METHOD OF CEMENTING OF WELLS WITH ABNORMALLY HIGH FORMATION PRESSURE Russian patent published in 1997 - IPC

FIELD: well drilling, in particular, cementing of wells with abnormally high formation pressure. SUBSTANCE: method includes supply of grouting mortar to annular space. Excessive pressure is applied on mortar from wellhead. In this case, reduction of hydrostatic pressure of grouting mortar is compensated. At the initial moment, excessive pressure is built up of value equalling the pressure loss for hydraulic resistance in annular space at the end of cementing. After that, pressure is maintained up to the moment of setting of grouting mortar on bottom hole. Then pressure is gradually increased up to the moment of setting of grouting mortar at wellhead. Value of excessive pressure is determined by the formula given in the invention description. EFFECT: excluded fluid flows during the time of waiting for cement setting.