Abstract
The positive experience and results obtained by using a new class of high temperature / high pressure (HT/HP) logging while drilling (LWD) tool in a slimhole (5-3/4-in.) exploration well in Italy's Po Valley opens new possibilities for trajectory and stratigraphic control while drilling in deep, HT/HP wells. Using the LWD suite, the operator was able to acquire real time, continuous temperature, gamma ray and resistivity data for analysis and correlations at 180°C (356°F) and 16,780 psi – conditions previously unachievable. As a result, the operator pinpointed the stratigraphic position of a main direct fault that raised the upper reservoir above the prognosis estimation and was able to:
achieve critical placement of the casing shoe to avoid a well control hazard posed by drilling into a partially depleted reservoir;
drill continuously without having to pull the bottomhole assembly out of the hole and change bit types for better, unaltered cuttings; and
identify a carbonate sequence in the lower section, which ultimately led to the decision to plug and abandon the lower section and produce the upper reservoir, with very good results.
Real time annular temperature measurements provided accurate temperature data for mud program optimization and operational considerations that are not usually available in exploration wells.
This paper will discuss the characteristics and operating limitations of the Villafortuna-Trecate HT/HP field; the objectives of the Cascina Cardama 1 Dir well; the LWD planning and implementation, and the operations, logs and results.
Based on the experience and results of this well, the operator will continue to use the high temperature LWD suite to drill future wells and projects.
