Unconventional Oil Production Research Articles

Study on repeated discharge frequency characteristics of plasma pulse equipment

In order to increase the production of unconventional oil and gas, it is necessary to improve its reservoir. Plasma pulse technology is one of a safe and environmentally friendly reservoir reconstruction technology. In this paper, the discharge test of plasma pulse equipment was carried out in the laboratory. The different discharge stages (pre-discharge, main-discharge, sinusoidal attenuation oscillation and post-discharge stage) of plasma pulse equipment in a single discharge were discussed, and the frequency characteristics in the repeated discharge were studied in detail. The discharge test shows that the energy and average power of main-discharge stage are about 109 J and 15.6 MW respectively, and the discharge frequency range is about 0–25 Hz. Furthermore, the linear attenuation function model of breakdown voltage change under the initial discharge frequency of 4 Hz, 9 Hz, 14 Hz and 19 Hz is established, and the change law of breakdown voltage decreases linearly with the increase of discharge frequency is revealed. The results show that the research content of this paper has an important guiding significance for revealing the variation law of repeated discharge frequency characteristics of plasma pulse equipment, which is helpful to further optimize the design of plasma pulse equipment and improve its working performance.

Limited increases in Arctic offshore oil and gas production with climate change and the implications for energy markets

Climate change impacts on sea ice thickness is opening access to offshore Arctic resources. The degree to which these resources are exploited will depend on sea-ice conditions, technology costs, international energy markets, and the regulatory environment. We use an integrated human-Earth system model, GCAM, to explore the effects of spatial–temporal patterns of sea-ice loss under climate change on future Arctic offshore oil and gas extraction, considering interactions with global energy markets and emission reduction scenarios. We find that under SSP5, a “fossil-fueled development” scenario, the effects of sea-ice loss are larger for Arctic offshore oil production than gas. Under SSP5, future extraction of Arctic offshore oil and gas through 2100 adds roughly 0.8–2.6 EJ/year to oil and gas markets but does not have large impacts on global oil and gas markets. Surprisingly, a low-carbon scenario results in greater Arctic offshore oil production to offset the more emissions-intensive unconventional oil production.

Conventional Fossil Fuel Extraction, Associated Biogeochemical Processes, and Topography Influence Methane Groundwater Concentrations in Appalachia.

The production of fossil fuels, including oil, gas, and coal, retains a dominant share in US energy production and serves as a major anthropogenic source of methane, a greenhouse gas with a high warming potential. In addition to directly emitting methane into the air, fossil fuel production can release methane into groundwater, and that methane may eventually reach the atmosphere. In this study, we collected 311 water samples from an unconventional oil and gas (UOG) production region in Pennsylvania and an oil and gas (O&G) and coal production region across Ohio and West Virginia. Methane concentration was negatively correlated to distance to the nearest O&G well in the second region, but such a correlation was shown to be driven by topography as a confounding variable. Furthermore, sulfate concentration was negatively correlated with methane concentration and with distance to coal mining in the second region, and these correlations were robust even when considering topography. We hypothesized that coal mining enriched sulfate in groundwater, which in turn inhibited methanogenesis and enhanced microbial methane oxidation. Thus, this study highlights the complex interplay of multiple factors in shaping groundwater methane concentrations, including biogeochemical conversion, topography, and conventional fossil extraction.

Pilot plant evaluation of membrane distillation for desalination of high-salinity brines

