Insurance Claim

Pore pressure in shale is more than hydrostatic pressure; however the well does not flow because shale is in permeable. While drilling through pressured shale formation, pressure in shale causes fractures of shale due to stress crack.

Shale finally falls into the well and results in stuck pipe incident.

Warning signs of geo-pressured shale

• Shale fractures are seen at shale shakers.

• Possibly observe change in d-exponent, which means a sign of abnormal pressure, from mud logger.

• Pump pressure abnormally increases.

• Increase in rate of penetration (ROP).

• When compared to a normal trend, torque and drag trend abnormally increase.

• Background gas may increase.

Indications when you stuck due to geo-pressured shale

• It could be happened either while tripping or drilling.

• When it happens, the hole may be completely packed off; therefore, circulate is restricted or impossible in some cases.

What should you do for this situation?

1. Attempt to circulate with low pressure (300-400 psi). Do not use high pump pressure because the annulus will be packed harder and you will not be able to free the pipe anymore.

2. If you are drilling or POOH, apply maximum allowable torque and jar down with maximum trip load.

3. If you are tripping in hole, jar up with maximum trip load without applying any torque.

4. Attempt until pipe free and circulate to clean wellbore.

Preventive actions

1. Use proper mud weight to create over balance. You may need to weight up prior to drilling in to high pressure shale zones.

2. Minimize surge pressure and equivalent circulating density (ECD) in the wellbore.

Reference: Drilling formulas blog in the section of stuck pipe

View the original article here

Overburden stress increases over depth (the more a well is drilled, the more overburden stress will be seen). When mud weight is not enough to support the overburden, the stress from the overburden will create shale fractures which will fall down into the wellbore. Finally, shale fractures will pack the wellbore and cause a stuck pipe incident,

(Mud weight is high enough to overcome overburden stress.)

(Mud weight is not high enough to overcome overburden stress.)

Warning signs of overburden stress shale

• Torque and drag increase.

• Pump pressure increase.

• Abnormal amount of shale at shale shakers

• Caving shape of shale at shakers

Indications when you stuck due to overburden stress shale

• It could be happened either while tripping or drilling (most likely while drilling).

• When it happens, the hole may be completely packed off or bridged off; therefore, circulation is very difficult or impossible to establish.

What should you do for this situation?

1. Attempt to circulate with low pressure (300-400 psi). Do not use high pump pressure because the annulus will be packed harder and you will not be able to free the pipe anymore.

2. If you are drilling or POOH, apply maximum allowable torque and jar down with maximum trip load.

3. If you are tripping in hole, jar up with maximum trip load without applying any torque.

4. Attempt until pipe free and circulate to clean wellbore.

Preventive actions:

1. Use drilling mud that heavy enough to stabilize overburden stress.

2. Weight up mud prior to drilling into stressed shale zones.

Reference: Overburden Stress Shale Causes Stuck Pipe in Drilling Formulas blog

View the original article here

Overburden stress increases over depth (the more a well is drilled, the more overburden stress will be seen). When mud weight is not enough to support the overburden, the stress from the overburden will create shale fractures which will fall down into the wellbore. Finally, shale fractures will pack the wellbore and cause a stuck pipe incident,

(Mud weight is high enough to overcome overburden stress.)

(Mud weight is not high enough to overcome overburden stress.)

Warning signs of overburden stress shale

• Torque and drag increase.

• Pump pressure increase.

• Abnormal amount of shale at shale shakers

• Caving shape of shale at shakers

Indications when you stuck due to overburden stress shale

• It could be happened either while tripping or drilling (most likely while drilling).

• When it happens, the hole may be completely packed off or bridged off; therefore, circulation is very difficult or impossible to establish.

What should you do for this situation?

1. Attempt to circulate with low pressure (300-400 psi). Do not use high pump pressure because the annulus will be packed harder and you will not be able to free the pipe anymore.

2. If you are drilling or POOH, apply maximum allowable torque and jar down with maximum trip load.

3. If you are tripping in hole, jar up with maximum trip load without applying any torque.

4. Attempt until pipe free and circulate to clean wellbore.

Preventive actions:

1. Use drilling mud that heavy enough to stabilize overburden stress.

2. Weight up mud prior to drilling into stressed shale zones.

Reference: Overburden Stress Shale Causes Stuck Pipe in Drilling Formulas blog

View the original article here

Pore pressure in shale is more than hydrostatic pressure; however the well does not flow because shale is in permeable. While drilling through pressured shale formation, pressure in shale causes fractures of shale due to stress crack.

