PWS_-_geomech_modeling_v2_-_final_updated_9.7.16.doc

Solicitation No.

Document Title

R16PS01744

Geomechanical & Flow Modeling

PWS Attachment 1 Performance Work Statement Geomechanical Modeling, Flow Modeling, and Reservoir Characterization Period of Performance (POP) – 120 Calendar Days from Date of Award

1. Introduction/Background

1.1. Reclamation’s Paradox Valley Unit (PVU) is a critical component of the Colorado River Basin Salinity Control Program, which is a multi-works program to control the salinity of water delivered to users in the United States and Mexico. PVU is located in western Colorado, approximately 90 km southwest of Grand Junction.

1.2. Using a field of shallow brine extraction wells located in Paradox Valley, PVU diverts highly saline groundwater which would otherwise flow into the Dolores River, a tributary of the Colorado River. The diverted brine is piped several miles, and then injected into a 16,000-foot-deep Class V waste-disposal well located on the margin of Paradox Valley. The disposal well was completed in 1988.

1.3. The PVU injection rate is currently about 7,000 barrels of brine per day, resulting in the disposal of about 100,000 tons of salt per year. Because of the relatively low permeability of the target injection formation (<20 md), brine injection at these rates results in surface pressures of about 5,000 psi, and down-hole pressures of about 12,000 psi, which is above the injection formation fracture closure pressure. The target injection formation is a Mississippian-age limestone. Additional information about the geology and background of the project may be found in the following references: King, V.M., et al., 2014, Geological structure of the Paradox Valley Region, Colorado, and relationship to seismicity induced by deep well injection. Journal of Geophysical Research: Solid Earth, 119(6): p. 4955-4978, Block, L. V., et al, 2015, Induced seismicity constraints on subsurface geological structure, Paradox Valley, Colorado, Geophysical Journal International, 200(2), 1170-1193., King, V.M., et al, 2016, Pressure/flow modeling and induced seismicity resulting from two decades of high-pressure deep-well brine injection, Paradox Valley, Colorado. Geophysics, 81(5), p. B119.

1.4. Reclamation is conducting technical studies to appraise drilling a second deep disposal well in the vicinity of Paradox valley, and is considering multiple sites for that well. A second well is just one of several alternatives that will be considered for an Environmental Impact Study.

1.5. Reclamation has selected specific comparison sites that are expected to have suitable reservoir and operational properties, based on results from separate studies, including reprocessing and interpreting of 500+ miles of 2D seismic reflection data, analysis of available well log and core data, aeromagnetic data survey and interpretation, gravity data interpretation, geologic structure interpretation, induced seismicity analysis, assessment of environmental impacts, drilling feasibility studies, and assessing the feasibility of constructing and operating surface infrastructure.

1.6. As part of this process for appraising and ranking potential second-well sites, Reclamation intends to contract appraisal-level analyses and reservoir characterization for the identified sites. These analyses will compare results from coupled 3D geomechanical and flow models that simulate brine injection at the identified sites. The analyses will be done by knowledgeable and qualified experts in the fields of petroleum engineering, reservoir engineering, geomechanical and flow modeling, geophysics, geology, or related fields. The results of these appraisal-level analyses are intended to be used by Reclamation only for planning and decision making, and not for actual design.

1.7. The analyses are intended to be used only for environmental studies comparing potential second injection well sites, and not for the design or operation of a new well. Due to limited formation property data and other data, the accuracy of modeling predictions is likely to be limited. It is expected that models will be constructed that are appropriate for appraisal-level, comparative studies based on limited data.

1.8. Because of the relatively low permeability and relatively high injection pressures experienced at the existing injection well, careful consideration should be given to the appropriate choice of numerical methods needed to achieve stability and convergence (e.g., possibly using finite volume methods for the flow modeling).

1.9. It may be useful to consider the cooling effects of the injected brine. Limited pre-injection and post-injection formation temperature data is available for the existing injection well.

2. Description of Products/Services

2.1. The contractor shall conduct an appraisal-level analysis of multiple potential disposal well sites, describing the evolution of various physical properties within the numerical models (such as pore pressure and stress) given an assumed injection history and initial stress state.

2.1.1. The contractor’s analysis shall analyze up to 5 potential new injection sites in the Paradox Valley area identified by Reclamation, as well as the existing PVU injection well.

2.1.1.1. For each site, the contractor shall perform and document the following minimum steps:

2.1.1.1.1. Construct a numerical model using data provided both by Reclamation and the contractor. Reclamation-provided data will include: interpreted 2D seismic sections (including contour and isopach maps of the Leadville target injection formation and the Paradox salt formation, contour map of the top of the Precambrian basement, and major faults), well logs, interpreted aeromagnetic data, interpreted gravity data, interpreted faults, interpreted formation horizons, initial formation properties, and a simple well model.

2.1.1.1.2. Perform a contractor-proposed validation and quality-assurance process, including test runs, on the constructed model.

