Frac Optimization by Sand Entry Distribution

Abstract

Billions of dollars are invested into hydraulic fracturing every year. However, how to optimize frac design parameters such as stage and cluster spacing, fluid and proppant volume into each stage, number of perforations per cluster and temporary isolation is still not clear. This paper proposes a new method to estimate the volume of proppant penetrating each perforation hole. By aid of high-resolution optical imaging technology, perforation hole size before and after frac treatment can be accurately measured and interpreted. The difference in area before and after Frac is the eroded perforation area. Eroded area represents the sand entry into a perforation. Sand Entry Distribution (SED) determines the frac efficiency. Better SED gives better frac efficiency. Operators understand that different frac treatment volumes and different cluster versus perforation holes designs will impact the productivity. With the technology proposed in this paper, different frac designs can be measured and calculated using SED. A better SED in a cluster and/or a stage is certainly a better frac design. The method described in this paper estimates the proppant volume penetrating into each perforation hole after frac. Furthermore, a number of statistics and comparison between clusters and stages are described in the paper to give operators a clear indication of which frac design gives better frac efficiency and more uniform distribution.