Бурение грунтовых зондов, установка энергетических колодцев

The Type 1-2-6 bits available are :

This is a milled tooth bit with sealed journal bearings. It is suitable for drilling soft formations with low compressive strength and high drillability. A bit of this type would tend to have long, widely spaced teeth, maximum offset and pin angle and, in this case, journal bearings.

Exercise 2 Cost per foot of a Bit Run

The process of selection of the best bit type from a number of offset wells requires a number of assumptions :

a. The lithology encountered in the offset bit runs must be similar to that lithology expected in the proposed well.

b. The depth of the offset bit runs are similar to that in the proposed well.

c. The bit runs in the offset wells were run under optimum operating conditions (hydraulics, WOB, RPM etc.)

Having made these assumptions, the ‘best bit’ will be selected on the basis of footage drilled, ROP, and most importantly Cost per Foot of bit run.

The results of these numerical criteria are shown in Table Solution 2. The ‘best’ bit is considered to be bit B since this bit had the most economical bit run (Ј/ft).

It is worth noting that bit A would have been selected on the basis of ROP and bit C would have been selected on the basis of footage drilled.

Consideration should of course be given to the fact that although bit A drilled at a very fast rate it had only drilled 206 ft. and therefore the bit may have still been in very good condition. Bits B and C would have been worn to a greater extent than bit A and their ROP would consequently have decreased over the bit run.

CO

CO

Bit A is the cheapest and gives the highest penetration rate, but is the least economical in terms of Ј/FT.. Bit В should be selected as the best bit for this hole section.

Комментарии запрещены.