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1

Rheological behavior of polymer used in drilling fluid

Daimallah A., Kherfellah N., Benhadid S.

International Journal of Applied Mechanics and Engineering

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2003

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Vol. 8, no spec.

19-24

EN

Drilling fluids perform a role of an interest of age for the good progress of drilling operations. They are exceedingly complex. Their rheological behavior are influenced by the high temperatures and the miscellaneous exterior coercion, where it's necessary to characterize their behavior for a better acquaintance from their rheological properties. Generally, they are adjusted by the addition of polymers and chemical additives in their formulations. The aim of our study is to characterize the rheological behavior of polymer used in drilling fluids with varying numerous factors (high temperatures, different concentrations of polymer).

2

Rheological behavior of oil base drilling mud at high pressure and high temperature

Kherfellah N., Bekkour K., Benhadid S.

International Journal of Applied Mechanics and Engineering

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2003

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Vol. 8, no spec.

49-54

EN

The drilling fluid, which was originally considered like a vehicle of transportation of cuttings is now recognized as one of the major factors for a successfully drilling operations. The success of the drilling operations mainly depends on rheological parameters of fluids (muds), the choice of an adequate mud to the specific particularities of a crossed formations and to a geological conditions permits therefore, not only to increase the efficiency of drilling apparatus, but also to avoid the damage (plugging) of producer layers allowing a better productivity of a drilled well. Two approaches have essentially been considered for the modelling of rheological behavior of different systems of drilling muds. The rheological models integrate one or several characteristic parameters of the fluid or the type of behavior: viscous, pseudoplastic or viscoplastic. These models suppose that the structure of the fluid is steady, therefore, the time of application of the constraint or shearing doesn't influence the model. The aim of this work is to study the influence of the pressure and the temperature on rheological behavior of drilling fluids composed of emulsions of oil, water and different additives.

3

Lost circulation problem analysis and evaluation of the types of lost circulation materials and their placement techniques

Kherfellah N., Bekkour K., Benhadid S.

International Journal of Applied Mechanics and Engineering

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2003

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Vol. 8, no spec.

55-60

EN

Different methodologies are presented to resolve severe lost circulation problems in different field of Algeria, involving naturally fractured or cavernous formation. Lost circulation events in these formations are compared to lost circulation events that are caused by induced fracturing or by drilling through permeable zones having intergranular porosity with excessive mud density. Much progress has been made in the control of lost circulation of drilling fluids as a result of improvements in drilling fluids and drilling techniques, and the developments of new lost circulation materials and remedial procedures.

4

Contact problem, novel polymer structure used in drilling mud to minimise formation damage

Kherfellah N., Bekkour K., Benhadid S.

International Journal of Applied Mechanics and Engineering

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2002

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Vol. 7, Spec. is

139-144

EN

A laboratory study has been undertaken to elucidate the influence of structural parameters of polymer/electrolyte systems commonly used for the formulation of water-based drilling fluids on their performances as filtrate reducers or viscosifiers.High temperatures and salt conditions encountered in the well may modify the rheological properties and this makes the use of polymers necessary. High molecular weight polymers (XC, gums, polyacrylamides, have been used in the formulation of water-based drilling fluids for reducing filtration, facilitating clay stabilisation, improving débris suspension capacity and drillstring lubrication in the drilling operation. The rheological behaviour has been modelised. The modele describe structural changes under shear or at rest as well as the associated stress growth makes it an attractive tool to use in order to improuve hydraulic predictions in drilling.

5

Rheological characterization of water-based drilling muds

Kherfellah N., Bekkour K., Benhadid S.

Applied Mechanics and Engineering

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1999

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Vol. 4, no spec.

339-344

EN

The thixotropic properties of the bentonite dispersions were analysed by the use of an approach derived from a Moore-Cheng model in which a single structure parameter 'lambda' varies within the range 0=<'lambda'<1. 'lambda'=0 corresponds to the complete break-down of structure at high shear rates, and 'lambda'=1 to the equilibrium gel structure at rest. In our method the Casson model (which was found to fit adequately the flow curves) was modified to incorporate the effect of changes in the structure parameter 'lambda'. This model was able to describe adequately the time-dependent behaviour of clay dispersions. Creep flow tests give indications about the elastic properties of the material. It was found that the viscoelastic behaviour of the bentonite dispersions could be represented by the generalised Kelvin-Voigt mechanical.