Cement plugging and sidetracking in complex formation at well Xinhedi1

Abstract:

A broken section of great thickness was encountered in well Xinhedi1 during drilling from 1314.00m to 1419.98m. The formation was highly broken with a large dip angle, and rich in aquifers. Falling stones and water sensitive collapse of the borehole wall were much serious. During the drilling operation, the drilling tools cannot be lowered into the borehole bottom due to the large resistance in the hole. Borehole incidents occurred frequently, and it was difficult to drill through the broken section. In order to deal with the borehole incident and to drill through the broken formation, cement plugging and side tracking were adopted in these zones. Influenced by the complex factors of the hole, especially the dilution of the drilling mud and the erosion resulted by the water systems in the broken belt from 1358.76m to 1396.46m, cement plugging failed early for many times, which wasted a lot of materials and the drilling time. A set of specific and practical measures were developed through field testing, which solved the technical difficulties of the cement plugging in the field, and improved the success rate of the wall protection with cement plugging and side tracking, providing reference for similar construction in the future.