Development and Stability Analysis of Degradable Frac Plug
Abstract
Degradable frac plug (DFP) can eliminate mill-out of frac plug and reduce the operational time in multi-stage hydraulic fracturing in unconventional reservoirs. High mechanical strength and degradation rate are necessary for components of DFP to hold a high differential pressure during fracturing and disintegrate promptly after fracturing.
In this study, degradation behavior and mechanical property of fast-degrading rubber, alloy, and polymer were evaluated to examine their applicability to DFP. The effect of various factors such as temperature, salinity, additives, acid, and alkaline on the degradation were investigated. Mechanical tests and pressure tests of DFP and its parts composed of the fast degrading materials were performed. Stability analysis of the components by the finite element method was also conducted. Stability of various designs of plug components under high pressure was quantified with ABAQUS, a finite element analysis (FEA) software.
Degradation rate of all fast-degrading materials were in general increased with increase in temperature. In contrast, salinity concentration, acid, alkaline, and additives affected degradation rate differently for each fast degrading material. Mechanical tests indicated that plug parts composed of the fast-degrading materials had enough strength for frac plug. Designs of plug components were optimized by FEA and designs that reduce deformation of rubber downstream decreased stress and strain on other plug parts. The DFP with optimized parts showed improved pressure tolerance in the pressure tests.
In this paper, the degradation behavior and mechanical property of the new fast-degrading material in various conditions were discussed. Based on the results, the materials can be used for not only DFP but also other applications in oil and gas industry. The novel frac plug composed of the new fast-degrading materials enables engineers to reduce the cost and time of the well completion process.
Citation
Yoshida, Hiroaki (2020). Development and Stability Analysis of Degradable Frac Plug. Doctoral dissertation, Texas A&M University. Available electronically from https : / /hdl .handle .net /1969 .1 /197607.