Technical Innovations and Important Guidelines for Demanding Drilling Applications

Abstract

Critical wells exceed the capabilities of S-135 drill strings. Drilling teams are evaluating advanced technologies to expand the drilling envelope. The paper details the development of ultra-high strength UD-165 drill pipe, provides comparisons with S-135, Al and Ti drill pipe and provides field trials summaries. New developments are necessary to drill and complete deeper and longer-reach wells. Rotary shoulder connections offer significant advantages when coupled with high-pressure seal technology for completion pipe and intervention risers. The paper provides details on critical applications that benefited from new connection technology.With water depths over 10,000 ft, well depths exceeding 34,000 ft, and extended-reach targets over 35,000 ft, operators are setting larger diameter and heavier casing. These casing strings require landing strings with setting capacities approaching 2.5-million pounds that extend the limits of tubular manufacturing and handling capabilities. The paper describes the technology advancements required to develop and implement an ultra-high capacity landing string system. A 6-5/8 in. drill pipe based riser system for offshore completion and intervention work has been successfully used for several years. The primary advantage of the drill pipe based system relates to the rotary shoulder connections (RSC). RSC makeup and breakout quickly, are rugged, and are superior at resisting galling and handling damage compared to casing connections that are often used for risers. The use of these intervention risers in sour gas areas has been prevented because there were no fully Sulfide Stress Cracking resistant tubular systems with RSC. This paper presents the successful result to develop and qualify an SSC resistant friction weld for intervention risers. Industry advancement has led to an increasing trend of drill stem downhole friction heating failures. The paper includes characteristics of these failures with case histories and prevention methods. Table 1 provides a summary of advanced material comparisons alongside S-135, Z-140, V-150 and UD-165 steel drill pipe products. 1 When considering strength to weight ratio, many publications have neglected to factor in the steel tool joints attached to the non-steel alternative material tubes. Rather, they have focused on the strength to weight ratio improvement of the material density only. This is somewhat misleading and errs on the side of promoting non-steel alternative materials. Table 1, however, factors the presence of steel tool joints and uses a conservative approach (optimistic) by analyzing Range III drill pipe products. Readers should note that Range III product lengths can offer handling efficiency advantages, but may present wear issues and higher potential for fatigue damage vs. Range II designs. Advanced Material TechnologiesAluminum drill pipe (Al DP) offers several potential advantages over conventional steel drill pipe including: lower weight, higher strength to weight ratio, superior corrosion resistance and enhanced resistance t...