Sand Production in Ultra-Weak Sandstones: Is Sand Control Absolutely Necessary?

Abstract

TX 75083-3836, U.S.A" fax 01·972·952·9435. AbstractThis study is focusing on sand production processes in weak sandstone formations with a uniaxial compressive strength in the range of 0 -10 MPa, with special emphasis on the ultraweak facies where uniaxial compression tests hardly can be conducted. The relative influence of rock mechanical properties on rock failure and sand production modes is addressed to understand sand production data from wells in a weakly consolidated basin, Results of physical model experiments of sand production from boreholes and perforation cavities as well as numerical simulations have been used along with the field data to evaluate different criteria for the onset of sand production in ultra-weak formations. It is shown how in particular the shallow and weakest strata deviates from the classical behavior of more competent formations, and a simple empirical criterion for estimation of the conditions for onset of sand production is proposed, Finally, alternatives to classical sand control strategies are discussed, which directly take into account the nature of weak sandstone,

Particulate Modeling of Sand Production Using Coupled DEM-LBM

“…It is evident that models with a smaller cavity and higher UCS require higher stress for catastrophic sanding. As suggested by Fattahpour et al [2], the variations of the stress levels with UCS are almost linear, yet non-linear correlations are also proposed [24]. Although the results indicate that the stress levels leading to catastrophic sanding are proportionate to the strength of the particle assembly, the slope of the corresponding trendlines is different for models with various hole diameters.…”

“…To study sand production in weakly-consolidated sandstones, Tronvoll et al [21][22][23][24][25] conducted a series of experimental-numerical studies on the stability of the cylindrical cavities. Thick-Walled Hollow Cylinder (TWHC) samples were used in the experiments to mimic field sandstone around boreholes.…”

Bonding Strength Effects in Hydro-Mechanical Coupling Transport in Granular Porous Media by Pore-Scale Modeling

“…Thus, in sand production simulation, the number of accumulative bond breakage will be monitored as an indicator of the damage in the sample, and the larger the number is, the closer the sample is to macroscopic failure. In cemented granular media, bond is a primary property determining its macroscopic behavior, and the failure of granular media is generally owing to the bond breakage [24]. Thus the number of cumulative bond breakage is monitored during the biaxial compression simulation to show the relationship between bond breakage and macroscopic mechanical behavior.…”

Adaptation of a triaxial cell for ultrasonic P-wave attenuation, velocity and acoustic emission measurements

“…Portland cement, sand and water were used to manufacture the sample and mixed proportionally as per procedures outlined in Nouri et al [24]. The aim of this test was to induce volumetric failure of the sample as would be expected in the vicinity of a well bore in very weak rock, where substantial pore pressure reduction is observed causing subsidence and sand production [24,25]. The petrophysical and static elastic constants are displayed in Table 2.…”