2.1.1.1.3. Apply or match an assumed injection flow rate history (provided by Reclamation) to the model.

2.1.1.1.4. Compute the evolution of various physical properties within the model, including pore pressure, stress, and displacements.

2.1.1.1.4.1. Pore pressures and stress shall be determined for at least 4 grids representing: the center of the Leadville formation, the center of the Paradox formation, a formation above the Paradox formation (to be determined in consultation with Reclamation), and the top of the Precambrian basement.

2.1.1.1.4.2. Displacements shall be computed for the ground surface.

2.1.1.1.4.3. The grids of the physical properties shall be output for the following times after the start of injection: 1 week, 1 month, 6 months, 1 year, 2 years, 5 years, 10 years, 20 years, and 50 years.

2.1.1.1.5. Compute the evolution of modeled well-head pressure for a 50-year time period.

2.1.1.1.6. Provide a written description of the model and computational results, including sensitivity to key input parameters, and an assessment of the stability and uncertainty of the model.

2.1.1.2. The first site to run shall be the existing PVU injection well site using the actual daily flow rates and wellhead injection pressures provided by Reclamation. Before proceeding with the other sites, the contractor shall provide preliminary results to Reclamation for comparison to the actual wellhead data and seismicity data, and shall work with Reclamation to refine model properties as necessary to better match the observed data.

2.1.1.3. All potential injection well sites will be identified to the contractor by Reclamation, based on separate studies such as the interpretation of seismic reflection data, well log data, formation properties, aeromagnetic data, geologic structure, induced seismicity, environmental impacts, drilling feasibility, and the feasibility of constructing and operating surface infrastructure.

2.1.1.4. The contractor’s analysis shall use a consistent methodology for all sites so that the results can be compared.

2.1.2. This appraisal analysis shall be documented in draft and final written reports.

2.2. Proposals must provide general information on the proposed modeling methods, and should include at minimum, the identification of the software to be used for geomechanical and flow modeling, a general description of how the computational grids will be constructed (including software to be used), the method to be used for coupling, and how convergence and stability will be addressed.

3. Personnel Qualifications: Contractor personnel shall provide resumes detailing education and employment history for the personnel who will perform the analysis. The resumes shall demonstrate at least 10 years of industry experience in reservoir characterization, and in the design, implementation, running and interpretation of coupled flow and geomechanical models of deep wells. It is expected that expertise in the fields of petroleum engineering, reservoir engineering, geomechanical and flow modeling, geophysics, geology, or related fields will be needed. Documented past professional experience on deep injection well projects would be highly beneficial.

4. Government Furnished Materials or Services: All potential sites will be identified to the contractor by Reclamation. Other data to be provided will include: interpreted 2D seismic sections (including derived contour and isopach maps, and major faults), well log data and report, interpreted aeromagnetic data, interpreted gravity data, interpreted faults, interpreted formation horizons, estimated formation properties, and a simple well model.

5. Travel and Government Vehicle Requirements: None

6. Security: The contractor shall sign a non-disclosure agreement agreeing to the terms of Reclamation’s license to use proprietary seismic reflection data and interpretations, and agreeing not to release any Reclamation-provided data or reports. No on-site visits to Reclamation offices are required.

7. Training Requirements: None

8. Schedule of Deliverables/Period of Performance (POP)

9. Deliverables

9.1. Executed non-disclosure agreement (NDA) must be provided to the Contracting Officer. The NDA will be provided by Reclamation at the time of award.

9.2. Preliminary XYZ grid results and modeled well-head pressure and flow results for the PVU injection well. Model results shall be provided in a format agreed to by Reclamation, and delivered as compressed ZIP archive(s).

9.3. Preliminary XYZ grid results and modeled well-head pressure and flow results for the remaining sites. Model results shall be provided in a format agreed to by Reclamation, and delivered as compressed ZIP archive(s).

9.4. Draft report in electronic format, including attachments. The report shall be in PDF or MS Word format.

9.5. Final XYZ grid results and modeled well-head pressure and flow results for all sites. Model results shall be provided in a format agreed to by Reclamation, and delivered as compressed ZIP archive(s).

9.6. Final report, including 3 paper copies in addition to the electronic copy and attachments. Data attachments shall be provided in compressed ZIP format.

10. Acceptance and Quality Assurance: The contractor shall notify Reclamation within 7 days of receipt of the identified sites and data, and shall report any issues with reading that information. The contractor shall provide preliminary results for the existing PVU injection well within 45 days of award, and shall work with Reclamation to refine model properties as necessary to better match the observed data. The contractor shall prepare a draft report for Reclamation’s review, which will be completed within 60 calendar days of award. The contractor shall remedy any deficiencies in the report identified by Reclamation, and shall submit a final report to Reclamation within 90 calendar days after award.

11. Quality Assurance Surveillance Plan (QASP) – All tasks listed below will be monitored by the COR.