Countermeasures against Improving Stimulation Effect after Fracturing Shallow and Medium-depth Gas Reservoirs, Western Sichuan Basin

For shallow and medium-depth gas reservoirs in western Sichuan Basin, there are many problems occurring in small-scale sand fracturing, such as poor stimulation effect, low backflow of drilling fluid and severe formation damage. In this study, two countermeasures against improving stimulation effect are presented, including large-scale sand fracturing and fiber sand high flowing back technology. After large-scale sand fracturing, facture-making is large in length; reservoir is connected widespread; and stimulation effect becomes better. Through high flowing back technology, both backflow rate and efficiency of drilling fluid can increase effectively; and retention of drilling fluid in formation can slow down, resulting in decreasing formation damage and increasing gas productivity after fracturing. In-situ application indicates that the two countermeasures can effectively increase not only stimulation effect but also recovery efficiency after fracturing.