GEOSYNTHESIS ENGINEERING

Development and service of drilling fluid

The liner was run in two sections. The first section was run the interval of 4596-4871 m and set with the help of oil-swelling packers. Such approach to setting is due to the fact that the running interval of the first liner section was drilled using invert-emulsion mud Witer II.

Cementing of wells with water-based cement slurry after drilling with the utilization of oil-based flush fluids provides for the use of special washing-demulsifying buffers necessary for wellbore cleaning from the hydrophobic filter cake. Such fluids do not guarantee complete cleaning of the hydrophobic surface or good adhesion of the cement stone to the walls of the well. Moreover, water phase of such solutions and the cement filtrate can lead to an irreversible deterioration of reservoir properties of pay-zone negating all the advantages of a primary opening of pay-zone in the well using OBM.

After setting the first section of the liner, invert-emulsion mud Witer II was replaced in the interval of the second section running with polymer-inhibited drilling mud PIBR-2M. Running and setting of the second section of the liner in the interval of 2100-4596 m provides for the liquidation of leakage of the previous Ø 244.5 mm casing.

PARAMETERS OF INVERT EMULSION DRILLING MUD WITER IІ BEFORE LINER RUNNING:
  • Density – 1,18 g/сm3;
  • Funnel viscosity – 67 s;
  • Gel – 67/67 dPa;
  • PV – 31 mPа*s,
  • YP – 139 dPa,
  • Filtration – 2,5 сm3/30 min;
  • ES - 1880 V.