Logging methodologies for identifying, measuring , and correlating key horizons in the subsurface have been around for some time as tools to conduct reservoir characterization. As exploration has progressively extended to ever deeper and more hostile environments, the economics of gathering this information as well as the technical challenge of overcoming high pressure and high temperature environments have come into focus. The need to gather data in real-time, and “see ahead of the bit ” have been identified as targets of paramount importance in both cutting costs for exploration and development and in overcoming the dangers of high pressure gas. Both engineering and geoscience disciplines are involved in this effort to design systems that are both cost effective and successful in obtaining needed deep subsurface data. New and or novel communications technology represents yet another challenge in this same area.

To address these challenges, DOE/NETL is developing a portfolio of research projects that advance real-time data acquisition (measurement-while-drilling or MWD), “look ahead” systems that employ seismic-while-drilling or SWD as well as high-temperature electronic components and systems that overcome temperatures in excess of 400 degrees F.

Methods that allow reliable and low-cost communications of reservoir characterization data from depths in excess of 20,000 feet are also under development at DOE/NETL. In cooperation with DOE/NETL, hardwired drill pipe (“Intellipipe(TM)”) has been successfully developed by Novatek, Inc.and is currently being marketed by Grant Prideco, Inc., a well known industry supplier. The use of electromagnetic or EM “through-the-earth” technology is another potentially less expensive method for communications that is currently undergoing tests and field trials.

In the area of real-time measurement, the DOE/NETL Deeplook consortium has initiated an effort to use borehole seismic imaging supplemented with electromagnetic methods, to map fluid content at distance up to 200 meters from the bore hole with resolution comparable to existing logging methods. The hypothesis being that seismic methods will provide information on the structural and mechanical properties of the medium and the conductivity will provide independent information on the fluid state. Jointly, these measurements will provide a more complete map of the fluid distribution and matrix properties.

Recent computational improvements have made it possible to obtain 3D electrical tomographs, providing the equivalent of electric logs deployed every few feet between existing wells. These high-resolution tomographs have been used with success for formation characterization and monitoring subsurface fluid movement (i.e. tank leaks, steam floods). This technique can address the problem of tracking the different fluids of interest (oil, water and gas) as their proportions change during stimulation or production. The ERT tomographs can be interpreted to show where the component fluid saturations are changing in the field, providing insight into production and stimulation performance.

The goal of this project is to demonstrate a semi-autonomous system that delivers data of sufficient quality to monitor the small changes resulting from production over time without additional drilling or intensive investment of manpower. This system would utilize the existing infrastructure, effectively mapping changes in the field with no disruption to production/stimulation activities; its operations would be transparent to the production engineer. The resulting maps would be used to assess production/stimulation performance and guide decisions on in-field development.

A downhole power generation and wireless communications system for “intelligent completion applications” is being developed. Its goal is to accelerate development and deployment of the system to optimize production of natural gas resources.

“Intelligent” wells have the capability for real-time downhole process control incorporated into their construction. This control relies on real-time, downhole pressure and temperature monitoring to optimize production performance and reservoir management. The task of incorporating a reliable, accurate and cost-effective system for acquiring this data and communicating it to the surface is a critical challenge to the widespread use of intelligent well completions. A wireless communication system driven by a downhole generator could allow intelligent completion sensors to be placed anywhere in the wellbore, without the need for cables to supply power or transmit data.

A project to design and demonstrate a 225°C MWD tool using a unique 225°C battery system. Both devices will incorporate silicon-on-insulator (SOI) fabrication technology into the manufacturing process for the microchips required. The goal is to improve the reliability of high-temperature electronic components found in measurement-while-drilling (MWD) tools needed to improve drilling efficiency and success rate at depths of 20,000 feet and below and temperatures greater than 225°C.

A project to develop an advanced hydraulic fracture mapping tool that provides industry with an improved system to measure created fracture geometry. These improvements are expected to lead to wider and more effective application of hydraulic fracture mapping. Microseismic and tiltmeter hydraulic fracture mapping are proving to be very useful technologies allowing producers to optimize individual fracture treatments and field development. Development of a combined microseismic receiver-tiltmeter system would eliminate the need for two observation wells and reduce overall costs.

Other areas of downhole measurement research include:

A project that is investigating the acoustic (compressional and shear wave) signatures of deforming rocks. The goal of the research is to provide, for the first time, a database on rock physics and rock deformational properties so that high resolution 3-D or 4-D seismic surveys can be used to image reservoir damage zones or to identify rock units where damage could potentially occur.

An offshore oil field characterization partnership project using electomagnetic (EM) methods. This project is developing a modeling code based on a fully 3D finite element analysis for marine geophysical electromagnetic exploration.

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