Onshore Oil Reservoir Research Articles

Making Sense of Oil Pollution: Thresholds of Harm in the Extractive Ecologies of Val d'Agri

This contribution investigates the politics of oil extraction and perceptibility in Val d'Agri, an area in the southern Italian region of Basilicata that sits on the largest onshore oil reservoir in the country. In this article, I examine the ways in which diffused industrial contamination emerges in the landscape and is intercepted and translated by human bodily senses. In doing so, I consider how material phenomena of slow and accretive environmental degradation have a spatial affect and shape ontologies of pollution in the region. To explore how oil becomes a highly political process of epistemological reconfiguration, I examine the rift between expert science and environmental monitoring, which are appropriated by oil corporations and the Italian State, and forms of knowledge that are mobilized by local citizens in an attempt to make sense of ecological degradation and claim environmental rights. Drawing from ethnographic fieldwork and open-source investigation, this contribution invokes accounts of situated practices of citizen sensing that navigate and assemble the evidence of slow and chronicle effects of hydrocarbon pollutants in Val d'Agri. Citizens generate fluxes and exchanges of knowledge that stimulate new political possibilities between inhabitants, activists, and experts and are constitutive of environmental resistance. I give resonance to the existing and emerging struggles around environmental justice in the region as an invitation to consider the possibilities of sensing and local knowledge to bring to the surface a different understanding of contamination and challenge the power of extractive economies.

Apportioning PM1 in a contrasting receptor site in the Mediterranean region: Aerosol sources with an updated sulfur speciation

A multi-parametric experimental campaign was performed in Agri Valley (Basilicata, southern Italy) from July 2017 to January 2018. The investigated area, though basically rural and devoted to agricultural activities, hosts a huge on-shore oil reservoir, i.e. Centro Olio Val d'Agri (COVA), bringing substantial environmental modifications and impacts to the district landscape. Daily concentrations of PM1 aerosol samples, Equivalent Black Carbon and number size distributions were evaluated. Chemical aerosol speciation based on elemental and ion analyses were carried out and source apportionment by Positive Matrix Factorization (PMF) was applied to reconstruct PM1 source profile. The most significant emission sources found are torches from the oil treatment facility (37 % w/w), an unresolved factor constituted by soil resuspension, Saharan dust, and biomass burning (24 % w/w), ammonium sulphate (23 % w/w), emissions from the oil desulfurization (Claus process) (13 % w/w), and traffic + road dust (3 % w/w). SEM analysis on PM1 single particles allowed to confirm the finding from PMF including the occurrence of elemental sulfur associated with the Claus process. The novelty of the present study consists in the identification of this latter fingerprint.

Screening of enhanced oil recovery techniques for Iranian oil reservoirs using TOPSIS algorithm

In recent decades, parallel to amazing advances in the development of data mining methods, screening, as the first step of any enhanced oil recovery (EOR) project, has become an interesting subject of data mining methods. Screening of EOR methods is a multi-criteria decision making process, and the Multi-Criteria Decision Making (MCDM) method as a systematic statistical method, can be applied in this regard. In this paper, the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) as one of the methods under the MCDM category was used to screen 65 Iranian oil reservoirs. The screening method was employed for 10 different EOR techniques using a wide range of properties and conditions. The analysis used a database including more than 800 successful EOR projects across the world and for 9 ideal reservoir parameter values. The relative importance of the reservoir parameters was determined based on the Analytic Hierarchy Process (AHP) at nine importance levels. The findings showed that among the considered screening parameters, to determine the best EOR technique, lithology of the reservoir is the most influencing parameter. Additionally, almost 74% of the oil reservoirs under study, as a first priority, were eligible for CO2 injection, either miscible or immiscible. Thermal methods were in the second stage of ranking. The first and second candidate choice for onshore oil reservoirs was immiscible CO2 and hydrocarbon gas injection, respectively. For offshore reservoirs, CO2 injection and steam flooding were the best choices. Also, miscible N2 injection was the least important technique, due to the huge difference of considered reservoir pressure with minimum miscibility pressure (MMP) of N2 injection. The proposed technique is computationally fast and less expensive than field simulation studies for ranking EOR projects for any oil reservoir in the world.

Biosurfactant-Producing Capability and Prediction of Functional Genes Potentially Beneficial to Microbial Enhanced Oil Recovery in Indigenous Bacterial Communities of an Onshore Oil Reservoir.

