A New Small Diameter, Memory Based, Microresistivity Imaging Tool Engineered for Oil-Based Mud: Design and Applications
Authors
Peter Williams (Weatherford International) | Scott McQuown (Weatherford International) | Maria de Belén Palacio (YPF S.A.)
Publisher
SPWLA - Society of Petrophysicists and Well-Log Analysts
Publication Date
June 25, 2016
Source
SPWLA 57th Annual Logging Symposium, 25-29 June, Reykjavik, Iceland
Paper ID
SPWLA-2016-AAA
Abstract
Microresistivity imager logs have broad application in geological, petrophysical and geomechanical studies. A new small diameter wireline-style logging tool with both real-time and memory capability has been engineered to reduce the acquisition risk and extend the application of these data into oil-based mud (OBM) wells that are technically or commercially challenging for conventionally-sized tools. These include narrow wells, high dogleg severity wells, horizontal wells and wells where logging out of drill pipe may be the only cost-effective evaluation option.
The innovative design of this tool allows image data acquisition from a small package that is not constrained by wireline data transmission rates.
The tools may be deployed on wireline, through drill pipe, or without wireline inside a drill pipe shuttle; the latter facilitates access into highly deviated wells and past bad hole conditions without compromising borehole coverage. In spite of the tool's small size and weight, coverage and image quality compare favorably with standard tools. Complete 360 degree wellbore images can also been presented using dynamic digital imaging technology that removes the gaps between the pads which may be present in larger boreholes.
A new speed-correction algorithm has been developed to take advantage of additional information recorded during memory operations to improve pad-to-pad alignment accuracy. This has proved to be very effective for drill pipe conveyance where there is often a significant stick-slip motion of the drill pipe.
Logs from both conventional and unconventional reservoirs demonstrate the robustness of the data over a broad range of common environments. Results have been applied to the description of clastic and carbonate reservoirs, natural fracture identification, hydraulic fracture design, and new well placement. Performance is reviewed from operations around the world and case histories are presented.