Drilling For Oil Research Articles

Novel logging while drilling azimuthal laterolog resistivity instrument design for oil-based mud

Abstract This paper proposes a novel structure for the logging while drilling azimuthal laterolog resistivity instrument specifically designed for oil-based mud (OBM). The instrument utilizes capacitive coupling to quantitatively evaluate formation resistivity, permittivity, and the standoff between the measuring electrode and the wellbore wall. This innovation addresses the challenges associated with azimuthal resistivity measurement in highly inclined and horizontal wells, while also offering a deeper depth of investigation (DOI). The tool response characteristics and data inversion methodology were analyzed through numerical calculations. Initially, a 3D numerical simulation model of finite element method that incorporates the instrument structure was developed and its accuracy was verified. By adjusting the electrode size, its DOI was optimized to >10 cm. The measurement impedance was examined in relation to varying measurement frequencies, the standoff, and the electrical parameters (resistivity, permittivity) of both the mud and the formation. Then, suitable instrument parameters and effects of formation and OBM were clarified. The simulation results show that the optimum frequency range is 0.1 to 100 MHz. To reduce the impact of standoff, the diameter of the drill collar should be larger than that of the conventional tool. Finally, a deep learning workflow was established, encompassing deep neural network training, parameter optimization, and testing. The accuracy and generalizability of the inversion method were validated using two complex synthetic stratigraphic models. The results of the inversed resistivity and standoff show good consistency with the set values of the two models. System numerical analysis demonstrates that the proposed instrument scheme can effectively address the drilling and formation evaluation requirements for ultra-deep wells and unconventional oil and gas resources, thereby providing a new option for data inversion.

ABOUT THE MAIN RESULTS OF DEEP DRILLING IN THE TERRITORY OF THE PREDVERKHOYANSKAYA OIL AND GAS AREA

This article presents the results of drilling wells in the Predverkhoyanskaya oil and gas area, where deep exploratory drilling for oil and gas was started in 1954 at the Kitchan, Sangar and Ust-Vilyu structures pre-pared by the seismic survey in combination with structural core drilling.According to the results of deep drilling in the Predverkhoyanskaya oil and gas area, the section of the sedimentary cover was studied, and ideas about the material composition of the foundation upper part were obtained. The pro-spects of oil and gas potential are evaluated: the reservoir properties are possessed by rocks of the subsalt Nizhnevendsky, Vendian-Lower Cambrian terrigenous and carbonate complex-es, which are associated with industrial oil and gas potential in nearby fields.The following fluid-bearing complexes are distinguished in the sedimentary section of the Preverkhoyanskiy trough: Permian (P), Lower Triassic (T1), Triassic-Lower Jurassic (T2–3–J1), Middle Upper Jurassic (J2-3), Lower Cretaceous (K1).Deposits of the Lower Triassic aquifer complex are deposited on Permian formations. The capacity of the complex is variable, due to the structural features of the Lower Triassicsediments, and it has not been established with-in the Predverkhoyanskiy trough. Thermobaric data were not obtained during the test. Reser-voir pressures are close to hydrostatic. Reser-voir temperatures, as in the Permian complex, increase from west to south-east to the Predverkhoyanskiy trough from 50 °C to 95 °C.The deposits of the Middle-Upper Triassic – Lower Jurassic aquifer complex are more widely developed. During the sampling and test-ing of oil and gas exploration wells, water and gas inflows were obtained from the deposits of the complex, including industrial ones on Ust-Vilyuiskaya, Sobo-Khainskaya Square. The flow rates of water inflows reached 300 m3/day (Sangarskaya 2), gas inflows up to 1800000 m3/day (Ust-Vilyuiskaya area). In the Sobo-Khainskaya 1 well, an industrial gas in-flow was obtained from the interval of 1328–1349 m.The prospects for oil and gas exploration at the Preverkhoyanskaya oil and gas area are associated with its northern part (Setas struc-ture), on which the Setas parametric well No. 1 with a design depth of 4000 m is being laid, and its southern part, where it is advisable to drill 2 parametric wells with a planned depth of 3000 m.

