geological drill pipeIn drilling work, drilling safety has always been an issue that everyone attaches great importance to. The following is an explanation of how to establish safe work steps and what specific operations are involved:

First, the use of drill bits

1. In the upper soft formation (drillability level value is less than 5), a milling bit with high mechanical drilling speed can be selected. In the formation of deep well section (drillability level value is greater than 5), insert bits with more footage can be selected.

2. The drag bit is suitable for drilling in soft and soft shale, argillaceous sandstone, shale and other plastic and plastic brittle formations.

3. Under normal circumstances, the formation drillability level value is less than 5, that is, PDC bit is selected for extremely soft to medium hard formation; formation drillability level value is greater than 5 and less than 8, that is, TSP bit is selected for medium hard to hard formation; formation drillability level value is greater than 8, that is, natural diamond bit is selected for hard to hard formation.

4. The bottom hole is clean, no falling objects, and the tripping speed is appropriate

5. The product of the drill pressure and the rotation speed recommend by the manufacturer shall be taken as the constraint condition, and the maximum drill pressure and the maximum rotation speed cannot be used at the same time.

6. if foundgeological drill pipeWhen the drill bit has no footage, the pump pressure is obviously increased or decreased, the penetration rate is suddenly decreased, the torque is increased, etc., if there is no problem with the ground equipment, the drill shall be tripped out for inspection.

Second, drilling fluid treatment, maintenance and storage

1) Maintain the density, viscosity, water loss, mud cake thickness, pH value, solid content, rheological properties, filtrate properties and other properties to meet the requirements of safe drilling.

2) Do a good job in maintenance and regular calibration of drilling fluid instruments.

3) Record the drilling fluid test, treatment and maintenance.

4) Reserve sufficient drilling fluid and weighting materials.

Site accident and complex situation prevention and treatment

① Shim

Adhesion sticking prevention

Use high-quality drilling fluids, such as high-valent cationic polymer systems, good lubricity, low solids and low fluid loss.

Adopt reasonable bottom hole assembly, use spiral drill collar, weightgeological drill pipe2. Stabilizer, etc., increase the support point of the drilling tool and reduce the contact area; use the jar while drilling.

Reduction of downhole rest time of drilling tools

Excellent wellbore quality.

Reasonable design, the watch cover must be sealed with soft layer, and the technical cover must be sealed to above the leakage layer.

Maintain the pressure of mud column to control the density of drilling fluid, and fill drilling fluid well during tripping out and shutdown.

Reduce pressure activation to control the speed of starting and tripping, and use drilling fluid with anti-collapse performance from slow to fast and from single to double when pumping. Cation, silicate, potassium base, low filtration and high salinity drilling fluid, etc., to prevent formation collapse.

② Prevention of well leakage

Use near-balanced pressure drilling; drill soft and easy-to-leak formations to control drilling speed, and operate such as tripping, pumping, and weighting to avoid pressure excitement caused by operations; strengthen drilling fluid inhibition treatment to minimize cutting force; add unidirectional sealant into drilling fluid to seal the upper leakage formation.