Degradable Materials for Multi-Stage Stimulation

Degradable plug-and-perf systems made of degradable alloys and polymers are being used extensively for multi-stage stimulation (MSS). This paper reviews the degradable materials available in the market, including degradable magnesium and aluminum alloys and degradable plastics and elastomers, compares their degradation mechanisms, and discusses the factors affecting their degradation behavior. A series of degradable aluminum alloys with good mechanical properties, and a tunable range of degradation rates were developed in Schlumberger for MSS applications. Key parameters, such as material formulation, temperature, and hydrostatic pressure are used to control the degradation behavior of these degradable alloys. Predictive models are established to predict the degradation time window under a broad range of downhole conditions for improved completions job planning. Comprehensive testing has been done to verify the performance of the materials in the simulated downhole conditions. In addition, field operation results are available to validate the performance of the degradable fracturing plugs made of these degradable alloys. Degradable materials enable degradable fracturing plug applications and eliminate the need for mechanical intervention. They receive more and more attention in the MSS market. We will see more rapid growth of their applications in the coming years.