一种酸溶水泥溶解促进剂

当目的层发生恶性漏失时，通常采用酸溶水泥进行堵漏，但是目前该堵漏技术尚不成熟。现有的酸溶水泥体系以水泥等胶凝材料附加碳酸盐为主，有的酸溶率低于90%，有的酸溶所需时间较长，不能很好地满足现场需要。通过对影响酸溶率的主要因素的评价分析得到，优化碳酸盐加量和细度，可使水泥石的酸溶率高于90%，但很难提高到95%以上。为了进一步提高水泥石的酸溶率，研发了一种溶解促进剂，该促进剂通过添加有机类发泡剂和含有磺酸根的饱和烷烃作为稳定剂，在碱性条件及一定温度下能够自身分解，产生少量细小的气泡，均匀地分散在水泥浆中，在水泥凝结物基体上预留下溶蚀孔洞，为酸液腐蚀提供通道，使水泥石酸溶率及酸溶速率都得到了很大地提高，30 min水泥石酸溶率可达96%以上。经现场试验检验，该套水泥浆体系性能易于调节，不仅解决了恶性漏失的难题，而且保护了储层。 

A Dissolution Accelerator of Acid-soluble Cement

Acid soluble cement is generally used in controlling severe mud losses. This technology is presently not mature. Acid soluble cements presently in use are mainly composed of cement and carbonate. Acid soluble cements are unable to satisfy the need of field application, some of them have acid solubility of less than 90%, while others need a long time to dissolve. It was found from the evaluation and analysis of the main factors affecting the acid solubility of cement that by optimizing the concentration and particle sizes of the carbonate added to the cement, the solubility of cement in acid can be increased to above 90%, still it is very difficult to increase the acid solubility to above 95%. To further increase the acid solubility of cement, a dissolving accelerator has been developed, which, when used with organic foaming agents and saturated alkanes (as stabilizer), can decompose at alkaline condition and a certain temperature to produce some small gas bubbles. These bubbles can be dispersed uniformly into a cement slurry and generate small dissolution holes in the gelled cement which serve as channels for acid dissolution. In this way the percent dissolving of cement in acid is greatly increased; 96% of the set cement can be dissolved in 30 min. The properties of the cement slurry in field application was easy to adjust. The application of this cement slurry not only solved the problem of severe mud losses, it also helped protect the reservoir from being damaged.