Rutledge, James T. and Urbancic, Ted (1999) Cotton Valley Imaging Project Phase IV Completion of Microseismic Mapping of the Phase I and II Hydraulic Fractures Wells CGU21-10 and CGU21-09. Technical Report. Gas Research Institute.
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Abstract
Microseismic monitoring was conducted for three stages of hydraulic fracture completions of wells CGU21-10 (Phase 1) and CGU21-09 (Phase 2) in May and July, 1997, respectively. ARCO wrote two reports summarizing the acquisition and field analysis of the Phase-1 and -2 microseismic data (Withers and Dart, 1997a; Withers and Dart, 1997b). The Phase 1 preliminary mapping results of ARCO were also presented in Walker (1997). ARCO mapped subsets of the data collected in the field using their process of visually matching calculated wavefront curves with full-array waveform displays. Based on an operator moving a graphical display of a trial event location, a single event’s final location is stored when the operator finds an acceptable match of the corresponding display of computed and observed arrival times. Los Alamos, The Engineering Seismology Group Canada (ESG), and Sandia each separately mapped different subsets of the Phase-1 data and presented preliminary results at the December, 1997 meeting of the Cotton Valley Imaging Consortia. The ESG analysis also include characterization of the microearthquake source parameters (Urbancic and Zinno, 1998). At the same meeting, ARCO presented their mapping results of the Phase-2 data. A number of problems or discrepancy were identified that warranted a more thorough investigation of the data and the various mapping techniques employed. After two preliminary studies investigating the asymmetry of fracture growth of the Phase-1, Stage-2 treatment (Rutledge, 1998) and a reevaluation of the single-well locations of the Phase-2 data (Urbancic, 1998), the Cotton Valley Consortia, under GRI management, funded both Los Alamos and ESG to complete the microseismic mapping and analysis of source parameters for the entire Phase-1 and -2 data sets. These efforts constitute Phase IV of the Cotton Valley Imaging Project and include the following tasks: 1. Calculation of event locations using inversion techniques for the Phase 1 and 2 hydraulic fractures (over and above previously located events). 2. Determination of source parameters for the above located events. 3. Confirmation of results through joint analysis of data subsets. 4. Evaluation of velocity and array geometry effects on event location and source parameter determinations. 5. Visualization of results and associated location errors. Part I of this report covers the microearthquake location analysis and involves tasks 1, 3, 4, and 5; Part II covers the analysis of source parameters and involves tasks 2, 3, 4 and 5.
| Item Type: | Reports (Technical Report) |
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| Subjects: | Methodology > Other-additional study Region > USA > Texas > Cotton Valley Inducing technology > Unconventional hydrocarbon extraction |
| Project: | SERA > COTTON VALLEY: uconventional hydrocarbon extraction |