Scope of Application

This technology is applicable to the well cementation of horizontal gas well.

Principles

To re-wipe well section of trip impeded for preparing good borehole conditions for laying down well casing and work of well cementation. To reasonably design the position of casing centralizer  and conduct encryption on centralizer at deflecting section and horizontal section by using eddy flow rigid centralizer at horizontal section for improving casing alignment. To inject oil displacing flushing fluid as forerunning slurry prior to well cementation for flushing casing and the wall of well completely and improving interface cement quality. Using aggravated isolation liquid with surfactant to isolate drill fluid from cement slurry, increase the replacement efficiency of cement slurry and reduce the contamination of slurry to cement slurry. Using anti-gas-channeling high density cement slurry to widen the grade difference of replacement slurry density, and increase the replacement efficiency of major deflecting section and horizontal section.

Technical Indicators and Performance Features 

1.Anti-gas-channeling high density cement slurry can rematch medium to low temperature fluid loss agent and high temperature fluid loss agent with some innate fluid loss effects.

2. The resistant temperature of cement slurry can be 140°C，so it enjoys good fluidity and rheological property with zero free fluid, water loss lower than 50ml and adjustable thickening time and can meet the requirement of deep well cementation operation.

3.Set cement has high anti-pressure strength and resilience, low coefficient of brittleness and effective function of anti-gas-channeling.

Field Applications

Since 2010, this technology has been applied to 15 wells in Zhongyuan Oilfields and North China Branch with 100% success ratio of operation and 80.6% success ratio of cementation.