Deep Underground Injection Research Articles

Fracture development during disposal of hazardous drilling cuttings by deep underground injection: A review

Drilling fluids with complicated compositions are becoming more common as the oil and gas industry develops. The production of hazardous cuttings is increasing, which not only stifles the oil and gas industry's development but also poses a severe environmental threat. Deep underground re-injection is a cost-effective and efficient method for dealing with hazardous cuttings. Numerous experiments and numerical studies on cuttings re-injection have been conducted in the past thirty years. However, there is still a divergence of views on the fracture development in the process of cuttings re-injection. A comprehensive review of existing studies is necessary to help researchers advance this technology. This paper provides a review of the fundamental studies on fracture behaviors during the deep underground re-injection of drilling cuttings. The limitations of the existing studies are also discussed to inspire new research endeavors.

Deep Underground Injection of Waste from Drilling Activities—An Overview

Oil and gas exploration and production activities generate large amounts of waste material, especially during well drilling and completion activities. Waste material from drilling activities to the greatest extent consists of drilled cuttings and used drilling mud with a smaller portion of other materials (wastewater, produced hydrocarbons during well testing, spent stimulation fluid, etc.). Nowadays, growing concerns for environmental protections and new strict regulations encourage companies to improve methods for the reduction of waste material, as well as improve existing and develop new waste disposal methods that are more environmentally friendly and safer from the aspect of human health. The main advantages of the waste injection method into suitable deep geological formations over other waste disposal methods (biodegradation, thermal treatment, etc.) are minimizing potentially harmful impacts on groundwater, reducing the required surface area for waste disposal, reducing the negative impact on the air and long-term risks for the entire environment. This paper gives a comprehensive overview of the underground waste injection technology, criteria for the selection of the injection zone and methods required for process monitoring, as well as a comprehensive literature overview of significant past or ongoing projects from all over the world.

Fracture and Strain Field Evolution in Faulted Brine-Saturated Sandstone

Abstract Geological carbon dioxide (CO2) sequestration has received significant attention over the past two decades as an effective method to reduce the emission of greenhouse gases to the atmosphere through deep underground injection of CO2. However, fractures or faults commonly exist in the rock mass, which provides the potential for CO2 leakage. To better understand the reactivation of preexisting fractures, it is essential to investigate fracture development and its effect on the stability of the rock. In this study, uniaxial compression tests were carried out on sandstone specimens by using a SANS rock mechanics servocontrolled testing system (MTS Systems Corporation, Eden Prairie, MN). Three kinds of Zunyi quartz-rich sandstone cylindrical specimens were tested, i.e., dry intact specimens, and both dry and brine-saturated specimens containing two preexisting faults. Based on the experimental results, the stress-strain curves and mechanical properties were analyzed and were closely related to the fault angle under both dry and saturated conditions. The macrofailure patterns can be classified into three modes: tensile coalescence failure, shear coalescence failure, and no coalescence failure. During the testing, a three-dimensional digital image correlation method was applied to the sandstone cylinders that contained two preexisting faults. Furthermore, acoustic emission (AE) sensors and strain gauges were bonded on the specimens to measure the AE signal and local strain in real time. The evolution characteristics of strain field, AE counts, and measured local strain were investigated. These findings can be regarded as a reference for future studies of fracture mechanisms in brine-saturated sandstones to better inform parameterization of constitutive geomechanical models in the study of CO2 injection in deep saline aquifers.

