Drilling in mudrocks: rock behavior issues

Fam, M.; Dusseault, Maurice B.; Fooks, J.C.

doi:10.1016/s0920-4105(03)00029-9

Cited by 36 publications

(7 citation statements)

References 20 publications

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“…Both radial (σ r ) and tangential (σ θ ) stresses vary with distance from the borehole and approach the far field stresses away from the borehole. In general, reduction in radial stresses and increases in tangential stresses are predicted around boreholes (Fam et al. 2003).…”

Section: Analysis Of the State Of Stress Near The Boreholementioning

confidence: 99%

Reanalysis ofin situpermeability measurements in the Barbados décollement

Bekins¹,

Matmon²,

Screaton³

et al. 2010

Geofluids

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A cased and sealed borehole in the Northern Barbados accretionary complex was the site of the first attempts to measure permeability in situ along a plate boundary dé collement. Three separate efforts at Hole 949C yielded permeability estimates for the dé collement spanning four orders of magnitude. An analysis of problems encountered during installation of the casing and seals provides insights into how the borehole conditions may have led to the wide range of results. During the installation, sediments from the surrounding formation repeatedly intruded into the borehole and casing. Stress analysis shows that the weak sediments were deforming plastically and the radial and tangential stresses around the borehole were significantly lower than lithostatic. This perturbed stress state may explain why the test pressure records showed indications of hydrofracture at pressures below lithostatic, and permeabilities rose rapidly as the estimated effective stress dropped below 0.8 MPa. Even after the borehole was sealed, the plastic deformation of the formation and relatively large gap of the wire wrapped screen allowed sediment to flow into the casing. Force equilibrium calculations predict sediment would have filled the borehole to 10 cm above the top of the screen by the time slug tests were conducted 1.5 years after the borehole was sealed. Reanalysis of the slug test results with these conditions yields several orders of magnitude higher permeability estimates than the original analysis which assumed an open casing. Overall the results based on only the tests with no sign of hydrofracture yield a permeability range of 10 )14 -10 )15 m 2 and a rate of increase in permeability with decreasing effective stress consistent with laboratory tests on samples from the dé collement zone.

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Section: Analysis Of the State Of Stress Near The Boreholementioning

confidence: 99%

Reanalysis ofin situpermeability measurements in the Barbados décollement

Bekins¹,

Matmon²,

Screaton³

et al. 2010

Geofluids

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“…A dimensionless clay reactivity number, N λ , as given by the following, can be used to express the sensitivity of the clays to aqueous solutions and temperature (Fam et al, 2003):…”

Section: Clay Reactivity Coefficientmentioning

confidence: 99%

Formation Damage Mechanisms and Their Phenomenological Modeling—An Overview

Civan

2007

All Days

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fax 01-972-952-9435. AbstractA review and phenomenological modeling of the various processes causing reservoir formation damage are presented. The mechanisms involved in the migration, deposition, and mobilization of the fine particles and inorganic and organic precipitates are described physically and mathematically. The various problems created by fine particles at the pore surface, clogging and dislodgment of the pore throats, aggregation, and interface particle transfer processes in multi-phase fluid systems flowing through porous media are described. The implications of the various mechanical, chemical, and thermal processes on the behavior of the particles are discussed. The various types of shock phenomena and their effects on the particulate processes are explained. The alteration of the pore connectivity, preferential hydraulic paths, permeability and porosity of porous media as a result of the various particulate processes are formulated. The phenomenological modeling of the particulate processes in single-and multiple-porosity reservoir formations is presented. The applications may concern with the damage by particles, injectivity decline in waterflooding wells, formation damage by drilling mud invasion, formation damage in naturally fractured reservoirs, asphaltene deposition, and sand production and gravel pack damage.

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“…1 É amplamente utilizado na indústria petrolífera como componente de fluidos de perfuração devido a sua elevada densidade (4,2 g cm -3 ) na forma de baritina. 2 O bário contido na baritina é relativamente imóvel e pouco biodisponível, devido à baixa solubilidade em água (2,47 mg L -1 a 25 ºC), entretanto, na forma Ba +2 é tóxico. 3 Durante a perfuração de poços para a prospecção e produção de petróleo, o fluido é misturado à rocha moída, liberando substâncias que estavam em sua composição 4 e, consequentemente, tornando-se uma das principais influências nos teores de bário e outras substâncias nos resíduos de poços de perfuração de petróleo.…”

Section: Introductionunclassified