Shale problems and water-based drilling fluid optimisation in the Hassi Messaoud Algerian oil field

Drilling fluid formulation and properties play a fundamental role in drilling operations. Clay minerals behave initially as a beneficial rheological adjuvant in drilling muds. Nevertheless, the contamination of oil reservoirs by clay minerals present in the drilled geological formation (shales) may generate major problems during drilling as plug formation. In this context, our study deals with the optimisation of drilling conditions in the Hassi Messaoud Algerian field. The mineralogical heterogeneity of this field is first discussed. The rheological and filtration characteristics of water-based muds with different polymer and electrolyte concentrations are investigated. The physical and chemical changes of both drilled formation and drilling fluid during the drilling process are studied. Therefore, depending on the clay present in the geological formation, an optimised drilling fluid system using a new filtration procedure is proposed. A good correlation is found between filtration/rheological properties and inhibition

Les fluides de forage : étude des performances et considérations environnementales

Lors des forages pétroliers, la traversée des formations argileuses pose des problèmes dont la résolution est étroitement liée à la compréhension des interactions argile - fluide de forage. Vu les imperfections des fluides à base d'eau (WBM) face aux problèmes des argiles, les systèmes de fluides émulsionnés à base d'huile (OBM) ont apporté des améliorations significatives. Cependant, la pollution qu’ils engendrent rend indispensable un traitement des boues usagées. Au cours de ce travail, nous avons voulu confronter le maximum de données de laboratoire à des données effectives de chantier et ce, dans l’espoir d’apporter une contribution à la résolution des problèmes réels. Trois systèmes modèles de fluides du type WBM on été sélectionnés : ils contiennent, en plus des polymères conventionnels (xanthane et cellulose polyanionique), des inhibiteurs de gonflement et de dispersion des argiles (polyacrylamide partiellement hydrolysé, silicates de sodium, polyalkylèneglycols). La comparaison de leurs perfo rmances, grâce à l'utilisation d'une nouvelle méthode basée sur la filtration sur pastilles compactées, a été discutée : - du point de vue macroscopique par l'analyse de leurs caractéristiques rhéologiques et de filtration, le suivi des interactions argile -fluide par l'étude des propriétés électrocinétiques, granulométriques et de rétention des polymères, - et à l'échelle microscopique par diffraction X in -situ (wet cell) et par diffraction de la lumière. Les caractéristiques rhéologiques et de filtration ont été corrélées aux propriétés électrocinétiques et complétées par l'étude des propriétés interfaciales et de mouillage. Le système aux silicates présente les meilleures performances en termes d'inhibition. L'étude de la stabilité des systèmes émulsionnés (OBM) a porté sur l'influence du type et de la concentration des tensioactifs, de la proportion de phase dispersée et de la présence d’autres additifs. La concentration optimale est celle donnant un compromis entre une stabilité électrique acceptable, un p ourcentage d’émulsion élevé et une meilleure résistance à la centrifugation. Le suivi de la variation de la phase émulsionnée, de la stabilité électrique et de la distribution granulométrique a permis de classer les différents émulsifiants. Parallèlement aux mesures rhéologiques, l'analyse des structures formées (émulsion-argile organophile) par diffusion des neutrons aux petits angles (SANS) a permis d'expliquer les mécanismes de stabilisation. Une nouvelle formulation d'émulsifiants, proposée pour un essa i sur chantier, a donné des résultats encourageants par rapport aux formulations commerciales. Au niveau du réservoir, l’impact des fluides de forage est appréhendé par l’étude des processus d’endommagement de la roche. Un de nos objectifs était de corrél er les résultats globaux obtenus pour la formulation complète avec l'endommagement induit par les additifs seuls. Les essais réalisés ont montré l'influence de la nature, de la composition chimique, et de la granulométrie des additifs. Vu la complexité des phénomènes mis en jeu, la prévision de l'endommagement par une tentative de modélisation a décelé des liens entre les propriétés des fluides utilisés, les caractéristiques de la roche et l'importance de l'endommagement induit. La filtration statique favor ise la formation du "cake" alors que la filtration dynamique contribue à l'invasion du filtrat. Sur le plan environnemental, en plus des pertes de circulation des fluides pendant et après le forage, le bourbier, en tant que collecteur des produits liquide s et solides issus du forage, représente une grande source de pollution et de danger. Le diagnostic des techniques de traitement utilisées a montré des imperfections majeures pouvant induire des nuisances pour la santé humaine, l'écosystème et l'environnement. Le présent travail s’est focalisé sur quelques éléments de réponse à l'équation performance -coûtenvironnement, en proposant un traitement biologique. ABSTRACT : In petroleum drilling operations, crossing shale formations poses problems whose solutio n is strongly related to the understanding of shale - drilling fluid interactions. Due to the lack of performances of water-based fluids (WBM) faced with shale problems, emulsified oilbased fluids (OBM) afforded significant improvements. However, the main t echnical difficulty lies in the treatment of the pollution generated by these emulsions. The present work intends to compare a maximum of laboratory data with actual field data and, hopefully, will bring a contribution to resolve practical problems. Three WBM model systems were chosen: to conventional polymers (xanthan and polyanionic cellulose) shale swelling and dispersion inhibitors (partially hydrolyzed polyacrylamide, sodium silicates, polyalkyleneglycols) were added. Thanks to the use of a new compacted pellet-based filtration technique, their performances were discussed: - from the macroscopic point of view, through the analysis of their rheological and filtration characteristics and the consideration of shale-fluid interactions by the study of electrokinetic properties, particle size distribution and polymer retention, - and, on the microscopic scale, by in situ X-ray diffraction (wet cell) and light iffraction. Rheological and filtration parameters were correlated with electrokinetic properties and confirmed by the variations of interfacial and wetting characteristics. The silicate system shows the best inhibition performances. The study of OBM stability concerned the influence of surfactant type and concentration, dispersed phase ratio and other ad ditives. The optimum surfactant concentration is that yielding a compromise between high electrical stability, high emulsion ratio and good resistance to centrifugation. The various emulsifiers were classified according to the variation of emulsion volume, electrical stability and drop size distribution. Parallel to rheological measurements, the analysis of the structures appearing in emulsion - organoclay mixtures by small angle neutron scattering (SANS) allowed to explain the mechanisms of emulsion stabilization. A new emulsifier mixture, proposed for a full-scale field test, yielded encouraging results, compared with those of commercial formulations. In the reservoir, the effect of drilling fluids was apprehended by a formation damage study. Our objective was to correlate the global results obtained by a whole drilling fluid system with the damage generated by individual components. The tests showed the influence of the nature, composition and particle size of additives used in fluids. Due to the complexity of the phenomena involved, an attempt to model and predict damage showed some links between fluid properties, porous medium characteristics and induced damage ratio. Static filtration favors cake formation whereas dynamic filtration contributes to filtrate invasion. As regards environment, in addition to circulation fluid loss during and after drilling, the pit, as a collector of liquid and solid products coming from drilling, is a big source of pollution and danger. The diagnosis of the treatment techniq ues used showed major imperfections able to induce hazards for human health, ecosystems and environment. With the proposal of a biological treatment, the present works approach a solution of performance -costenvironment equatio