Demonstration of Non-Endangerment at the Secarb Anthropogenic Test Site

The Southeast Carbon Sequestration Partnership (SECARB) Anthropogenic Test became the first fully integrated carbon capture, transport, and storage project to successfully demonstrate non-endangerment towards the closure of a Alabama Department of Environmental Management (ADEM) underground injection control (UIC) permit. Despite being a state-issued UIC Class V experimental well permit, this permit contained many elements specific to geologic sequestration of CO2 included in the United States Environmental Protection Agency (EPA) regulations for Class VI wells. This paper will outline the permit structure and the steps taken to demonstrate non-endangerment for the first fully integrated Carbon Capture and Storage (CCS) project on a coal-fired power plant using advanced amines for CO2 capture. The SECARB Anthropogenic Test is a U.S. Department of Energy (DOE), Southern Company, and Electric Power Research Institute (EPRI) funded, Southern States Energy Board (SSEB) managed, project designed to demonstrate deep underground injection and containment of anthropogenic CO2 sourced from a 750 MW (net) coal -fired electric generating unit at Plant Barry, Alabama. From August 2012 to September 2014, a total of 114,104 metric tonnes of CO2 were captured and transported via a 12-mile pipeline from Alabama Power Company’s Plant Barry and successfully injected and stored in the upper Paluxy formation, a Lower Cretaceous sandstone unit, at the Denbury Onshore operated Citronelle Oil Field in Citronelle, Alabama. One CO2 injection well and three monitoring wells were drilled for this project. The initial Class V experimental technology UIC permit application was modified to include some Class VI permit requirements by the EPA to demonstrate protection of underground sources of drinking water (USDWs). These requirements included but were not limited to bottom to top cement coverage, a model-based Area of Review (AoR) determination with periodic updates, and a suite of Monitoring, Verification and Accounting (MVA) methods to track and monitor the CO2 plume migration and containment within the permitted injection zone. The UIC permit required extensive monitoring of the injected CO2 with objectives to create and sustain well integrity, assure safe CO2 injection operations, verify the location and migration of the CO2 plume, and monitor for any CO2 leakage. As such, a suite of technologies were applied and developed to demonstrate non-endangerment of underground sources of drinking water (USDW’s) and to ensure that CO2 does not migrate out of the intended storage zones. This involved several levels of monitoring: surface monitoring, shallow groundwater monitoring, and deep reservoir monitoring via commercially available and experimental MVA methods. Sufficient evidence was provided by the suite of monitoring efforts to indicate successful non-endangerment of USDWs at the Citronelle site. No CO2 release or build-up was detected using groundwater analysis, tracer detection, and soil CO2 flux monitoring to indicate any shallow or surficial leakage of CO2. Additionally, no evidence of gas saturation was observed within or above the confining zone, based on the results of time-lapse pulsed neutron capture logging. Cross-well seismic results show no negative velocity anomalies in or above the confining unit, which implies that there is no detectable leakage out of the injection zone. The associated models simulating the distribution of CO2 through the injected geological layers agreed with observed monitoring data, demonstrating confinement within the injected zone and confirming that the Citronelle Dome structure forms an ideal CO2 storage complex for the confinement of CO2 in the subsurface.

Obfuscation Does Not Provide Comfort

Obfuscation Does Not Provide Comfort

Shaking Up The Fracking Debate

Earthquakes near hydraulic fracturing and waste-fluid injection wells in the central U.S. may be being triggered by massive earthquakes thousands of miles away, according to a new study (Science 2013, DOI: 10.1126/science.1238948). The study notes the recent rise in the U.S. of small to midsized earthquakes. It points to a relationship between that rise and the increased deep underground injection of large amounts of water and wastewater for hydraulic fracturing, or fracking, for natural gas and oil. The researchers looked at past earthquake recordings near three U.S. hydraulic fracturing injection sites. They found that pressure in faults at these sites was already approaching critical levels when major earthquakes occurred far away. The distant earthquakes triggered a rise in frequency and intensity of local tremors, the scientists report. “The injected fluids are driving the faults to their tipping point,” explains lead author Nicholas J. van der Elst, a researcher at Columbia ...

Probabilistic Analysis of Fracture Reactivation Associated with Deep Underground CO2 Injection

In the context of carbon capture and storage, deep underground injection of CO2 induces the geomechanical changes within and around the injection zone and their impact on CO2 storage security should be evaluated. In this study, we conduct coupled multiphase fluid flow and geomechanical modeling to investigate such geomechanical changes, focusing on probabilistic analysis of injection-induced fracture reactivation (such as shear slip) that could lead to enhanced permeability and CO2 migration across otherwise low-permeability caprock formations. Fracture reactivation in terms of shear slip was analyzed by implicitly considering the fracture orientations generated using the Latin hypercube sampling method, in one case using published fracture statistics from a CO2 storage site. The analysis was conducted by a coupled multiphase fluid flow and geomechanical simulation to first calculate the three-dimensional stress evolution during a hypothetical CO2 injection operation and then evaluate the probability of shear slip considering the statistical fracture distribution and a Coulomb failure analysis. We evaluate the probability of shear slip at different points within the injection zone and in the caprock just above the injection zone and relate this to the potential for opening of new flow paths through the caprock. Our analysis showed that a reverse faulting stress field would be most favorable for avoiding fracture shear reactivation, but site-specific analyses will be required because of strong dependency of the local stress field and fracture orientations.