Exploration of Offshore Drilling for Oil and Gas Operations Based on the Probabilistic Linguistic Dombi Aggregation Decision Model

Exploration of Offshore Drilling for Oil and Gas Operations Based on the Probabilistic Linguistic Dombi Aggregation Decision Model

The edge between regional and exploratory work in ethnological expertise

Recently, there has been an urgent need to accelerate exploration for oil and gas in Eastern Siberia, including the Sakha Republic (Yakutia). The need is due to the reversal of the country’s energy industry in the eastern direction due to the illegal sanctions of a number of Western countries. For territories with complex transport logistics and difficult climatic conditions, one of the main factors of the success of geological exploration is the availability of sufficient time to fulfill the planned plans. Using the example of the regional law “On ethnological expertise in places of traditional residence and traditional economic activity of indigenous small-numbered peoples of the North of the Sakha Republic (Yakutia)”, the risks of non-fulfillment of license obligations by subsoil users are shown. Seismic exploration works are considered as the main tools for regional justification, areal prospecting and preparation of objects of exploratory drilling for oil and gas. It is noted that in areas with weak seismic exploration studies, the exploratory stage of geological exploration has the characteristics and scope of the regional stage of work. The main criterion for the regional understudy of promising oil and gas territories is proposed to accept a low density of seismic observations. For promising territories with seismic exploration studies with a profile density of less than 0.2 km/km2, it is proposed to make a relaxation in the form of exemption from passing an ethnological examination in places of traditional residence and traditional economic activity of indigenous small-numbered peoples of the North in the Sakha Republic (Yakutia) regardless of whether they are carried out on a state assignment or at the expense of the subsoil users’ own funds.

Numerical and experimental investigation on tensile fatigue performance of reinforced thermoplastic pipes

With the rapid development of offshore drilling for harvesting oil and gas from the deep sea, the fatigue performance of offshore risers is increasingly demanding. This study investigated the tensile fatigue performance of reinforced thermoplastic pipes (RTPs). The theory of three-dimensional (3D) anisotropic elastic mechanics was combined with a strain potential-energy density function to construct the 3D constitutive relation of RTPs. The stiffness degradation law of RTPs was predicted by introducing a modified 3D Hashin failure criterion and the residual stiffness model. A user-defined material (UMAT) subroutine was developed to evaluate the progressive fatigue failure process of RTPs. A uniaxial tensile fatigue experiment of RTPs was designed to validate the numerical model's correctness. The analysis examined the damage failure modes of RTPs under cyclic loading conditions and revealed the stiffness degradation mechanism. Results suggested that the matrix fatigue damage of the reinforced layer of RTPs is the primary cause of the rapid stiffness degradation, which was observed to be faster with increasing cyclic load stress levels.

A fully coupled thermo-poro-elastic model predicting the stability of wellbore in deep-sea drilling. Part B: Sensitivity analysis

A good understanding of the mechanical behavior around the wellbore is important for predicting wellbore stability in deep-sea drilling (DSD) for oil and gas production. In Part A of the companion papers, a fully coupled thermo-poro-elastic (THM) model has been developed by combining fluid circulation in the wellbore and rock deformation in the reservoir to predict the mechanical behaviors of a wellbore/reservoir system during DSD, and the analytical solution is obtained in Laplace space. In this paper, a comparison is made first to show the difference between land drilling (LD) and DSD. A sensitivity analysis is carried out to study the effect of different parameters, i.e. drilling depth, rock permeability, density and injection rate of drilling fluid, on the mechanical behaviors of wellbore/reservoir system. The results show that (1) The injection rate plays a dominant role in affecting the BHT. In the case studied, the BHT decreases by around 9 °C when the injection rate increases by 4 kg/s (3.64 × 10−3 m3/s). This will lead to a large temperature decrease after long time circulation. The injection rate does not have a significant effect on the pressure evolution; (2) Due to existence of the geothermal gradient, when the drilling depth varies, the change of temperature and pressure in the rock formation is approximately linearly proportional to the change in the drilling depth. The larger the drilling depth is, the larger the absolute value of the displacement and failure risk at the wellbore; (3) When the rock permeability varies from k = 4 × 10−8 D to 4 × 10−5 D, the hoop stress and failure index (FI) distribution change at small time; (4) Too large and too small fluid densities may cause wellbore instability; (5) The DSD model is degenerated into the LD model when the depth of seawater approaches 0 m. The difference in the temperature and pressure changes between the two models are relatively small. While the magnitude of radial and hoop stresses in LD is larger than that in DSD due to the in-situ stress fields and the failure index in LD is lower than that in DSD around the wellbore, but larger in the far field.

