1.under sleeves
Sleeves design can be said is the highlight of drilling. During drilling of any well in the Central Standing Committee met with a number of different geology, depth or unexpected situations, production and development requirements, etc., so the need to protect several layers of casing wells, in order to successfully target drilling drilling.
Well is perforated by holes drilling wells to depths or after the formation of a level, the next layer sleeves, and then change to a smaller size of the drill bit. After 141 wells in the pit, for example, the first phase to 171/2 "drill after drill to 1,500 meters, the first under the 133/8" Surface sleeves, only with 121/4 "drill drilling and so on.
2.from the drill, drill
In order to replace it with a blunt after the drill core samples taken or prepare, repair equipment, as well as going to the well to do other work, the need to upgrade to the ground with the drill bit, and then with a blunt drill to remove the old, the other new properly connected selected new drill bit and drill according to the reverse order from the time, and then down to the bottom of the opening so that the original drilling.
Drilling deeper, tripping the more time-consuming, but the real relative reduction of drilling time, so how to choose a good drill to increase drilling progress, reducing the number of tripping, shorten the construction period, the project is also the responsibility of people away.
3.with the drilling mud
The greatest feature of rotary drilling method is the use of mud as a circulating fluid wells, the earliest use in the drilling fluid is "water", far away in ancient Egypt, the Egyptians in the quarry to manually rotate a drill depth of twenty feet when the borehole, the water will be removed debris. Of the Zhou dynasty (BC eleven hundred years), salt well drilled in the Sichuan region, but also with water to remove debris. Water, can be said to be the first for drilling "mud." Until now, the water is still a major component of the mud. Especially in the low proportion of mud, water accounts Eighty-five percent or more of the total composition.