Schlumberger

Oilfield Review October 1994


Neutron Porosity Logging Revisited

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Neutron Porosity Log

The IPL Integrated Porosity Logging tool features a downhole accelerator, updated source-to-detector spacings and greater detector efficiency to improve the accuracy of formation evaluation, especially neutron porosity measurements.


Coiled Tubing Takes Center Stage

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Coil Tubing

Coiled tubing operations have ceased being on the fringe. In the past five years, the scope of coiled tubing has expanded dramatically. This article looks at the causes of this expansion: coiled tubing technology developments, improved service reliability, increasing coiled tubing diameter and an ever-growing need to drive down industry costs. Using case studies, we then describe advances in coiled tubing drilling, the deployment of reeled completions, coiled tubing logging of high-angle boreholes and the use of coiled tubing to deliver sophisticated treatment fluids downhole.


Measuring Permeability Anisotropy: The Latest Approach

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Permeability Anisotrophy

Permeability is an elusive beast. Its value changes with scale and also with direction—vertical permeability may differ from horizontal permeability giving rise to the term permeability anisotropy. We look at how this anisotropy affects reservoir management, review the various techniques used to measure permeability anisotropy, and, in particular, describe how new generation MDT Modular Formation Dynamics Tester wireline testing can provide measurements at a scale that complements other techniques.


The Promise of Elastic Anisotropy

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Elastic Anisotropy

Elastic anisotropy has blossomed from a bothersome anomaly into a promising measure of reservoir properties. This phenomenon, in which waves travel with different velocities in different directions, indicates the presence of alignments such as cracks or fractures, tectonic stresses, depositional layers or ordered anisotropic grains. Formerly of concern only to theorists, elastic anisotropy can now be measured in ultrasonic, sonic, crosswell and borehole seismic experiments. This article examines how elastic anisotropy is being used to enhance reservoir description and impact reservoir development decisions.


Oilfield Anisotropy: Its Origins and Electrical Characteristics

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Oilfield Anisotropy

Anisotropy is a phenomenon simultaneously as big as the earth and as small as the atom. In the oilfield, anisotropy of rock properties at a wide range of scales affects nearly all exploration and production disciplines-geophysics, petrophysics, geology and reservoir engineering. Taking advantage of anisotropy begins with understanding its origins in sedimentology. Here is a look at the geologic foundations of anisotropy and a summary of recent findings on the anisotropy of electrical properties of the earth.


All pages in this issue
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