What is resistivity in drilling?

1. n. [Formation Evaluation] The ability of a material to resist electrical conduction. It is the inverse of conductivity and is measured in ohm-m.

Which resistivity logging tool can identify the thin beds sharply?

Shallow resistivity tools with high vertical resolution are used for the identification of the thin beds. The vertical resolution varies from a centimetre to 1.2 inches.

Can we use resistivity log to identify the type of fluids within the formation?

Hydrocarbon Indicators One of the most useful applications of resistivity logs is identifying hydrocarbon saturation vs. water saturation in a formation. Also, by distinguishing between water and hydrocarbon saturation, resistivity logs can be used to identify oil-water contacts.

Does water increase resistivity?

Resistivity in water is the measure of the ability of water to resist an electrical current, which is directly related to the amount of dissolved salts in the water. Water with a high concentration of dissolved salts will have a low resistivity, and vice versa.

What is the resistivity of shale?

Model’s reliability has been verified using laboratory measurements covering very wide range of shale content “0–0.8”, shale resistivity “0.1– 48 ohm. m”, formation water resistivity “0.02–10 ohm.

Does oil have a higher resistivity than water?

Resistivity logs: Water is a better conductor of electricity than oil and gas. Petroleum fluids are much more resistive to electricity than formation water having measurable salinity.

What do you mean by micro resistivity devices?

Microresistivity devices measure the resistivity of the flushed zone and delineate permeable beds by detecting the presence of mudcake.

What is flushed zone in well logging?

The volume close to the borehole wall in which all of the moveable fluids have been displaced by mud filtrate. The flushed zone contains filtrate and the remaining hydrocarbons, the percentage of the former being the flushed-zone water saturation, Sxo.

What is resistivity log used for?

Resistivity logging is used in mineral exploration (for example for exploration for iron and copper ore bodies), geological exploration (deep geological disposal, geothermal wells), and water-well drilling. It is an indispensable tool for formation evaluation in oil- and gas-well drilling.

What is the resistivity of RO water?

A RO water purification system with a deionizer and/or several modules connected in series can produce water containing less than 0.1 ppm TDS (resistivity about 1 megohm-cm).

What is the resistivity of limestone?

The resistivity values of limestone and overburden of the study area in tropical region identified with value of 63-550 Ωm and 6-62 Ωm respectively.

Does shale have high resistivity?

As a result, resistivity values are not necessarily low, but there is little resistivity contrast between oil and water zones. Because of its inherent conductivity, clay, and hence shale, is the primary cause of low-resistivity pay (previous page).