Until early 2006, in Brazil, the focus used to be on oil and gas exploration/exploitation of post-salt carbonates. This changed when the industry announced the existence of large fields in pre-salt layers across the South Atlantic Ocean from nearshore zones up to almost 350 [km] from the shore. With the discovery of pre-salt hydrocarbons reservoirs, new challenges appeared. One of the main challenges is the necessity to optimize the drilling processes due to their high operational costs. Drilling costs are considerably high, which leads the oil and gas industry to search for innovative and entrepreneurial methods. The coupling of the mechanical specific energy (MSE) and the rate of penetration (ROP) is a method that allows for the identification of ideal conditions to efficiently enhance the drilling process. In addition, the performance of the drilling process can be estimated through pre-operational tests, which consist in continuously testing the applied drilling mechanic parameters, such as the weight-on-bit (WOB) and drill string rotary speed (RPM), looking for optimum sets that would ultimately provide the most desirable ROP. Thus, the goal of this research was to analyze field data from pre-salt layer operations, using a multi-objective optimization based on the play-back methodology for pre-operational drilling tests, through the ideal combination of the highest ROP and the lowest MSE. The results showed that the new concept of pre-operational tests based on the MSE proved to be effective in the drilling process optimization. The combination of the highest ROP and the lowest MSE allows for a high-performance drilling process. For WOB intervals of 5 and 7 [klb], a good fit of the parameters was obtained. Through the parameters obtained from pre-operational tests, the eventual cost-saving and time-saving values could be estimated, respectively, ranging from USD 1,056,180 to 1,151,898 and 19.50 to 21.27 [h], respectively. In addition, the results of this research can be applied to the exploration of other natural resources, such as natural hydrogen and geothermal sources.

Developing clean and renewable energy instead of the ones related to hydrocarbon resources has been known as one of the different ways to guarantee reduced greenhouse gas emissions. Geothermal systems and native hydrogen exploration could represent an opportunity to diversify the global energy matrix and lower carbon-related emissions. All of these natural energy sources require a well to be drilled for its access and/or extractions, similar to the petroleum industry. The main focuses of this technical–scientific contribution and research are (i) to evaluate the global energy matrix; (ii) to show the context over the years and future perspectives on geothermal systems and natural hydrogen exploration; and (iii) to present and analyze the importance of developing technologies on drilling process optimization aiming at accessing these natural energy resources. In 2022, the global energy matrix was composed mainly of nonrenewable sources such as oil, natural gas, and coal, where the combustion of fossil fuels produced approximately 37.15 billion tons of CO₂ in the same year. In 2023, USD 1740 billion was invested globally in renewable energy to reduce CO₂ emissions and combat greenhouse gas emissions. In this context, currently, about 353 geothermal power units are in operation worldwide with a capacity of 16,335 MW. In addition, globally, there are 35 geothermal power units under pre-construction (project phase), 93 already being constructed, and recently, 45 announced. Concerning hydrogen, the industry announced 680 large-scale project proposals, valued at USD 240 billion in direct investment by 2030. In Brazil, the energy company Petroleo Brasileiro SA (Petrobras, Rio de Janeiro, Brazil) will invest in the coming years nearly USD 4 million in research involving natural hydrogen generation, and since the exploration and access to natural energy resources (oil and gas, natural hydrogen, and geothermal systems, among others) are achieved through the drilling of wells, this document presents a technical–scientific contextualization of social interest.

Optimizing the drilling process is critical for the exploration of natural resources. However, there are several mechanic parameters that continuously interact with formation properties, hindering the optimization process. Rate of penetration (ROP) and mechanical specific energy (MSE) are considered two key performance indicators that allow the identification of ideal conditions to enhance the drilling process. Thus, the goal of this research was to analyze field data from pre-salt layer operations, using a 2D analysis of parameters as a function of depth, response surface methodology (RSM), and multi-objective optimization. The results show that the RSM method and multi-objective optimization provide better results when compared with 2D analysis of parameters as a function of depth. The RSM method can be used as a tool to analyze the effects of the independent drilling mechanical parameters (WOB, RPM, FLOW, and TOR) on the response variables (ROP and MSE) with a 95% confidence level. Through multi-objective optimization, it was possible to concomitantly achieve an ROP of approximately 22 ft/h and MSE of nearly 11 kpsi using the values of WOB, RPM, FLOW, and TOR of about 11 klb, 109 rev/min, 803 gpm, and 3 klb-ft, respectively. Using high WOB values, i.e., from the mean value up to the maximum value of approximately 43 klb, reflects a low ROP and most likely indicates an operation beyond the foundering point. High FLOW promotes a more efficient hole cleaning and higher rates of cuttings transport, thus preventing eventual in situ drill-bit sticking. Flow adjustment also ensures an adequate balance of dynamic bottom hole pressure, in addition to controlling the force impact force of the drilling fluid in contact with the rock being drilled, expressing importance in terms of efficiency and rock penetration. Finally, it is important to mention that the results of this research are not only applicable to hydrocarbon exploration but also to geothermal and natural hydrogen exploration. Values analyzed and presented with decimal precision should be logically focused as integers when in industrial application.

