Marine Oil Field Research Articles

Study on the screening of marine beneficial bacteria and the inhibition of sulfate-reducing bacteria corrosion in marine oil field produced water

PurposeThe purpose of this study is to provide ideas and theoretical guidance for green, environmentally friendly and efficient “bacteriostasis with bacteria” technology.Design/methodology/approachIn this paper, a beneficial strain of bacteria was extracted and purified from marine mud. Weight-loss test, morphological observation and electrochemical test were used to systematically study the effect of sulfate-reducing bacteria (SRB)-induced corrosion inhibition on X65 steel in simulated offshore oil field production water.FindingsThe results showed that a beneficial strain was selected and identified as Vibrio alginolyticus. Under the condition of co-culture of SRB, the average corrosion rate of X65 steel was significantly reduced. In the mixed bacterial system, the surface of X65 steel samples was relatively flat, and the structure of biofilm and corrosion product film was dense. The number of corrosion pits, the average diameter and depth of corrosion pits were significantly reduced. The localized corrosion of X65 steel was significantly inhibited.Originality/valueThe complex and changing marine environment makes the corrosion problem of marine steel increasingly severe, and the microbiologically influenced corrosion (MIC) caused by SRB is particularly serious. The research and development of environmentally friendly corrosion protection technology is a long-term and difficult problem. The use of beneficial microorganisms to control MIC is a green and efficient anticorrosion measure. Compared with terrestrial microorganisms, marine microorganisms can adapt to complex environments, and their metabolites exhibit special biological activities. The use of marine beneficial bacteria can inhibit SRB activity to achieve the corrosion inhibition effect.

Bayesian joint inversion of seismic and electromagnetic data for reservoir lithofluid facies, including geophysical and petrophysical rock properties

A Bayesian approach is developed to estimate lithofluid facies and other rock properties conditioned on seismic and electromagnetic data for reservoir characterization. Prior distributions are assumed to be facies-related Gaussian modes of geophysical rock properties directly acquired or converted from petrophysical properties by calibrated rock-physics modeling. An original generalization includes two distributions in the same marginalization integral, analytically solved under a linearized Gaussian assumption to provide a facies model likelihood conditioned on geophysical data. Because computing this probability for all possible facies configurations may be impractical, a Markov chain Monte Carlo algorithm efficiently samples models to provide a full posterior distribution. The linearized Gaussian approach allows the computation of the conditional distributions of geophysical and petrophysical rock properties by applying local deterministic inversions over the many sampled facies models. The inversion uses simulated geophysical data from a 1D synthetic model based on the geologic scenario and a well from a selected marine oil field. Two other wells from the same reservoir are used to gather prior distributions. Data from the well, calibration of the rock-physics modeling, and facies matching between the priors and the synthetic model are presented and discussed. Numerical tests validate nonlinear forward-modeling adaptations based on the assumed linearized Gaussian approach. The simulated stand-alone and joint geophysical data sets are then inverted for lithofluid facies models under different prior inputs. Two challenging geoelectric scenarios also are tested, one with lower resistivity contrasts and another with a misguided background model. All results demonstrate a gain in precision and accuracy when associating these geophysical signals to estimate the oil column. Facies-conditioned inversions for the rock properties also indicate potential for quantitative reservoir interpretations.

Impact of structural geometry of tilted fault blocks on hydrocarbon entrapment and deposition of syn-rift clastic reservoirs: Belayim Marine field (Gulf of Suez rift)

Belayim Marine oilfield is representative of the Gulf of Suez fields with hydrocarbon production from pre-rift and syn-rift reservoirs. Detailed subsurface mapping using a complete 3D seismic and borehole dataset throws light on the trapping mechanisms of tilted fault blocks in rift basins where the strike of the tilted block is parallel to the bounding fault. For such one-way tilted fault traps, linkage of rift-parallel and rift-oblique faults at the updip sides of the tilted blocks is necessary for trap integrity of laterally continuous reservoirs like the Nubia Sandstone. For laterally discontinuous reservoirs like tidal sand bars aligned normal or oblique to the block-bounding faults, a combination trap can be laterally closed by lateral change in facies of the reservoir unit along fault strike. Fault sealing of the proved hydrocarbon traps is mainly through juxtaposition. Shale smearing is valid for thick shale units with reasonable fault displacement and shale gouge is a proven sealing mechanism especially in clay-rich units. The ductile nature of syn-rift sediments leads to fault-propagation folding above the main-bounding faults of tilted fault blocks where folding is the trapping mechanism of these syn-rift reservoirs.The structural geometry of tilted fault blocks also controls the distribution of syn-rift reservoirs as the linkage of rift-parallel and rift-oblique faults controls the entry of main valleys transporting syn-rift clastics into the basin. Longitudinal depressions sculptured at the crests of tilted fault blocks represent another location for deposition of syn-rift reservoirs.

