Improved Resistivity Interpretation Utilizing a New Array Laterolog Tool and 
Associated Inversion Processing

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractResistivity logs, as directly used for the determination of Water Saturation profiles, have always been of focal interest for the oil industry; it's clear that the quality of these measurements, currently used in the net pay and hydrocarbonin-place determination, must be very high. As a consequence, more accurate and flexible resistivity tools have been developed in recent years. We are addressing here the family of array tools, and especially the HRLA 1 , which makes available a set of 5 galvanic resistivity measurements at different depths of investigation.Unfortunately, the most common types of environmental noise (borehole effects, shoulder bed resistivity contrasts, invasion, the presence of dips, anisotropy), still alter the measured resistivity, thus affecting the estimation of the true resistivity in hydrocarbon bearing levels.In order to remove these alterations, Schlumberger, in cooperation with ENI-AGIP, has developed a 2D resistivity modeling & inversion technique that can simultaneously correct a number of environmental effects. This paper presents the results obtained in two wells of a reservoir in the offshore Norway area where the sandstone bodies are interbedded with deltaic shales. The values of porosity and permeability are generally very high and a complete set of data (conventional & special core analysis, conventional wireline logs, microresistivity imaging logs, NMR, sedimentological analysis from core and images) is available. Mark of SchlumbergerThe 2D modeling provided a better definition of the water saturation in the thinner sandstone bodies of the sequence and in the presence of anomalous invasion profiles.When comparing the resistivity modeling results with those obtained by standard interpretation techniques, we can see the effectiveness of the developed methodologies (both hardware and software) in improving the reservoir characterization and in maximizing the return of the investments in logging and well data measurements.

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“…A description of the HALS and HRLA laterolog tools can be found in the following references [13,14].…”

Section: Operational Informationmentioning

confidence: 99%

Resistivity Modeling of Array Laterolog Tools: An Application in an Offshore Norway Clastic Reservoir

Galli¹,

Gonfalini²,

Mele³

et al. 2002

SPE Annual Technical Conference and Exhibition

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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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“…In addition, the Dual Laterolog deep measurement is subject to the Groningen effect when evaluating low-resistivity formations that are situated below thick, very resistive beds. Several high-resolution array laterologs developed during the 1990s improve the vertical, radial and azimuthal resolution of the measured formation resistivity around the borehole (Khokhar and Johnson, 1989;Vallinga et al, 1991;Davies et al, 1992;Smits et al, 1995;Smits et al, 1998;Galli et al, 2002;Hakvoort et al, 1998). All these devices provide logs with several depths of investigation in moderate formation-to-mud resistivity contrast environments.…”

Section: Introductionmentioning

confidence: 99%

Comparison of a New Multi Laterolog Tool and a Formation Resistivity Imager in the Phiops Field of Egypt

Abdel-Shafy¹,

Fattah²,

Corley

et al. 2011

All Days

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The Multi Laterolog is a newly developed array laterolog logging device based on the Dual Laterolog principle, consisting of four independent focused measurements of differing depths of investigation with high vertical resolution. A model-based adaptive borehole correction (ABC) technique corrects the Multi Laterolog measurements for borehole effect in very conductive muds and large boreholes by solving for tool position as an unknown. This approach guarantees that in non-invaded intervals, all four laterolog curves are properly "stacked", even in large washouts, while invaded intervals show a consistent resistivity profile. The correction algorithm is very fast and is applied in real time during data acquisition. It also provides an estimate of true formation resistivity (R t ) that can be significantly higher than the deepest laterolog measurement. This results in a more accurate estimation of hydrocarbon saturation. With the addition of a micro-resistivity device, it is also possible to estimate the length of mud filtrate invasion (L xo ). Advantages of the new Multi Laterolog logging tool and advanced processing principles in combination with other wireline logging tools like the Formation Resistivity Imager are illustrated by an example from the Phiops field in Egypt.

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Improved Resistivity Interpretation Utilizing a New Array Laterolog Tool and Associated Inversion Processing

Cited by 4 publications

References 0 publications

Resistivity Modeling of Array Laterolog Tools: An Application in an Offshore Norway Clastic Reservoir

Resistivity Modeling of Array Laterolog Tools: An Application in an Offshore Norway Clastic Reservoir

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

Comparison of a New Multi Laterolog Tool and a Formation Resistivity Imager in the Phiops Field of Egypt

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