New-Generation Drill Barge for Deep HP/HT Wells
Authors: Bybee Karen 
Published: February 2015

This article, written by Assistant Technology Editor Karen Bybee, contains highlights of paper SPE 99210, "Re-Engineering Barge Drilling for Deep Miocene HP/HT Frontiers in a Mature Basin," by F.J. Husband, SPE, G. Bitar, SPE, T. Begnaud, SPE, and T. Petticrew, Parker Drilling Co., prepared for the 2006 IADC/SPE Drilling Conference, Miami, Florida, 21–23 February.

The full-length paper details the re-engineering of a conventional deep-drilling barge rig to deliver a new-generation high-pressure/high-temperature (HP/HT)/high-flow barge rig designed for increased reliability and specification for deep-gas-drilling programs in the U.S. Gulf Coast region. Upgrading the main power and distribution systems and high-performance pump configuration is discussed as well as auxiliary-system modifications.

Introduction

Although heavily explored since the 1920s, the onshore Miocene of south Louisiana has produced more economic discoveries in the past 10 years than the Flex Trend subsalt play. More-recent Miocene discoveries are deep, geopressured, and contain reservoirs that are not associated with seismic amplitude. Large discoveries have been on faulted anticlines found with the aid of detailed regional maps using well logs, biostratigraphy, and 2D-seismic data. Exploration of this play has expanded into the shallow-water shelf, which to date has produced more than 40 billion bbl of oil equivalent.

Optimizing drilling performance and well control for the well design requires the right drilling rig. New-generation jackup rigs are designed for shallow-water deep gas but have draft limitations in certain areas of interest. As exploration of deep targets expands in water depths from 6 to 18 ft, the availability and performance of ultradeep barge rigs becomes increasingly valuable. The marketable Gulf of Mexico (GOM) deep-drilling-barge fleet consists of 32 rigs. Of these, few are rated to 30,000 ft. Deep gas exploration is an area of particular interest for the barge-rig market because successful exploration results could drive demand higher and diversify specification requirements of the fleet.

Leveraging previous frontier rig designs and customer demand to mitigate the higher drilling risks of planned deep exploration targets, a project to upgrade Barge Rig 76 B in New Iberia, Louisiana, was undertaken to deliver a new-generation HP/HT and high-flow barge rig to execute these challenging drilling programs.

Mud Pumps and System

Barge Rig 76 B previously operated three 5,000-psi A1700-PT pumps. However, rig power distribution was challenged to run all three pumps simultaneously. These were replaced with 2,200-hp W-2215 pumps each driven by two high-torque 752 DC traction motors and powered by four runs of number 535 cable. The pumps are rated for 7,500-psi maximum operating pressure and weigh 115,000 lbm each. The main structure in the pump room was modified to accommodate the increased weight.

The existing 5,000-psi piping and valves were replaced with 7,500-psi components. Most assemblies were prefabricated, tested, and painted at supplier facilities before installation and integration testing in the shipyard. This reduced installation time and final integration-testing time, and it streamlined troubleshooting. This was especially true for high-pressure piping that required specialized welding