Schlumberger Technology Corporation

Richard Jackson

Oliver Clinton Mullins

Youxiang Zuo

Ilaria De Santo

Ankit Agarwal

Adriaan Gisolf

Cosan Ayan

Peter S Hegeman

Stephane Vannuffelen

Chengli Dong

Ricardo Vasques

Go Fujisawa

Hadrien Dumont

Michael O'Keefe

Prasanna Kumar Tellapaneni

Sourabh Shukla

Harshad Dixit

Ahmad Saputra

Upper and lower asphaltene weight fractions of fluid proximate ends of an oil column are obtained based on measured OD. Upper and lower maltene partial densities are obtained based on the asphaltene weight fractions. A maltene partial density distribution is obtained utilizing the maltene partial densities and a predetermined diffusion model. An asphaltene partial density distribution is obtained based on the maltene partial density distribution and an estimated mass density gradient. An asphaltene weight percentage is obtained based on the asphaltene partial density distribution and the mass density gradient. The asphaltene weight percentage distribution is converted to an OD distribution utilizing a predetermined correlation. An optimization then reduces differences between the OD distribution and the measured OD data to within a predetermined range to refine a biodegradation time of the predetermined diffusion model. A viscosity distribution may be obtained based on the optimized OD distribution.

Evaluating reservoir oil biodegradation

The present disclosure relates to a downhole fluid analysis method that includes withdrawing formation fluid into a downhole tool at a plurality of stations within a wellbore, analyzing the formation fluid within a fluid analyzer of a downhole tool to determine properties of the formation fluid for the plurality of stations, and developing, based on the determined properties of the formation fluid, a relationship for predicting viscosity from a measured optical density.

Downhole fluid analysis method and apparatus for determining viscosity

A methodology for IPTT (interval pressure transient testing) design which allows estimation of the reliability of the transient tests. A normally distributed random noise is superimposed on analytical pressure profile computed for a given formation, PVT, and gauge metrology. The IPTT success in a particular environment is estimated based on the theoretical pressure derivative and noise superimposed pressure derivative. This approach is repeated for a range of rock, fluid properties, and practical limits, for a successful IPTT.

Formation tester interval pressure transient test and apparatus

A method for using an optical spectrum of mud filtrate for analysis of fluid drawn from a formation is provided. The method includes performing downhole fluid analysis of formation fluid drawn at a wellbore measurement station and determining an optical spectrum of mud filtrate in the formation fluid drawn at the wellbore measurement station. The method also includes performing downhole fluid analysis of formation fluid drawn at an additional wellbore measurement station, and performing the downhole fluid analysis of formation fluid drawn at the additional wellbore measurement station includes using the determined optical spectrum of the mud filtrate in the formation fluid previously drawn at the wellbore measurement station. Additional methods, systems, and devices are also disclosed.

Estimation of mud filtrate spectra and use in fluid analysis

Methods of calibrating a fluid analyzer for use in a wellbore are described. An example method of generating calibration data for a fluid analyzer for use in a downhole tool involves lowering a downhole tool including a fluid analyzer to a location in a wellbore, measuring, via the fluid analyzer, a characteristic value of a calibration fluid or a vacuum while the fluid analyzer is at the location, obtaining an expected characteristic value for the calibration fluid or the vacuum at the location, and comparing the measured characteristic value to the expected characteristic value to generate a calibration value for the fluid.

Methods of calibrating a fluid analyzer for use in a wellbore

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Cape Town, South Africa

Richard Jackson