Sixteen chrome coiled tubing (16Cr CT) was introduced in the spring of 2003 and over 200 strings have been put into field use as velocity strings. Following preliminary testing, two 16Cr CT reels were deployed at Prudhoe Bay, Alaska to evaluate feasibility as an intervention workstring. The two reels performed a variety of standard CT applications on a daily basis. Observations and data were gathered to determine operating guidelines, applicability, and limitations. The field trial indicated that 16Cr CT can be deployed in the field with only minor operational modifications.

16Cr has superior abrasion resistance in 13Cr production tubulars and little CT surface (external) wear was seen during the field trial. The second reel developed a pinhole failure earlier than expected; however, analysis of the adjacent material indicates that 16Cr has increased low cycle fatigue life when compared to standard carbon steel CT. Additional testing is ongoing, and it is felt that the conditions resulting in the failure can be mitigated to avoid future premature failure.

This paper documents the lab and field trial results. Standard operating procedures for 16Cr CT are described that provide easily implemented guidelines. 16Cr has applicability as an intervention workstring, particularly in corrosive environments and in areas where abrasive 13Cr production tubulars must be endured.

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