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Geomechanics Research

Geomechanics of Gas Shale

... is it possible to break down a natural composite (bone, shale, concrete) to a scale where mechanical properties do not change from one specimen to another, and 'nanoengineer' its behavior from the nanoscale to the macroscale of large scale engineering applications?

About GeoGenome™

 

  • GeoGenome™ of sedimentary rocks and earth material is a basis for quantifiable mechanical classification based on Nanotechnology, Genetic Sequencing, Earth material history.
  • GeoGenome™ is an upscaling for geoengineering applications similar to human genome.
  • The identification of the fundamental physico-chemical functional units in shales (geogenes)

Determination of the relative positions of these fundamental units (geogene mapping and/or geogene sequencing)

Ascribe thermo-chemo-mechano behaviors to both these fundamental units and their physical 3-D arrangement (geogene expression), and describe interactions between fundamental particles to build a macroscopic behavior.

The Human Genome Project involves physical and genetic mapping of each human chromosome at increasingly finer resolution.

This approach is being used in the development of high performance clay-polymer nanomaterials.

The breaking of the geogenomic code of porous material, such as rocks, calls for multiscale experimental, theoretical and numerical approaches, that bridge from nanoscales to continuum medium and to macroscales.

Blending mineralogy science experiments and porosimetry measurement techniques, with advanced microscopy (SEM, ESEM, AFM), and mechanical testing of properties, that start at nanoscales with nanoindentation experiments to Ultrapulse Velocity Measurements and macroscopic triaxial testing of rocks. Nanoscale

Three different methods employed for different scales under investigation

Nanoscale
To perform massive grid indentation tests on small sample rocks with dimensions not exceeding the millimeter range.

The indentation test gives access to stiffness properties, primary and secondary consolidation properties, and hardness values that can be linked to elastic/poroelastic properties, permeability and creep properties and strength properties of rocks.

Given the small scale under investigation, it is possible to determine, by means of nanoindentation, the intrinsic material properties of the different phases that build up the rock, and determine spatial distribution, packing density, and other morphology information required to break the genomic code of sedimentary rocks, in particular the most problematic or intriguing ones such as shale rock.

Microscale
Microindentation tests give access to the properties of the homogenized multi-grain / multi-structure rock material: stiffness, strength, permeability, etc.

Using the technique of massive grid indentation at this scale gives access to the effect of fabric and texture on material properties, such as anisotropy, percolation of phases, layered structure, effect of inclusions on strength properties, etc.

Combined with nanoindentation performed at a scale below (nanoscale), microindentation is a powerful quantitative tool to identify if and how invariant rock properties change at larger scales.

Macroscale
The macroscale is the classical and the only standard procedure, so far, for rock mechanics characterization and laboratory tests, ranging from Ultra-Pulse Velocity and acoustic measurements of the dynamic stiffness of rocks to hydrostatic, uniaxial and triaxial testing of saturated or dry rocks under undrained and drained conditions.

Combined with nano- and microindentation, macroscopic testing provides a tool of validation and scale calibration of how rock behavior subjected to in-situ conditions are identified at smaller scales translates into macroscopic mechanical and physical properties.

Large Scale Testing (LST)
The upscaling of acoustic measurement and quasi-static mechanical and poromechanical rock characterization, from ISRM rock size samples is only possible if large scale equipment is available.

Poromechanics Wellbore Stability

Theories of coupled processes in geomechanics as applied to wellbore stability and virtual rock testing simulation. PBORE-3D is becoming the industry standard for wellbore analysis and design in real time. It applies the coupled fluid flow and rock deformation analyses in the studies of wellbore stability and drilling mud design.

Similarly, PCORE-3Dnet is used for predicting time-dependent responses of thick wall cylinder samples in a variety of testing configurations and with different rock types, to simulate openhole stability and sanding initiation. In addition, the tool helps tune the testing frame and pinpoint anomalies in the actual testing results.

Multilateral Stability

QMLSS, an analytical-based multilateral stability simulator, can help analyze and predict wellbore and junction stability during drilling and extended openhole completion as well as during production in terms of formation pore pressure depletion. The tool can also assist the optimization of junction placement in terms of formation properties and wellbore trajectories.

ABAQUS Finite Element Modelling

Finite element modeling of petroleum, geology and geotechnical problems using ABAQUS. The ABAQUS code is a general-purpose, nonlinear finite element analysis program. It can handle 2-D & 3-D, static & dynamic, stress/displacement, coupled pore fluid flow and stress, as well as heat transfer and thermal stress analysis. The analysis materials can be isotropic & anisotropic, elastic (visco-, hypo-, hyper-, etc.) & plastic. ABAQUS has been used to analyze wellbore (petroleum), listric fault (geology) and dynamic compaction (geotechnical).

Shale Testing and IDSTD™

Developing new technologies in shale testing and shale properties measurement. The iPMI laboratory testing facilities allow testing of large shale samples (up to 8"x20") in thick wall cylinder geometry under simulated in-situ wellbore conditions with 20,000 psi confining pressure and at testing temperatures as high as 200°C.

The integrated PoroMechanics Institute has developed and patented (Patent Number 7650795, September 11, 2008) the Inclined Direct Shear Testing Device (IDSTD™) which provides the capability of testing disc-shaped samples with approximate sizes of 0.80 inch diameter and 0.30 inches in thickness. The patented IDSTD™ provides the capability of evaluating the effect of contact by different fluid chemistries on sample strength and dynamic mechanical properties of various test sample material. The IDSTD™ can be utilized under unconfined conditions of within any of the triaxial test vessels available in the laboratory.

The IDSTD™ has been used for testing of consortium members' core samples which were not of sufficient size or quality to allow preparation of conventional triaxial test specimens (for example, 2 1/8" x 4 1/4", 1 1/2" x 3", or 1" x 2"). Most recently, the IDSTD™ has been utilized in the evaluation of core samples provided by Saudi Aramco and for evaluation of integrated PoroMechanics Institute's Woodford Shale core samples.

Our facilities also allow testing small (1") plugs of rocks, and IDSTD™ size specimens.

Mechanics of Soft Sediments

Investigating the mechanics of soft sediments and sanding assessment during oil and gas production. The Undrained Sanding Criteria (USC) is a new and innovative test procedure that allows characterizing strength properties of soft sediments and weak rocks as well as assessing the susceptibility of the formation to sanding during production.

Poromechanics Laboratory

The Poromechanics laboratory facility includes over 5 million dollars of testing equipment for acquisition of acoustic mission, ultrasonic tomography, acoustic velocity, and permeability of rock samples subjected to simulated downhole conditions. The equipment includes a three-million pound capacity load frame, two 600,000 lb. load frames, two 50,000 lb. load frames, and a large polyaxial cubic cell.