Improved Production Log Interpretation in Horizontal Wells Using Pulsed Neutron Logs

Brady, Jerry L.; Kohring, James; North, Rob

doi:10.2118/36625-ms

Cited by 4 publications

(6 citation statements)

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“…The values in the track increase from right to left. The increase in the ∑pbw value (curve moving toward left) indicates areas where the borax water was placed in the formation, indicating permeable and productive zones (Brady et al 1996(Brady et al , 1998. According to Brady et al (1996) and Brady et al (1998), more permeable and productive formations have moderate to low ∑psw values (indicated by the curve moving toward the right).…”

Section: Examplementioning

confidence: 98%

“…The increase in the ∑pbw value (curve moving toward left) indicates areas where the borax water was placed in the formation, indicating permeable and productive zones (Brady et al 1996(Brady et al , 1998. According to Brady et al (1996) and Brady et al (1998), more permeable and productive formations have moderate to low ∑psw values (indicated by the curve moving toward the right). These layers marked by large separation between ∑psw and ∑pbw are shaded in black and also shown by double-sided broken green arrows.…”

Section: Examplementioning

confidence: 98%

“…Therefore, the tool response mainly depicts the lithology contrast. The authors (Brady et al 1996(Brady et al , 1998 have used the words "permeability" and "productivity" interchangeably in their papers while discussing the same diagram, which is shown in Fig. 13.…”

Section: Examplementioning

confidence: 99%

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A review of basic well log interpretation techniques in highly deviated wells

Ghosh

2022

J Petrol Explor Prod Technol

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Drilling deviated wells has become customary in recent times. This work condenses various highly deviated and horizontal well log interpretation techniques supported by field examples. Compared to that in vertical wells, log interpretation in highly deviated wells is complex because the readings are affected not only by the host bed but also the adjacent beds and additional wellbore-related issues. However, understanding the potential pitfalls and combining information from multiple logs can address some of the challenges. For example, a non-azimuthally focused gamma ray logging while drilling (LWD) tool, used in combination with azimuthally focused density and neutron porosity tools, can accurately tell if an adjacent approaching bed is overlying or underlying. Moreover, resistivity logs in horizontal wells are effective in detecting the presence of adjacent beds. Although the horns associated with resistivity measurements in highly deviated wells are unwanted, their sizes can provide important clues about the angle of the borehole with respect to the intersecting beds. Inversion of horizontal/deviated well logs can also help determine true formation resistivities. Additionally, observed disagreement between resistivity readings with nuclear magnetic resonance (NMR) T2 hydrocarbon peaks can indicate the presence or absence of hydrocarbons. Furthermore, variations in pulsed neutron capture cross sections along horizontal wells, measured while injecting various fluids, can indicate high porosity/permeability unperforated productive zones. Finally, great advances have been made in the direction of the bed geometry determination and geologic modeling using the mentioned deviated well logs. More attention is required toward quantitative log interpretation in horizontal/high angle wells for determining the amount of hydrocarbons in place.

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Section: Examplementioning

confidence: 98%

Section: Examplementioning

confidence: 98%

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A review of basic well log interpretation techniques in highly deviated wells

Ghosh

2022

J Petrol Explor Prod Technol

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“…The BHGM might be used in many applications that have been described in several studies (Rassmussen, 1973;Schultz, 1989;Ander;Herring, 1990;Brady and Wolcott, 1993;Alixant and Mann, 1995;Brady et al, 1998;Loermans and Kelder, 2006;Alshakhs et al, 2008). The BHGM might be used in many applications that have been described in several studies (Rassmussen, 1973;Schultz, 1989;Ander;Herring, 1990;Brady and Wolcott, 1993;Alixant and Mann, 1995;Brady et al, 1998;Loermans and Kelder, 2006;Alshakhs et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

Three-Dimensional Inversion of Borehole Gravity Measurements for Reservoir Fluid Monitoring

