Well completions are an integral part of providing safe, reliable and continuous access to underground resources such as oil, gas and geothermal resources. Completions are typically considered to be the final step of drilling engineering which includes processes such as setting casing, cementing, and perforating to reach the target formation. Completions provide the conduit from the resource to the surface. Although completions encompass a wide range of disciplines, several key factors ultimately determine the quality of the completion. One of those is cementing and centralizing casing within the wellbore. This white paper examines the current state of the art for centralizers in the context of well completions. The paper will include an introductory primer on well completions to provide the framework for the centralizer discussions. The types of centralizers currently available and how they are used will be discussed in addition to alternative centralizer techniques.

The project provides an updated Energy Return on Investment (EROI) for Enhanced Geothermal Systems (EGS). Results incorporate Argonne National Laboratory's Life Cycle Assessment and base case assumptions consistent with other projects in the Analysis subprogram. EROI is a ratio of the energy delivered to the consumer to the energy consumed to build, operate, and decommission the facility. EROI is important in assessing the viability of energy alternatives. Currently EROI analyses of geothermal energy are either out-of-date, of uncertain methodology, or presented online with little supporting documentation. This data set is a collection of files documenting data used to calculate the Energy Return On Investment (EROI) of Engineered Geothermal Systems (EGS) and erratum to publications prior to the final report. Final report is available below, or from the OSTI web site (http://www.osti.gov/geothermal/). Data in this collections includes the well designs used, input parameters for GETEM, a discussion of the energy needed to haul materials to the drill site, the baseline mud program, and a summary of the energy needed to drill each of the well designs. EROI is the ratio of the energy delivered to the customer to the energy consumed to construct, operate, and decommission the facility. Whereas efficiency is the ratio of the energy delivered to the customer to the energy extracted from the reservoir.

This engineering design and specification document contains the applications, specifications, testing, materials, and running methods for the Open-Hole Packer. The Open Hole Packer is designed to seal 8.5 to 9.75 inch open-holes with a 7 inch casing. The design is intended to seal up to 6,000 psi of differential pressure and temperatures of up to 437F (225C). This document is the first step in the design process.

The Newberry Volcano EGS Demonstration in central Oregon, a 3 year project started in 2010, tests recent technological advances designed to reduce the cost of power generated by EGS in a hot, dry well (NWG 55-29) drilled in 2008. First, the stimulation pumps used were designed to run for weeks and deliver large volumes of water at moderate well-head pressure. Second, to stimulate multiple zones, AltaRock developed thermo-degradable zonal isolation materials (TZIMs) to seal off fractures in a geothermal well to stimulate secondary and tertiary fracture zones. The TZIMs degrade within weeks, resulting in an optimized injection/ production profile of the entire well. Third, the project followed a project-specific Induced Seismicity Mitigation Plan (ISMP) to evaluate, monitor for, and mitigate felt induced seismicity. Stimulation started October 17, 2012 and continued for 7 weeks, with over 41,000 m3 of water injected. Two TZIM treatments successfully shifted the depth of stimulation. Injectivity, DTS, and seismic analysis indicate that fracture permeability in well NWG 55-29 was enhanced by two orders of magnitude. This submission includes all of the files and reports associated with the geophysical exploration, stimulation, and monitoring included in the scope of the project.

The Newberry Volcano EGS Demonstration in central Oregon, a 5 year project begun in 2010, tests recent technological advances designed to reduce the cost of power generated by EGS in a hot, dry well (NWG 55-29) drilled in 2008. First, the stimulation pumps used were designed to run for weeks and deliver large volumes of water at moderate well-head pressure. Second, to stimulate multiple zones, AltaRock developed thermo-degradable zonal isolation materials (TZIMs) to seal off fractures in a geothermal well to stimulate secondary and tertiary fracture zones. The TZIMs degrade within weeks, resulting in an optimized injection/ production profile of the entire well. Third, the project followed a project-specific Induced Seismicity Mitigation Plan (ISMP) to evaluate, monitor for, and mitigate felt induced seismicity. An initial stimulation was conducted in 2012 and continued for 7 weeks, with over 41,000 m3 of water injected. Further analysis indicated a shallow casing leak and an unstable formation in the open hole. The well was repaired with a shallow casing tieback and perforated liner in the open hole and re-stimulated in 2014. The second stimulation started September 23rd, 2014 and continued for 3 weeks with over 9,500 m3 of water injected. The well was treated with several batches of newly tested TZIM diverter materials and a newly designed Diverter Injection Vessel Assembly (DIVA), which was the main modification to the original injection system design used in 2012. A second round of stimulation that included two perforation shots and additional batches of TZIM was conducted on November 11th, 2014 for 9 days with an additional 4,000 m3 of water injected. The stimulations resulted in a 3-4 fold increase in injectivity, and PTS data indicates partial blocking and creation of flow zones near the bottom of the well. This submission includes all of the files and reports associated with the stimulation, pressure testing, and monitoring included in the scope of the project.

Picture and video records of SECARB field trips, DAS site, DAS instrumentation, and casing installations.

This test was conducted at the Chevron Cymric oilfield in the California central valley near Bakersfield. A reflected seismic signal was observed in all three components (x, y, z) of the 3-component Episensor geophone, as well as all phones on the single component array. The arrival time of the reflected seismic signal matches calculations based on a reasonable velocity model (~650 m/s). The seismic data has three channels that are from the 3-C Broadband Episensor, then from 4th -- 12th channels has no data. Channel 13 -- 25 are surface single change vertical geophones. The source of this seismic survey is weight drop. More info could be found from the data header and the attached PPT file.

The objective of this field test is to validate several technologies for non-invasive well integrity assessment using existing wells with a known completion. The tests were made at the Cymric oil field, which is a steam flood operation. The wells therefore undergo similar downhole conditions as geothermal wells. The Cymric field is mainly a cyclic steam operation where wells are 1000-15-00 ft in depth and the reservoir occupies the bottom 400ft. The maximum temperatures can exceed 500 degrees F and the well spacing is very close, often less than 50m. The field plan consisted of applying the Time Domain Reflectometry (TDR) method to the wells. The input voltages were set as 70 V shows the TDR responses at frequencies of 450 kHz, 2500 kHz, and 4500 kHz. There is a summary report will full information about the field tests.