Advanced Technologies and Practical Guidelines for Challenging Drilling Applications

Abstract

This paper provides a review of recent technology advancements and addresses practical considerations associated with drillpipe and drill stem components for extreme drilling applications. Ultra-high torque double-shoulder rotary connections are often employed in these applications potentially complicating proper design and material selection for cross-overs, top-drive subs, pup joints and other accessories. These new connections often employ materials with higher strength requirements than standard API connections. The paper outlines recommendations for material strength and design parameters for various drills stem accessories. The latest generation of high angle and extended reach wells are encountering significantly higher side loads between the drillpipe and casing creating unprecedented levels of casing wear. Proper hardband selection, application and maintenance are essential to successfully and safely drill these critical projects. Hardband system trends for critical applications are highlighted, and recent hardband casing wear and tool joint protection test results obtained using an advanced hardband wear machine are discussed.Due to the dramatic increase in oil prices the industry has seen a re-emergence of deep and ultra-deep drilling projects that encounter H 2 S gas. The paper provides an update on the latest sulphide stress cracking resistant drillpipe grades along with initial results from a study of the effect on S-grade drillpipe samples to various H 2 S exposure concentrations, representing typical conditions when circulating a gas kick to surface. Sour service drillpipe, built with SSC resistant upset tubes and tool joints, has been available for some time. The friction welds joining the upset tubes and tool joints were not resistant to SSC. This paper presents the successful development and qualification of SSC resistant friction welds for critical sour applications. The surge in critical drilling has led to an increasing trend of drill stem friction heating failures. The paper includes characteristic features of these failures along with case histories and prevention methods.