Research Progress of Chelating Agent and Plugging Removal Technology for Barite Pollution in Oil Wells

Barite blockage formed by drilling fluid filter cake with barite weighting agent as the main component is one of the main factors causing oil and gas reservoir damage and affecting oil and gas production. Conventional acidification measures are difficult to dissolve the barite blockage, and the development of a cost-effective non-acid chelating removal agents and the formulation of a scientific blocking removal construction process are effective engineering means to solve the barite blockage. Amino carboxylic acid chelating agent forms strong chelate with barium ions on the surface of barite, promotes the rapid dissolution of barite, and helps to relieve the blockage of barite filter cake. However, key technologies such as the commercial selection of chelating removal agents, the material chemical design of chelating removal agents, the evaluation method of chelating removal agents, and the construction technology of chelating removal agents, seriously affect the engineering application value of barite blocking removal. In this paper, the structural characteristics of the special chelating agent for barite blocking removal are summarized, the main factors affecting the blocking removal effect of the chelating removal agents are reviewed, the guiding principles for designing the product formulation of the chelating removal agents, the product performance evaluation method and the potential industrial by-product raw materials that can be used for the preparation of the chelating removal agents are proposed, and the construction process design method and control essentials of on-site blocking removal are analyzed. Finally, through the analysis of two typical application cases in sandstone and carbonate reservoirs, it provides readers with new ideas for the chemical design of chelating removal agents for barite filtrate cake and field-removing techniques.