Ralf Heidler

US Patent:

6714009, Mar 30, 2004

Filed:

May 16, 2002

Appl. No.:

10/147749

Inventors:

Ralf Heidler - Richmond TX

Assignee:

Schlumberger Technology Corporation - Sugar Land TX

International Classification:

G01V 300

US Classification:

324303

Abstract:

A method for determining an earth formation property from nuclear magnetic resonance measurements includes applying suppression functions to spin echoes in at least one burst measurement set to produce a modified burst data set, the suppression functions to suppress contribution of spin echoes having non-negligible polarization correction; inverting the modified burst data set and at least one standard spin echo measurement set to produce a nuclear magnetic resonance parameter distribution, the at least one standard spin echo measurement set and the at least one burst measurement set being acquired on an earth formation sample; and computing the earth formation property from the nuclear magnetic resonance parameter distribution. The nuclear magnetic resonance parameter includes at least one selected from longitudinal relaxation time, transverse relaxation time, a ratio of longitudinal relaxation time to transverse relaxation time, and diffusion constant.

US Patent:

6808028, Oct 26, 2004

Filed:

Dec 3, 2002

Appl. No.:

10/308957

Inventors:

Charles Woodburn - Missouri City TX
Ralf Heidler - Richmond TX

Assignee:

Schlumberger Technology Corporation - Sugar Land TX

International Classification:

E21B 4706

US Classification:

175 48, 175 50, 16625007, 1662542

Abstract:

A method is provided for gathering information on the pore pressure in an earth formation surrounding a wellbore. The method includes the initial steps of selecting at least one suitable property (e. g. , porosity, drilling fluid composition, etc. ) of the drilling environment (which is defined by the wellbore and the surrounding formation) and at least one NMR parameter (e. g. , T2 distribution) in an NMR measurement response. The method selects a suitable property for which values over a plurality of wellbore depths can be correlated with the characteristics or behavior of the pore pressure in the earth formation. The method further includes conducting an NMR measurement at a plurality of wellbore depths, thereby generating an NMR response from the drilling environment. The measured values of the NMR parameter in the NMR response are then correlated with values of the suitable property. Next, the values of the suitable property are compared over the plurality of depths, and then the correspondence between the property values is correlated with the behavior of the pore pressure over the plurality of depths.

US Patent:

6956370, Oct 18, 2005

Filed:

Oct 4, 2002

Appl. No.:

10/065334

Inventors:

Ralf Heidler - Richmond TX, US

Assignee:

Schlumberger Technology Corporation - Sugar Land TX

International Classification:

G01V003/00

US Classification:

324303

Abstract:

A method of reducing ringing artifacts in a nuclear magnetic resonance measurement is provided. The method utilizes a new pulse sequence that offers ringing cancellation opportunities as well as compensation for otherwise accumulating spin dynamics errors. Ringing cancellation is accomplished by forming linear combinations of spin echoes induced as a result of the pulse sequence. Because the linear combinations are formed between closely spaced spin echoes (i. e. , echoes within the same sequence), the likelihood that the ringing artifact will have changed between measurements is diminished.

US Patent:

7603237, Oct 13, 2009

Filed:

Jun 20, 2007

Appl. No.:

11/765484

Inventors:

Nicholas J. Heaton - Den Haag, NL
Jack A. La Vigne - Houston TX, US
Ralf Heidler - Houston TX, US
Henry N. Bachman - Missouri City TX, US

Assignee:

Schlumberger Technology Corporation - Sugar Land TX

International Classification:

G01V 1/40

US Classification:

702 6

Abstract:

A method to determine formation properties using two or more data sets in which the solutions corresponding to the data sets represent shared and distinct formation properties. The method analyzes the data sets and computes distributions for the shared and distinct formation properties from which the formation properties are determined.

US Patent:

61846813, Feb 6, 2001

Filed:

Nov 5, 1998

Appl. No.:

9/187130

Inventors:

Ralf Heidler - Stafford TX
Roger A. Dworak - Sugar Land TX
Bruno Luong - Stafford TX
Martin E. Poitzsch - Sugar Land TX

Assignee:

Schlumberger Technology Corporation - Houston TX

International Classification:

G01V 300

US Classification:

324303

Abstract:

The present invention is directed to a method for computing a distribution of spin--spin relaxation times. The spin-echo amplitudes are obtained by hardware integration of the receiver voltages over a time window. A linear operator is utilized to map a relaxation-time distribution to spin-echoes, produce a singular value decomposition (SVD) of the linear operator, determine vectors of the SVD, and compress the spin-echo data using the vectors. To eliminate a telemetry bottleneck, the T. sub. 2 spectrum is computed downhole and transmitted to the surface.

US Patent:

62919954, Sep 18, 2001

Filed:

Nov 5, 1998

Appl. No.:

9/186721

Inventors:

Peter Speier - Stafford TX
Ralf Heidler - Stafford TX

Assignee:

Schlumberger Technology Corporation - Houston TX

International Classification:

G01V 300

US Classification:

324303

Abstract:

The present invention is directed to a method for generating a pulse sequence using a logging tool. A pulse programmer is provided for adaptively controlling the creation and application of a sequence of RF magnetic field pulses to an earth formation. In order to control the RF pulses, a portion of a memory device is partitioned into a plurality of tables and control information is stored in the tables. The pulse programmer creates the pulse sequence using information found in the memory device and the operating conditions of the tool. The structure of the partitioned memory device allows the pulse programmer to adapt and change the timing of the pulse sequences autonomously downhole.

US Patent:

62374044, May 29, 2001

Filed:

Feb 27, 1998

Appl. No.:

9/031926

Inventors:

Steven F. Crary - Sugar Land TX
Ralf Heidler - Stafford TX
Cengiz Esmersoy - Sugar Land TX
Martin E. Poitzsch - Sugar Land TX

Assignee:

Schlumberger Technology Corporation - Houston TX

International Classification:

G06F 1900
E21B 4500
E21B 4700
G01V 140

US Classification:

7315203

Abstract:

There are many natural pauses during rotary drilling operations where a portion of the drill string remains stationary. Pauses include drill pipe connections, circulating time, and fishing operations. These pauses are used to obtain formation evaluation measurements that take a long time or that benefit from a quiet environment, as opposed to the naturally noisy drilling environment. Various techniques that are sensitive to the mud flow, weight-on-bit, or motion of the drill string may be used alone or in combination to identify the drilling mode and control the data acquisition sequence.

US Patent:

63267845, Dec 4, 2001

Filed:

Nov 5, 1998

Appl. No.:

9/186951

Inventors:

Krishnamurthy Ganesan - Sugar Land TX
Steven F. Crary - Sugar Land TX
Ralf Heidler - Stafford TX
Bruno Luong - Stafford TX
Peter Speier - Stafford TX

Assignee:

Schlumberger Technology Corporation - Houston TX

International Classification:

G01V 300

US Classification:

324303

Abstract:

The present invention relates generally to an apparatus and method for obtaining an azimuthally resolved nuclear magnetic resonance measurement of an earth formation traversed by a borehole. The measurement can be made while drilling or using a wireline tool. At least one gradient coil is positioned circumferentially around the tool. A magnetic field is produced by the coil in a region of the formation facing the coil. The magnetic field is substantially parallel to the static magnetic field produced by a pair of permanent magnets which form a part of the tool. The additional field causes an additional phase shift for spins located in the region so that the spins subjected to the additional field do not form a spin-echo.