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Well logging methods
Caliper
Density
Gamma ray
Mud
Resistivity
Sonic
Spontaneous potential
Logging while drilling (LWD)
Measurement while drilling (MWD)
Nuclear magnetic resonance (NMR)
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Logging while drilling (LWD) is a technique of conveying well logging tools into the well borehole downhole as part of the bottom hole assembly (BHA).
Although the terms Measurement while drilling (MWD) and LWD are related, within the context of this section, the term MWD refers to directional-drilling measurements, e.g., for decision support for the smooth operation of the drilling, while LWD refers to measurements concerning the geological formation made while drilling.[1]LWD tools work with its measurement while drilling (MWD) system to transmit partial or complete measurement results to the surface via typically a drilling mud pulser or other improved techniques, while LWD tools are still in the borehole, which is called "real-time data". Complete measurement results can be downloaded from LWD tools after they are pulled out of hole, which is called "memory data".
LWD, while sometimes risky and expensive, has the advantage of measuring properties of a formation before drilling fluids invade deeply. Further, many wellbores prove to be difficult or even impossible to measure with conventional wireline tools, especially highly deviated wells. In these situations, the LWD measurement ensures that some measurement of the subsurface is captured in the event that wireline operations are not possible. Timely LWD data can also be used to guide well placement so that the wellbore remains within the zone of interest or in the most productive portion of a reservoir, such as in highly variable shale reservoirs.[1]
LWD technology was developed originally as an enhancement to the earlier MWD technology to completely or partially replace wireline logging operation. With the improvement of the technology in the past decades, LWD is now widely used for drilling (including geosteering), and formation evaluation (especially for real time and high angle wells).[2]
^"logging while drilling - Schlumberger Oilfield Glossary". Archived from the original on 2016-01-31.
^Gravem, Trond; Hughes, Baker (November 2006). "Demonstrating Capability" (PDF). GEO ExPro. pp. 24 to 26. Archived from the original (PDF) on 2007-09-28.
and 28 Related for: Logging while drilling information
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...
surface by the circulating drilling medium (most commonly drilling mud). Mud logging is usually performed by a third-party mud logging company. This provides...
for future well operations. The terms measurement whiledrilling (MWD), and loggingwhiledrilling (LWD) are not used consistently throughout the industry...
Resistivity logging is a method of well logging that works by characterizing the rock or sediment in a borehole by measuring its electrical resistivity...
Directional drilling (or slant drilling) is the practice of drilling non-vertical bores. It can be broken down into four main groups: oilfield directional...
a wireline logging method used in mining, mineral exploration, water-well drilling, for formation evaluation in oil and gas well drilling and for other...
geotechnical engineering, drilling fluid, also known as drilling mud, is used to aid the drilling of boreholes into the earth. Used whiledrilling oil and natural...
attenuation of the drilling fluid. The decentralization arm typically present on a density logging tool may also be used to create a crude caliper log, which is...
Nuclear magnetic resonance (NMR) logging is a type of well logging that uses the NMR response of a formation to directly determine its porosity and permeability...
ionic concentrations. In the case of SP logging, the two aqueous solutions are the well bore fluid (drilling mud) and the formation water (connate water)...
motor and rotary steerable system (RSS), measurement whiledrilling (MWD), and loggingwhiledrilling (LWD) tools. The components are joined together using...
taken in the borehole, either during logging-while-drilling or in separate drill hole logging. Baryte used for drilling petroleum wells can be black, blue...
Density logging is a well logging tool that can provide a continuous record of a formation's bulk density along the length of a borehole. In geology,...
planned trajectory and to also include whatever LoggingWhileDrilling (LWD) / Measurement WhileDrilling (MWD) tools for formation evaluation. As such...
Sonic logging is a well logging tool that provides a formation’s interval transit time, designated as Δ t {\displaystyle {\Delta }t} , which is a measure...
logging (or Wellsite Geology) is a well logging process in which drilling mud and drill bit cuttings from the formation are evaluated during drilling...
While the borehole is being drilled according to the well plan, new geological information is gathered from mud logging, measurement whiledrilling (MWD)...
Measurement while drilling and Loggingwhiledrilling. Information acquired thousands of feet below ground, whiledrilling, is sent through the drilling hole to...
provide additional power to the bit while drilling. The PCPD pump uses drilling fluid (commonly referred to as drilling mud, or just mud) to create eccentric...
with gamma rays or neutron); conveyance (wireline or loggingwhiledrilling); and type of drilling mud (water-based mud or oil-based mud). Erygmascope –...
lower mud noise which assists with better measurement whiledrilling (MWD) and loggingwhiledrilling (LWD) decoding. The "normal" mud pump consists of two...
deep hole drilling which can often cause the drill to break. A special coolant is usually used to aid in this type of drilling. Gun drilling was originally...
Well drilling is the process of drilling a hole in the ground for the extraction of a natural resource such as ground water, brine, natural gas, or petroleum...
and manufacturing team introduced the Navi-Drill line of downhole drilling motors, which has led the drilling industry in performance and reliability for...
LWD may refer to: Large woody debris Loggingwhiledrilling, on oil wells Lotnicze Warsztaty Doświadczalne, a Polish aerospace manufacturer Leigh Warren...
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