New visualized fracture-cavity type malignant leakage evaluation device and experimental evaluation of plugging system

Abstract:

Fracture-cavity formation malignant leakage is one of the most common and difficult to control drilling in engineering. To solve the problem of the lack of indoor evaluation means for fracture-cavity type malignant leakage， a new visualized evaluation device for fracture-cavity type malignant leakage was developed. The maximum experimental temperature was 180℃， the maximum simulated length of fracture-cavity was 60cm， the maximum rated experimental pressure was 5MPa， and the maximum diameter of the filling and plugging module was 5cm. The evaluation experiment of 1cm and 2cm gravel simulated plugging was carried out by using the new visualized fracture-cavity type malignant leakage evaluation device， and the optimal plugging system formula suitable for the 1cm and 2cm gravel simulated fracture-cavity system was formed. The formula optimization of DY9 well plugging system was carried out， and the on-site plugging pressure reached 5MPa， and the plugging was successful once. The research shows that the sealing layer can be visually evaluated by the new visualized fracture-cavity malignant leakage evaluation device， which is convenient for the optimization of the plugging slurry formula. The reasonable combination of "rigid material + fiber material + elastic material" in the plugging system can form a dense pressure sealing， so as to realize the effective plugging of the fracture-cavity.