Modeling of coupled deformation and permeability evolution during fault reactivation induced by deep underground injection of CO 2

The interaction between mechanical deformation and fluid flow in fault zones gives rise to a host of coupled hydromechanical processes fundamental to fault instability, induced seismicity, and associated fluid migration. In this paper, we discuss these coupled processes in general and describe three modeling approaches that have been considered to analyze fluid flow and stress coupling in fault-instability processes. First, fault hydromechanical models were tested to investigate fault behavior using different mechanical modeling approaches, including slip interface and finite-thickness elements with isotropic or anisotropic elasto-plastic constitutive models. The results of this investigation showed that fault hydromechanical behavior can be appropriately represented with the least complex alternative, using a finite-thickness element and isotropic plasticity. We utilized this pragmatic approach coupled with a strain-permeability model to study hydromechanical effects on fault instability during deep underground injection of CO 2. We demonstrated how such a modeling approach can be applied to determine the likelihood of fault reactivation and to estimate the associated loss of CO 2 from the injection zone. It is shown that shear-enhanced permeability initiated where the fault intersects the injection zone plays an important role in propagating fault instability and permeability enhancement through the overlying caprock.

Model Components of the Certification Framework for Geologic Carbon Sequestration Risk Assessment

Chapter 1 MODEL COMPONENTS OF THE CERTIFICATION FRAMEWORK FOR GEOLOGIC CARBON SEQUESTRATION RISK ASSESSMENT Curtis M. Oldenburg 1 , Steven L. Bryant 2 , Jean-Philippe Nicot 3 , Navanit Kumar 2,5 , Yingqi Zhang 1 , Preston Jordan 1 , Lehua Pan 1 , Patrick Granvold 4 , Fotini K. Chow 4 Earth Sciences Division, 90-1116, 1 Cyclotron Rd., Lawrence Berkeley National Laboratory, Berkeley CA 94720 Department of Petroleum and Geosystems Engineering, The University of Texas at Austin, 1 University Station C0300, Austin, TX 78712 Bureau of Economic Geology, Jackson School of Geosciences, The University of Texas at Austin, University Station, Box X, Austin, Texas 78713 Department of Civil and Environmental Engineering, University of California, Berkeley, Berkeley, CA 94720 Shell Oil and Production Company, 200 North Dairy Ashford, Houston, TX 77079 ABSTRACT: We have developed a framework for assessing the leakage risk of geologic carbon sequestration sites. This framework, known as the Certification Framework (CF), emphasizes wells and faults as the primary potential leakage conduits. Vulnerable resources are grouped into compartments, and impacts due to leakage are quantified by the leakage flux or concentrations that could potentially occur in compartments under various scenarios. The CF utilizes several model components to simulate leakage scenarios. One model component is a catalog of results of reservoir simulations that can be queried to estimate plume travel distances and times, rather than requiring CF users to run new reservoir simulations for each case. Other model components developed for the CF and described here include fault characterization using fault-population statistics; fault connection probability using fuzzy rules; well-flow modeling with a drift-flux model implemented in TOUGH2; and atmospheric dense-gas dispersion using a mesoscale weather prediction code. INTRODUCTION We have developed a novel and practical risk-based framework for certifying that the leakage risk of a potential geologic carbon sequestration (GCS) site is below agreed-upon thresholds [1, 2, 3]. The approach we developed, known as the Certification Framework (CF), proposes a standardized way for project proponents, regulators, and the public to analyze and understand risks and uncertainties of GCS in a simple and transparent way. The CF goes beyond the scope of regulations of deep underground injection permitted by the U.S. Environmental Protection Agency (EPA) which protect underground sources of drinking water (USDW) to consider risks to a broader set of resources and environmental assets as well as loss of emission-reduction credits due to CO 2 leakage. The CF uses physically grounded models for the movement of injected CO 2 and brine, and for assessing the likelihood that CO 2 or injection-related pressure perturbation will intersect wells and faults. The CF and an example case study have been fully described elsewhere [3]. This paper describes the essential model components that we have developed for carrying out a CF analysis. These model components include the catalog of simulation results, fault population statistics, fault connectivity analyses, well-bore flow, and dense gas dispersion.

