What is well logging interpretation?
Well logs present a concise, detailed plot of formation parameters versus depth. From these plots, interpreters can identify lithologies, differentiate between porous and nonporous rock and quickly recognize pay zones in subsurface formations.
What is the importance of well logging?
Well logs are important to the petroleum industry because they provide numerous rock property measurements, like the reservoir conditions of pressure, temperature, and fluid content. The quality of well logs can vary significantly from one well to the other.
What is DT in well log?
DT sonic log microseconds per foot travel time of sound waves. (delta time) (US/F or S/FT) __________________________________ DTL sonic log – deep microseconds per foot travel time of sound waves.
What is porosity in well logging?
The porosity or percentage pore volume of reservoir rocks can be measured from well cuttings, core samples from drilling or wireline well logs. Typical generally admissible porosity values for an oil reservoir range from between 10% and 25%, with porosity values of above 25% desirable [1].
How do I read a gr log?
Well Logging : Gamma Ray Log – YouTube
What is SW in geology?
Porosity and water saturation (Sw) relationships from core data of three wells.
What are the 4 parameters that are evaluated in well logging?
The following Petrophysical parameters: porosity, water saturation, reservoir thickness and volume of shale were estimated for each hydrocarbon-bearing zone delineated for each well.
How many types of well logging are there?
Three type of logs: Gamma Ray Log, Neutron Ray Log and Density Log. A- GAMMA RAY LOG: -All substances are assemblages of atoms.
How do you read a well log?
Well Log Interpretation Review Ab – YouTube
What is PEF log?
1. n. [Formation Evaluation] A log of photoelectric absorption properties. The log measures the photoelectric absorption factor, Pe, which is defined as (Z/10) 3.6 where Z is the average atomic number of the formation.
How many types of porosity are there?
Seven porosity types (interparticle, intraparticle, intercrystal, moldic, fenestral, fracture, and vugs) are common and volumetrically important.
What does GR log measure?
Gamma ray (GR) logs measure the natural radioactivity in formations and can be used for identifying lithologies and for correlating zones. Shale-free sandstones and carbonates have low concentrations of radioactive material and give low gamma ray readings.
What is gamma ray in well logging?
Gamma ray logging is a method of measuring naturally occurring gamma radiation to characterize the rock or sediment in a borehole or drill hole. It is a wireline logging method used in mining, mineral exploration, water-well drilling, for formation evaluation in oil and gas well drilling and for other related purposes.
What is a well log data?
Well logs are records of petro-physical data acquired along a borehole, providing direct information about what is in the subsurface. The data collected by logging wells can have significant economic consequences, due to the costs inherent to drilling wells, and the potential return of oil deposits.
What is Nphi in well logging?
Neutron Porosity (NPHI) Finding hydrocarbon bearing zone, porosity calculation, etc. Sonic (DT) Porosity calculation, wave velocity calculation, rock physics properties (AI, SI, σ, etc.)
What is well evaluation?
Rock and fluid properties will determine how much oil and natural gas can be recovered from a reservoir. After an exploratory well has been drilled, it is evaluated to determine if there is enough oil and natural gas in the reservoir to make it economically feasible to initiate recovery operations.
What are 4 types of logging?
Types of logs
- Electrode resistivity devices.
- Induction logging.
- Microresistivity logs.
- Spontaneous (SP) log.
What are the types of well logs?
Wireline logs can be divided into broad categories based on the physical properties measured.
- History.
- Electrical logs.
- Porosity logs.
- Lithology logs.
- Miscellaneous.
- Logging while drilling.
- Corrosion well logging.
- Memory log.
What is PE log?
The photoelectric index (Pe) is a supplementary measurement by the latest generation of density logging tools, and records the absorption of low-energy gamma rays by the formation in units of barns per electron.
What are 3 main causes of porosity?
Cause. Porosity is caused by the absorption of nitrogen, oxygen and hydrogen in the molten weld pool which is then released on solidification to become trapped in the weld metal.
What is a good porosity percentage?
Most textbooks talk about an ideal soil having 50% solids and 50% pore space. Pore space is that portion of the soil not occupied by solid material–the spaces between the particles. These pores may contain air or water.
What is GR in oil and gas?
What does high gamma ray mean?
Gamma Ray Logs
Consequently, the production of gamma rays by radioactive decay is greater in the presence of shale. A high gamma ray response implies the presence of shales, while a low gamma ray response implies the presence of clean sands or carbonates.
How do you read gamma ray well logs?
What is the value of gamma ray?
Gamma-ray photons have the highest energy in the EMR spectrum and their waves have the shortest wavelength. Scientists measure the energy of photons in electron volts (eV). X-ray photons have energies in the range 100 eV to 100,000 eV (or 100 keV). Gamma-ray photons generally have energies greater than 100 keV.