Weatherford Technology Holdings, LLC

Gregory J Schmid

Richard R Pemper

Natasa Mekic

Darrell Dolliver

Paul Pavlakos

John Willick

Methods and systems for determining formation salinity using pulsed neutron (PN) tools are described. Embodiments of the described methods involve binning chlorine yields or chlorine count rates arising from capture events into early and late capture regimes, which may be used to attribute the events to either the borehole or the formation.

Determination of formation water salinity using time resolved chlorine capture gamma spectroscopy

Methods, tools, and systems for determining COsaturation in a porous formation using pulsed neutron logging are described. Embodiments of a pulsed neutron logging tool feature a pulsed neutron generator configured to emit pulsed neutrons into the formation and at least two detectors configured to receive emitted photons. The first detector is located closer to the neutron generator than the second detector. Embodiments of the method involve determining first detector formation capture counts indicative of neutron capture photons originating from the formation and detected at the first detector, determining second detector borehole capture counts indicative of neutron capture photons originating from the borehole and detected at the second detector, using the first detector formation capture counts and the second detector borehole capture counts to estimate the saturation of COin the formation.

Pulsed neutron monitoring of carbon dioxide in reservoirs

Methods, tools, and systems for determining porosity in an earth formation are disclosed. Neutrons are emitted into the formation to induce inelastic scattering gamma rays and thermal capture gamma rays in the formation. The induced gamma rays are detected at a proximal gamma detector and a far gamma detector, which are spaced at different axial distances from the neutron source. A measured proximal-to-far inelastic ratio (a ratio of inelastic scattering gammas detected at the proximal and far detector) and a proximal-to-far thermal capture ratio (a ratio of thermal capture gammas detected at the proximal and far detector) are determined and used to calculate the formation porosity. Techniques are disclosed for removing borehole and casing configuration effects from the measured proximal-to-far thermal capture ratio, leaving only porosity dependence.

Borehole compensation during pulsed-neutron porosity logging

Fail-safe methods for deactivating the pulsed neutron generator (PNG) of a logging tool are described herein, as are logging tools configured to execute the fail-safe methods. The fail-safe methods deactivate the PNG if the logging tool is disposed in air outside of a borehole. Measurements taken using one or more gamma ray detectors of the logging tool are used to calculate a value for a parameter that is indicative of the tool being disposed in an air environment. Examples of such parameters include ratios of capture gamma rays and burst gamma rays. The disclosed methods operate without reference to sensors and/or control from outside the tool. The methods do not inadvertently deactivate the tool when it encounters an air-filled borehole.

Pulsed neutron logging tool with in-air automatic shutdown

Methods, tools, and systems for determining the lithium concentration of a formation traversed by a wellbore using pulsed neutron logging are described. Since determining lithium directly using pulsed neutron logging is problematic, this disclosure provides ways of determining lithium concentration indirectly using models that relate lithium concentration with concentrations of other elements that are predicted to be associated with lithium.

Pulsed neutron logging for petrolithium

A caliper-behind casing apparatus and method determines a location and size of a washout (i.e., a void) behind casing in a borehole for a salt cavern used for storing hydrocarbons. The cavern and tubing in the casing are filled with brine. Gaseous nitrogen is used to fill an annulus between the tubing and the casing above and below a casing shoe to obtain image responses from operating a pulsed neutron logging tool in the tubing along the borehole. Analysis of burst ratios of near and far detectors on the pulsed neutron logging tool from these passes is used to detect and estimate a void or washout in the formation behind the casing.

Growing community of inventors

Sugar Land, TX, United States of America

Gregory J Schmid