Development and Construction of a High Resolution Measurement While Drilling Tool
Mukul M. Sharma
We propose to develop a revolutionary measurement while drilling (MWD) tool capable of measuring high resolution, real-time fluid saturations, and other parameters of oil and gas reservoirs. The prototype tool shall be built to meet requirements for high temperature, high pressure drilling service. The concept involves using a high rate of penetration anti-whirl drill bit designed to incorporate a ring of sensors coupled to a downhole data acquisition, storage and transmission system.
Two-dimensional resistivity tomograms will be generated with centimeter resolution as the bit passes through the formation. Other electrical, acoustic, pressure or temperature sensors could be added to probe the well-defined rock volume as it is drilled. Data will be stored in the tool and transmitted to the surface as drilling proceeds. Data interpretation will be done by specially designed software. The high resolution, high temperature and high pressure measurement while drilling instrument offers significant advantages over existing MWD tools.
The centimeter resolution of the MWD tool will be two orders of magnitude better than the meter resolution currently available from logs and other MWD tools.
For the first time estimates of fluid saturation will be available from direct in situ measurements, before changes take place due to drilling fluid invasion or imbibition.
High-resolution data will be collected and analyzed in real time, making valuable reservoir information available to geologists and engineers at the rig. Data sets can be readily transmitted to project teams for further analysis. Coupled with information from other sources the high-resolution data will enable wellsite and office personnel to rapidly make informed decisions on geosteering, drilling and well completion strategies.
The technology will provide detailed measurements over the entire drilled interval, greatly increasing the understanding of fluid saturation variations and lithology.
This new MWD technology presents the opportunity for achieving significant economic advantages. Drilling costs for the deep hot wells can run well over $250,000 a day, so having detailed reservoir information even hours earlier will save significant amounts of money. Having high-resolution MWD data will reduce the need for separate logging runs. In addition, the acquisition of high resolution reservoir information will improve geosteering, increase the likelihood of correctly identifying all pay zones; especially zones with beds thinner than the resolution of existing logging tools. And finally, the detailed saturation estimates provided by the tool will improve engineers' ability to identify zones most likely to produce dry gas, greatly improving completion efficiency.
Mukul M. Sharma
Center for Petroleum and Geosystems Engineering
1 University Station C0304
The University of Texas at Austin
Austin, Texas 78712-0228
Phone: (512) 471-3257 FAX: (512) 471-9605