Membrane distillation (MD) is a hybrid thermal-membrane desalination process that can use either low-grade waste heat and/or solar energy with hydrophobic membranes to desalinate high-salinity brines and produce high quality distillate. A research consortium was launched to investigate the application of the MD process, at lab and pilot scale, for desalination of concentrated brines. Bench scale results showed the presence of antiscalants in the concentrated brines minimized the scale precipitation potential and offered stable membrane permeability performance. Various MD technologies were screened, and two suitable technologies were selected for field-testing. Pilot unit A was based on multi-effect vacuum showed a stable flux of 6.2 LMH with excellent salt rejection (> 99.9%) from the concentrated brine discharged from thermal desalination plant in Qatar. That pilot unit was also field tested on hypersaline groundwater in Texas (USA) to generate fresh water for reservoir fracking in unconventional oil production operations. The MD unit was coupled with humidification/dehumidification (HDH) unit to achieve zero liquid discharge (ZLD) for inland applications. The MD unit was operated at 40% recovery producing distillate of < 20 mg/L total dissolved solids (TDS) and observed a stable flux of 5 LMH. Key challenges that are critical for large-scale deployment of MD technology were identified at the end of the field-testing program. Finally, a review of active MD technologies was conducted to highlight recent promising developments for full-scale applications.

A feasibility study on time-lapse controlled-source electromagnetic method for hydraulic fracturing monitoring of Well Eyangye-2HF in Yichang, Hubei Province, China

Abstract Hydraulic fracturing plays a crucial role in enhancing reserves and production of unconventional oil and gas resources. Injecting fracturing fluids into the ground to improve reservoirs also introduces the risk of inducing earthquakes; thus, monitoring the migration of these fluids is crucial. The microseismic positioning method determines the fracturing fluid by locating microseismic events generated by the fractured rock strata; however, this method is susceptible to errors. Low-resistivity subsurface fluids can directly change electromagnetic field signals, making the electromagnetic method a technically advantageous approach for monitoring the migration of hydraulic fracturing fluids. The monitoring test data of Well Eyangye-2HF show that the time-lapse controlled-source electromagnetic (CSEM) method is suitable for hydraulic fracturing and has good monitoring effects. The results of CSEM method can also compensate for deficiencies in microseismic monitoring. The electric field (Ex) observed using the CSEM method can directly predict the distribution edge of the fracturing fluid, and the anomalous zone of the Exrate of change is consistent with the fracturing-fluid injection parameters and microseismic monitoring results. The analysis of field data and forward simulation, based on electrical logging results, led to the conclusion that hydraulic fracturing operations can cause changes in the resistivity of the target layer and surrounding strata. These changes are attributed to the synergistic effects of formation stress, temperature, and the fracturing fluid. The electric-field changes observed using the CSEM method may be caused by multiple factors; however, use of time-lapse CSEM for monitoring hydraulic fracturing is still feasible.

A novel self-degradable gel (SDG) as liquid temporary plugging agent for high-temperature reservoirs

In recent years, the liquid temporary plugging agent has drawn extensive attention, especially in the repeated fracturing operation for stimulating unconventional oil and gas reservoir production. This paper developed a novel self-degradable gel (SDG) as a liquid temporary plugging agent for high-temperature reservoirs. The gelation process, viscoelasticity, pressure-bearing capacity, self-degradation, and formation protection performance of the SDG were systematically investigated. Moreover, the gelation and self-degradation mechanism of the SDG were revealed by studying the viscosity variation and the microstructures. Considering the gelation time and gel strength, the composition of the SDG was optimized as 6.0–10.0 wt% monomer, 0.004–0.012 wt% initiator, and 0.2–0.4 wt% crosslinker. The SDG transformed from liquid to solid-like gel within 30 to 90 min at 90–130 °C. The rheological results showed that the duration of the low viscosity state exceeded 75 % of the total gelation process at high temperatures, which was conducive to the injection of the SDG. In addition, the viscosity of the SDG after gelation was more than 100 Pa·s, which ensured its effective plugging in fractures. The experimental results with fractured cores showed that the bearing pressure of the SDG remained above 30 MPa/m in fracture with a width of 2.05–5.04 mm, which could meet the requirements of the repeated fracturing operation. Moreover, the SDG could spontaneously degrade from solid-like gel to liquid with a viscosity of lower than 10 mPa·s in 10–105 h at 90–130 °C. The broken-gel liquid could be completely displaced out of the fractured core, and the core damage rate was less than 5.0 %, which ensured the restoration of conductivity of the previously existing fractures. Micrographs showed that the dense three-dimensional network structure with high viscosity was formed by polymerization and crosslinking. Then, the acrylic acids in the polymer chain were broken at high temperatures, resulting in the gradual destruction of the gel and the spontaneous degradation of SDG.

