Enhanced Efficiency in Deep Water Testing Operations Delivered by Smart DST String

Abstract

This paper discusses the smart Drill Stem Test (DST) string, run for a Deep Water (DW) well test operation, which enabled considerable saving of rig time, reduced risks, and provided best reservoir data quality, while performing a commingled DST in a single run. Evaluation of the zones was made without any wireline intervention runs such as Production Logging Tool (PLT) or Surface Read Out (SRO). Acoustic telemetry provided seamless access to downhole data, including production profiles from both zones, throughout the DST operations. This paper will help the well testing fraternity conduct well test operations efficiently and safely in a deep-water environment using new technology tools and innovative methods. Well testing costs and risks can be reduced significantly. The smart DST string, run in hole (RIH) for the DW well test, consisted of a combination of conventional DST tools, a new generation packer and below packer, acoustically operated tools including: Acoustically Operated Sliding Side Door (SSD) - provided access to the reservoir for Well Kill Operations after the standalone screens became plugged with unconsolidated sand and Loss Control Material (LCM) pills.Multiple Discrete Temperature Sensor Array - Eliminated the requirement of running a conventional PLT to evaluate the commingled flow of two zones, provided valuable production logs, and resulted in unexpected, additional information evident from the thermal transient data.Acoustically Activated Bottom Hole Samplers - collected bottom hole samples selectively, at different drawdowns, without wire line intervention or without applying annulus pressure.Wireless Gamma (GR) Depth Correlation Tool - Provided accurate TCP gun placement, without running a conventional wireline GR/CCL, by using a tubing conveyed Gamma Ray logging tool; results were collected wirelessly in less time than a conventional wireline run.New Generation Packer -The large size 9-5/8" Hydraulic Set Retrievable seal bore type packer was used for the first time by the company. This is a most suitable packer for DW DSTs, which eliminated the requirement for slip joints, drill collars and safety joints or the running of a permanent packer, which would have required multiple trips and restricted the gun size.