Shale finally falls into the well and results in stuck pipe incident.

Warning signs of geo-pressured shale

• Shale fractures are seen at shale shakers.

• Possibly observe change in d-exponent, which means a sign of abnormal pressure, from mud logger.

• Pump pressure abnormally increases.

• Increase in rate of penetration (ROP).

• When compared to a normal trend, torque and drag trend abnormally increase.

• Background gas may increase.

Indications when you stuck due to geo-pressured shale

• It could be happened either while tripping or drilling.

• When it happens, the hole may be completely packed off; therefore, circulate is restricted or impossible in some cases.

What should you do for this situation?

1. Attempt to circulate with low pressure (300-400 psi). Do not use high pump pressure because the annulus will be packed harder and you will not be able to free the pipe anymore.

2. If you are drilling or POOH, apply maximum allowable torque and jar down with maximum trip load.

3. If you are tripping in hole, jar up with maximum trip load without applying any torque.

4. Attempt until pipe free and circulate to clean wellbore.

Preventive actions

1. Use proper mud weight to create over balance. You may need to weight up prior to drilling in to high pressure shale zones.

2. Minimize surge pressure and equivalent circulating density (ECD) in the wellbore.

Reference: Drilling formulas blog in the section of stuck pipe

View the original article here

Pore pressure in shale is more than hydrostatic pressure; however the well does not flow because shale is in permeable. While drilling through pressured shale formation, pressure in shale causes fractures of shale due to stress crack.

Shale finally falls into the well and results in stuck pipe incident.

Warning signs of geo-pressured shale

• Shale fractures are seen at shale shakers.

• Possibly observe change in d-exponent, which means a sign of abnormal pressure, from mud logger.

• Pump pressure abnormally increases.

• Increase in rate of penetration (ROP).

• When compared to a normal trend, torque and drag trend abnormally increase.

• Background gas may increase.

Indications when you stuck due to geo-pressured shale

• It could be happened either while tripping or drilling.

• When it happens, the hole may be completely packed off; therefore, circulate is restricted or impossible in some cases.

What should you do for this situation?

1. Attempt to circulate with low pressure (300-400 psi). Do not use high pump pressure because the annulus will be packed harder and you will not be able to free the pipe anymore.

2. If you are drilling or POOH, apply maximum allowable torque and jar down with maximum trip load.

3. If you are tripping in hole, jar up with maximum trip load without applying any torque.

4. Attempt until pipe free and circulate to clean wellbore.

Preventive actions

1. Use proper mud weight to create over balance. You may need to weight up prior to drilling in to high pressure shale zones.

2. Minimize surge pressure and equivalent circulating density (ECD) in the wellbore.

Reference: Drilling formulas blog in the section of stuck pipe

View the original article here

 Overburden stress increases over depth (the more a well is drilled, the more overburden stress will be seen). When mud weight is not enough to support the overburden, the stress from the overburden will create shale fractures which will fall down into the wellbore. Finally, shale fractures will pack the wellbore and cause a stuck pipe incident,

(Mud weight is high enough to overcome overburden stress.)

(Mud weight is not high enough to overcome overburden stress.)

Warning signs of overburden stress shale

• Torque and drag increase.

• Pump pressure increase.

• Abnormal amount of shale at shale shakers

• Caving shape of shale at shakers

Indications when you stuck due to overburden stress shale

• It could be happened either while tripping or drilling (most likely while drilling).

• When it happens, the hole may be completely packed off or bridged off; therefore, circulation is very difficult or impossible to establish.

What should you do for this situation?

1. Attempt to circulate with low pressure (300-400 psi). Do not use high pump pressure because the annulus will be packed harder and you will not be able to free the pipe anymore.

2. If you are drilling or POOH, apply maximum allowable torque and jar down with maximum trip load.

3. If you are tripping in hole, jar up with maximum trip load without applying any torque.

4. Attempt until pipe free and circulate to clean wellbore.

Preventive actions:

1. Use drilling mud that heavy enough to stabilize overburden stress.

2. Weight up mud prior to drilling into stressed shale zones.

Reference: Overburden Stress Shale Causes Stuck Pipe in Drilling Formulas blog

View the original article here