Schlumberger Technology Corporation

Jonathan Mitchell

Edmund John Fordham

Adam Colbourne

Ashley Bernard Johnson

Trevor Lloyd Hughes

Ravinath Kausik Kadayam Viswanathan

Lukasz Zielinski

Colin Stewart

Débora Campos De Faria

Sean Lovett

A method for measuring at least one property of a sample includes obtaining a sample of fluid including at least fines from a downhole environment, exposing the sample to a magnetic field, measuring a magnetic susceptibility of the fines in the sample in response to the magnetic field, and identifying at least one mineral present in the fines based at least partially on the magnetic susceptibility.

Systems and methods for determining the mineralogy of drill solids

Tools and methods are used to determine the oil, water, and solids volume fractions in a drilling fluid at the rig site. The volume fractions can be determined in-line with returned drilling fluid by using an NMR magnet and a flow line or sample chamber that receives a fluid sample and loads it into the NMR magnet. Using an RF probe, spectrometer, and computing device, data processing and interpretation of NMR data from the spectrometer is performed, while also raising a flag when iron contamination exceeds a predefined threshold.

Digital retort measurement systems and methods

Methods for improved interpretation of NMR data acquired from industrial samples by simultaneously detecting more than one resonant nucleus without removing the sample from the sensitive volume of the NMR magnet or radio frequency probe are disclosed. In other aspects, the present disclosure provides methods for robust imaging/analysis of spatial distribution of different fluids (e.g., 1H, 23Na, 19F) within a core or reservoir rock. NMR data may be interpreted in real-time during dynamic processes to enable rapid screening, e.g. of enhanced oil recovery techniques and products and/or to provide improved interpretation of well-logs. Measurements of resonant nuclei other than 1H may be performed in the laboratory or downhole with a NMR logging tool. In other aspects, the present disclosure describes a novel kernel function to extract values for underlying parameters that define relaxation time behavior of a quadrupolar nucleus.

Methods for interpreting NMR data

A porous material with liquid in the pores is examined by submerging the material in a bathing liquid, possibly a perfluorocarbon, which is immiscible with the liquid in the pores, is non-wetting towards the material, is immiscible with and differs in density from any liquid on the outside of the material, and does not contain a resonant element found in the bathing liquid. This bathing liquid displaces fluid from the surface of the porous material but not the liquid in the pores. Nuclear magnetic resonance signals from liquid in the pores give a measurement of pore volume. Volume of bathing liquid displaced by the porous material gives the bulk volume and porosity can be derived from these measurements. Sample preparation is minimal and a benchtop spectrometer can be used, making the method practical for examination of drill cuttings from a borehole while drilling.

Determining properties of porous material by NMR

An apparatus and method for NMR analysis of a plurality of core samples includes a core holder () that holds a core sample under pressurized conditions. A radio frequency coil () disposed about the core holder () generates a pulsed-mode magnetic field component over a sample volume occupied by the core sample. A support structure is removably secured to the respective core holder. A permanent magnet (A,B) has an open configuration such that it is removably disposed into a position within the support structure about the radio frequency coil and the core holder. The open configuration allows the same permanent magnet to be used for NMR analysis of a plurality of core samples without the need for depressurizing the respective core holder and disassembling the core holder and corresponding load frame for each core sample. It also allows multiple core samples to be prepared for NMR analysis while separated from the NMR measurement apparatus.

NMR analysis of a core sample employing an open permanent magnet removable from a core holder

Apparatus for examining a fluid-containing porous sample, by a combination of centrifuging to move fluid into, out of, and/or within the sample and NMR to monitor the amount of fluid present at locations within the sample has a magnet system to provide a magnetic field; and a centrifuge rotor comprising a holder () for the sample and mounted to move the sample within the magnetic field. The apparatus preferably includes gradient coils () superimposing a magnetic field gradient onto a field provided by magnets (). At least one radio-frequency coil () is located on the centrifuge rotor in a positionwhich surrounds the sample in the holder. The coil axis is transverse to the magnetic field and field gradient when measurement is made. Consequently NMR measurement of the distribution of fluid in the sample can be made while the centrifuge is in motion.

Examining porous samples

A method of analyzing properties of a porous sample, typically a cylinder of porous rock, comprises centrifuging the sample while it contains at least one liquid, determining the distribution of at least one liquid in the sample by magnetic resonance imaging of the sample, and also determining the distribution of at least one magnetic resonance parameter, where the parameter is one of longitudinal relaxation time T, transverse relaxation time Tand diffusion coefficient D. Pore throat sizes can be determined from the distribution of at least one liquid in the sample and pore body sizes can be determined from the distribution of the magnetic resonance parameter enabling determination of a relationship between pore throat sizes and pore body sizes in the sample. This can be a relationship between individual values of pore throat size and an average of body sizes of pores having that individual pore throat size.

Magnetic resonance examination of porous samples

Properties of a porous solid sample, which may be a core of rock taken from below ground are carried out using apparatus which performs both nuclear magnetic resonance (NMR) and porosimetry measurements. The apparatus has a magnetproviding a magnetic field and a radio frequency coilfor transmitting and/or receiving electromagnetic radiation so as to bring about NMR in the magnetic field, a pressure vesselto hold a samplewithin the magnetic field, a supply of a non-wetting liquid connected to the vessel, means to apply pressure to the non-wetting liquid to force liquid into pores of the samplemeans to measure applied pressure of the non-wetting liquid and means to measure volume thereof taken up by the sample. The pressure of non-wetting liquid may be increased in steps, using intruded liquid volume at each step to give a measurement of pore throat size using NMR at each step to give a measure of pore size such as diameter of equivalent sphere. The non-wetting liquid may be mercury and NMR may observe the Knight shift of 99 Hg.

Examination of porosity by NMR and intrusion porosimetry

A laboratory NMR methodology (and corresponding laboratory apparatus) defines a sample volume. The method stores downhole tool data corresponding to a hydrocarbon-bearing sample collected from a given subsurface formation. The downhole tool data includes parameters pertaining to magnetic fields used by a downhole tool during a suite of NMR measurements of the given subsurface formation. The sample is positioned in the sample volume of the laboratory apparatus, which applies a static magnetic field in the sample volume. Furthermore, the laboratory apparatus applies a suite of NMR measurements to the sample volume to thereby determine a property of the sample. The NMR measurements of the suite each include a pulse sequence of oscillating magnetic field in conjunction with a pulsed-mode gradient field. The pulsed-mode gradient field is based on the stored downhole tool data corresponding to the sample. A laboratory NMR methodology for optimizing downhole NMR measurements is also described.

System for emulating nuclear magnetic resonance well logging tool diffusion editing measurements on a bench-top nuclear magnetic resonance spectrometer for laboratory-scale rock core analysis

System and method for emulating nuclear magnetic resonance well logging tool diffusion editing measurements on a bench-top nuclear magnetic resonance spectrometer for laboratory-scale rock core analysis

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Great Cambourne, United Kingdom

Jonathan Mitchell