Optimization method of oriented perforation parameters improving uneven fractures initiation for horizontal well fracturing

Horizontal well oriented perforation fracturing is a common technique for unconventional oil and gas production. With the wide application of this technology, issues such as uneven fracture initiation and high initiation pressure appeared, which limited the fracturing effect for unconventional oil and gas. To improve the current situation for oriented perforation fracturing, we establish a numerical model of oriented perforation fracturing for horizontal wells using three-dimensional lattice method. The effects of perforation depth and diameter on fracture initiation pressure, fracture morphology and stimulating area are obtained through numerical simulation. Meanwhile, we propose a depth-controlled and a diameter-controlled oriented perforation design method for uniform fracture initiation. The research results show that, the growth of perforation depth and diameter would lower fracture initiation pressure. Increasing the perforation depth can improve the issue of uneven fracture initiation for oriented perforation fracturing in horizontal wells. Compared with conventional oriented perforation, the depth-controlled and diameter-controlled oriented perforation can significantly improve the uneven fracture initiation issue. The depth-controlled oriented perforation can effectively increase the stimulating area, and induce narrow and long fractures in high elastic modulus formations. The diameter-controlled oriented perforation is suitable for high in-site stress and can reduce fracture initiation pressure. The depth-controlled oriented perforation optimal design is applied to an objective well, Well H-21 of the Chang 73 target layer in Changqing Oilfield, China. Numerical results show that the proposed method can reduce the fracture initiation pressure by 12.6% and increase the fracture area by 11.80%, which can effectively solve the issue of uneven fracture initiation.

Composite stimulation technology for improving fracture length and conductivity of unconventional reservoirs

Unconventional reservoirs have strong heterogeneity, with significant differences in the distribution of porosity and permeability. Fracturing is an important technology for increasing natural gas production in unconventional oil and gas reservoirs. For unconventional reservoirs with high temperature and low permeability, the rapid increase in acid rock reaction rate leads to a significant decrease in the effective distance of acidic fluids and fracture conductivity, especially the inability to obtain effective support at the fracture tip, which restricts the increase in production of high-temperature unconventional oil and gas reservoirs. To address the above issues, a composite fracturing method is proposed, which first uses a proppant to support the crack tip, and then uses gelled acid to corrode the middle and rear parts of the crack. According to the fracture conductivity achievement test experiment and proppant migration experiment, when 40/70 mesh ceramsite and 100 mesh ceramsite are mixed at a mass ratio of 1:4, the fracture conductivity can reach 21.8 μm·cm2 under the effective closing pressure of 60 MPa, which is 123% higher than the fracture conductivity of cementitious acid corrosion. The gel is used to carry 40/70 mesh and 100 mesh ceramsite, and the Equilibrium level of the sand embankment can reach 38 cm. At the same time, the sand dike formed by different particle sizes of ceramic particles is smoother than the sand vein formed by a single particle size of proppant, and the migration ability of ceramic particles to the fracture tip is better. The composite stimulation technology has been applied to 9 wells in carbonate and shale oil and gas reservoirs. After fracturing, the production of oil and gas wells is 210% higher than that of gelled acid fracturing, and the composite stimulation technology has achieved good stimulation effects.

