The Design and Performance Characteristics of Aluminum Drill Pipe

Abstract

Abstract This paper outlines the approach and solutions to the problems associated with the design and development of aluminum as a drill stem for rotary drilling. A current field history on aluminum as a drilling tool is included to assist the reader in judging the selection of engineering compromises in the light of present field performance and to acquaint the reader with the present status of aluminum drill stem in the drilling art. Following proof of satisfactory operation of the first aluminum drill string, 25 more strings (see Table 1) have gone into worldwide operational use. A study of their performance indicates:no operational disadvantages,compatibility with present drilling muds,mixed-string operations are successful,hand and power slips are operational,no failures in the tool-joint area,no problems in fishing or other special uses,normal wear on pipe body comparable to steel andless than normal wear on tool joints. These facts about the present operational status of aluminum drill pipe demonstrate that successful drilling tools can be designed and constructed of aluminum. Field and laboratory studies are continuing in order to improve and expand the use of aluminum for drill pipe. Introduction To make functional drill pipe from aluminum required more than a casual selection of engineering compromises. The target was a drilling tool that would substantially meet the physical characteristics of Grade E steel drill pipe but, if possible, also incorporate the many desirable characteristics found in low-alloy steel drill pipe (Grade D) such as toughness, concentric wear and low embrittlement rate. It was recognized early in the aluminum drill pipe program that aluminum alloys could not be best utilized in a design that copied the then available steel drill pipe. It was necessary to balance the design, alloy choice, strength, corrosion and wear resistance of aluminum alloys into a workable tool, one capable of sustaining the stresses of rotary drilling. The application of steel tool joints to aluminum pipe posed many problems in order to achieve a satisfactory transfer of stresses and a satisfactory fatigue life. This and other design and performance considerations are dealt with in this report. After the development of a satisfactory aluminum drill pipe it was necessary to demonstrate the economic advantage of this tool. This too has been accomplished and data are available to show the competitive position of aluminum drill pipe. Acceptance of aluminum drill pipe is attested to by demonstrated success and by re-orders by present users. Five users have purchased their second strings of aluminum drill pipe. One user has purchased his fourth string. Statement of Theory If aluminum could be successfully fabricated into dependable drill stem, the advantages of this light material should reduce drilling costs. A few of the readily apparent areas of improved economy are:rig investment,transportation,wireline life,hoisting fuel savings andhoisting time reduction. TABLE 1-REYNOLDS DRILL STRINGS-JULY 1, 1963 Length Footage No. Avg.(ft) Drilled Wells Depth Location 4/2-in. Pipe 1. 10,400 148,361 15 9,890 Central Texas, Calif. 2. 5,250 106,280 23 4,620 Kansas 3. 1,020 101,945 16 6,350 Okla. 4. 7,500 6,563 1 6,563 Chile 5. 11,010 38,254 4 9,550 N.E. Texas 6. 11,010 68,000 8 8,500 N.E. Texas 7. 5,010 36,176 8 4,500 Alberta, Canada 8. 5,010 56,583 12 4,650 Alberta, Canada 9. 14,520 19,600 1 1/2 13,200 N.E. Texas, Calif. 10. 4,000 * * * 11. 11,520 77,000 9 8,550 N.E. Texas 12. 12,000 61,634 5 12,300 La., Miss. 13. 1,050 39,013 10 3,900 Oklahoma 14. 12,510 11,355 1 11,355 Libya 15. 5,010 15,000 6 * Mont. 16. 4.020 9,670 1 * Utah 17. 5,010 e * * Calif. 18. 7,020 4,558 1 * Colo. 19. 4,740 57,351 12 7,790 N. Okla. 20. 8,520 25,190 2 1/2 10,080 N.E. Texas 4.in. Pipe 21. 11,520 113,427 19 5,950 Miss.3 1/2in. Pipe 22. 7,030 201,372 33 6,100 La., Miss.. Tex, 23. 7,500 9,000 * Saudi Arabia 24. 6,000 5,800 * Alaska 25. 10,020 * * * Calif. 26. 2,520 * * * Utah JPT P. 1285^