A new slim full bore electrical micro-imaging tool conveyed through the drill string and bit for geological and reservoir characterization of unconventional reservoirs

摘要

Microelectrical imaging is a highly versatile geological and reservoir characterization technique that produces representative and photorealistic images of the formations intersected by a wellbore to form the basis of a thorough and reliable geological interpretation. These images are used to characterize geological structures, natural fractures, faults and interpret sedimentary features and rock facies. The data is also used for gathering in-situ stress information which is an important input for geomechanical studies and well completion design. In this paper, a new slim full-coverage imaging tool is presented that can be conveyed in a driller-friendly and low risk manner through the drill string and bit. It is specifically designed to acquire high-resolution images in lateral wells of unconventional reservoirs. The tool has an outside diameter of 2.125 inch and provides a borehole coverage of 76 and 57 percent in 6 and 8-inch hole sizes respectively. Special circuitry ensures that the measuring currents are focused into the formation to acquire microconductivity data used for imaging and dip interpretation. The tool provides six caliper measurements for more accurate hole shape and cement volume estimation. It is fully combinable with all other through-the-bit measurements to provide the most complete suite of measurements for geo-engineered completion design from a single and efficient descent in the well. Field application examples using data from this new tool are presented from both vertical and horizontal wells along with comparisons to full-size industry standard imaging tools in different unconventional reservoirs in North America.