The Research and Application of Low Density Cement Slurry System at Low Temperature in Daqing Oilfield

During long sealing cementing of low temperature shallow gas well in Daqing oilfield, for the low density cement slurry at low temperature, the setting time is longer, gelling strength development is slower, filter loss is greater and the anti-channeling ability is weak. It would make the happening of annular gas channeling and fluid emitting, affect the cement job quality. Low density low temperature anti-channeling cement slurry system was studied with compound early strength agent, polyacrylate polymer latex drop loss of water, dispersed polymer powder anti-channeling agent, improve the comprehensive performance low density cement slurry. Laboratory experiments showed that setting time shortened by 50%, early strength increased by 46%, permeability decreased by 50%, interfacial bond strength increased by 47%, compared with the low density cement and the class G well cement. The application tests in the field were carried out in 18 wells. High-quality rate of well cementing increased by 11.1 percentage points. The incidence rate of fluid emitting is decreased by 1.6%. This cement slurry system can satisfy the requirements of cementing operation. It will improve the cementing quality of long sealing section in a shallow layer in Daqing Oilfield.