Table of Contents
How is irreducible water saturation measured?
The laboratory measurements of Nuclear Magnetic Resonance (NMR) in conventional reservoirs provide accurate levels of mobile water and irreducible water saturation which is the sum of clay bound water and capillary bound water (BVW + BVI).
How do you read well log data?
Follow the Ko Ko Rules:
- Tight non-reservoir: Right-Right-Right-Right.
- Shale: Right-Right-Right-Left.
- Low porosity (tight) reservoir: Left-Right-Right-Right.
- Water bearing reservoir: Left-Left-Left-Left.
- Oil bearing reservoir: Left-Right-Left-Left.
- Gas reservoir: Left-Right-Left-Right.
How do you find the porosity of a well log?
The most common method of determining porosity is with Well Logs….
- ϕsl is the porosity from the sonic log (log measurement) , fraction.
- Δtsl is value of the acoustic transit time measured by the sonic log, μsec/ft.
- Δtma is value of the acoustic transit time of the rock matrix measured in the laboratory, μsec/ft.
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.
How do you calculate connate water saturation?
Connate water saturation is the amount of the water which adsorbs on the surface of the grains of the rock or on the walls of the porous pore channels (immobile with the traditional displacement methods) divided by the pore volume.
What is the difference between connate water and irreducible water?
The lowest water saturation, Swi, that can be achieved in a core plug by displacing the water by oil or gas. The related term connate water saturation is the lowest water saturation found in situ. …
What is well log data?
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.
How do you interpret resistivity logs?
Three depths of resistivity can be logged (shallow, medium, and deep) that record the resistivity of the formation with increasing distance away from the borehole. Resistivity logs can be interpreted to infer information about the porosity of a formation, the water saturation, and the presence of hydrocarbons.
How is oil porosity calculated?
Porosity (ɸ) = (Vp ÷ Vb) × 100
- Direct methods: measurement from core flush by fluid or air.
- Indirect methods: well logging tools (density, neutron, and sonic)
How is porosity measured?
6.1. One way is to measure the pore volume by sealing the sample in a pressure vessel, decreasing the pressure by a known amount, and measuring the increase in volume of the contained gas. Conversely, the grain volume can be measured and, if the bulk volume is known, porosity can be determined.
How are well logs measured?
Logging tools developed over the years measure the natural gamma ray, electrical, acoustic, stimulated radioactive responses, electromagnetic, nuclear magnetic resonance, pressure and other properties of the rocks and their contained fluids. Real-time data is recorded directly against measured cable depth.