What is in a well log?

Well logs are acknowledged as legal documents which record the history of a well through the drilling stages and up to its completion. The well logs record physical properties of the borehole which must then be petrophysically interpreted to obtain the associated rock and fluid properties of the well.

What is the main purpose of well logging?

A well log is a record of the formations and any events that are encountered in the well drilling process. It is also referred to as borehole logging. The main purpose of keeping a well log is to determine the suitability of the well for its intended use.

Which is the geophysical logging technique?

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 well log analysis?

Well log analysis provides the information on petrophysical properties of reservoir rock and its fluid content. Crossplotting techniques are adopted for identification of lithology and fluid type using log responses.

What is meant by well logging?

Well logging, also known as borehole logging is the practice of making a detailed record (a well log) of the geologic formations penetrated by a borehole. Some types of geophysical well logs can be done during any phase of a well’s history: drilling, completing, producing, or abandoning.

What are the well logging tools?

Presents the commonly used logging tools–SP, gamma ray, resistivity and porosity–and their characteristics and functions including coverage of Magnetic Resonance Logging….Content:

• Magnetic Resonance Logs.
• Spontaneous Potential Log.
• Gamma Ray Log.
• Resistivity Logs.
• Dielectric Logs.
• Density Logs.
• Neutron Logs.
• Acoustic Logs.

Who uses well logging?

Engineers and drillers use well logs to measure depths of formation tops, thickness of formations, porosity, water saturation, temperature, types of formations encountered, presence of oil and/or gas, estimated permeability, reservoir pressures and formation dip — ultimately determining whether a well is commercially …

What are the different types of well logging?

Types of Well Logging

• Acoustic logging. Acoustic logging includes those techniques that use a transducer to transmit an acoustic wave through the fluid in the well and surrounding elastic materials.
• Electrical Methods. Spontaneous Potential Log.
• Flow Logging.
• Hole-to-Hole Logging.
• Hydrophysical Logging.
• Nuclear Logging.

What is oil well logging?

Oil well logging, also known as borehole logging, is a process where specialized instrumentation is inserted into a borehole to determine the properties of the geological formations surrounding the bore.

What is RT in well logging?

Rxo= Resistivity of flushed zone. Rw= Resistivity of formation water. Rmf= Resistivity of mud filtrate. Rt= Resistivity of uninvaded zone.

What are the types of well logging?

How many types of well logging are there?

All these logs require fluid in the well to couple the signal to the surrounding rocks. Four types will be described here: acoustic velocity, acoustic waveform, cement bond, and acoustic televiewer. Spontaneous potential (SP) is one of the oldest logging techniques.

What is a well log?

A well log is a record of the formations and any events that are encountered in the well drilling process. It is also referred to as borehole logging. The main purpose of keeping a well log is to determine the suitability of the well for its intended use. Well logs are also used by researchers to explore the underground.

What does the vertical axis of a well log tell you?

When you are looking at a well log, one axis tells you how deep you are. The other axis tells you your results for your various tests. In this well log example, the vertical axis shows you your depth, and the horizontal axis gives you your test results, with each test having its own column.

What is an electrical resistivity well log?

Electrical resistivity well logs tell you how hard it is for an electric current to pass through a formation. This is also an indication of whether the water in the potential well is fresh or salty. (Salt water conducts more electricity making it easier for the electric current to pass through.)

What are induction and spontaneous potential well logs?

Induction well logs are used in place of electrical resistivity logs when working with wells containing air or oil. Spontaneous potential (SP) well logs indicate the porosity or permeability of a formation. To unlock this lesson you must be a Study.com Member.