Schlumberger Technology Corporation

Ashok Belani

Tarek M Habashy

Terizhandur S Ramakrishnan

Lalitha Venkataramanan

Aria Abubakar

Denise E Freed

Fikri John Kuchuk

Yves Manin

Charles Woodburn

Vladimir L'vovich Druskin

Cindy Demichel

Gokhan Saygi

Mikhail Zaslavsky

Mohamed Watfa

Luis Ayestaran

Source-receiver compression is used to help design surveys and mitigate the computational costs of data set inversion. The source-receiver compression is based on data redundancy and sensitivity. More particularly, a compressed source array is produced for minimum redundancy and maximum sensitivity to reservoir model parameters. The synthesized transmitter array has a reduced number of sources, thereby reducing the number of forward model simulations needed to carry out the inversion. Furthermore, the data collected at the receivers employed in the survey can be compressed. This has the implication of reducing the computational cost of constructing the Jacobian matrix and inverting the corresponding Hessian matrix.

Data set inversion using source-receiver compression

A main borehole is drilled into an underground reservoir comprising a plurality of layers of different fluid mobilities. The fluid mobility in each of the plurality of layers is determined. A number of lateral boreholes extending from the main borehole in each of the plurality of layers are then drilled based on the determined fluid mobility in each of the plurality of layers, such that resulting fluid production rates in each of the plurality of layers are substantially similar.

Drainage method for multilayer reservoirs

Methods and related systems are described for estimating fluid or rock properties from NMR measurements. A modified pulse sequence is provided that can directly provide moments of relaxation-time or diffusion distributions. This pulse sequence can be adapted to the desired moment of relaxation-time or diffusion coefficient. The data from this pulse sequence provides direct estimates of fluid properties such as average chain length and viscosity of a hydrocarbon. In comparison to the uniformly-spaced pulse sequence, these pulse sequences are faster and have a lower error bar in computing the fluid properties.

Modified pulse sequence to estimate properties

Methods and apparatus for estimating values for formation parameters such as permeability, relative permeability, and skin factors for a plurality of locations in the formation are provided. Fluid is forced into a capped borehole at a measured rate, and a borehole logging tool is run in the borehole to measure indications of pressure and conductivity. Estimates of the parameters and the measured fluid flow rate(s) into the formation are used in conjunction with a jointly inverted pressure transient model and saturation-conductivity model in order to compute indications of expected pressure and indications of expected conductivity-related profiles as a function of depth and time. The expected pressures and expected conductivity related profile indications are then compared to the pressures and conductivity indications measured by the borehole logging tool, and an iterated comparison between the computed values and the measured values is used to provide determinations of the formation parameters. According to a preferred embodiment, the pressure transient model is for compressible flow and provides an estimated calculated fluid flow into the layers of the formation; the estimated calculated fluid flow being an input to the saturation-conductivity model which is for incompressible flow.

Method and apparatus for characterizing earth formation properties

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Paris, France

Ashok Belani