Precise Dynamic Managed-Pressure Cementing Technologies for ϕ139.7 mm Liner Cementing in Well Hutan-1

Due to long cementing intervals and high bottomhole temperature, the ϕ139.7 mm liner cementing in Well Hutan-1 was exposed to various technical difficulties, such as high lost circulation and overflow risks, high requirements on the performance of the cement slurry, and difficult control of the thickening time of the cement slurry. Precise dynamic managed-pressure cementing technologies were tested in the ϕ139.7 mm liner cementing section in this well to address the above technical difficulties. Specifically, the cement slurry formulation was improved, the slurry column was precisely designed, and the casing centralizer placement was optimized. Technical measures were developed to ensure that the dynamic wellbore pressure was between the formation pore pressure and the lost circulation pressure, and the precise managed-pressure drilling equipment was utilized. Managed-pressure liner running, cement slurry injection, and waiting-on-cement were thereby implemented. As a result, a “whole-process” precise dynamic managed-pressure cementing was ultimately achieved. The ϕ139.7 mm liner cementing in Well Hutan-1 was considered up to standard. The successful implementation of precise managed-pressure cementing during the ϕ139.7 mm liner cementing in Well Hutan-1 indicates that precise managed-pressure cementing can effectively enhance the cementing quality of long cementing intervals of ultra-deep wells in formations with narrow safety pressure window and can provide technical assurances for the exploration of deep oil and gas at the southern margin of the Junggar Basin.