Carbon Dioxide Huff and Puff as Environmentally Friendly Method for Enhanced Heavy Oil Recovery

Heavy oil and bitumen are making up approximately 70 percent of the remaining estimated hydrocarbon reserves. Many Enhanced Oil Recovery (EOR) methods such as chemical flooding, thermal recovery, gas injection, etc., were developed to make advances in the production of unconventional oil. Among all the variety of EOR methods, thermal recovery produces practically all of the heavy oil and bitumen among the various EOR methods. But at the same time, throughout its application, there are several disadvantages were revealed such as it is an expensive and not environmentally friendly process, heat loss in surface facilities and distribution lines, the efficiency is low after injection, increases in the extracted oil’s surface viscosity have caused polymerization reactions of free radicals created during the steam injection process, and the requirement for continuous steam injection is attempting to keep a hot oil-water interface at the front of the flow. For these reasons, the solvent-based non-thermal recovery method can be used to enhance heavy oil and bitumen recovery in unconventional reservoirs (thin or deep reservoirs) to prevent or reduce unwanted effects as described above. Toluene, carbon dioxide (CO2), ethane, propane, normal butane, and mixture solvents, among others, can be used as the injection solvent for the solvent-based non-thermal recovery method. That is why the researchers have concentrated on carbon dioxide as a solvent with Huff & Puff method to develop the production of heavy oil and bitumen to overcome all these negative issues because CO2 has several characteristics that make it an excellent option for this application. In this paper, the CO2 Huff and Puff method is reviewed. The CO2 Huff and Puff method’s viscosity reduction and oil swelling procedures have been the most significant factors in increasing heavy oil production. As a results, impacts of oil swelling at various temperatures and pressures as well as the viscosity reduction ratio with CO2 injection have been studied.

“A Rigged Process from the Beginning”: Power and Procedural Injustice Within the Colorado Oil and Gas Task Force1

Unconventional oil and gas (UOG) production has reinvigorated US production while creating conflicts over governance and environmental injustices. Here, we focus on relationships among power, regulatory conflict, and procedural justice around UOG by examining the Colorado Oil and Gas Task Force (TF) and its decision‐making processes. Instead of statewide voting on UOG ballot measures, Colorado convened a 21‐member TF tasked with making regulatory recommendations. We draw on interviews, participant observation, and policy ethnography to examine: who sets the rules of the game, how players are chosen, and by whom. We ask the following questions: (1) How did TF members and other political actors exert state and institutional power, and how did that shape the structure, composition, processes, and outcomes of the TF?; (2) As a state‐created body, how did the TF and its internal processes disrupt or reinforce power relations favoring industry and fossil fuel development?; and (3) What were the procedural justice implications of TF processes? We advance scholarship on procedural justice by demonstrating how people operate at institutional scales to shape decision‐making structures, processes, and outcomes. We show how nonelected bodies can work as state interventions for industry, reinforcing industry power and procedural injustices rather than disrupting them.

Preparation of two-component polyacrylamide inverse emulsion drag reducer for slick water and investigation of its rheological and drag reduction properties

In this paper, a slick water drag reducer with excellent drag reduction and a simple molecular structure, called QIE-0, was prepared by inverse emulsion copolymerization. QIE-0 is a copolymer emulsion of acrylamide and 2-acrylamide-2-methylpropyl sulfonic acid with an average molecular weight of 5.17 × 106 Da. QIE-0 has excellent thermal stability, and the temperature resistance can reach 220 °C. Prolonged static storage (180 days) did not change the viscosity-increasing properties, and the viscosity of 0.1% QIE-0 solution is 5.2 mPa s. QIE-0 presents a three-dimensional network structure in an aqueous solution and the structure changes with concentration. QIE-0 has special fluidity and a linear viscoelastic domain from 0.1% to 100%. QIE-0 solution has no thixotropy and is a stable structure. The drag reduction rate of ultra-low concentration (0.01%) slick water systems reaches 82.10%. The drag reduction rates of different systems are fitted by the established exponential function model and the power function model, and the correlation coefficient between the predicted values and the experimental values is greater than 0.999. QIE-0 meets the needs of slick water fracturing fluid applications and has huge potential applications in unconventional oil and gas production.

