what is the differance between Differential sticking and Mechanical
?stucking
Differential sticking one of the most common problem occure during drilling as aresult of differential pressure between hydrostatic pressure of mud and formation pressure of mud ie when the hydrostatic pressure is greater than the formation pressure which cause pushing adrill string into afilter cake of permeable formation
هذه عمليه مشهوره جدا تحدث اثناء الحفر وذالك نتيجه زياده ضغط سائل الحفر عن ضغط التكوين الصخرى والذى يودى بدوره الى دفع عمود الحفر الى جانب البئر مما يودى الى التصاقها بااحد الجوانب الذى يقل فيه الضغط
when the Differential sticking occure moving the pipe string
in the upward and downward direction is impossible
but
free circulation is easily established
فى حاله حدوث Differential sticking يكون من الصعب تحريك انبوبه الحفر للاعلى او للاسفل نتيجه التصاقها بجدار البئر ولكن يكون من السهل عمل عمليه circulation للبئر
?What should i do for this situation
Reducing of hydrostatic pressure by circulation and reducing mud
weight
Displacing the choke
Maintain drill string rotation at all times if possible
Reduce contact area by using spiral drill collers and heavy weight drill pipe
Dont use high mud weight
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Mechanical stuck pipe
When drill cutting or sloughing formation pack off the annular
space around the drill string as aresult of improper cleaning
يحدث هذا النوع عندما تقوم ال cutting بسد الفتحات حول drill string وذالك لعدم حدوث عمليه تنظيف البئر من شوائب الحفر بصوره جيده وبطريقه مستمره
The settling of alarge amount of suspended cutting to the bottom when the pump is shut down
عندما يتم قفل معدات الضخ المسئوله عن ضخ سائل الحفر تقوم شوائب الحفر بالترسيب فى قاع البئر
When drill string is run too fast it hits abridge or tight spot
عندما يتم تشغيل عمود الحفر بسرعه كبيره جدا وذالك للتغلب على الصخور الصعبه او الجسور
Tight spots can result from drilling undersized holes due to the use
of worn drill bits
The usual method used to free mechanical stuck pipe is to work the drill string either by rotation and pulling it or by activating adrilling jar