Environmental bonds and the challenge of long-term carbon sequestration

The potential to capture carbon from industrial sources and dispose of it for the long-term, known as carbon capture and sequestration (CCS), is widely recognized as an important option to reduce atmospheric carbon dioxide emissions. Specifically, CCS has the potential to provide emissions cuts sufficient to stabilize greenhouse gas levels, while still allowing for the continued use of fossil fuels. In addition, CCS is both technologically-feasible and commercially viable compared with alternatives with the same emissions profile. Although the concept appears to be solid from a technical perspective, initial public perceptions of the technology are uncertain. Moreover, little attention has been paid to developing an understanding of the social and political institutional infrastructure necessary to implement CCS projects. In this paper we explore a particularly dicey issue—how to ensure adequate long-term monitoring and maintenance of the carbon sequestration sites. Bonding mechanisms have been suggested as a potential mechanism to reduce these problems (where bonding refers to financial instruments used to ensure regulatory or contractual commitments). Such mechanisms have been successfully applied in a number of settings (e.g., to ensure court appearances, completion of construction projects, and payment of taxes). The paper examines the use of bonding to address environmental problems and looks at its possible application to nascent CCS projects. We also present evidence on the use of bonding for other projects involving deep underground injection of materials for the purpose of long-term storage or disposal.

Effects of industrial outfalls on tropical macrobenthic sediment communities in Reunion Island (Southwest Indian Ocean)

Temporal changes in the composition of soft bottom macrobenthic assemblages at Reunion Island (Southwest Indian Ocean) were studied in the context of a long-term environmental monitoring programme studying the impacts of effluents of industrial sugar cane refineries that are transferred to shallow and deep coastal environments by different pathways: surface discharge and deep underground injection. Seven stations (between 20 and 160 m depth) were surveyed between 1994 and 2003 on the industrial zone. One additional station was surveyed on a reference site. Spatio-temporal changes in the composition of macrobenthic communities were assessed using several diversity indices, ABC curves, MDS and associated ANOSIM tests and biotic indices. Among the 171 taxa recorded, polychaetes were dominant (89 species), followed by crustaceans and molluscs. The analysis of spatial changes in the composition of macrobenthos showed the existence of distinct benthic communities along the depth gradient. Temporal changes in macrobenthos composition were most prominent at the shallowest station. They mainly corresponded to the decline of several initially dominant taxa and the increase of the Eunicid polychaete Diopatra cuprea. This station further showed increasing macrofaunal abundance, biomass and sediment organic content over time, concomitant with decreasing sediment grain sizes. In deeper environments, temporal changes were much smaller. Macrofaunal abundance and species richness increased progressively, suggesting a moderate impact on benthic ecosystems resulting from slight enrichments due to effluents rich in organic matter. Our results highlight an original response to disturbance pattern involving opportunistic Eunicidae species ( D. cuprea) not previously described. Moreover, they allow for the comparison of the impact on macrofauna caused by industrial effluents exported by two distinct and different pathways in a tropical coastal high-energy marine environment.

Sequestration of Carbon Dioxide in Coal with Enhanced Coalbed Methane RecoveryA Review

This article reviews the storage of captured CO2 in coal seams. Other geologic formations, such as depleted petroleum reservoirs, deep saline aquifers and others have received considerable attention as sites for sequestering CO2. This review focuses on geologic sequestration of CO2 in unmineable coalbeds as the geologic host. Key issues for geologic sequestration include potential storage capacity, the storage integrity of the geologic host, and the chemical and physical processes initiated by the deep underground injection of CO2. The review topics include (i) the estimated CO2 storage capacity of coal, along with the estimated amount and composition of coalbed gas; (ii) an evaluation of the coal seam properties relevant to CO2 sequestration, such as density, surface area, porosity, diffusion, permeability, transport, rank, adsorption/desorption, shrinkage/swelling, and thermochemical reactions; and (iii) a treatment of how coalbed methane (CBM) recovery and CO2-enhanced coalbed methane (ECBM) recovery are performed (in addition, the use of adsorption/desorption isotherms, injection well characterization, and gas injection are described, as well as reservoir screening criteria and field tests operating in the United States and abroad); (iv) leak detection using direct measurements, chemical tracers, and seismic monitoring; (v) economic considerations using CO2 injection, flue gas injection, and predictive tools for CO2 capture/sequestration decisions; (vi) environmental safety and health (ES&H) aspects of CO2-enhanced coalbed methane/sequestration, hydrodynamic flow through the coal seam, accurate gas inventory, ES&H aspects of produced water and practices relative to ECBM recovery/sequestration; (vii) an initial set of working hypotheses concerning the chemical, physical, and thermodynamic events initiated when CO2 is injected into a coalbed; and (viii) a discussion of gaps in our knowledge base that will require further research and development. Further development is clearly required to improve the technology and economics while decreasing the risks and hazards of sequestration technology. These concerns include leakage to the surface, induced seismic activity, and long-term monitoring to verify the storage integrity. However, these concerns should not overshadow the major advances of an emerging greenhouse gas control technology that are reviewed in this paper.