IN-DEPTH ANALYSES OF POSTHYDRAULIC FRACTURING PROCESSES IN UNCONVENTIONAL TIGHT RESERVOIRS

Hydraulic fracturing is the most widely used approach for unconventional tight or shale oil production. An appropriate postfracturing process usually refers to a certain shut-in period, which could be of critical importance to enhance ultimate oil recoveries. The shut-in period comprises processes of fluid filtration and spontaneous imbibition. In this study, the pressure decay characteristics during the fluid filtration process after hydraulic fracturing were studied. First, a pore-scale imbibition model with forced pressure was constructed on the basis of capillary model and fractal theory. Then, in addition to the theoretical model, coreflooding tests were performed in the core samples for optimizing the injection pressure difference with the assistance of low-field nuclear magnetic resonance (LF-NMR). Furthermore, the fluid filtration process was modeled and evaluated through another coreflooding test, which was conducted with declining injection pressure. It was found from the theoretical model and experiments that the synergistic effect of the displacement and capillary pressure was maximized for improving oil recovery with an optimized pressure difference of 5 MPa. Moreover, the pressure decay process was divided into fast-declining, transitional, and steady periods. The lab-scale shut-in time was determined to be 30 hours, which was exactly the time when the pressure decay reached the stable stage. This study will support the foundation of more general applications pertaining to hydraulic fracturing, especially fluid filtration processes in unconventional tight or shale oil reservoirs.

A review of Oil–Solid Separation and Oil–Water Separation in Unconventional Heavy Oil Production Process

Unconventional heavy oil ores (UHO) have been considered an important part of petroleum resources and an alternative source of chemicals and energy supply. Due to the participation of water and extractants, oil-solid separation (OSS) and oil-water separation (OWS) processes are inevitable in the industrial separation processes of UHO. Therefore, this critical review systematically reviews the basic theories of OSS and OWS, including solid wettability, contact angle, oil-solid interactions, structural characteristics of natural surfactants and interface characteristics of interfacially active asphaltene film. With the basic theories in mind, the corresponding OSS and OWS mechanisms are discussed. Finally, the present challenges and future research considerations are touched on to provide insights and theoretical fundamentals for OSS and OWS. Additionally, this critical review might even be useful for the provision of a framework of research prospects to guide future research directions in laboratories and industries that focus on the OSS and OWS processes in this important heavy oil production field.

Reservoir Porosity Improvement Device based on Underwater Pulse Arc Fracturing and Frequency Resonance Technology

SummaryThe low porosity of the reservoir has a significant impact on the production of unconventional oil and gas, hence a device to increase reservoir porosity and enhance unconventional oil and gas recovery was developed. The device can be lowered to 3000 m and operate continuously for more than 30 minutes under a discharge voltage of 11 kV in the frequency range of 0–60 Hz to improve reservoir porosity by causing reservoir resonance. The equipment structure includes an energy storage circuit, trigger switch, and energy transducer. The theoretical model of the energy storage circuit was established by the state space averaging method to obtain the time constant which was verified by a simulation experiment. The gas spark switch with an adjustable gap was used, the frequency control of the discharge pulse was achieved by rectifier voltage regulation, and the underwater pulse arc fracturing experiment was performed to confirm the accuracy and stability of the frequency control. Additionally, the effect of frequency resonance on reservoir porosity improvement was examined through comparative experiments, and the images of the distribution of pore texture in shale obtained by the X-ray computed tomography (CT) system demonstrate that resonance excitation can significantly promote the development of fractures and the improvement of shale samples’ porosity. The stimulation operation field experiment was carried out on coalbed methane wells in Shanxi Province, and the multipole array acoustic logging image verified that the equipment has a good reservoir porosity improvement effect. Experimental results indicate that this study has a potential application value in the field of unconventional reservoir stimulation.

