Avaliação do possível impacto das técnicas de MEOR (Microbial Enhanced Oil Recovery) no fator de recuperação das reservas de petróleo e gás do Brasil

Os métodos tradicionais de estimular a produção de petróleo, envolvendo a injeção de água, vapor, gás ou outros produtos, estabeleceram a base conceitual para novos métodos de extração de óleo, utilizando micro-organismos e processos biológicos. As tecnologias que empregam os processos de bioestimulação e bioaumentação já são amplamente utilizadas em inúmeras aplicações industriais, farmacêuticas e agroindustriais, e mais recentemente, na indústria do petróleo. Dada a enorme dimensão econômica da indústria do petróleo, qualquer tecnologia que possa aumentar a produção ou o fator de recuperação de um campo petrolífero gera a expectativa de grandes benefícios técnicos, econômicos e estratégicos. Buscando avaliar o possível impacto de MEOR (microbial enhanced oil recovery) no fator de recuperação das reservas de óleo e gás no Brasil, e quais técnicas poderiam ser mais indicadas, foi feito um amplo estudo dessas técnicas e de diversos aspectos da geologia no Brasil. Também foram realizados estudos preliminares de uma técnica de MEOR (bioacidificação) com possível aplicabilidade em reservatórios brasileiros. Os resultados demonstram que as técnicas de MEOR podem ser eficazes na produção, solubilização, emulsificação ou transformação de diversos compostos, e que podem promover outros efeitos físicos no óleo ou na matriz da rocha reservatório. Também foram identificadas bacias petrolíferas brasileiras e recursos não convencionais com maior potencial para utilização de determinadas técnicas de MEOR. Finalmente, foram identificadas algumas técnicas de MEOR que merecem maiores estudos, entre as técnicas mais consolidadas (como a produção de biossurfatantes e biopolímeros, e o controle da biocorrosão), e as que ainda não foram completamente viabilizadas (como a gaseificação de carvão, óleo e matéria orgânica; a dissociação microbiana de hidratos de gás; a bioconversão de CO2 em metano; e a bioacidificação). Apesar de seu potencial ainda não ser amplamente reconhecido, as técnicas de MEOR representam o limiar de uma nova era na estimulação da produção de recursos petrolíferos existentes, e até mesmo para os planos de desenvolvimento de novas áreas petrolíferas e recursos energéticos. Este trabalho fornece o embasamento técnico para sugerir novas iniciativas, reconhecer o potencial estratégico de MEOR, e para ajudar a realizar seu pleno potencial e seus benefícios.

Production planning aids for a modular pond system

This paper presents a series of short mathematical expressions that may be used to determine the necessary variables in production planning in a modular pond system for fish culture.

Economic evaluation of marine fisheries in India for sustainable production and coastal zone development

The article highlights briefly the economics of different types of fishing units operating along the Indian coast; analyzes the exploitation trend of major marine fishery resources in relation to its potential yield; and suggests policy measures for optimum exploitation of resources, conservation and management.

Promotion of substrate based microbial biofilm in ponds: a low cost technology to boost fish production

Microbial biofilms have been found to increase fish production in ponds by increasing heterotrophic production through periphyton proliferation on available substrates. In this paper, the role of substrate based microbial biofilm in the production of Cyprinus carpio and Labeo rohita grown in ponds is investigated, using an easily available and biodegradable agricultural waste product (sugarcane bagasse) as substrate.

Escalation in shrimp production in the Sierra Leone industrial fishery

Applying Turkey's jackknife method on MSY estimates from the surplus production models of Schaefer and Fox showed that the optimum yield for shrimps in industrial fishery in Sierra Leone is estimated at 2,686.8 t with 15,822 fishing days. Annual catch for 1996 was 2,788 t, indicating an escalation in exploitation which, if prolonged, could bring reduced productivity as experienced in the fishery some years ago.

Fisheries production in Asia: its role in food security and nutrition

This paper reviews the status and some management issues of fisheries production in Asia, as well as the supply and demand situation. Its food security and nutritional roles and opportunities for value addition are also discussed.

Simple method for backyard production of snakehead (Channa striata Bloch) fry

The snakehead (Channa striata ) is a common freshwater fish species in Malaysia. Details are given of a simple technique for breeding this species, suitable for small-scale farmers practising backyard aquaculture. Two techniques were used to induce spawning - the first used water level manipulation to simulate rain and the second used injected with human chorionic gonadotropic hormone. The former, more natural, spawning technique was found to provide a viable alternative for the small-scale farmer, being much simpler than hormone injection.

Effects of El Niño events on energy demand and egg production of rockfish (Scorpaenidae: Sebastes): a bioenergetics approach

Fish bioenergetics models estimate relationships between energy budgets and environmental and physiological variables. This study presents a generic rockfish (Sebastes) bioenergetics model and estimates energy consumption by northern California blue rockf ish (S. mystinus) under average (baseline) and El Niño conditions. Compared to males, female S. mystinus required more energy because they were larger and had greater reproductive costs. When El Niño conditions (warmer temperatures; lower growth, condition, and fecundity) were experienced every 3−7 years, energy consumption decreased on an individual and a per-recruit basis in relation to baseline conditions, but the decrease was minor (<4% at the individual scale, <7% at the per-recruit scale) compared to decreases in female egg production (12−19% at the individual scale, 15−23% at the per-recruit scale). When mortality in per-recruit models was increased by adding fishing, energy consumption in El Niño models grew more similar to that seen in the baseline model. However, egg production decreased significantly — an effect exacerbated by the frequency of El Niño events. Sensitivity analyses showed that energy consumption estimates were most sensitive to respiration parameters, energy density, and female fecundity, and that estimated consumption increased as parameter uncertainty increased. This model provides a means of understanding rockfish trophic ecology in the context of community structure and environmental change by synthesizing metabolic, demographic, and environmental information. Future research should focus on acquiring such information so that models like the bioenergetics model can be used to estimate the effect of climate change, community shifts, and different harvesting strategies on rockfish energy demands.