Method and apparatus for controlling precession in a drilling assembly

1. A drilling apparatus comprising:

a non-rotating stabilizer;

the non-rotating stabilizer including a first blade and a second blade, the first blade being arranged opposite the second blade;

wherein the first blade is biased radially outwardly by a force of a first value;

wherein the second blade is not biased radially outwardly by a force corresponding to the first value;

wherein the second blade slidably attached to the non-rotating stabilizer in an axial direction of the non-rotating stabilizer, and

wherein the first blade is a non-steering blade.

2. The drilling apparatus according to claim 1 , wherein the second blade is substantially unbiased.

3. The drilling apparatus according to claim 1 , wherein the force of the first value biasing the first blade is provided by a spring.

4. The drilling apparatus according to claim 1 , wherein the non-rotating stabilizer includes a fixed stabilizer and an adjustable stabilizer and the first blade and the second blade are part of the fixed stabilizer.

5. The drilling apparatus according to claim 4 , wherein the adjustable stabilizer comprises a plurality of adjustable stabilizer blades which are extendable.

6. The drilling apparatus according to claim 1 , wherein the second blade is slidably attached such that the second blade can move at least 0.3 inches in the axial direction.

7. The drilling apparatus according to claim 1 , wherein the second blade is slidably attached such that the second blade can move at least 0.5 inches in the axial direction.

8. The drilling apparatus according to claim 1 , wherein the first blade and the second blade are identical in shape and size.

9. The drilling apparatus according to claim 1 , wherein the force of the first value biases the entire first blade.

10. The drilling apparatus according to claim 1 , wherein each of the first blade and the second blade comprises a plurality of pyramid shaped spikes.

11. The drilling apparatus according to claim 1 , wherein the non-rotating stabilizer does not rotate with a drill bit.

12. A drilling apparatus comprising:

a non-rotating stabilizer comprising a fixed stabilizer that controls precession and an adjustable stabilizer that controls direction of drilling;

wherein the fixed stabilizer comprises a plurality of blades;

wherein at least one of the plurality of blades of the fixed stabilizer is biased radially outwardly by a force different than another one of the plurality of blades; and

wherein one of the plurality of blades is slidably attached to the non-rotating stabilizer in an axial direction of the non-rotating stabilizer.

13. The drilling apparatus according to claim 12 , wherein the another one of the plurality of blades is substantially unbiased.

14. The drilling apparatus according to claim 12 , wherein the plurality of blades comprises four blades circumferentially arranged around the non-rotating stabilizer.

15. The drilling apparatus according to claim 12 , wherein the plurality of blades comprises five blades circumferentially arranged around the non-rotating stabilizer.

16. The drilling apparatus according to claim 12 , wherein the plurality of blades comprises six blades circumferentially arranged around the non-rotating stabilizer.

17. A drilling apparatus comprising:

a non-rotating stabilizer unit comprising a fixed stabilizer that is freely slidable and that controls precession and an adjustable stabilizer that controls direction of drilling;

wherein the fixed stabilizer comprises a plurality of blades;

wherein at least one of the plurality of blades of the fixed stabilizer is slidable along the non-rotating stabilizer unit in an axial direction of the non-rotating stabilizer unit.

18. The drilling apparatus according to claim 17 , wherein the at least one of the plurality of blades is slidable at least 0.1 inches in the axial direction.

19. The drilling apparatus according to claim 17 , wherein the at least one of the plurality of blades is slidable at least 0.3 inches in the axial direction.

20. The drilling apparatus according to claim 17 , wherein at least one of the plurality of blades is slidable at least 0.5 inches in the axial direction.

21. The drilling apparatus according to claim 17 , wherein the non-rotating stabilizer unit further comprises an adjustable stabilizer, the adjustable stabilizer comprising a plurality of adjustable blades which are extendable and retractable.

22. A drilling apparatus to minimize precession comprising:

a non-rotating stabilizer unit comprising a first blade, a second blade, a third blade and a fourth blade arranged around the circumference of the non-rotating stabilizer unit;

wherein the first and second blades are spring loaded by springs of a first spring constant;

wherein the third blade is opposite the first blade and the fourth blade is opposite the second blade and the third blade and the fourth blade are not spring loaded; and

wherein the first and second blades are non-steering blades.

23. The drilling apparatus according to claim 22 , wherein the first and second blades are loaded by springs of approximately 500 lbs of spring force.

24. A drilling apparatus comprising:

a non-rotating stabilizer;

the non-rotating stabilizer including a first blade and a second blade, the first blade being arranged opposite the second blade;

wherein the first blade is biased radially outwardly by a force of a first value;

wherein the second blade is not biased radially outwardly by a force corresponding to the first value;

wherein the second blade is slidably attached to the non-rotating stabilizer and the first blade is not slidably attached to the non-rotating stabilizer; and

wherein the first blade is a non-steering blade.

25. The drilling apparatus according to claim 24 , wherein the second blade is slidably attached to the non-rotating stabilizer such that the second blade moves between 0.3 inches to 0.5 inches in the axial direction.

26. A drilling apparatus comprising:

a non-rotating stabilizer;

the non-rotating stabilizer including a first blade and a second blade, the first blade being arranged opposite the second blade;

wherein the first blade is directly biased radially outwardly by a force of a first value exerted by an element dedicated to the first blade;

wherein the second blade is not biased radially outwardly by a force corresponding to the first value; and

wherein only one of the first blade and the second blade is mounted on a sliding axial support.

27. The drilling apparatus according to claim 26 , the element is a dedicated spring directly biasing the first blade.

28. The drilling apparatus according to claim 27 , wherein increasing load on the first blade, recompresses the element.

29. The drilling apparatus according to claim 26 , wherein the slidable blade is mounted in the free sliding support that moves the slidable blade only in a downward direction with the non-rotating stabilizer.