Description of the Proposed Paper:

Professor Ciobanu has developed a new concept for defining and evaluating the effective stresses from discontinuous rocks. Starting from this concept, he succeeded in building up mathematic models that calculate effective values of the stresses from rocks with a more accurate precision than the previous models. A part of these results have been recently presented in conferences where they have been appreciated by the audience.

In this paper the authors present their own results obtained by applying and customizing the models mentioned above for particular cases of undersea rocks, involved in different offshore activities.

Application:

The information and results presented in this paper are useful and sometimes vital in evaluating of those deformations of undersea rocks that are important in case of some phenomena or technological operations, such as:

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    compaction and subsidence of rocks that constitute the basement for different equipment that are supported on the seabed or ocean bed;

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    hydraulic cracking, collapse or tightening in case of rocks that build up the offshore boreholes.

Results, Observations and Conclusions:

Practically, in this abstract there are presented the following:

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    a more developed model for the calculation of effective values of primary stresses of cohesive, porous rocks that build up reservoirs and undersea massive;

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    the way that the geometric parameters of pores, pore pressure, pressure on the seabed or certain physic-mechanic constants of rocks influence effective stresses.

The observations and the conclusions in the abstract have been stated based on the results obtained by numeric analysis. The basic models of the above stated concept have been previously verified in laboratory test.

Significance of Subject Matter:

The results from this paper are different from the others published in previous papers by the following elements:

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    the new model of calculation of effective stresses - herein proposed, is based on a concept more precise and accurate than the other known models;

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    the new introduced parameter for quantifying the form and pores distribution leads to unprecedented results and conclusions;

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    reduces risk of using such calculation models in situations where they are not compatible.

Keywords:
horizontal stress, maximum shear stress, effective value, terzaghi model, shear stress, apparent stress, discontinuity, relation, homogeneous rock, terrestrial massif
Subjects:
Reservoir Characterization, Reservoir geomechanics
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2014. Offshore Technology Conference
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