Celebrating 100 Years of the Rocky Mountain Association of Geologist

In 2022, the Rocky Mountain Association of Geologists (RMAG) celebrated its centennial anniversary. Founded on January 26, 1922, RMAG (called Rocky Mountain Association of Petroleum Geologists until 1947) grew out of a desire and need for petroleum geologists in Denver to come together in a collegial environment. Petroleum geology had become an important component of exploration and development, with significant discoveries in the greater Denver Basin (Florence Field) as well as east-central Wyoming (Salt Creek Field) and northwest Colorado (Rangely Field). Through the first 25 years (1922–1947), membership hovered around 50, reflecting an initial boom of World War I through the 1920s, and then surviving the Great Depression and World War II. Post-World War II through the early 1980s, the world saw a huge increase in demand for oil (less-so for natural gas), spurring the “golden years” of Rocky Mountain exploration and development of many now-famous discoveries. Denver grew as a petroleum business center with large (major) to small (independent) companies, leading to steady RMAG membership growth, which peaked at 4,524 in 1984. During this period, RMAG established a legacy of publishing (The Mountain Geologist and the Geologic Atlas of the Rocky Mountain Region, aka “the Big Red Book”), sponsored multi-day field trips and symposia, hosted weekly luncheons with 200–300 attendees at the peak, and maintained a dedicated office staff located in downtown Denver. The legacy “golden” years ended with the “crash” in oil prices in 1985–86, and membership declined about 7% per year until the mid-1990s, levelling out at 1,900 members. Within the ashes of the 1984–1995 period, however, RMAG began its On the Rocks field trip series (1986) and published several sold-out guidebooks. It inaugurated the 3D Seismic Symposium (1995) co-hosted with the Denver Geophysical Society (DGS) and hosted several successful AAPG and Rocky Mountain Section AAPG annual meetings. In the 1990s, natural gas hosted in “unconventional” reservoirs began an exploration/development revolution, spurred on by federal price supports and construction of a major gas pipeline to the West Coast in 1992. By 2000, huge natural gas resources locked in Rocky Mountain “tight gas” reservoirs became economically viable with improved hydraulic fracturing technology and increasing gas prices. RMAG membership began growing along with the increased natural gas-drilling activity, and RMAG offered multiple well-attended symposia and publications highlighting unconventional gas plays. A new boom began in 2008 with the advent of horizontal drilling for oil in the Bakken Shale of the Williston Basin and Niobrara Formation of the Denver Basin, and a massive increase in oil price. Consequently, RMAG membership reached a secondary peak of 2,978 in 2012. However, as oil prices began declining steadily in 2014, membership also decreased. By 2016, oil price decline led to the familiar cycle of company closings and layoffs. In 2020, the Covid-19 pandemic shut down all in-person RMAG activities, heavily impacting the organization. RMAG pivoted to online (virtual) luncheons, symposia, and field trips. Even so, membership declined to about 1200 members in 2022. The challenges that the RMAG will face in the next 100 years will be daunting. Long-term sustainability of the RMAG will require its members and member-leaders to recognize and embrace changes as they occur.

Soil Contamination Assessments from Drilling Fluids and Produced Water Using Combined Field and Laboratory Investigations: A Case Study of Arkansas, USA.

Rotary drilling for oil and natural gas uses drilling fluid for lubrication of the bit, to seal off unstable shale layers, and floating out rock cuttings. Drilling fluid is a water–clay chemical mixture. Produced water is a water–sand chemical mixture. Land farming is a common disposal technique of drilling fluid and produced water. In the land farming process, amendments of fluid are repeatedly applied to the soil surface. Plant growth and soil chemical properties may be altered by additions of drilling fluid, because of alkalinity, salinity, trace elements, and petroleum residue contained in waste. The objective of this study was to determine the change in soil pH, electrical conductivity (EC), total nitrogen and carbon, and extractable nutrient levels following the land application of drilling fluid and produced water. The study was a comparison of three plots with similar soil properties and conditions. The three study plots had various levels of drilling fluid and produced water applications. The data show a major difference from field-to-field for EC, Na, and Cl levels. The EC and salt levels increased with additional applications of drilling fluid and produced water. The percent total nitrogen values and plant available P levels were very low in all fields. High EC and salt values, coupled with low N and P levels, would be detrimental to plant growth and development. To successfully vegetate this land-farm site, application of N and P fertilizer would be required. This study help to give a better understanding of practical ways to land-farm drilling fluid and produced water in a fashion that both minimizes environmental issues and is economically feasible in Arkansas. Thus, this research will provide important information for soil contamination management and contributes on understanding of the responses of soil properties to drilling fluid and produced water in the future.