New HTHP fluid loss control agent for oil-based drilling fluid from pharmaceutical waste.

In oil-based drilling fluid systems (OBM, for Oil-Based Mud) the oil phase is the major source of contamination and hydrocarbon pollution is, by far, the main concern. However, the release and accumulation of mud additives in the environment may be deleterious on grounds of volume and/or concentration. This paper describes a waste valorisation study from an antibiotic large-scale manufacturing for the preparation of a new drilling fluid additive (Fluid-Loss-Control agent: FLC) for OBM. This additive is environment-friendly, biomaterial in nature, and totally biodegradable and thus expected to have no detrimental effects on the surrounding environment and ecosystems. After product washing, heating, grinding, and screening, a cationic surfactant was used to improve fluid stability and filtration properties. Our results show that: According to drilling fluid requirements, the treatment of this pharmaceutical reject yields a product with good properties, i.e. satisfactory as far as thermal stability, filtration characteristics, and rheology property are concerned. The pre-treatment of those products (according to their original state and particle size, as well as the type and concentration of added surfactant) enhances additive quality and shows good compatibility in drilling fluid systems. The substitution of this new product for conventional additives affords good drilling fluid stability and performance under high temperature and high pressure (HTHP) conditions, economic, and environmental solutions to improve the environmental standing of OBMs further

Power Quality Enhancement in Electricity Grids with Wind Energy Using Multicell Converters and Energy Storage

In recent years, the wind power industry is experiencing a rapid growth and more wind farms with larger size wind turbines are being connected to the power system. While this contributes to the overall security of electricity supply, large-scale deployment of wind energy into the grid also presents many technical challenges. Most of these challenges are one way or another, related to the variability and intermittent nature of wind and affect the power quality of the distribution grid. Power quality relates to factors that cause variations in the voltage level and frequency as well as distortion in the voltage and current waveforms due to wind variability which produces both harmonics and inter-harmonics. The main motivation behind work is to propose a new topology of the static AC/DC/AC multicell converter to improve the power quality in grid-connected wind energy conversion systems. Serial switching cells have the ability to achieve a high power with lower-size components and improve the voltage waveforms at the input and output of the converter by increasing the number of cells. Furthermore, a battery energy storage system is included and a power management strategy is designed to ensure the continuity of power supply and consequently the autonomy of the proposed system. The simulation results are presented for a 149.2 kW wind turbine induction generator system and the results obtained demonstrate the reduced harmonics, improved transient response, and reference tracking of the voltage output of the wind energy conversion system.Peer reviewedFinal Accepted Versio

Higgs ptp_t distribution in Higgs + jet production at hadron colliders within the non-commutative Higgs effective standard model

We use the non-commutative Higgs effective standard model to make a phenomenological prediction for the transverse momentum distribution of the Higgs boson produced in association with a jet at hadron colliders. We calculate at leading order in the non-commutative parameter $\Theta$ as well as leading order in the strong coupling $\alpha_s$, the one-loop $p_t$ distribution of the Higgs boson. As in the standard model, the fixed-order distribution suffers from large logarithms at small $p_t$ which require an all-orders resummation. We find that the large-$p_t$ region of the distribution is strongly affected by the non-commutativity, while small-$p_t$ region is not. Following this observation, we propose a simple matching method that allows us to compute a result that is also valid at small $p_t$ obtained with standard-model parton showers such as Pythia 8.Comment: 9 pages, 3 figure