Well Cementing Technology for Well Yangtan-1 with High Circulation Pressure

High circulation pressure prior to well cementing has long been a problem that remains unsolved. In cementing the well Yangtan-1, after running liner strings and circulating for 51 h, flow rate was still so low, only 0.9 m³/min, but the pump pressure was unreasonably high, up to 22 MPa. The well finally had to be cemented at high circulation pressures. Several measures were adopted to avoid accidents during cementing, such as using high strength surface manifolds, improving the rheology of drilling fluid and cementing fluids (prepad fluids, spacers, and cement slurries etc.), minimizing the volume of redundan t (additional) cement slurries, reasonably prolonging the thickening of cement slurry, and displacing at low pump rates. CBL-VDL logging data after 48 h show that of all the cemented length of the wellbore, 7% cemented are perfect, 52.5% cemented acceptable, and the rest 40.5%, are poorly cemented. Depth of the cement top in the annular space and the quality of the cementing job satisfy the needs for subsequent well operation.