High-definition resistivity logging while drilling (LWD) imaging tools can offer real-time solutions for wellbore placement, detailed reservoir characterization, structural interpretation, and optimized wellbore integrity management while drilling in complex reservoirs. However, these tools have been traditionally limited to drilling with water-based muds (WBM) due to the innate conductivity of these drilling fluids. At the same time, many operators prefer the use of invert emulsion oil-based fluids, especially in complex lateral and reservoir sections, due to the invert emulsion fluids' inherent higher performance and ability to reduce operational risks. The combination of high-definition, real-time imaging and oil-based drilling fluids in unconventional reservoirs can drive well efficiency with ideal fracture placements while retaining optimum drilling performance. Thus, an electrically conductive oil-based mud (OBM) has been a goal sought after by the drilling fluid industry for the past twenty-five years.
This paper will report the successful development of an invert emulsion drilling fluid that enables real-time resistivity imaging. The properties of the electrically conductive OBM and its response to a low-frequency resistivity imaging tool will also be discussed. Recorded images captured on a multi-layer sandstone formation with real-time, LWD technology will be presented with data interpretation.
The oil and gas industry is under increasing pressure to reduce the production cost per barrel of oil equivalent, especially for the unconventional sector. There is a renewed interest in technology to effectively improve drilling efficiency and reduce operating cost to help the shale sector remain profitable.
A general rule for the shale sector is that one-third of wells are not economical, one-third are marginally economical, and one-third carry the economics for the whole project.1 The major reason why two-thirds of all wells are marginal to non-profitable investments is the common practice of placing fracturing stages at regular intervals in a well with only limited information to evaluate the zones of productivity.
