Oil and Gas Wastewater Components Alter Streambed Microbial Community Structure and Function

The widespread application of directional drilling and hydraulic fracturing technologies expanded oil and gas (OG) development to previously inaccessible resources. A single OG well can generate millions of liters of wastewater, which is a mixture of brine produced from the fractured formations and injected hydraulic fracturing fluids (HFFs). With thousands of wells completed each year, safe management of OG wastewaters has become a major challenge to the industry and regulators. OG wastewaters are commonly disposed of by underground injection, and previous research showed that surface activities at an Underground Injection Control (UIC) facility in West Virginia affected stream biogeochemistry and sediment microbial communities immediately downstream from the facility. Because microbially driven processes can control the fate and transport of organic and inorganic components of OG wastewater, we designed a series of aerobic microcosm experiments to assess the influence of high total dissolved solids (TDS) and two common HFF additives—the biocide 2,2-dibromo-3-nitrilopropionamide (DBNPA) and ethylene glycol (an anti-scaling additive)—on microbial community structure and function. Microcosms were constructed with sediment collected upstream (background) or downstream (impacted) from the UIC facility in West Virginia. Exposure to elevated TDS resulted in a significant decrease in aerobic respiration, and microbial community analysis following incubation indicated that elevated TDS could be linked to the majority of change in community structure. Over the course of the incubation, the sediment layer in the microcosms became anoxic, and addition of DBNPA was observed to inhibit iron reduction. In general, disruptions to microbial community structure and function were more pronounced in upstream and background sediment microcosms than in impacted sediment microcosms. These results suggest that the microbial community in impacted sediments had adapted following exposure to OG wastewater releases from the site. Our findings demonstrate the potential for releases from an OG wastewater disposal facility to alter microbial communities and biogeochemical processes. We anticipate that these studies will aid in the development of useful models for the potential impact of UIC disposal facilities on adjoining surface water and shallow groundwater.

Mitigating injection-induced seismicity to reduce seismic risk

Over the past decade, parts of the central United States have experienced elevated number of earthquakes and seismic damage to buildings and infrastructure. These earthquakes are caused by underground injection of wastewater from oil and gas operations, which increases pore pressures, in some cases leading to slip on faults in the geologic basement. Mitigation strategies have been proposed or implemented to reduce these earthquakes, while minimizing impact on operations, but the effectiveness of these strategies in terms of seismic risk is not well understood. Here, we show that the most effective strategies for reducing earthquake occurrence may not be the best for reducing regional seismic risk in terms of economic loss. Well locations have a large impact on seismic risk, and increasing the distance between wells typically reduces risks, with the least interruption to injection operations. Results also quantify the dramatic decrease in risk achieved by locating injection operations farther from population centers. Decreasing injected volume reduces both earthquake occurrence and risk, but large reductions in volumes are needed to achieve significant reductions in risk. These findings can be used to inform design and selection of mitigation strategies that most reduce seismic risk.

Blockchain Applications in Oilfield Underground Injection Operations

This research project has successfully built a Distributed Ledger Technology (DLT) based prototype using R3 Corda open source. Its purpose applies in the oil & gas underground injection control (UIC) operations for the underground aquifer protection. This DLT prototype is a permissioned network that allows oil & gas companies to create, disseminate, and trace immutable records. The network enables oil and gas companies, government regulatory agency, and all other participants to share secure records such as well information while maintaining data integrity, traceability, and security. The purpose is to create a network of trust among all the stakeholders in the UIC processes for underground aquifer protection. In this DLT network, a company submits well information, which will be digitally signed and notarized. Unauthorized changes to the information, ownership, or history will become infeasible, thanks to the underlying cryptographic technologies of DLT. The network designs so that information stored and communicated will have a high level of trustworthiness. Every participant in the network can get simultaneous access to a common view of the data. Corda platform also provides multiple functionalities, e.g., Smart contract, Vault, Identity Management, Scheduler, Notary Services, etc. Many of the functionalities automate the data processing within the DLT databases. This project's results expect to enhance public safety and improve the aquifer protection review and operational processes. Kern County uniquely poises for a project to develop more streamlined, effective, and entirely digitized DLT-based workflows that will secure regional environmental data integrity. Water contamination is a primary concern in a region where water and petroleum play vital roles in the economy. Both industries and regulatory agencies pay close attention to environmental quality. Data integrity is a primary issue concern for those that monitor and analyze environmental data. Monitoring and forecasting based on available immutable data are imperative to mitigate complications. We have changed the manual workflow into DLT applications which takes advantage of built-in functionalities. The new review process can avoid repetitive reviews among all participants and shorten the approval time. The embedded smart contracts on the DLT network will also help automate the workflows, and therefore, will be able to help eliminate human errors and improve the turnaround time. The prototype model proves the concept of using DLT. Our research work demonstrates DLT successfully implement into energy technology. The prototype model will further expand to all the UIC processes, such as thermal, wastewater disposal, waterflood, gas injection & disposal, etc. It is a substantial cost and time savings for all the oil and gas companies. The results of this analysis could provide the government with valuable information for significant policy and regulation decisions to further benefit the community and society.

