INNOVATION IN HDD CONSTRUCTION AND ENGINEERING: AN 8,850-FT. 32-IN. SINGLE DRILL HDD

摘要

This paper presents the construction of an 8,850-foot horizontal directional drill (HDD) crossing of the Rio Grande River in Santa Cruz, Bolivia. The crossing is a key component of a 32-inch diameter steel natural gas line traversing two countries to deliver gas from the fields in Bolivia to the coast of neighboring Brazil. The HDD river crossing will be performed as a single drill as opposed to utilizing the intersect method typical of longer crossings. This challenging project necessitated developing innovative solutions to the various issues inherent to an HDD crossing spanning over a mile and a half. Factors that are not necessarily a concern for shorter crossings become engineering challenges that must be accounted for early in construction planning. In addition to hydrofracture and pullback loads evaluation, analysis of the drill pipe strength, critical buckling loads, fluid pressure losses, and maximum torque were vital in performing an adequate evaluation of this bore. A unique low friction pipe pulling plan along with a modified buoyancy control method was developed to reduce the pullback loads and ensure successful installation of the nearly 9,000 feet of steel pipeline. This paper discusses the specific challenges associated with this impressive bore along with the engineering solutions devised to ensure a successful and timely installation.