Sedimentological studies of marine oil fields in order to reduce drilling risk and environmental pollution: a case study of South of Iran

Detailed studies of sedimentology and petrology of oil fields, especially oil fields located in the seas, play avery important role in reducing the risk of danger, increasing harvest, and reducing the amount of environmentalpollution. The South Pars gas field in the waters of the Persian Gulf on the joint border line of Iran and Qatar andon the south coast of Iran has been used as a comprehensive model for this type of study. In these studies, thesedimentary environment and sequential stratigraphy of the Scorpion and Sarvak Formations in the South Parsgas field in wells 1 and 3 have been investigated. Microscopic studies and analysis of gamma-ray and acousticdiagrams of these formations have led to the identification of 9 facies in three facies belts related to wetland,dam, and open sea. Dam facies have been identified only in Sarvak formation. This study shows that the faciesbelts of the abovementioned formations in a ramp platform are also sloping. Sequence stratigraphy of Kazhdomiand Sarvak Formations in the study wells shows that Kazhdomi Formation has one sedimentary sequence (thirdcategory cycle) and Sarvak Formation has two sedimentary sequences. The lower boundaries of sequences 1 and2 and the upper boundary of sequence 3 have type 1 (SB1) discontinuities, and the boundary between sequences2 and 3 has type 2 (SB2) discontinuities.

Sedimentological Studies of Marine Oil Fields in Order to Reduce Drilling Risk and Environmental Pollution: A Case Study of South of Iran

Detailed studies of sedimentology and petrology of oil fields, especially oil fields located in the seas, play a very important role in reducing the risk of danger, increasing harvest, and reducing the amount of environmental pollution. The South Pars gas field in the waters of the Persian Gulf on the joint border line of Iran and Qatar and on the south coast of Iran has been used as a comprehensive model for this type of study. In these studies, the sedimentary environment and sequential stratigraphy of the Scorpion and Sarvak Formations in the South Pars gas field in wells 1 and 3 have been investigated. Microscopic studies and analysis of gamma-ray and acoustic diagrams of these formations have led to the identification of 9 facies in three facies belts related to wetland, dam, and open sea. Dam facies have been identified only in Sarvak formation. This study shows that the facies belts of the abovementioned formations in a ramp platform are also sloping. Sequence stratigraphy of Kazhdomi and Sarvak Formations in the study wells shows that Kazhdomi Formation has one sedimentary sequence (third category cycle) and Sarvak Formation has two sedimentary sequences. The lower boundaries of sequences 1 and 2 and the upper boundary of sequence 3 have type 1 (SB1) discontinuities, and the boundary between sequences 2 and 3 has type 2 (SB2) discontinuities.

Mathematical Modeling of Oil Spill Dispersion in Marine Waters

During the extraction and transportation of oil in marine waters, oil spills may occur. It not only caused serious pollution in some sea areas but also have a grave impact on the marine environment. Studying the oil dispersion pattern is important for addressing oil spills accurately and timely. Therefore, through the mathematical knowledge, such as continuity equation and momentum equation, we establish a mathematical model for the dispersion of oil spills in marine water. The methods that are used include data statistics, construction of graphs and charts, example analogy, hierarchical analysis, and random calculation. The research and analysis are conducted for the oil spill process in marine oil fields.

3D Slicing of Weighted Index for Reservoir Quality of Lower Miocene Rocks, Belayim Marine Oil Field, Gulf of Suez, Egypt

This study aims to have a single coefficient resulting from the integration of all the reservoir parameters through which a decision can be taken to determine the best quality places in the reservoir. The conventional well logging data in nine wells were used to determine the reservoir parameters in the study area. Seven different parameters were calculated, five of them were directly proportional to the quality of the reservoir, while the remaining two parameters which represent shale volume and water saturation were inversely proportional to the reservoir quality. The index of each parameter was calculated. A new value was created from the integration of the seven different parameter indexes called the weighted index for the reservoir quality. The reservoir quality values were sliced in the three dimensions depending on the effect of all reservoir parameters and not on any single parameter. It is clear from the results of this study that horizontal and vertical slicing, as well as cut-off values, illustrates that the middle and upper parts are the best places for the reservoir to explore hydrocarbons, where the values of the weighted index of the reservoir quality range from 0.65 to 0.9. Meanwhile, the quality of the reservoir decreases in its lower parts.

