A novel array laterolog method

Chen, Yong H.; Chew, Weng Cho; Zhang, G.J.

doi:10.1190/1.1885833

Cited by 3 publications

(3 citation statements)

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“…where K is the tool constant (K LLd for LLd and K LLs for LLs), V N is usually assumed to be negligible since N is often located relatively far away from A 0, and V can be considered as the average of the potentials (V avr ) measured at the four monitoring electrodes. The tool constraint K can be determined in a homogeneous medium where the measured apparent resistivity should be equal to the medium resistivity (Chen et al, 1998).…”

Section: Synthetic Focusingmentioning

confidence: 99%

“…Lovell (1993) developed a simulation method based on the frequency-dependent partial differential equations of the current potential. Chen et al (1998) applied the current potential concept to DC array-laterolog simulation. Yang et al (2007) introduced a second-order FEM to improve the accuracy of simulated 2D frequency-dependent DLL measurements.…”

Section: Introductionmentioning

confidence: 99%

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Simulation of DC dual-laterolog measurements in complex formations: A Fourier-series approach with nonorthogonal coordinates and self-adapting finite elements

2009

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Dual laterolog (DLL) makes use of a galvanic conduction principle to focus electrical currents into rock formations, thereby minimizing shoulder and borehole effects in the measurement of formation resistivity. The tool includes two separate focusing systems: deep-sensing (LLd) and shallow-sensing modes (LLs). Laterolog current-focusing systems were designed for operation primarily in vertical boreholes penetrating horizontal layers; only recently their design has been revised for operation in deviated wells in the presence of electrical anisotropy. We simulated three-dimensional (3D) DLL measurements in dipping, invaded, and electrically anisotropic formations and appraised the corresponding effects on apparent resistivity logs. Simulations were performed by combining the use of a Fourier-series expansion in a nonorthogonal system of coordinates with an existing 2D goal-oriented, higher-order, and self-adaptive finite-element method. This numerical algorithm yields accurate solutions in limited CPU time because only a few Fourier modes are needed to simulate practical applications. For the calculation of focused currents, we introduced an embedded postprocessing method that incorporates a synthetic focusing principle to compute current intensities at each iterative step of optimal mesh refinements. Our numerical method accurately simulates 3D DLL measurements in rock formations that exhibit extreme contrasts of electrical resistivity. Simulations indicate that LLs resistivity logs are more sensitive to both invaded and anisotropic layers than LLd resistivity logs. In deviated wells, shoulder-bed effects on apparent resistivity logs increase with an increase of dip angle, and are emphasized across thin conductive layers. Electrical anisotropy effects on apparent resistivity logs increase substantially with dip angle.

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Section: Synthetic Focusingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Simulation of DC dual-laterolog measurements in complex formations: A Fourier-series approach with nonorthogonal coordinates and self-adapting finite elements

2009

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“…Schlumberger developed a high-resolution array tool (HRLA) (Chen et al, 1998;Smits et al, 1998), which provides six electric log curves with different radial detection and depth of investigation to characterize the formation with higher vertical resolution and more radial coverage (Griffiths et al, 1999;Dun et al, 2010;Deng et al, 2011). In addition to the HRLA and high-definition lateral log (HDLL) developed by Western Atlas (Itskvich et al, 1998), CNPC Logging company also developed its array laterolog tool (HAL) (He et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

Study on array laterolog response simulation and mud-filtrate invasion correction

Zhao

Qin

Pan

et al. 2019

Adv. Geo-Energy Res.

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It is a complicated task to evaluate the reservoirs influenced by mud-filtrate invasion. This study presents numerical simulation results of array laterolog response and the approach for mud-filtrate invasion correction. Considering differential equations and boundary conditions of the steady current field in the rock medium, finite element method is utilized to solve the Laplace equation. Then the potential value at each node is calculated along with the apparent resistivity of six measuring modes of array laterolog. Based on the numerical results, the array laterolog response is affected by various parameters including borehole radius, mud-filtrate resistivity, mud-filtrate invasion radius and invaded zone resistivity. Correction charts for borehole and mud-filtrate invasion are developed to accurately obtain the mud-filtrate invasion depth and the true resistivity of the uninvaded formation. The correction chart has been applied to the real array laterolog data of a sandstone reservoir, which the corrected resistivity is closer to the true formation resistivity.

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Analysis and comparison of azimuthal resistivity measurement modes for laterolog tool

Gao

Rao

2019

Journal of Petroleum Science and Engineering

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A novel array laterolog method

Cited by 3 publications

References 1 publication

Simulation of DC dual-laterolog measurements in complex formations: A Fourier-series approach with nonorthogonal coordinates and self-adapting finite elements

Simulation of DC dual-laterolog measurements in complex formations: A Fourier-series approach with nonorthogonal coordinates and self-adapting finite elements

Study on array laterolog response simulation and mud-filtrate invasion correction

Analysis and comparison of azimuthal resistivity measurement modes for laterolog tool

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