This paper presents a comprehensive study on sand production with the objective to develop a practical sand production model to estimate amount and rate of sand produced. The study comprised three components; laboratory experiments, numerical modeling and field case study for model validation. An experiment program was carried out on seven weak sandstones with various strengths. The experiments were conducted on relatively large samples under realistic effective reservoir stress and drawdown conditions with oil and gas flow. The large sample size allowed a meaningful amount of sands to be produced with minimum boundary effect. Real-time borehole monitoring using a borescope and X-ray CT scanning on the tested samples enabled rock failure and sanding mechanisms to be investigated. The laboratory experiments were simulated by numerical modeling using discrete element and finite difference methods. A sand production quantification model was developed by correlating the critical plastic volume obtained from the numerical modeling with the cumulative amount of sand produced from the sanding experiments. The sand quantification model was applied to a field case study aiming for model validation. The modeling result has been so far consistent with field observations.