‘Frack off’: Towards an anarchist political ecology critique of corporate and state responses to anti-fracking resistance in the UK

This paper puts forward an anarchist political ecology critique of extreme energy extractivism by examining corporate and state responses (or ‘political reactions from above’) to anti-fracking resistance in the UK. The planned drilling for unconventional gas and oil through hydraulic fracturing has triggered unprecedented opposition, with protest camps, direct actions, and legal challenges disrupting operations and slowing down planning and exploration development. Drawing on green anarchist thought, critiques of extractivism, statism, and industrialism, and a (corporate) counterinsurgency framework, I examine the strategies adopted by drilling companies and state actors to manage resistance and win the ‘hearts and minds’ of the population, deploying tactics from greenwashing in local schools to harsh policing of dissent. The latter has included the criminalisation and stigmatisation of land defenders, targeting campaigners as ‘domestic extremists’, physical abuse, targeting protesters with disabilities, and entering public-private security partnerships with local police forces which involve the ‘outsourcing’ of police communication to drilling companies. Such actions are complimented by the contracting of PR firms, lobbying, sponsorships of sports clubs and school competitions, ‘astroturfing’, and influencing local so-called democratic procedures. This has gone hand in hand with political efforts to classify operation sites as ‘Nationally Significant Infrastructure projects’ to facilitate the suppression of protest. These strategies are embedded in a recently well-documented history of police infiltration and corporate spying, laying bare an unapologetic commitment to sacrifice human and nonhuman wellbeing for industrial growth, commitment to extractivist ideology and centralisation of power at the cost of further eroding local autonomy and control.

Landscape impacts of 3D-seismic surveys in the Arctic National Wildlife Refuge, Alaska.

Although three‐dimensional (3D) seismic surveys have improved the success rate of exploratory drilling for oil and gas, the impacts have received little scientific scrutiny, despite affecting more area than any other oil and gas activity. To aid policy‐makers and scientists, we reviewed studies of the landscape impacts of 3D‐seismic surveys in the Arctic. We analyzed a proposed 3D‐seismic program in northeast Alaska, in the northern Arctic National Wildlife Refuge, which includes a grid 63,000 km of seismic trails and additional camp‐move trails. Current regulations are not adequate to eliminate impacts from these activities. We address issues related to the high‐density of 3D trails compared to 2D methods, with larger crews, more camps, and more vehicles. We focus on consequences to the hilly landscapes, including microtopography, snow, vegetation, hydrology, active layers, and permafrost. Based on studies of 2D‐seismic trails created in 1984–1985 in the same area by similar types of vehicles, under similar regulations, approximately 122 km2 would likely sustain direct medium‐ to high‐level disturbance from the proposed exploration, with possibly expanded impacts through permafrost degradation and hydrological connectivity. Strong winds are common, and snow cover necessary to minimize impacts from vehicles is windblown and inadequate to protect much of the area. Studies of 2D‐seismic impacts have shown that moist vegetation types, which dominate the area, sustain longer‐lasting damage than wet or dry types, and that the heavy vehicles used for mobile camps caused the most damage. The permafrost is ice rich, which combined with the hilly topography, makes it especially susceptible to thermokarst and erosion triggered by winter vehicle traffic. The effects of climate warming will exacerbate the impacts of winter travel due to warmer permafrost and a shift of precipitation from snow to rain. The cumulative impacts of 3D‐seismic traffic in tundra areas need to be better assessed, together with the effects of climate change and the industrial development that would likely follow. Current data needs include studies of the impacts of 3D‐seismic exploration, better climate records for the Arctic National Wildlife Refuge, especially for wind and snow; and high‐resolution maps of topography, ground ice, hydrology, and vegetation.

The Blue Fix: What's driving blue growth?

