skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: A COMPARISON OF COLLAPSING AND PRECISE ARRIVAL-TIME MAPPING OF MICROSEISMICITY

Abstract

In this paper they compare the improvements in microseismic location images obtained using precise arrival times with that obtained by the collapsing technique. They first collapse the initial locations for a hydraulic-fracture data set from the Carthage Cotton Valley gas field, they then use the precise-arrival-time locations as measure for the effectiveness of the collapsing. Finally, they examine the changes when applying collapsing to the precise-arrival-time locations.

Authors:
 [1];  [1]
  1. Los Alamos National Laboratory
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
OSTI Identifier:
1000491
Report Number(s):
LA-UR-07-0059
TRN: US201101%%360
DOE Contract Number:
AC52-06NA25396
Resource Type:
Conference
Resource Relation:
Conference: 69TH EUROPEAN ASSOC. OF GEOSCIENTIST & ENGINEERS CONF & EX ; 200706 ; LONDON
Country of Publication:
United States
Language:
English
Subject:
58; ENGINEERS; NATURAL GAS FIELDS; LANL

Citation Formats

RUTLEDGE, JAMES T., and JONES, ROB H. A COMPARISON OF COLLAPSING AND PRECISE ARRIVAL-TIME MAPPING OF MICROSEISMICITY. United States: N. p., 2007. Web.
RUTLEDGE, JAMES T., & JONES, ROB H. A COMPARISON OF COLLAPSING AND PRECISE ARRIVAL-TIME MAPPING OF MICROSEISMICITY. United States.
RUTLEDGE, JAMES T., and JONES, ROB H. Fri . "A COMPARISON OF COLLAPSING AND PRECISE ARRIVAL-TIME MAPPING OF MICROSEISMICITY". United States. doi:. https://www.osti.gov/servlets/purl/1000491.
@article{osti_1000491,
title = {A COMPARISON OF COLLAPSING AND PRECISE ARRIVAL-TIME MAPPING OF MICROSEISMICITY},
author = {RUTLEDGE, JAMES T. and JONES, ROB H.},
abstractNote = {In this paper they compare the improvements in microseismic location images obtained using precise arrival times with that obtained by the collapsing technique. They first collapse the initial locations for a hydraulic-fracture data set from the Carthage Cotton Valley gas field, they then use the precise-arrival-time locations as measure for the effectiveness of the collapsing. Finally, they examine the changes when applying collapsing to the precise-arrival-time locations.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Fri Jan 05 00:00:00 EST 2007},
month = {Fri Jan 05 00:00:00 EST 2007}
}

Conference:
Other availability
Please see Document Availability for additional information on obtaining the full-text document. Library patrons may search WorldCat to identify libraries that hold this conference proceeding.

Save / Share:
  • In May and July, 1997, a consortia of operators and service companies conducted a series of hydraulic fracture imaging tests in the Carthage Cotton Valley gas field of East Texas (Walker, 1997). Microseismic data were collected and processed for six hydraulic fracture treatments in two wells (3 completion intervals per well) (Mayerhofer et al., 2000). One well was completed with gel-proppant treatments in which a viscous crosslink gel was injected to entrain high concentrations of sand proppant into formation. The second well was completed using treated water and very low proppant concentrations (waterfracs). Waterfracs have been shown to be justmore » as effective as the conventional gel-proppant treatments in Cotton Valley reservoirs, but at greatly reduced cost. Mayerhofer and Meehan (1998) suggest two possible reasons why waterfracs are successful: (1) Induced shear displacement along natural and hydraulic fractures results in self-propping (shear dilation enhanced by fracture branching, proppant and spalled rock fragments), and (2) Fracture extension and cleanup is easier to achieve with low-viscosity fluids. With improved source location precision and focal mechanism determination (fracture plane orientation and sense of slip), we have reexamined the Cotton Valley data, comparing the seismicity induced by water and gel-proppant treatments at common depth intervals. We have improved the location precision and computed focal mechanism of microearthquakes induced during a series of hydraulic fracture completions within the Cotton Valley formation of East Texas. Conventional gel-proppant treatments and treatments using treated water and very low proppant concentrations (waterfracs) were monitored. Waterfracs have been shown to be just as effective as the conventional gel-proppant treatments in Cotton Valley reservoirs, but at greatly reduced cost (Mayerhofer and Meehan, 1998). Comparison of the seismicity induced by the two treatment types show similar distributions of event locations and focal mechanisms for common depth intervals. We interpret the induced seismicity to be primarily controlled by the natural fracture geometry and independent of treatment design. By implication, we expect the effectiveness of shear-induced fracture propping to be independent of the treatment fluid in Cotton Valley reservoirs.« less
  • In many applications employing photodetectors, the determination of the arrival time of individual photons at the surface of the detector can be used to localize the photon source. For the case where the photon intensity is extremely low, the most common type of detector used is the photomultiplier tube. The optimal arrival time estimators for single and multiple photons arriving at the surface of a photomultiplier tube are developed in this paper. The optimal timing estimator considered is a weighted non-linear least squares estimate of the detection time for a high gain PMT with gaussian statistics. The lease squares estimatormore » is constructed using the mean and covariance function of the photomultiplier output for different arrival times. The RMS error for the leant squares arrival time estimator was calculated and compared with the performance of other common timing estimators, including the first photoelectron timing estimators, using a Burle/RCE 8850 PMT.« less
  • We describe a new pulse arrival-time recording system that is being developed at Los Alamos. The new PATRM/PCI (Pulse Arrival-Time Recording Module/Peripheral Component Interconnect) has had several features added. These features enhance our time-correlation measurement capabilities. By applying the latest advances in electronics and computer technology we are able to increase capability over existing instrumentation while lowering the per channel cost. The modular design approach taken allows easy configuration of both small and large systems.