Barnett Shale - New LWD sensor technology provides crucial formation evaluation information at reduced cost and risk for land operations

摘要

With rising oil and gas prices, unconventional plays in North America are gaining more attention. Fractured shale is evolving as a key source of natural gas production. These plays are primarily developed with horizontal wells. Production intervals are stimulated through hydraulic fracturing. An accurate assessment of the natural fracture system and present day stress field is essential to being able to plan the different stages of hydraulic fracturing, as well as assessing the lateral extent of hydraulic fracture propagation. Previously, wireline resistivity imaging tools were used in horizontal wells to acquire the data required for this type of detailed geological analysis. With the introduction of the latest generation LWD tools to the land market, it is now possible to obtain these data in a more cost efficient way, minimizing non-productive time (NPT) and benefiting from the capability of being able to acquire the data while drilling.This paper documents the challenges of obtaining high resolution borehole images in high angle and horizontal wells. This paper will examine datasets from wireline tools and different generations of LWD imaging tools, compare the resolution of these images and their suitability to the task. Interpreted examples will be used to illustrate the benefits that this novel imaging technology offers operators working in these nonconventional plays both in terms of time and cost reduction without sacrificing data quality. Geological models derived from wireline data acquired in vertical wells will be supplemented with data obtained from LWD tools in horizontal wells. Lessons learned in terms of data acquisition, data QC and image interpretation will be summarized.