FLUID DYNAMIC ANALYSIS OF A MARINE SOIL IN JETTING EXCAVATION EMPLOYING RHEOLOGICAL MODELS: INFLUENCE OF DRILLING FLUID ON SOIL DEFORMATION

With the exploration of marine oil fields in deep and ultra-deepwater regions, the need for studying different methods of well construction has increased. Nowadays, the technique of laying conductive casing by jetting is the most widely used for the starting phase of a well in such conditions. In this scenario, in early layers, where the marine soil is in contact with seawater, this material can present itself as a fine mud, characterizing a cohesive non-drained soil, with low shear strength, being considered a material with viscoplastic behavior. Thus, as such, using fluid rheology to analyze it may represent a valid option; being possible to classify it as a Herschel-Bulkley fluid. The use of computational modeling and numerical simulation represent an alternative to understand the behavior of soil during jetting. In this context, this work focuses on developing a computational modeling of the jetting of marine soil, based on the soil fluid dynamics approach, using computational fluid dynamics (CFD - Computational Fluid Dynamics) software SIMULIA XFLOW, version 2020. This work aims to investigate the deformation in the seabed in response to an incident vertical jet using different drilling fluids, also modeled as viscoplastic materials. Drilling fluids suitable for jetting and a fluid with a higher specific mass were considered. For the proposed modeling of the soil and drilling fluids considered, the main parameters used were the yield point, consistency index, behavior index, and the boundary viscosity. The latter was necessary to implement the modified Herschel-Bulkley model used by the software. Results show that the excavated cavity presented a similar behavior for the drilling fluids suitable for jetting, indicating that the rheology of the drilling fluid does not interfere with the deformation of the soil. However, a significant influence on the profile of the excavated cavity was observed when implementing the drilling fluid of higher specific mass in the jetting, which deformed the soil at greater depths.

MULTICRITERIA DECISION-MAKING IN THE SELECTION OF WARSHIPS: A NEW APPROACH TO THE AHP METHOD

The budgetary constraints for the Brazilian Navy (BN) have caused several negative effects, resulting in an undersized fleet, decreasing the capacity to protect marine oil and natural gas fields, combat marine pollution from ships, and monitor other illegal activities at sea and inland waters. This paper aims to choose a medium-sized warship to be built by the BN, through the application of the Analytic Hierarchy Process (AHP) method. After a bibliometric study on Multiple-Criteria Decision-Making (MCDM), the AHP was chosen as the most appropriate method for the proposed case study. We analyzed three ship projects with regard to nine operational and economic criteria, taking into account the evaluations of BN officers with recognized experience and knowledge in military operations. We also introduced a sensitivity analysis based on the relationship between standard deviation and mean scores in order to verify and increase the reliability of the ranking. As a result, the methodology suggested that the best option is to build a brand-new ship with more significant modernizations to provide for the operational needs of the BN.

Simulation on Incipient Particle Motion in Highly-Inclined Annulus

Background: Highly-inclined and horizontal wells have been widely used for the development of mature oilfield, marine oilfield, and low permeable oilfield. During drilling operations, cutting particles will accumulate in the low side of wellbore and cuttings bed may be formed, which may lead to high drag and torque, stuck pipe, and other drilling problems. We reviewed the patents about cutting bed cleaning tool. Objective: The goal of this work is to determine the incipient motion velocity or rate to re-suspend and remove the cutting particles. Methods: In this study, the random distribution function of particles is introduced to determine the percentage of incipient particle motion, and the mechanical models for rolling and lifting method considering the net gravity, drag force, lift force, additional mass force, adhesive force and flow pressure gradient force are developed to predict the incipient motion velocity or rate. Also, the model has been verified by published experimental data. Results: The critical particle size of incipient motion rate is approximately 1 mm. The incipient motion rate decreases as the height of cuttings bed decreases, and the minimum flow rate that prevents the bed formation may be estimated when bed height is small enough. Also, increasing wellbore inclination or fluid density has a positive effect on incipient motion rate, but increasing particle density or percentage of incipient particle motion has an adverse effect. Conclusion: This study may provide a guideline for designing hydraulic parameters and sand washing in the highly-inclined and horizontal wells, thereby contributingin economic production.