This article explores the politics behind the promise of ‘blue growth’. Reframing it as a ‘blue fix’, we argue that the blue growth discourse facilitates new opportunities for capital accumulation, while claiming that this accumulation is compatible with social and ecological aims as well. The blue fix is made up of three underlying sub-fixes. First of all, the conservation fix quenches the social thirst for action in the face of climate change. Here we see how protecting marine areas can be an important part of mitigating climate change, but in practice, gains at the national level are overshadowed by the ongoing expansion of offshore drilling for oil and gas. Second, the protein fix satisfies the growing global demand for healthy food and nutrition through the expansion of capital-intensive large-scale aquaculture, while ignoring the negative socio-ecological impacts, which effectively squeeze small-scale capture fishing out, while industrial capture fishing remains well positioned to expand into as well as supply industrial aquaculture with fish feed from pelagic fish. And third, an energy fix offers a burst of wind energy and a splash of new deep-sea minerals without disturbing the familiar and persistent foundation of oil and gas. This dimension of the blue fix emphasizes the transition to wind and solar energy, but meanwhile the deep sea mining for minerals required by these new technologies launches us into unknown ecological territories with little understood consequences. The synergy of these three elements brought together in a reframing of ocean politics manifests as a balancing act to frame blue growth as ‘sustainable’ and in everyone’s interest, which we critically analyze and discuss in this article.

Simulation and experimental analysis of critical stress regions of deep-water annular blowout preventer

In deep-water drilling for oil and gas, the annular blowout preventer (BOP) is subjected to sustained high pressure or impact loads, causing the concentration of stress in some regions, which can easily cause cracks or fatigue damage. The top cover and housing of the annular BOP are the main pressure-containing parts. Once they fail during the emergency shut-in process, a blowout accident will occur, and there may be casualties and major economic losses. Therefore, the stress concentration regions of the top cover and the housing must be analysed to ensure safe operation. In this study, a high-fidelity approach to monitor the stress was established. This approach combines the theoretical calculation method (TCM), finite-element analysis (FEA) and stress testing experiment (STE). The stress distribution laws of the top cover and housing were measured under the rated working pressure and hydrostatic test pressure. The results indicated that the TCM, FEA, and STE exhibited the same curve trend of stress. Moreover, the FEA results were almost identical to the STE results for the stress values of testing points. The FEA results indicated that there were two critical stress regions in the housing. These were regions where cracks and failures had actually occurred in the past. The main technical contribution of the study is that it may serve as the basis for additional investigations into abandonment evaluation, fatigue analysis, and residual life evaluation.

Baseline characterization of aerobic hydrocarbon degrading microbial communities in deep-sea sediments of the Great Australian Bight, Australia.

Exploratory drilling for deep-sea oil and gas resources is planned for the Great Australian Bight (GAB). There is scant knowledge of the region's benthic ecosystems and no baseline information of the region's indigenous oil degrading bacteria. To address this knowledge gap, we used next generation sequencing (NGS) of three marker genes (alkB, c23o and pmoA) to detect and characterize the microbial communities capable of aerobic hydrocarbon degradation. Unique, highly novel microbial communities capable of degrading hydrocarbons occur in surface sediments at depths between 200 and 2800 m. Clustering at 97% demonstrated differences in community structure with depth, changing most markedly between 400 and 1000 m depth on the continental slope, and identified putative functional 'ecotypes' related to depth. Observed differences in community structure showed strong correlations with temperature, other physicochemical properties of the overlying water column and are further modulated by differences in sediment grain size. This study provides important baseline data on hydrocarbon degrading microbial communities prior to the start of petroleum resource extraction. Our data will inform future ecological monitoring of the GAB deep-sea ecosystem.

On the technology of utilizing drilling sludge for the purpose of building material production

The paper considers the technologies of the drilling sludge industrial utilization. Deep-well drilling for oil and gas extraction results in wastes in the form of sludge that is hazardous for the environment. The research aim is to study the existing technologies for working the drilling wastes into salvage that can be used in construction and road building at the oil and gas fields.

