Schlumberger Technology Corporation

Saudi Arabian Oil Company

Schlumberger Technology Coproration

George Bordakov

David Furse Allen

John C Rasmus

Steve F Crary

Edward Alan Clerke

Ramsin Yacood Eyvazzadeh

Johannes J Buiting

Philip Savundararaj

Paul Smith

Jim Funk

Processes and systems for synchronizing driller depth data as a function of time with downhole tool acceleration data as a function of time. In some embodiments, the process can include determining one or more in slips conditions for a drill pipe; determining one or more in slips conditions for a downhole tool; interpolating the in slips status indicators on to a common time grid; determining one or more shifts for which an allowed minimum overlapping time period between the acceleration data and the driller depth data is not less than an allowed minimum overlapping time period; determining a correlation coefficient between the interpolated in slips status indicators for each of the one or more shifts; determining a maximum correlation coefficient and a time shift associated with the maximum correlation; and synchronizing the acceleration data and the driller depth data.

Synchronization of tool acceleration vs time data and driller depth vs time data

A petrophysically regularized time domain nuclear magnetic resonance (NMR) inversion includes using an NMR tool to acquire NMR data and inverting the acquired NMR data in a time domain using petrophysical constraints. The inverted NMR data is analyzed. The petrophysical constraints may be identified by: determining a number of porobodons to seek, defining a plurality of zones in which only a subset of porobodon sets is present, and stacking all NMR echoes in each zone satisfying discriminators. The number of porobodons to seek may be based on knowledge of core samples, logs, and NMR sensitivity. The discriminator logs may be logs sensitive to porosity partitioning. A computing system having a processor, a memory, and a program stored in memory may be configured to perform the method. The system may be conveyed downhole on a wireline, a while-drilling drill string, a coiled tubing, a slickline, or a wired drill pipe.

Petrophysically regularized time domain NMR inversion

A method for generating a porosity log for a reservoir in an organic shale. The method includes receiving data representing one or more parameters in a reservoir in an organic shale. At least one of the parameters includes porosity. By stochastically inverting the data, a distribution of porobodon features is estimated that matches an observed pulse decay curve. The porosity data relates to petrophysical restrictions on at least one of the porobodon features.

Petrophysically-regularized nuclear magnetic resonance inversion

A method includes accepting as input to a processor measurements of a characteristic of a subsurface formation made at a plurality of spaced apart positions along a pipe string moved along a wellbore. Measurements are made of pipe string depth in the wellbore from the Earth's surface. The measurements of pipe string depth include measurements of apparent depth of each of the spaced apart locations. The subsurface formation is identified from the measurements of the characteristic. A true depth of the subsurface formation is made using the measurements of pipe string depth and apparent depth of the formation from each of the spaced apart positions. A record of measurements of the characteristic with respect to depth corrected for changes in length of the pipe string caused by axial forces along the pipe string is generated.

Determining correct drill pipe length and formation depth using measurements from repeater subs of a wired drill pipe system

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Richmond, TX, United States of America

George Bordakov