Assessment of the Prospects of Developing the Western Arctic Shelf Fields on the Basis of Evaluation of the Technical-Economic Potential of Fields

The paper discusses the methodological issues of assessing the technical and economic potential of the Arctic hydrocarbon fields which can be used to make strategic decisions on the management of the oil and gas sector and the exploitation of natural resources. The sequence of calculation steps of the technical and economic potential of marine oil and gas fields of the Arctic which, unlike the existing ones, is based on an integral indicator that combines the financial, technical, climatic, and service-infrastructure characteristics of the fields what allows rating the fields to determine priority of the start of their development is proposed. The need to take into account a wide range of factors in a comparative analysis of oil and gas fields of the Arctic in order to make strategic management decisions on the priority of field exploitation is proved.

On the transport and landfall of marine oil spills, laboratory and field observations

The dynamics of crude oil and different surface ocean drifters were compared to study the physical processes that govern the transport and landfall of marine oil spills. In a wave-tank experiment, drifters with drogue did not follow oil slicks. However, patches of undrogued drifters and thin bamboo plates did spread at the same rate and in the same direction as the crude oil slicks. Then, the trajectories of the Deepwater Horizon oil spill and 1300 drifters released near the spill source were investigated. Undrogued drifters were transported twice as fast as drogued drifters across the isobaths. 25% of the undrogued drifters landed, versus about 5% of the drogued ones, for the most part, on the same coastline locations where oil was found after Deepwater Horizon. Results highlight the importance of near surface gradients in controlling the cross-shelf transport and landing of surface material on the Gulf of Mexico's northern shores.

Energy efficiency to increase production and quality of products in industrial processes: case study oil and gas processing center

The emphasis of this paper is to show the existence of some non-energy benefits that can be taken into account in an energy efficiency investment aimed to reduce energy consumption and increase production and product quality in an oil and gas processing center (OGPC) in Mexico. The function of OGPC is to separate crude oil, gas, and saltwater coming from marine and terrestrial oil fields. Traditionally, application of process energy integration techniques has been aimed to reduce energy consumption associated with heating and cooling services. In this paper, the process energy integration (standard pinch analysis) of an OGPC shows the possibility of reducing natural gas and electricity consumption by 75 % and 98 %, respectively. However, the novel aspect of this work is the identifications and use of some waste heat streams available in processes to reduce energy consumption, and more importantly couple them with some non-energy-related benefits to produce massive economical savings. For example, by allowing an improvement in the quality of heavy crude oil for exportation (reduction in salt content), an increased sale price of 0.6 USD/barrel is achieved, rising profit to 156.88 MMUSD/year. Additional economic benefits came from the restauration of the production of 3,711 barrel of naphtha per day (33.86 MMUSD/year), by solving security issues related to the use of direct-fire heaters in the condensate stabilization plant.

Special aspects of modeling on accidental oil spills in inland sea waters

Intensive development of marine oil fields is characterized by significant pollution of sea environment, linked with leaks of diesel fuel and oil products during production activities on ships, or as a result of technical means accidents. To assess the potential scale of environmental impact mathematical modeling of hypothetical spills is required. The main processes of distribution and physico-chemical transformation of diesel fuel determined. The spreading of diesel fuel slicks on sea surface in case of accidental spills in storm conditions evaluated. Assessment of spatial-temporal picture of emergency development allows to select and prove a strategy for spills control during a storm wind.

Improving the corrosion resistance of steels intended for use in seawater

The results of study of influence of the chemical composition of steel, the structural condition and contamination of nonmetallic inclusions of various types on its corrosion resistance in seawater are presented in the paper. The requirements for increased-corrosion-resistance steel for marine conditions and oilfield pipelines have been compared. It has been shown that a mandatory requirement for ensuring high corrosion resistance of steels is to ensure the purity of steels from unfavorable types of nonmetallic inclusions. It has also been shown that reducing the carbon content and alloying with nickel lead to an increase in the corrosion resistance of steel.

Hydrocarbon-generating potential of the Eocene Thebes Formation, Gulf of Suez: 1D basin modeling as a supplementary tool for source rock evaluation

The present work provides high-resolution modeling of the thermal maturation of the Eocene Thebes Formation using a multi-1D approach. The model focuses not solely on the thermal maturity but also on timing of hydrocarbon generation (primary generation and secondary cracking), adsorption by organic matter, and expulsion. The time-lapse conceptual model was developed using well log data, geochemical analyses, and composite logs. The stratigraphic sequence of the Belayim Marine oil field was subdivided into a time series based on the tectonic framework of the Gulf of Suez. An elevated basal heat flow has been assigned throughout the rifting phases and basin evolution. The simulation developed for seven wells reveals variations in burial, thermal history, and accordingly the thermal maturity. The predicted thermal maturity ranges from immature to mature with a different tendency to generate hydrocarbons (both primary generation of oil and/or gas secondary cracking) dependent on kerogen type, basin development, and burial history. Hydrocarbon generation (oil) starts after the Messinian Time Event during the deposition of the Post-Zeit Formation. Hydrocarbon generation was related to burial rather than basin evolution for the 113-M-27, BM-23, BM-65, and BM-70 wells. Conversely, generation correlated principally to basin development particularly Messinian Time Event for the 113-M-34 well. Expulsion occurred subsequent to generation of thermogenic gas (secondary cracking of generated oil). It is not possible to investigate the relationship between the production index and thermal maturity as a consequence of expulsion that reduced the S1 values. The different levels of thermal maturity (potential, active, and effective source rock) allow for the differentiation of regions of potential hydrocarbon accumulation that were charged from the Thebes Formation.