Evaluation of Thick-Film Materials for High-Temperature Packaging

High-temperature electronics are required for applications such as automotive, down-hole drilling for oil and geothermal energy, aircraft, and space exploration. SiC and GaN devices are capable of operating in these high-temperature environments and challenging the packaging materials and technology to be compatible with these environments. Thick-film materials and technology have the potential of building reliable interconnections at high temperatures. This paper investigated the electrical reliability of two thick-film conductors (PtPdAu, Au) and two dielectrics at 300 °C. Test vehicles were fabricated with thick-film materials as capacitor and interdigitated finger test structures. For the test vehicles with PtPdAu thick-film, the leakage current of the capacitor structures with thin multilayer dielectrics increased in a short time during 300 °C aging with a 100-V bias, while the leakage current of capacitor structures with thick dielectrics had only a slight increase or remained constant during 300 °C aging with bias. Cross-sectional scanning electron microscopy and energy dispersive spectroscopy analysis showed that bismuth (Bi) in the PtPdAu paste diffused into the dielectrics from both the top and bottom conductors during the high-temperature firing steps in fabrication. If the Bi was continuous through the thin dielectric, the leakage current increased during aging with bias. The leakage current of the Au conductor in capacitor and interdigitated finger structures (both thick and thin dielectrics) did not increase with biased aging in high temperature. The Au conductor did not contain Bi.

Regulatory Capture by Default: Offshore Drilling for Oil and Gas

This article examines a form of regulatory capture that occurs when significant ambiguity exists regarding the environmental protection standards for new types of activities in the marine environment. To begin with, there is little research that categorizes the typologies of regulatory capture despite the ubiquity of the phenomenon. After a discussion of theoretical approaches to regulatory capture, I describe the operative definition and theory appropriate to the situation related to authorization of oil and natural gas production in Israel following the discovery of large offshore reserves in 2010. This approach, embodying several facets of existing typologies, is applied to decisions made authorizing construction of the Gabriella offshore exploratory drilling platform. The analysis highlights the nature of capture in the absence of clear agency jurisdiction over new activities located in offshore environs organized as temporal and spatial “vacuums”. I conclude that comprehensive marine spatial planning would result in less capture and the development of more capture-resistant regulations.

Regulatory Capture by Default: Offshore Exploratory Drilling for Oil and Gas

This article examines a form of regulatory capture that occurs when significant ambiguity exists regarding the environmental protection standards for new types of activities in the marine environment. To begin with, there is little research that categorizes the typologies of regulatory capture despite the ubiquity of the phenomenon. After a discussion of theoretical approaches to regulatory capture, I describe the operative definition and theory appropriate to the situation related to authorization of oil and natural gas production in Israel following the discovery of large offshore reserves in 2010. This approach, embodying several facets of existing typologies, is applied to decisions made authorizing construction of the Gabriella offshore exploratory drilling platform. The analysis highlights the nature of capture in the absence of clear agency jurisdiction over new activities located in offshore environs organized as temporal and spatial “vacuums”. I conclude that comprehensive marine spatial planning would result in less capture and the development of more capture-resistant regulations.

A New Method for Calculating the Equivalent Circulating Density of Drilling Fluid in Deepwater Drilling for Oil and Gas

We have developed a simple and accurate method for calculating the equivalent circulating density for drilling fluid which can be used for deepwater drilling calculations. The calculation takes into account depth, the properties of the rock cuttings (size, density), the concentration of solid particles, the geothermal gradient, the water temperature, and the properties of the drilling fluid. We discuss the influence of these factors on the equivalent density. The proposed method will make it possible to reduce risks in deepwater drilling.

Regulatory capture by default: Offshore exploratory drilling for oil and gas

This article examines a form of regulatory capture that occurs when significant ambiguity exists regarding the environmental protection standards for new types of activities in the marine environment. To begin with, there is little research that categorizes the typologies of regulatory capture despite the ubiquity of the phenomenon. After a discussion of theoretical approaches to regulatory capture, I describe the operative definition and theory appropriate to the situation related to authorization of oil and natural gas production in Israel following the discovery of large offshore reserves in 2010. This approach, embodying several facets of existing typologies, is applied to decisions made authorizing construction of the Gabriella offshore exploratory drilling platform. The analysis highlights the nature of capture in the absence of clear agency jurisdiction over new activities located in offshore environs organized as temporal and spatial “vacuums”. I conclude that comprehensive marine spatial planning would result in less capture and the development of more capture-resistant regulations.

Shale Gas Extraction in North Carolina: Research Recommendations and Public Health Implications

Shale Gas Extraction in North Carolina: Research Recommendations and Public Health Implications