Real-Time Formation Dip From a Logging-While-Drilling Tool

Logging while drilling (LWD) plays a crucial role in geo-steering, which can determine the formation boundary and resistivity in real time. In this study, an efficient inversion, which can accurately invert formation information in real time on the basis of fast-forward modeling, is presented. In forward modeling, the Gauss–Legendre quadrature combined with the continued fraction method is used to calculate the response of the LWD instrument in a layered formation. In inversion modeling, the Levenberg–Marquardt (LM) algorithm, combined with the line search method of the Armijo criterion, are used to minimize the cost function, and a constraint algorithm is added to ensure the stability of the inversion. A positive and negative sign is added to the distance parameter to determine whether the LWD instrument is located above or below the formation boundary. We have carried out a series of experiments to verify the accuracy of the inversion. The experimental results suggest that the forward algorithm can make the infinite integral of the Bessel function rapidly converge, and accurately obtain the response of the LWD instrument in a layered formation. The inversion can accurately determine the formation resistivity and boundary in real time. This is significant for geological exploration.

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Design of a New Acoustic Logging While Drilling Tool

Sensors ◽

10.3390/s21134385 ◽

2021 ◽

Vol 21 (13) ◽

pp. 4385

Author(s):

Kai Zhang ◽

Baohai Tan ◽

Wenxiu Zhang ◽

Yuntao Sun ◽

Jian Zheng ◽

...

Keyword(s):

Impedance Matching ◽

Sine Wave ◽

Azimuthal Anisotropy ◽

Dipole Source ◽

Pulse Excitation ◽

Drilling Tool ◽

Overall Design ◽

Logging While Drilling ◽

Physical Construction ◽

Exciting Wave

To obtain qualified logging while drilling (LWD) data, a new acoustic LWD tool was designed. Its overall design is introduced here, including the physical construction, electronic structure, and operation flowchart. Thereafter, core technologies adopted in this tool are presented, such as dominant exciting wave bands of dipole source, a sine wave pulse excitation circuit, broadband impedance matching, and an intellectualized active reception transducer. Lastly, we tested this tool in the azimuthal anisotropy module well, calibration well, and normal well, working in the model of the cable, sliding eye, and logging while drilling. Experiments showed that the core technologies achieved ideal results and that the LWD tool obtained qualified data.

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The Use of Real-Time and Time-Lapse Logging-While-Drilling Images for Geosteering and Formation Evaluation in the Breitbrunn Field, Bavaria, Germany

SPE Drilling & Completion ◽

10.2118/89016-pa ◽

2004 ◽

Vol 19 (03) ◽

pp. 133-138 ◽

Cited By ~ 3

Author(s):

Hendrik Rohler ◽

Ted Bornemann ◽

Alexis Darquin ◽

John Rasmus

Keyword(s):

Real Time ◽

Time Lapse ◽

Formation Evaluation ◽

Logging While Drilling

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New LWD Image Improvement Method to Mitigate Interpretation Risks

10.2118/205222-ms ◽

2021 ◽

Author(s):

Tianhua Zhang ◽

Shiduo Yang ◽

Chandramani Shrivastava ◽

Adrian A ◽

Nadege Bize-Forest

Keyword(s):

High Resolution ◽

Real Time ◽

Best Practice ◽

Synthetic Data ◽

Image Resolution ◽

Drilling Process ◽

Drilling Tool ◽

Stick Slip ◽

Geological Interpretation ◽

Wellbore Temperature

Abstract With the advancement of LWD (Logging While Drilling) hardware and acquisition, the imaging technology becomes not only an indispensable part of the drilling tool string, but also the image resolution increases to map layers and heterogeneity features down to less than 5mm scale. This shortens the geological interpretation turn-around time from wireline logging time (hours to days after drilling) to semi-real time (drilling time or hours after drilling). At the same time, drilling motion is complex. The depth tracking is on the surface referenced to the surface block movement. The imaging sensor located downhole can be thousands of feet away from the surface. Mechanical torque and drag, wellbore friction, wellbore temperature and weight on bit can make the downhole sensor movement motion not synchronized with surface pipe depth. This will cause time- depth conversion step generate image artifacts that either stop real-time interpretation of geological features or mis-interpret features on high resolution images. In this paper, we present several LWD images featuring distortion mechanism during the drilling process using synthetic data. We investigated how heave, depth reset and downhole sensor stick/slip caused image distortions. We provide solutions based on downhole sensor pseudo velocity computation to minimize the image distortion. The best practice in using Savitsky-Golay filter are presented in the discussion sections. Finally, some high-resolution LWD images distorted with drilling-related artifacts and processed ones are shown to demonstrate the importance of image post-processing. With the proper processed images, we can minimize interpretation risks and make drilling decisions with more confidence.

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Development of a directional resistivity logging-while-drilling tool using a joint-coil antenna and its geosteering applications

Geophysics ◽

10.1190/geo2017-0780.1 ◽

2018 ◽

Vol 83 (5) ◽

pp. D165-D171

Author(s):

Zhong Wang ◽

Huaping Wang ◽

Treston Davis ◽

Jing Li ◽

Suming Wu ◽

...