Optimization-based technoeconomic comparison of multi-stage membrane distillation configurations for hypersaline produced water desalination

Unconventional oil and gas production raises concerns regarding sustainable management of high salinity wastewaters generated in this process. Membrane distillation (MD) is a thermal desalination process capable of treating hypersaline brines such as produced water. The low single pass recovery in MD systems operated in a single stage requires a large recycle stream to achieve the desired recovery, resulting in high energy consumption and operating cost. Multistage configurations in continuous recirculation operation mode offer the potential to reduce the energy intensity of MD systems. However, rigorous analysis is needed to assess the performance of MD configurations when operating in multi-stage mode. We present an optimization-based comparison of economic and energetic performance for five configurations of MD (including DCMD, AGMD, PGMD, CGMD, and VMD) operating in multi-stage continuous recirculation mode. Our findings demonstrate that multistage operation reduces the treatment cost and energy intensity of all MD configurations compared to single stage MD, with the greatest benefit for VMD and PGMD. AGMD with five stages outperforms other configurations with 3.58 $/m3feed treatment cost, followed by VMD, CGMD, DCMD, and PGMD with 3.8, 4.2, 5.4, and 9.06 $/m3feed treatment costs corresponding to twelve, eight, eight, and sixteen stages, respectively.

Experimental investigation on proppant transport and distribution characteristics in coal hydraulic fractures under true triaxial stresses

Fracturing is one of the key technologies for unconventional oil and gas production. However, the closure stress will cause the hydraulic fractures to close, and proppant is often injected into the fracture to maintain the effective conductivity of the fractures for a long time. The proppant distribution in the fractures is one of the key factors affecting the efficient exploitation of unconventional natural gas. However, there are few studies on the proppant transport and distribution characteristics in the real hydraulic fractures. A self-developed high-pressure sand injection triaxial hydraulic fracturing experimental system was used to study the proppant migration and distribution in hydraulic fractures. The results show that the proppant migration process mainly includes four stages: water filling stage, fracture reopening stage, proppant transport stage, and pressure relief stage. The basic characteristics of proppant transport in horizontal fractures is mainly along slope gradient transport or dispersion, and reverse slope gradient or low valley deposition. The sedimentary areas mainly include peak climbing deposition, ring peak deposition, and convection-diffusion deposition. The surface roughness of horizontal fractures is one of the key factors affecting the proppant transport and distribution. The fracture inlet roughness determines the proppant transport direction, and the overall roughness of the fracture surface determines the proppant distribution form. The proppant deposition is the most in the open hole parallel area, followed by the sealed hole parallel area in vertical fractures. The stress concentration at the hole bottom forms horizontal wing branch fractures, and a little proppant is deposited in the fractures. Generally, the stress required for proppant transport in horizontal fractures is smaller than that in vertical fractures. The findings of this study can help us better understand the migration and distribution of proppant in hydraulic fractures, and provide theoretical guidance for the efficient exploitation of unconventional natural gas.

The PSR-FA-NAR model for assessing and forecasting environmental impacts: An empirical analysis of Changning–Weiyuan shale gas play in China

The largest ever investment in shale gas resources has induced potential environmental threats in China. The assessment and forecasting of environmental impacts associated with shale gas production is highly challenging due to the characteristics of high uncertainty, nonlinearity, and complexity. This paper proposes a new hybrid model by combining the pressure-state-response (PSR) framework with the firefly algorithm (FA) and a nonlinear auto-regressive (NAR) dynamic neural network (the PSR-FA-NAR model) to detect and forecast the state of the environment as well as send warning signals for shale gas production. Then, an empirical sample, the Changning-Weiyuan national-level shale gas pilot zone that produces more than 50% of Chinese shale gas output, is used to test the effectiveness of the proposed model. The results show that Changning play will predictably face severe environmental threats imposed by rapid development, and the model is not only able to capture nonlinearity time-series and present cause-effect relationships but is also able to improve the predictive performance and forecasting accuracy. It proves that the PSR-FA-NAR model can effectively address the problems with high dimensionality, complexity, and nonlinearity and provides a practical methodology to quantify and identify the potential environmental impacts of unconventional oil and gas production.

