FEW04-012298

Goal:
Develop and test an advanced system incorporating both seismic sensors and tiltmeters in one tool. Instrumentation will be developed and tested to improve viewing distance and accuracy.

Background:
The industry has made significant progress in hydraulic fracturing, with much support by the DOE, but this continues to be an area ripe for progress. Stimulation of unconventional formations is a particular challenge. The complex fracture geometries that result from stimulating wells in unconventional formations make it difficult to optimize individual treatments to ensure pay zone coverage, adequate fracture length and sufficient conductivity. Field development strategy and determining the most efficient well spacing and pattern is also very difficult in these reservoirs and is largely affected by the hydraulic fracture geometry. By increasing the field of application and accuracy of fracture mapping this project will play a key role in improving development economics.

This project will address limitations in hydraulic fracture mapping technology and provide industry with an improved system to measure created fracture geometry. The improvements will 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 eliminating the need for two observation wells will help reduce costs and simplify field operations.

This project is a joint effort with Pinnacle Technologies (NT42108) to develop a combined microseismic and tiltmeter mapping system. Pinnacle Technologies is the lead organization on this project and they will perform field and lab tests, most of the design work, most fabrication, and various analysis elements. Sandia will support Pinnacle in analysis of tool performance, selection of sensors (for microseismic), analysis of field results, development of a joint inversion analysis, development of source mechanism technology, and technology transfer.

Performer:
Sandia National Laboratories

Location:
Albuquerque, New Mexico 87185

Potential Impact:
Many unconventional reservoirs require fracture stimulation. Mapping this stimulation provides knowledge of internal reservoir structure and performance of the frac job, both important parameters in further development and controlling costs. This new tool will be able to operate in a single observation well with a greater range of operations allowing its use in fields with larger well spacing.

Accomplishments:
Overall work completed by Sandia for Pinnacle:

• Evaluation of various accelerometer designs has been completed with the selection of several Endevco accelerometer packages for further testing and evaluation. Both the Endevco 7703A series piezoelectric accelerometers and the 7251HT series piezoelectric accelerometers have been selected for incorporation into a combined microseismic tool.
• Work is completed on the evaluation of the current uncertainty analysis associated with grid searches (used for processing data in the presence of velocity structure) and incorporating the uncertainty into more aspects of the location and analysis process.
• Development of a joint-inversion routine is completed. Tiltmeter and microseismic data sets are extremely diverse as the ?tilts? of the rock is an aerial mechanical response and microseismic events of points of released energy. These data sets are diverse. The computer code architecture needed to extract the desired parameters to process this data is the Marquardt-Levenburg code which is in FORTRAN and was converted to C++.
• Source characterization is critical in establishing the bearing between source and tool and probably more important, the orientation of the stress axis. This orientation will change depending on the regional tectonic environment and whether or not it is in extension or compression. This work is completed.

  Current Status and Remaining Tasks:
  Sandia?s portion of this project is completed. With the recent testing of the accelerometer/tiltmeter combined tool by Pinnacle, remaining work is essentially evaluation of the data from each of the combined tool configuration field tests. Any further field tests will depend on the results of this data evaluation.

  Project Start: April 15, 2004
  Project End: October 14, 2006

  DOE Contribution: $300,000
  Performer Contribution: $0

  Contact Information:
  NETL - Tim Grant (tim.grant@netl.doe.gov or 412-386-5457)
  Pinnacle Technologies ? Norman Warpinski (norm.warpinski@pinntech.com or 281-876-2323)
  Sandia National Labs. - Greg Elbring (gjelbri@sandia.gov).