Definition - What does Borehole Integrity mean?
Borehole integrity refers to the structural stability and tightness of the formation during the well construction and operation phase. Losing the drilling borehole integrity is a trenchless construction hazard that can lead to borehole collapse. Depending on the borehole function, hole fragility can cause damage to equipment or potential injury to employees.
Borehole integrity depends on good bore design, selection of right construction material and good cementing between casing and borehole wall.
Trenchlesspedia explains Borehole Integrity
Geomechanical Study of rock and sub-surface formation helps in determining formation integrity during drilling of boreholes and during pullback. Engineers find this study important in modeling and predicting rock and soil behavior in order to reduce the risk of project failure. Geomechanics also helps in understanding borehole integrity which is crucial in designing the right mud mix by adjusting drilling fluid parameters for viscosity, plasticity, and gel strength.
Borehole integrity can be tested by tests such as tightness test and examination and assessment of borehole integrity. These tests help determine as to how long and under what circumstances these wells can be continued to be operated safely.
Boreholes become unstable in different ways such as by borehole closure or narrowing, borehole fracturing, enlargement of the borehole, and borehole collapse. Instability of the borehole is usually caused by mechanical failure or due to shale instability.