A whole of systems approach to improved understanding of the environmental, economic and social values of a frontier marine oil and gas field: Establishment, success factors and lessons learnt

The Great Australian Bight is one of Australia's most valuable marine ecosystems supporting globally significant populations of marine mammals, seabirds, and diverse and highly endemic benthic assemblages, as well as important fishing, aquaculture and ecotourism industries. The region is also considered a significant frontier for potential offshore petroleum resources and is actively being explored for oil and gas. The Great Australian Bight Research Program (GABRP) was an innovative, multi-year, $20 million, inter-disciplinary research collaboration involving BP Developments Australia (BP), CSIRO, the South Australian Research and Development Institute (SARDI), the University of Adelaide and Flinders University, that was developed in response to exploration activities in the region. The Program was the first large-scale, integrated study of the Great Australian Bight that involved more than 100 of Australia's leading scientists to generate a whole-of-system understanding of the region's environmental, economic and social values. We outline the processes to establish this strategic research collaboration, identify the key areas for success, and critically the lessons learned in order to guide future initiatives in regions open to exploration and development. As a result of the GABRP, there is now a legacy of data, information and models to inform future sustainable development in the Great Australian Bight; leading to the region now being one of the better understood deep water Australian marine systems.

Особенности стратегического управления нефтегазовым комплексом и транспортировки углеводородной продукции при освоении морских нефтегазовых месторождений Арктики

Особенности стратегического управления нефтегазовым комплексом и транспортировки углеводородной продукции при освоении морских нефтегазовых месторождений Арктики

Radiogenic heat production in Rudeis Formation, Lower Miocene, Belayim marine oil field, Gulf of Suez, Egypt

This study describes radiogenic heat production (RHP) estimated from two sets of well logging data recorded in Rudeis Formation, Belayim marine oil field. Subsurface total count gamma-ray (GR) data were recorded in nine wells, seven of which possessed spectrometric data (eU, eTh, and K). The data show that RHP estimated from GR logs (ABR) varies from 0.13 to 1.73 µW/m3, with an average of 0.7 µW/m3 and a standard deviation of 0.26 µW/m3. In addition, 72.9% of RHP values fall within the range of 0.6–1.0 µW/m3. RHP estimated from the concentrations of radioactive elements (AR) vary from 0.13 to 2.1 µW/m3, with an average 0.71 µW/m3 and a standard deviation of 0.38 µW/m3. 50% of these RHP values fall within the range of 0.6–1.0 µW/m3. Cross-correlation of ABR and AR calculations yielded a moderate fit of 0.75. The three-dimensional (3D)-slicing of the reservoir shows that the northern and north-western parts of the study area have higher RHP compared to other parts. The estimated RHP can produce enough heat which has an effect on the hydrocarbon potential in Rudeis Formation.

New insights into the carbonate karstic fault system and reservoir formation in the Southern Tahe area of the Tarim Basin

As worldwide hydrocarbon exploration has extended from shallowly to deeply buried strata, reservoir quality has attracted substantial and persistent interest in petroleum geology. In particular, deeply buried strata (>5500 m) in the Tarim Basin have attracted considerable attention because carbonate reservoirs that have experienced fracture or dissolution have also been shown to demonstrate considerable hydrocarbon potential. Therefore, it is necessary to determine how these reservoirs are developed and distributed in detail from both scientific and practical standpoints.In this paper, we address this issue using a case study in the southern Tahe area, which is contained within the largest Palaeozoic marine oilfield in China. In the northern Tahe area, mega-paleokarst systems developed in the Ordovician strata; however, the reservoir quality in the southern part of the Tahe area is relatively poor because it is covered by insoluble formations during karstification. Observations of cores and analyses of images of well logging demonstrate that these reservoirs are dominated by caves, vugs and fractures that have developed near faults. We speculate that the faults penetrating insoluble formations represent the main dissolution passages that originally developed these karstic fault systems. