Study on plugging mechanism and acidizing plugging removal technology of shale reservoir

Abstract Ordos Basin is rich in unconventional oil and gas resources. Shale resources are developed in source rock series. With the continuous development, many oil wells have different degrees of blockage in the production process. It has different levels of complex performance in wellhead, wellbore and formation, which seriously restricts reservoir production. The formation fluid, reservoir rock samples and plugging materials were analyzed from multiple angles by means of nuclear magnetic electron microscopy, X-ray and acid dissolution to determine the source and formation mechanism of plugging materials. The analysis results show that the main component of the formation mineral is quartz, and the formation crude oil is mainly alkane. The scale sample is a mixture of formation minerals, scaling and corrosion products, and the content varies greatly. It is considered that the particle migration in the reservoir is an important cause of inorganic damage, and the organic matter damage cooperates with the inorganic damage to make the damage more serious. On this basis, this paper puts forward the organic cleaning of wellhead and wellbore, and then inorganic plugging removal of formation plugging, and constructs the deep acidification system of 12 % HCL + 10 % HBF 4 and 10 % GT-α. The experiment shows that the effective production ratio can reach 3.6, and the effect of acidizing and plugging removal is remarkable. This study has formed an effective plugging treatment technology for shale reservoir, which can provide technical support for similar reservoir acidification.