Technologies to improve the quality of liner cementing in BZ19-6 Block

The high-quality rate of liner cementing in BZ19-6 Block is not high, and circulation loss occurs frequently in the process of drilling.To solve this problem, the factors affecting the quality of liner cementing were analyzed.Then, some technical measures to improve the cementing quality were put forward and applied in field.It is indicated that the main factors affecting the quality of liner cementing in BZ19-6 Block are circulation loss, low flushing efficiency of prepad fluid and active gas reservoir.In view of these problems, it was proposed to improve the quality of liner cementing from three aspects, i.e., designing prepad fluid and slurry system to develop cementing leakage prevention and plugging technology, optimizing slurry formula to enhance the channeling prevention performance of slurry system, and optimizing prepad formula to improve the hole cleaning ability.The results of field application show that by virtue of this technology, the high-quality rate of liner cementing in this block is improved significantly and the poor cementing quality caused by the coexistence of gas channeling and leakage risk in the process of liner cementing is solved successfully.