Dissolvable Frac Plug with Metal Seal for Hydraulic Fracturing in HTHP Wells

Abstract In recent years, the metal seal dissolvable frac plugs have been well-applied in the development of unconventional oil and gas. The body of these frac plugs is entirely made by dissolvable magnesium-aluminum alloy materials, featuring characteristics such as no rubber element, small volume, large internal diameter, and simple structure. These features effectively resolve issues such as low dissolution rate and insufficient rubber element dissolution seen in traditional dissolvable frac plugs, significantly enhancing the dissolution rate of the frac plugs and playing an important role in the development of frac plug technology and the extraction of unconventional oil and gas. Metal seal dissolvable frac plugs have gradually replaced rubber-element-type dissolvable frac plugs, becoming the primary tool for zonal isolation in fracturing operations. Although the metal seal dissolvable frac plugs have entered the application stage, specialized research on them is still relatively scarce. Current research on dissolvable frac plugs mainly focuses on performance evaluation, technical issues during processes, and field application conditions. Among the limited studies on metal seal dissolvable frac plugs, most investigate the structural features and applications in medium to low-temperature wells (below 250°F), with a lack of research at high temperatures (above 250°F). As unconventional oil and gas well drilling becomes increasingly deeper, with higher downhole temperatures and downhole pressures, the application of metal seal frac plugs in high-temperature conditions faces challenges. Under high temperatures, the dissolution rate of magnesium-aluminum alloy is rapid, and the uniformity of material strength and ductility is poor, resulting in extremely unstable performance of high-temperature and high-pressure (HPHT) metal seal frac plugs. By considering the characteristics of metal seal dissolvable frac plugs under high-temperature conditions and combining the PDCA (Plan-Do-Check-Act) cycle principle (as shown in Figure 1), suitable materials were selected from existing. The successful development of a metal seal dissolvable frac plug suitable for high-temperature and high-pressure conditions will play a positive role in promoting the safe and efficient extraction of unconventional oil and gas. The advancement of this technology not only can enhance operational efficiency but also helps to minimize environmental risks during oil and gas production.