A pirólise é uma tecnologia verde que permite separar o alumínio do polietileno das embalagens Tetra Pak. Essa alternativa pode ser utilizada para reduzir o impacto ambiental decorrente da destinação inadequada desses resíduos modernos. Além disso, a reciclagem permite recuperar materiais de alto valor agregado. Para a recuperação de alumínio e óleos parafínicos de resíduos de embalagens cartonadas, este artigo de revisão visa destacar os avanços na ciência e na tecnologia para a recuperação de alumínio de embalagens cartonadas. Dentre os reatores analisados, os leitos de jorro e os leitos fluidizados podem ser apontados como novas oportunidades e grandes sucessos do setor nos próximos anos. Em relação ao potencial econômico, dois fatores apontam a pirólise de resíduos de embalagens cartonadas como uma técnica promissora: o valor agregado dos materiais reciclados e a economia de energia do processo. Com base na análise econômica, a pirólise tem um potencial econômico positivo de 190,5 US$/por tonelada de produto. Quando comparada ao processo tradicional de produção de alumínio, a pirólise pode economizar 0,745 MWh por cada tonelada de embalagem cartonada recuperada. No que diz respeito à rentabilidade do processo, a pirólise por plasma tem uma relação de caixa acumulada de 3,27 milhões e uma taxa de retorno do investimento de 2,04%, mostrando-se um investimento atraente.

Nowadays, the exploration of different deep subsurface energy-related natural resources (oil/gas, natural hydrogen, geothermal, among others) is gaining importance. The exploration of these deep subsurface resources can present several challenges, such as complex lithology to be drilled, high depth to be reached, and considerable rock hardness, among others. In this context, the implementation of methodologies focused on real-time operational efficiency improvement has gained attention. Mechanical specific energy (MSE), rate of penetration (ROP), and even vibrations are key indicators that can be combined and used for drilling process optimization and efficiency improvement. These indicators are linked to operational drilling mechanic parameters, such as weight on bit (WOB), rotary speed (RPM), torque (TOR), and flow rate (FLOW). Despite this, multi-objective research considering both MSE and torsional vibration (stick–slip) has been largely overlooked in drilling optimization studies. Therefore, the main objective of this paper is to analyze field data from carbonate reservoirs using a multi-objective optimization approach based on torsional vibration, by means of stick–slip and MSE analyses. The focus is to minimize MSE values and mitigate stick–slip using self-developed decision matrices which consider WOB, RPM, and FLOW as key elements. The research results demonstrated that FLOW is a crucial parameter for minimizing torsional vibrations and should be prioritized in drilling operations, also for mitigating undesirable events. The optimization process yielded optimal WOB values for each RPM range (from 100 to 180 [rev/min]) and FLOW range (from 2200 to 3900 [L/min]). The decision matrix revealed that regions with high desirability correspond to high RPM (above 120 [rev/min]), with WOB varying from 5 to 13 [tf], and FLOW rates above 2300 [L/min]. Critical drilling conditions occur when low RPM, low FLOW, and high WOB (above 13 [tf]) are applied, as these conditions and this combination of parameters are most susceptible to release severe torsional vibrations, indicating a higher risk of operational problems.

The global energy matrix needs to undergo considerable changes to achieve the clean and affordable energy target as per the Sustainable Development Goals determined by the United Nations (UN) by 2030. Hydrogen has stood out worldwide as a potential substitute for current non-renewable sources. Once thought to be minor, if not non-existent, natural hydrogen is now becoming a more significant alternative that is being explored. Natural hydrogen can be obtained from subsurface rocks by the generation process of serpentinization, radiolysis, rock fracturing, or magma degassing, using extraction technology similar to that already used in the oil and gas industries. Thus, the goal of this research was to perform a consistent technical–scientific and bibliometric review of natural hydrogen, presenting the Brazilian context. The results showed that from 2017 onwards, there has been an increase in research publications related to the topic. France is the country with the most publications. In Brazil, the potential of natural hydrogen sources has been studied in states such as Goias, Tocantins, Minas Gerais, Roraima, Bahia, and Ceará. It is still difficult to predict the potential cost of natural hydrogen production. However, estimates through the Hydroma company show a cost of 0.5 USD/kg, and Australia and Spain target price projects at approximately 1 USD/kg of natural decarbonization could be aided by natural hydrogen, which could supply the world’s energy needs for generations. Geological processes, reserve behavior, and the efficiency of extraction are among the unknowns, though. Brazil requires a strong regulatory framework and additional research. For exploration to be sustainable, cooperation between the government, businesses, and society is essential.