may alternatively seek to return to existing or older wells that are no longer profitable or useful for larger oil companies.

What is the purpose of wireline?

While a slickline is a thin cable introduced into a well to deliver and retrieve tools downhole, a wireline is an electrical cable used to lower tools into and transmit data about the conditions of the wellbore. Usually consisting of braided cables, wirelines are used to perform wireline logging, as well.

What signal is used for wireline?

To summarize, we use transmission lines for high-frequency wireline signal communication. In wireline communication, we have a direct, physical connection—a circuit—between transmitter and receiver.

What is formation in a well?

A general term for the rock around the borehole. In the context of formation evaluation, the term refers to the volume of rock seen by a measurement made in the borehole, as in a log or a well test. These measurements indicate the physical properties of this volume.

What is mud logging in oil and gas?

Mud logging is the creation of a detailed record (well log) of a borehole by examining the cuttings of rock brought to the surface by the circulating drilling medium (most commonly drilling mud). In hydrocarbon exploration, hydrocarbon surface gas detectors record the level of natural gas brought up in the mud.