Hi Umair,


I don't see any reason for hook load to decrease during the pressure test of casing. However, if it is case of pressure test after liner hanger setting, then any axial load due to piston effect would be transmitted to the hanger slips, and the circumferential area difference in liner and setting tool might face an uplift force due to pressure exertion. Just a random thought.

Good posts all. 

My MLT i.e. Mass length and Time, suggestion, in regard to these physical core Drilling elements, to better 'Manage Lost time', would be,

First and Always, Hand Draw a wellbore schematic of situation, scenario, operating, and note ably the physical conditions (of mass, length and time) that evidently exists. e.g. As taught by our peers many moons ago. 

If you cant then evaluate the MLT physical things for yourself. Please afford the SPREAD members the wellbore schematic, (suitably populated with all the evident facts that you can*) with your post.

*This avoids having to make numerous assumptions and fill in all the evident gaps generally needed.

From your hand drawn wellbore schematic. Timeline and Piece together to better understand the evident MLT physical (parts) relationships and then consider other people, paperwork and oddity evident factors that may also be going on.

What results? should far more evident from within your schematics and evidence gathering afforded. This is key.

Why do this?, is because the more you do this the more enabling this will become. That in conjunction with your evident data and often quite unique well and specific case conditions / situations / operations gathered. You and your teams should be able to start figuring these day to day 'safety' observational things, for ones-self.

When drillers can better understand all aspects of MLT from the drill floor, at the rig-site. Far more proactive and better problem-solving, decision-making, dynamic risk assessment, and management of change, outcomes, benefits and value shall result.

Festive greetings to all. 
 

It is called hydraulic force, multiply the force x inches squared and it will give you the string weight decrease. So multipy your pressure x the sq. In. In the rams or hydril.. I use .7854 x od of item in rams or hydrl. Apply too much force and out the hole it comes...just ask any old school driller who near hung the kelly over the monkey board with his big, new high horse power mud pump....

Hi Umair,
Assuming that the casing is hanging free in the well in mud/brine or wet cement, this indication can be induced by the ballooning effect of the casing when applying pressure during the test. When the size of the submerged balloon (casing) increases, the buoyancy force increases and cause the reduction in effective hookload.

Regards,
Jelle.

Hi Umair,

 

Any bended pipe is straightened out once it is internal pressurized (Bourdon Effect).

If you are familiar with Fisher Actuator you can see the application of this effect on valve position controller. What is happening is not weight lost but length increase along the vertical direction of the well. Since the pipe is free on one of its ends (upper end - Rig Hooke) the MD Weight Indicator is simply showing the lifting effect on the Rig Hook.

Dan