Data analytics to investigate the cohort of injection wells with earthquakes in Oklahoma

The number of recorded earthquakes in Oklahoma has substantially increased during the last few decades, a trend that coincides with the increases in the injected volume in underground injection control (UIC) wells. Several studies have suggested the existence of spatial and temporal links between earthquakes and injection wells. However, creating a spatial connection between the earthquakes and UIC wells requires making a prior assumption about the radius of induced seismicity. In this study, we use intrinsic features of the UIC wells to find the cohort of wells with associated earthquakes, based on the level of activity and proximity of the wells to the events. For this purpose, a hybrid genetic algorithm–K-means (GA-K-means) algorithm was applied over UIC wells, and the geographical representation of the clustered wells was co-visualized with earthquake data to determine wells with induced seismic activities. The analysis was performed every year since 2002, and the most critical attributes to distinguish the behavior of wells were identified. The analysis showed a distinct change in cluster identifiers before the year 2010, which is believed to be the beginning of increased seismic activities, compared to later dates. Our approach was able to group the earthquake-associated wells from the rest of the data, and centroid analysis of these wells helped us identify the critical pressure and cumulative volume range that result in induced seismicity. These findings can be used as guidelines for designing safer injection sites for sustainable energy production in Oklahoma.

Advanced Geomechanical Model to Predict the Impact of CO2-Induced Microstructural Alterations on the Cohesive-Frictional Behavior of Mt. Simon Sandstone

We investigated the influence of CO2-induced geochemical reactions on the cohesive-frictional properties of host rock within the context of CO2 storage in a saline aquifer and focused on the Mt. Simon sandstone. The research objective was to model geo-mechanical changes due to host rock exposure to CO2-saturated brine while accounting for heterogeneity, double-scale porosity, and granular structure. We formulated a three-level multi-scale model for host rocks. We conducted scanning electron microscopy analyses to probe the microstructure and grid nanoindentation to measure the mechanical response. We derived new nonlinear strength upscaling solutions to correlate the effective strength characteristics and the macroscopic yield surface to the micro-structure at the nano-, micro-, and meso-scales. Specifically, our theoretical model links CO2-induced microstructural alterations to a reduction in the size of the yield surface, and a drop in the value of the friction coefficient. In turn, regarding the Illinois Basin Decatur Project, the CO2-induced drop in friction coefficient is linked to an increase in the risk of fault slip and a higher probability of induced microseismicity during and after the end of CO2 underground injection operations. The theoretical model presented is essential for the geo-mechanical modeling of CO2 underground injection operations at multiple length-scales.

Michigan Oil and Gas Update

The Michigan Department of Environment, Great Lakes, and Energy (“EGLE”), formerly the Michigan Department of Environmental Quality, is in the process of seeking primary enforcement responsibility from the United States Environmental Protection Agency (“EPA”) for its Underground Injection Control (“UIC”) program for Class II wells pursuant to Part C of the Safe Drinking Water Act (“SDWA”).

Evaluation of effectiveness of CO2 sequestration in geological reservoir based on Unified Pipe-network Method

The underground injection and geological sequestration of carbon dioxide (CO2) is a promising approach for reducing the levels of CO2 in the atmosphere. To mitigate the leakage of CO2 resulting from natural fracture networks in rock masses, the sequestration process is commonly accompanied by the injection of reactive Portland cement representing a coupled hydro-chemo-mechanical process. In this work, a numerical approach based on the unified pipe network method (UPM) is presented that considers the coupled permeation and diffusion processes with chemical precipitation. Most input parameters are derived from the published literature. The proposed approach is validated through a comparison with analytical solutions, which are applied to simulate the CO2 sequestration process in a fractured rock mass. The results indicate that the long-term sequestration effect, which is highly influenced by the fracture distribution, can be captured effectively by the model. Consequently, the presented approach can assist engineers in properly designing the arrangement of boreholes and determining the concentration of the grouting material.

Perbandingan Laju Lindi Landfill Kelas I dan II untuk Limbah NORM dari Industri Minyak dan Gas Bumi Menggunakan Model Hydrologic Evaluation of Landfill Performance (HELP)

In the process of oil and gas production, it can produce large amounts of Naturally Occurring Radioactive Materials (NORM) with increased radioactivity as by-products. NORM disposal methods currently used in the oil & gas industry are landfills, land-spreading, surface burial, underground injection, off-shore discharge. The biggest threat to groundwater caused by landfills is leachate. This study is a comparison of the leachate rates of Class I and Class II Landfill results using the Hydrologic Evaluation of Landfill Performance (HELP) modeling software developed by the United States Environmental Protection Agency (US EPA). For the operational phase, there were significant differences in leachate rate from the base layer between Class I and Class II landfills. For the phase after closure of waste, Class I and Class II landfills have the same performance in terms of holding back the rate of leachate. ABSTRAKDalam proses produksi minyak dan gas dapat menghasilkan sejumlah besar Naturally Occurring Radioactive Materials (NORM) dengan konsentrasi radioaktivitas yang meningkat sebagai limbah hasil samping. Metode pembuangan NORM yang saat ini digunakan dalam industri minyak & gas adalah landfill, land-spreading, surface burial, underground injection, off-shore discharge. Ancaman terbesar terhadap air tanah yang ditimbulkan oleh landfill adalah air lindi. Pada penelitian ini akan dilakukan perbandingan laju lindi landfill Kelas I dan Kelas II berdasarkan hasil menggunakan software pemodelan Hydrologic Evaluation of Landfill Performance (HELP) yang dikembangkan oleh United States Environmental Protection Agency (US EPA). Untuk fase operasional ditemukan perbedaan laju lindi dari lapisan dasar yang signifikan antara landfill Kelas I dan Kelas II. Untuk fase setelah penutupan limbah, landfill kelas I dan kelas II memiliki kinerja yang sama dalam hal menahan laju produksi air lindi.Kata kunci : NORM; landfill; lindi; HELP