Hadj-Sassi

Donadille

2010

All Days

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TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractThe fluids in the reservoir are redistributed in response to pressure gradients caused by hydrocarbon production, which is often coupled with injection of water or gas. It is known from density logging that the density of pore fluids is an important physical property useful in inferring oil, water, or gas saturation in a rock. Thanks to the density difference of the different phases, the borehole gravity measurement is a candidate for tracking the movement of fluids hundreds of feet away from wellbores. Such data are measured in time lapse to provide the three-dimensional distribution of density changes in time through an inversion procedure.Because gravity is a potential field, the inversion of borehole gravity data is inherently non-unique. The decrease of the sensitivity to the recorded data away from the measurement location is also a challenge for the inversion problem. The approach implemented in this work uses an iterative algorithm that minimizes a global objective function. The objective function includes the data misfit functional and a three-dimensional regularization that is needed to constrain the inversion to reasonable solutions. A weighting function based on the distance between each gravity source and the recording instrument is introduced to help mitigate the geometric decay of gravity kernels with distance from the sensor. Synthetic inversions are presented that indicate borehole gravity can be instrumental in detecting and monitoring a large water front. This study also points out the optimal conditions for using borehole gravity for fluid front monitoring, in terms of number of wells, relative well positions to the target, vertical sampling, and measurement accuracy.

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“…This paper will discuss four major topics. First a brief review of the two Pulsed Neutron Capture (PNC) techniques described in previous work 1 . These technique consist of comparing PNC logs recorded while pumping seawater or crude oil into the well with logs run after injecting a saturated borax solution.…”

Section: Introductionmentioning

confidence: 99%

Improved Production Log Interpretation in Horizontal Wells Using a Combination of Pulsed Neutron Logs, Quantitative Temperature Log Analysis, Time Lapse LWD Resistivity Logs and Borehole Gravity

Brady

Watson

Warner

et al. 1998

Proceedings of SPE International Oil and Gas Conference and Exhibition in China

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TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractA novel combination of logs and their unique interpretations are used to improve the understanding of production in horizontal wells on the North Slope of Alaska. Two techniques using Pulse Neutron Capture (PNC) logs to identify and quantify liquid productive intervals were previously presented in a paper by Brady et. al 1 . These techniques are compared and combined with two additional techniques: 1) the use of time lapse LWD resistivity to determine productive intervals and liquid flow profiles while drilling, and 2) a non trial-and-error method to determine quantitative gas production using temperature logs in a twophase flow. Finally, modeling shows borehole gravity logs can be used to track the vertical movement of gas or water tens of feet above or below horizontal wells.Integrating the time lapse differences between shallow LWD resistivity logs run while drilling and logs run several hours after drilling show a strong correlation with PNC liquid flow profiles for wells producing at solution GOR. Additionally, combining a quantitative gas flow rate analysis from the temperature log with the liquid profile provides a complete analysis of the production profile for two-phase flow in horizontal wells. Finally by combining the production profile analysis from a horizontal well with the modeled timelapse borehole gravity data, a complete understanding of the fluid movements in the well borehole and up to two hundred feet into the formation can be obtained.These techniques can be applied to both horizontal and vertical wells with both slotted liner and cemented perforated completions to obtain a quantitative production profile. The LWD resistivity data, collected while drilling, provides an indication of the productive reservoir rock before the well is completed. Time lapse borehole gravity provides an understanding of the reservoir fluid movements affecting the wellbore flow profiles after the well has been put on production.

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Improved Production Log Interpretation in Horizontal Wells Using Pulsed Neutron Logs

Cited by 4 publications

References 0 publications

A review of basic well log interpretation techniques in highly deviated wells

A review of basic well log interpretation techniques in highly deviated wells

Three-Dimensional Inversion of Borehole Gravity Measurements for Reservoir Fluid Monitoring

Improved Production Log Interpretation in Horizontal Wells Using a Combination of Pulsed Neutron Logs, Quantitative Temperature Log Analysis, Time Lapse LWD Resistivity Logs and Borehole Gravity

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