Comparative Analysis of Sand Production Mitigation in Semi-Consolidated and Consolidated Sandstones Through Formation Strength Enhancement

ABSTRACT: Sand production is a significant problem in the oil and gas industry, damaging equipment and reducing well productivity. Oil companies invest millions of dollars annually to address this issue. Sand production increases sharply as water saturation increases during the water injection process. In principle, the rate of sand production mainly depends on rock strength inside sandstone formations. Hence, this study investigates the impact of quartz hydrolysis, a chemical reaction between quartz and water, leading to silica dissolution on sandstone strength as a function of water saturation through a dynamic approach. Also, present an inhibitor to prevent or reduce this reaction and to bolster the formation strength. Dynamic core flooding experiments were used to establish correlations between silica dissolution and sandstone strength as a function of various water saturation for both semi-consolidated and consolidated sandstone formations. Furthermore, this study examines the impact of temperature and time on silica dissolution and core strength. Finally, study the efficacy of an inhibitor in various concentrations to control this dissolution and its effect on core strength. The experiment results showed a clear correlation between increased water saturation and significantly enhanced silica dissolution, consequently reducing the core strength. In semi-consolidated sandstone, core strength has been dropping from 9.56 MPa (dry condition) as water saturation increased from 20 % to 100 %, companied by an increase in silica dissolution; this decline in core strength was steady until reaching the peak of reduction at 100 % Sw, where it reached 5.4 MPa, coinciding with the highest measured silica dissolution of 19.8 mg/l. In the case of consolidated sandstone, a similar trend of dissolution and strength reduction was observed. However, the maximum reduction in strength was 19.5 MPa, down from an initial strength of 33 MPa. This indicates that consolidated sandstone still has a higher strength to withstand failure. Additionally, the results showed a direct sensitivity of silica dissolution and core strength to temperature and time. Concerning the effect of inhibitor, sodium phosphate demonstrates a notable ability to suppress silica dissolution, particularly at concentrations of 0.1 wt% and 1 wt%. This inhibition effectively maintains core strength near its original value. This study presents a novel approach to mitigating the main source of increased sand production during water breakthrough rather than applying traditional sand control techniques.