Microbial enhanced oil recovery (MEOR) is a bio-based technology with economic and environmental benefits. The success of MEOR depends greatly on the types and characteristics of indigenous microbes. The aim of this study was to evaluate the feasibility of applying MEOR at Mae Soon Reservoir, an onshore oil reservoir experiencing a decline in its production rate. We investigated the capability of the reservoir's bacteria to produce biosurfactants, and evaluated the potentials of uncultured indigenous bacteria to support MEOR by means of prediction of MEOR-related functional genes, based on a set of metagenomic 16s rRNA gene data. The biosurfactant-producing bacteria isolated from the oil-bearing sandstones from the reservoir belonged to one species: Bacillus licheniformis, with one having the ability to decrease surface tension from 72 to 32mN/m. Gene sequences responsible for biosurfactant (licA3), lipase (lipP1) and catechol 2,3-dioxygenase (C23O) were detected in these isolates. The latter two, and other genes encoding MEOR-related functional proteins such as enoyl-CoA hydratase and alkane 1-monooxygenase, were predicted in the bacterial communities residing the reservoir's sandstones. Exposure of these sandstones to nutrients, consisting of KNO3 and NaH2PO4, resulted in an increase in the proportions of some predicted functional genes. These results indicated the potentials of MEOR application at Mae Soon site. Using the approaches demonstrated in this study would also assist evaluation of the feasibility of applying MEOR in oil reservoirs, which may be enhanced by an appropriate nutrient treatment.

Effect of inorganic nutrients on bacterial community composition in oil-bearing sandstones from the subsurface strata of an onshore oil reservoir and its potential use in Microbial Enhanced Oil Recovery.

Microbial Enhanced Oil Recovery (MEOR) is a promising strategy to improve recovery of residual oil in reservoirs, which can be performed by promoting specific indigenous microorganisms. In this study, we performed preliminary evaluation of the possibility of conducting MEOR at Mae Soon reservoir, an onshore reservoir in Northern Thailand. The reservoir’s physicochemical characteristics, including the characteristics of the wells, the oil-bearing sandstone cores, and the reservoir’s produced water, were determined. The microbiological characteristics of the oil wells in the reservoir were also investigated by submerging the reservoir’s sandstone core samples, obtained from 6 oil wells, in the reservoir’s produced water and in the produced water added with inorganic nutrients (KNO3 and NaH2PO4). The uncultured bacteria in both treatments were determined, using tagged 16S rRNA gene amplicon with Ion Torrent Sequencing Analysis. The effects of inorganic nutrients and the reservoir’s parameters on the bacterial communities were analysed. A total number of 16,828 OTUs were taxonomically classified into 89 classes and 584 genera. In the controls (sandstone cores submerged in the produced water), the dominant bacterial populations were related to Deinococcus-Thermus, and Betaproteobacteria; while in the nutrient treated samples, there was a marked increase in the relative abundance of Gammaproteobacteria in three samples. Thermus, Acinetobacter, and Pseudomonas were the most abundant genera, and these are potential microorganisms for MEOR. Analysis of correlations between physiochemical properties of the reservoir and bacterial genera, using spearman’s correlation analysis, suggested that some of the reservoir’s properties, especially of the well and the rock, could influence some bacterial genera. To our knowledge, this is the first demonstration of the effect of inorganic nutrients on alteration of bacterial communities attached to reservoir’s rock, and how the bacterial, physical, and chemical properties of a reservoir were co-analysed to serve as a basis for designing a MEOR process.

Disjunctive Optimization Model for the Production Planning and Blending of Crude Oil in a Conventional Oil Field

This work presents a multiperiod nonlinear formulation based on generalized disjunctive programming (GDP) that integrates the production planning and pooling problems in a conventional onshore oil reservoir with fixed topology and a surface interconnection scheme. The model optimizes the well production and blending decisions, while complying with product specifications, such as the sulfur content required by refineries downstream of the oil field. It considers wells from different reservoirs belonging to a given oil field, which are interconnected through manifolds at a network of pipes. The nonlinear behavior of well pressure as a function of time and bilinearities in mass balances are also taken into account. The objective function maximizes the accumulated production of the end products. Numerical results show that obtaining end products as result of blending operations is affected by production planning in wells, the capacity of intermediate tanks, and sulfur specification.

Evaluation of the Water Flooding Development Potential at High Water Cut Reservoirs with the Multi-Level Fuzzy Synthetic Evaluation Method

At present, most of China's onshore oil reservoirs are facing big challenges as they have entered the stage of high water content. For high water cut reservoirs, conventional reservoir engineering methods, such as the production decline curve analysis method, the water drive characteristic curve analysis method, the forecasting model method and so on, are away from the actual situation at some degree in predicting the difference of water flooding development potential. And it is hard to meet the requirements in mid-to-late stage of high water cut reservoir development by accurately judging the development potential. This paper, through reservoir response, optimizes the elected geological and development indexes that can reflect the water flooding development potential combining the grey correlation and Delphi methods. Then the multi-level fuzzy synthetic evaluation method was established by combining the analytic hierarchy process and the fuzzy evaluation process considering the geological and development factors, and was applied to objectively evaluate the water flooding development potential. At last, through case study of the Baikouquan Reservoir in the 21st Wellblock, it has been proved that this method is effective and feasible.