Keyword(s):

Oil And Gas ◽

Gas Production ◽

Voltage Response ◽

Drilling Tool ◽

Detection Depth ◽

Logging While Drilling ◽

Resistivity Logging ◽

Coil Antenna ◽

Production Zone ◽

Distance To The Boundary

Geosteering is a key technique to increase oil- and gas-production rates, especially within a thin reservoir layer. The purpose of geosteering in the production zone is to keep the drilling path in oil- and gas-bearing reservoirs. To keep the drilling system inside the production zone, downhole sensors must be able to detect bed boundaries, which include identifying the boundary location with respect to the sensor and the boundary distance from the sensor. We have developed a directional resistivity logging-while-drilling (LWD) tool for geosteering applications. The directional LWD tool is equipped with a joint-coil antenna composed of an axially polarized coil Rz connected in series with two transversely polarized coils Rx. During a revolution around the axis of the tool, the voltage of the axial coil VRz, voltage of the transverse coils VRx, and tool face angle [Formula: see text], which indicates the boundary direction, can be extracted through curve fitting the total voltage response of the joint-coil antenna. The distance to the boundary can be derived from a 1D inversion. The LWD tool has been tested in several reservoirs in China, and it has a demonstrated capability to provide reliable and accurate estimations of the boundary direction and distance. Field data indicate that the boundary detection depth can reach 2.1 and 1.7 m when the tool is in a sand and shale formation. Using wireline-logging data from surrounding wells as reference, deviations between the reference and the measured distance to the boundary are within 0.2 m.

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Dynamic Formation Evaluation to Reduce Uncertainty and Confirm Completed Intervals in Brown Fields

10.2118/204758-ms ◽

2021 ◽

Author(s):

Muhamad Aizat Kamaruddin ◽

Ayham Ashqar ◽

Muhammad Haniff Suhaimi ◽

Fairus Azwardy Salleh

Keyword(s):

Real Time ◽

Optical Sensors ◽

Sensor Technology ◽

Innovative Technology ◽

Fluid Type ◽

Formation Evaluation ◽

Reservoir Fluid ◽

Logging While Drilling ◽

Dynamic Formation

Abstract Uncertainties in fluid typing and contacts within Sarawak Offshore brown field required a real time decision. To enhance reservoir fluid characterisation and confirm reservoir connectivity prior to well final total depth (TD). Fluid typing while drilling was selected to assure the completion strategy and ascertain the fluvial reservoir petrophysical interpretation. Benefiting from low invasion, Logging While Drilling (LWD) sampling fitted with state of ART advanced spectroscopy sensors were deployed. Pressures and samples were collected. The well was drilled using synthetic base mud. Conventional logging while drilling tool string in addition to sampling tool that is equipped with advanced sensor technology were deployed. While drilling real time formation evaluation allowed selecting the zones of interest, while fluid typing was confirmed using continually monitored fluids pump out via multiple advanced sensors, contamination, and reservoir fluid properties were assessed while pumping. Pressure and sampling were performed in drilling mode to minimise reservoir damage, and optimise rig time, additionally sampling while drilling was performed under circulation conditions. Pressures were collected first followed by sampling. High success in collecting pressure points with a reliable fluid gradient that indicated a virgin reservoir allowed the selection of best completion strategy without jeopardising reserves, and reduced rig time. Total of seven samples from 3 different reservoirs, four oil, and three formation water. High quality samples were collected. The dynamic formation evaluation supported by while drilling sampling confirmed the reservoir fluid type and successfully discovered 39ft of oil net pay. Reservoir was completed as an oil producer. The Optical spectroscopy measurements allowed in situ fluid typing for the quick decision making. The use of advanced optical sensors allowed the sample collection and gave initial assessment on reservoir fluids properties, as a result cost saving due to eliminating the need for additional Drill Stem Test (DST) run to confirm the fluid type. Sample and formation pressures has confirmed reservoir lateral continuity in the vicinity of the field. The reservoir developed as thick and blocky sandstone. Collected sample confirmed the low contamination levels. Continuous circulation mitigated sticking and potential well-control risks. This is the first time in surrounding area, advanced optical sensors are used to aid LWD sampling and to finalize the fluid identification. The innovative technology allowed the collection of low contamination. The real-time in-situ fluid analysis measurement allowed critical decisions to be made real time, consequently reducing rig downtime. Reliable analysis of fluid type identification removed the need for additional run/service like DST etc.

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Geosteering in a Complex Lithology Environment of Wara Sand Using the Multi-Function Logging While Drilling Tool in the Minagish Field of Kuwait

10.3997/2214-4609-pdb.151.iptc13665 ◽

2009 ◽

Author(s):

T. El-Gezeery ◽

F. Al-Saqran ◽

E. Archibong ◽

O. Oyeyemi ◽

V. Chimirala

Keyword(s):

Drilling Tool ◽

Logging While Drilling

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Application Status of the Technology of Logging While Drilling

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1010-1012.1650 ◽

2014 ◽

Vol 1010-1012 ◽

pp. 1650-1653

Author(s):

Qun Peng ◽

Quan Hou Li ◽

Qi Zhang

Keyword(s):

Shock Wave ◽

Real Time ◽

Rapid Development ◽

The Future ◽

Logging While Drilling ◽

Logging Tool ◽

Large Improvement ◽

Numerous Work ◽

Original Information

The data of Logging While Drilling is used for Geosteering and evaluation of layers. Compared with traditional logging, LWD has its own advantages, real-time, security, and it could obtain original information of the destination formation.With the rapid development of logging tools design, LWD tools have a large improvement, and various tools used for measuring the parameters of layers have been designed and applied , resistivity imaginary logging tool, MPR, InSite ADR, Shock Wave have been invited and innovated. However, there are still a lot of unsolved problems existing, such as interpretation of logging, the accuracy of the evaluation on layers and so on. Therefore, numerous work need to be done in the future.

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