Visualization and quantitative statistics of experimental hydraulic fracture network based on optical scanning

The formation of hydraulic fracture-network is an important goal for stable and increased production of unconventional oil and gas resources. However, due to the extremely complex mechanical behavior of hydraulic-fracture propagation, there is still a lack of fine, effective and systematic evaluation methods on 3D fracture-network structure. The quantitative characterization of hydraulic-fractures is of great significance to reveal the law of fracture propagation and to evaluate the reservoir stimulation effectiveness reasonably. Although the micro-cracks evolution process follows a random rather than deterministic pattern, the overall fracture morphology is featuring statistical regularity. In this study, after the indoor hydraulic-fracturing simulation experiments of the tight sandstone specimens, 3D optical scanning was used to visualize the fracture-network. On this basis, two aspects of quantitative statistics of 3D complex fracture-networks were established by plane and sphere cuttings for the first time, including angle distribution statistics and spatial variation statistics. Comparative analyses with reported methods showed that, the overall deflection of the macroscopic fracture-networks varies synchronously with the local roughness of the main hydraulic fractures closest to the wellbore, which satisfied exponential function or power-law function relationship between them. The variation of the area proportion with the propagation radius reflects the specific fracture propagation process such as crack initiation, bifurcation and arrest, and could be used to assess the complexity of the fracture-network. Moreover, a new stimulation evaluation index Es was established by comprehensively considering the stimulated-reservoir-area, the dispersion degree of the angle distribution and the complexity of spatial variation for 3D fracture-network. The insights gained warrant further applicability on hydraulic-fracturing in the actual engineering scale.

Surface microseismic data denoising based on sparse autoencoder and Kalman filter

Microseismic technology is widely used in unconventional oil and gas production. Microseismic noise reduction is of great significance for the identification of microseismic events, the location of seismic sources and the improvement of unconventional oil and gas production. In this paper, a denoising filter is proposed based on sparse autoencoder and Kalman filtering. Firstly, a sparse autoencoder is pre-trained to learn the feature of the microseismic data. Sparse autoencoding is a back-propagation neural network algorithm based on unsupervised learning, in which there are three layers: the input layer, the hidden layer and the output layer. The hidden layer is the spare, which makes the algorithm learn features better, represents samples in harsh environments and reduces dimensionality effectively. Besides, Kalman filter is used to deal with the uncertainty factors. Using a dataset of 600 surface microseismic synthesis traces and simulation noise. Sparse autoencoders and Kalman filtering are trained to suppress noise. The denoising filter based on sparse autoencoder and Kalman filter model obtains a higher signal noise ratio than the conventional model. The experiment results for the filtering of surface microseismic signals show the feasibility and effectiveness of the proposed method.

Enforcing Hopelessness: Complicity, Dependence, and Organizing in Frontline Oil and Gas Communities

Abstract Fossil fuel companies hold enormous political, economic, and knowledge production power. Recently, industry operators have pivoted from pushing climate denialism to campaigns aimed at individualizing responsibility for climate crisis. In this paper, we focus on one related outcome of such efforts – people’s experiences of complicity – here in the context of unconventional oil and gas (UOG) production. We ask: How do mobilized activists experience fossil fuel scapegoating, and what does it mean for their goals as they organize against UOG production? We show that even activists fighting UOG production feel complicit in fossil fuel production, and these feelings of complicity diminish their demands for UOG accountability. We argue that these outcomes have been especially pernicious in cultural contexts like that of the United States, where neoliberal ideologies are normalized, centering personal responsibility, individualization, and identification as consumers rather than citizens. We marshal an extensive qualitative dataset and advance a theory of complicity as a way to understand: a) how social movements intersect with neoliberalized patterns of life; b) how experiences of complicity affect activism; and c) how this may contribute to fossil fuel firms’ goals of undercutting organizing. We end by examining how a sub-set of activists works to dismantle this complicity narrative.