Characterisation of the permeability anisotropy of Cretaceous platform carbonates by using 3D fracture modeling: the case study of Agri Valley fault zones (southern Italy)

In the Agri Valley, high-angle faults crosscut platform carbonates that are analogues of the lithological units that host the deep seated largest onshore oil reservoir in Europe. The main faults are W-NW oriented with a left-lateral strike-slip kinematics; additionally, three sets of related secondary faults are present: ( i ) N-NE oriented with right-lateral/transtensional kinematics; ( ii ) E-W trending left-lateral transtensional and ( iii ) N-NW trending left-lateral transpressional. Two of the secondary N-NE striking faults, strike-slip and transtensional, together with the adjacent host rock, were selected to build a Discrete Fracture Network model eventually used to evaluate the hydraulic properties and permeability anisotropy of these faults. The outcomes of this modelling show that the total permeability of the fault zones is higher than that one of the host rock. Moreover, the results are consistent with the transtensional fault having higher permeability values relative to the strike-slip one. The permeability anisotropy within the fault damage zone as well as in the host rock is mainly related to the fracture orientation.

Land cover changes and forest landscape evolution (1985–2009) in a typical Mediterranean agroforestry system (high Agri Valley)

Abstract. The present study focuses on the transformations of a typical Mediterranean agroforestry landscape of southern Italy (high Agri Valley – Basilicata region) that occurred over 24 years. In this period, the valuable agricultural and natural areas that compose such a landscape were subjected to intensive industry-related activities linked to the exploitation of the largest European onshore oil reservoir. Landsat imagery acquired in 1985 and 2009 were used to detect changes in forest areas and major land use trajectories. Landscape metrics indicators were adopted to characterize landscape structure and evolution of both the complex ecomosaic (14 land cover classes) and the forest/non-forest arrangement. Our results indicate a net increase of 11% of forest areas between 1985 and 2009. The major changes concern increase of all forest covers at the expense of pastures and grasses, enlargement of riparian vegetation, and expansion of artificial areas. The observed expansion of forests was accompanied by a decrease of the fragmentation levels likely due to the reduction of small glades that break forest homogeneity and to the recolonization of herbaceous areas. Overall, we observe an evolution towards a more stable configuration depicting a satisfactory picture of vegetation health.

Theoretical analysis of long offset time-lapse frequency domain controlled source electromagnetic signals using the method of moments: Application to the monitoring of a land oil reservoir

[1] We present a sensitivity study applied to water front monitoring of an onshore oil reservoir, using a remote controlled source electromagnetic method (CSEM) with electric dipoles and a borehole‐to‐surface configuration. We have developed an optimized and parallelized code based on the method of moments, in order to study the influence of several static or time‐varying background uncertainties on the time‐lapse CSEM signal (also called 4‐D CSEM). Analysis of the relative and absolute variations in phase or quadrature of the time‐lapse signal induced by the fluid substitution process, inside the reservoir, has shown that the vertical electric dipole allows the shape of the water front to be monitored, while remaining less sensitive (compared to a horizontal electric source dipole) to the total volume of substituted fluid. We have examined the influence of missed anomalies (1‐D/3‐D), with more or less conductive properties, near to the ground surface or the reservoir, and with or without time‐varying properties. In most cases, the 4‐D signal behaves like a reliable filter, canceling almost all response anomalies. However, it can also lead to strong, local perturbations of the time‐lapse signal. We have also shown that in the presence of steel cased boreholes at the source location, or with outlying steel cased boreholes, the recording of exploitable data does not present insurmountable difficulties at low frequencies (∼1 Hz), and for a dense array of surface receivers. These positive results with CSEM monitoring suggest that minimal, coarse‐time 3‐D explorations should be used to ensure reliable interpretation of the monitored data.

DEFINIÇÃO DA IDADE DEPOSICIONAL DA FORMAÇÃO AÇU (BACIA POTIGUAR, NORDESTE DO BRASIL) 40 39 ATRAVÉS DA DATAÇÃO

Crescimentos autigênicos precoces de K-feldspato são abundantes nos arenitos fluviais cretácicos da Formação Açu (Bacia Potiguar), um dos mais importantes reservatórios onshore de hidrocarbonetos do Brasil. Estes crescimentos foram formados diretamente ao redor de K-feldspatos detríticos, em condições superficiais (eodiagênese inicial). A continuidade física entre crescimentos e grãos detríticos impossibilitou sua separação visando a aplicação do método convencional 40K- 40Ar. Assim, optou-se em aplicar o método 40 39 Ar- Ar diretamente nos crescimentos autigênicos de K-feldspato. Como resultado, foi obtida uma idade mínima de 120 Ma, muito próxima à idade bioestratigráfica previamente estabelecida para os arenitos da Formação Açu, o que demonstra a viabilidade da aplicação do método 40Ar- 39Ar na determinação de idades deposicionais de arenitos-reservatório. Entretanto, para fins de aprimoramento do método e melhor precisão nas idades, é sugerido o uso de equipamentos que utilizam sonda a laser ultravioleta (UV), o que reduz a possibilidade de contaminação por diferentes fases minerais.