Key technologies of ultra-high density drilling fluid performance adjustment in Well Guanshen-1

The problems of ultra-high density drilling fluid are difficulty to improve the density of drilling fluid, poor mobility and settlement stability, and difficulty to control the performance. When ultra-high pressure layer is penetrated in drilling Well Guanshen-1, barite is used as the weighting agent, and the ultra-high density polysulfonate drilling fluid is implemented with the density of 2.50 ~ 2.87 g/cm3. It is lasted more than 100 days, and the total footage amounted to 785.9 m, with stable performance, normal circulating pump pressure, and safe operation. This is the record of the highest drilling density, the shortest operation time and the greatest footage. Combined with the actual operation condition, the key technologies of how to control the density, rheology and sedimentation stability of drilling fluid are analyzed. It provides useful techniques and methods for the application of ultra-high density drilling fluid in ultra-high pressure complex formation.