Influence of Drill-in Fluids Composition on Formation Damage
| Autor: | Annie Audibert-Hayet, Lionel Rousseau, Erna Sanchez |
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| Rok vydání: | 2004 |
| Předmět: | |
| Zdroj: | SPE Journal. 9:403-410 |
| ISSN: | 1930-0220 1086-055X |
| DOI: | 10.2118/82274-pa |
| Popis: | Summary Drill-in fluids are generally water-based muds (WBMs) containing a viscosifier, a fluid-loss reducer, salts, and sized calcium carbonate particles. Formation damage mechanisms induced by the use of WBM formulations have been extensively studied and correspond to different phenomena such as water trapping, polymer adsorption and retention, and particle plugging. In this paper, a detailed study was carried out on the behavior of scleroglucan-based formulations generally proposed for high-temperature zones and/or high-permeability reservoirs and on the comparison with performances of xanthan-containing formulations. This work covers not only the effect of the fluid composition, including the presence or absence of drilled solids, but also the filtration conditions, such as shear rate and temperature. Mud filtrates have been characterized in terms of polymer content and by multiangle laser light scattering coupled with size-exclusion chromatography (SEC/MALLS) and filter cakes by cryo-SEM. Filtration curves obtained under static conditions can be related to the rheological behavior and thermal stability of the biopolymer used as a viscosifier but not related to the solid content of the mud. Under dynamic conditions, the filtration curve strongly depends on the aggregation tendency of the scleroglucan sample. Scleroglucan-based drill-in fluids present very good properties compared to classical water-based formulations at 120°C using a commercially available scleroglucan sample. The cryo-SEM dynamic filter-cake observations confirm a lower filter-cake permeability obtained under dynamic conditions with an homogeneous structure, no aggregates, and a structural polymer network. When in contact with a borehole, for the same circulation time, a scleroglucan formulation will invade half the zone invaded by a xanthan-based formulation. |
| Databáze: | OpenAIRE |
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