TY - THES

T1 - Methods of diverting water-based resins for sand consolidation

AU - Mörtl, Monika

N1 - embargoed until null

PY - 2009

Y1 - 2009

N2 - Is it better to consolidate an entire production zone prone to sand influx at least a little or is it preferable to consolidate a little properly? Even in case of discovering the most challenging downhole environments for applying chemical consolidation as sand control technique this question never arises. In sand control it is not an option to prevent sand influx only from part of the productive horizons. Further it can not be tolerated to consolidate the whole production zone insufficiently und non-uniform. Permeability anisotropy over long production intervals will favour non-uniform resin distribution which results in consolidated formation layers showing various compressive strengths. In order to achieve uniform sand consolidation over the productive zones proper resin diversion is necessary. In the course of this thesis the suitability of three fluid loss additives regarding their diversion ability has been tested based on the following concept. The diverting agent and the resin should be pumped in the same stage of the consolidation treatment. Therefore the resin has to invade the formation as spurt loss before the fluid loss additive plugs the pore space and diverts the remaining resin to lower permeable zones. This concept raises the need for a high spurt loss in order to achieve an appropriate consolidation radius around the wellbore. In addition to their ability to create high spurt loss and good fluid loss control over time suitable fluid loss additives have to show low susceptibility to vary spurt loss with formation permeability. Testing showed that within a small temperature spot one of the tested products meets the prerequisites of the defined concept. The thin and uniform filter cakes created during testing showed high spurt values and good fluid loss control over time as well as low variations in spurt loss with test bed permeability.

AB - Is it better to consolidate an entire production zone prone to sand influx at least a little or is it preferable to consolidate a little properly? Even in case of discovering the most challenging downhole environments for applying chemical consolidation as sand control technique this question never arises. In sand control it is not an option to prevent sand influx only from part of the productive horizons. Further it can not be tolerated to consolidate the whole production zone insufficiently und non-uniform. Permeability anisotropy over long production intervals will favour non-uniform resin distribution which results in consolidated formation layers showing various compressive strengths. In order to achieve uniform sand consolidation over the productive zones proper resin diversion is necessary. In the course of this thesis the suitability of three fluid loss additives regarding their diversion ability has been tested based on the following concept. The diverting agent and the resin should be pumped in the same stage of the consolidation treatment. Therefore the resin has to invade the formation as spurt loss before the fluid loss additive plugs the pore space and diverts the remaining resin to lower permeable zones. This concept raises the need for a high spurt loss in order to achieve an appropriate consolidation radius around the wellbore. In addition to their ability to create high spurt loss and good fluid loss control over time suitable fluid loss additives have to show low susceptibility to vary spurt loss with formation permeability. Testing showed that within a small temperature spot one of the tested products meets the prerequisites of the defined concept. The thin and uniform filter cakes created during testing showed high spurt values and good fluid loss control over time as well as low variations in spurt loss with test bed permeability.

KW - Sandkontrolle

KW - Sandverfestigung

KW - gleichmäßige Harzverteilung

KW - Permeabilität

KW - Anisotropie

KW - Filterkuchen

KW - Flüssigkeitskontrolle

KW - sand control

KW - sand consolidation

KW - uniform resin distribution

KW - permeability

KW - anisotropy

KW - filter cake

KW - fluid loss control

M3 - Master's Thesis

ER -