Evaluation of the Interactions Between Oilfield Chemicals and Reservoir Rocks

Abstract

Sand failure and production occurs when the formation stress exceeds the strength of the formation, which is derived majorly from the natural material that cements the sand grain and cohesive forces. This study investigates the effects of scale inhibitor, biocide and corrosion inhibitor on the geomechanical strength of reservoir rocks (carbonate and sandstone). Integration of geomechanical, petrophysical and analytical techniques is used to establish the failure effects of the interaction of these chemicals on the geomechanical strength of reservoir rocks and failure mechanisms resulting from such interaction. The results confirm that chemical adsorption, dissolution, precipitation and ionic substitution reactions took place between the oilfield chemicals and the formation rocks leading to weakening of the reservoir grain fabrics and reduction in unconfined compressive strength which in turn causes sand failure.

Sand failure: effect of biocide on the geomechanical properties of outcrop carbonate rock under static condition

“…It is noteworthy that there are instances where the precipitated materials that fill the pore spaces may not be as strongly cemented as in their original state. This can cause grain fabric weakening which may lead to rock failure (Wuyep et al 2018(Wuyep et al , 2020. XRPD further confirms the preponderance of dolomite (95.1 wt%) in the carbonate.…”

“…A cross section of untreated carbonate (Edward brown) under SEM ( Fig. 1a) revealed dolomitized limestone with moderately sorted euhedral-subhedral dolomite (CaMg(CO 3 ) 2 ) mineral with sucrosic texture (Wuyep et al 2020). Observed in the SEM micrograph were cloudy centres and light rims which are typical of dolomites (dotted spheres in Fig.…”

Sand Failure: Effect of Biocide on the Geomechanical Properties of Outcrop Carbonate Rock Under Static Conditions

“…A cross-section of untreated carbonate (Edward brown) under SEM revealed dolomitized limestone with moderately sorted euhedral-subhedral dolomite (CaMg(CO3)2) mineral with sucrosic texture (Wuyep et al 2018b) [6] . Observed in the SEM micrograph are cloudy centres and light rims which are typical of dolomites.…”