Regulating the ultimate sink: managing the risks of geologic CO2 storage.

The geologic storage (GS) of carbon dioxide (CO2) is emerging as an important tool for managing carbon. While this Journal recently published an excellent review of GS technology (Bruant, R. G.; Guswa, A. J.; Celia, M. A.; Peters, C. A. Environ. Sci. Technol. 2002, 36, 240A-245A), few studies have explored the regulatory environment for GS or have compared it with current underground injection experience. We review the risks and regulatory history of deep underground injection on the U.S. mainland and surrounding continental shelf. Our treatment is selective, focusing on the technical and regulatory aspects that are most likely to be important in assessing and managing the risks of GS. We also describe current underground injection activities and explore how these are now regulated.

A study of caprock hydromechanical changes associated with CO2-injection into a brine formation

A numerical study of hydromechanical changes during a deep underground injection of supercritical CO2 in a hypothetical brine aquifer/caprock system is conducted. The injection process is simulated using a newly developed computer model for multi-phase analysis of CO2 and brine water flow, coupled with heat transfer and rock deformations. In this modeling, CO2 is injected at a constant rate over a 10-year period at a depth of 1,300–1,500 m. The injection zone is overlain by a 100-m-thick caprock, located at 1,200–1,300 m, which in one of the studied cases is intersected by a vertical fault. The hydraulic, mechanical as well as hydromechanical responses caused by the injection are studied. This includes the spread of the CO2 plume, effective stress changes, ground surface uplift, stress-induced permeability changes, and mechanical failure analysis. The analysis shows that most hydromechanical changes are induced in the lower part of the caprock near its contact with the injection zone, whereas the sealing mechanism of the upper part may remain intact, despite an injection pressure close to the lithostratic stress value.

DEEP WELL DISPOSAL OF SECONDARY EFFLUENT IN DADE COUNTY, FLORIDA1

ABSTRACT: Data were obtained from drilling and testing of a test injection well for deep underground injection of waste water effluent from the proposed 50‐million‐gallon‐per‐day (mgd) South District Regional Wastewater Treatment Plant of the Miami‐Dade Water and Sewer Authority, Dade County, Florida. The drilling operation progressed in stages, each stage coverting the strata to be sealed off by the 48‐inch, 40‐inch, 30‐inch, and 20‐inch casings, respectively. Total depth of the well is 3,200 feet. The top of the saline, cavernous, dolomitic Boulder Zone was found at 2,790 feet below the surface and is separated from the Floridan aquifer above by approximately 1,100 feet of confining limestone layers. These confining layers were determined, by packer testing, to be very effective. The transmissivity of the Boulder Zone was estimated to be 14 × 106 gallons per day per foot (gpd/ft) from the data obtained from pump out tests. An 8,000‐gallon‐per‐minute (gpm) injection test was conducted to confirm well performance under operating conditions. Based on all of the data obtained, it was concluded that underground injection into the Boulder Zone of secondary waste water effluent from the proposed treatment plant is feasible, both hydraulically and environmentally. A monitoring system was proposed to provide a record of the effects of injection on the subsurface environment.

GEOTECHNICAL INVESTIGATIONS DURING DRILLING OF A DEEP DISPOSAL WELL IN DADE COUNTY, FLORIDA

Abstract.A test‐injection well was drilled to a depth of 3,200 feet (976 m) to determine the feasibility of deep underground injection of 50 mgd (190,000 m 3/day) ADF of secondary treated waste water in south Dade County, Florida. Geological formation samples and water samples were collected and analyzed during the drilling of the well and geophysical logging was performed in the well at several stages. At this site, the Floridan aquifer extends from a depth of 920 feet (281 m) to 1,680 feet (512 m) and generally consists of limestone which is fossiliferous in part. Water from this aquifer is brackish, with chlorides ranging from 700 mg/l at the top to 15,000 mg/l at the bottom. The strata from 1,680 feet (512 m) to 2,790 feet (851 m) are essentially nonwater‐producing and act as a confining bed between the Floridan aquifer and the Boulder Zone.The Boulder Zone begins at 2,790 feet (851 m) in depth and consists of a very hard, fractured, cavernous, dark dolomite. The water from this aquifer is very similar to sea water. The subsurface temperature gradient at this site is reversed from the normal gradient, cooling with depth at an average rate of approximately 0.4° F (0.22°C) per 100 feet (30 m). The injection zone extends from approximately 2,830 feet (863 m) to 2,920 feet (891 m) in depth. Results of pumping tests indicate that the Boulder Zone is very transmissive and has a good confining bed above it.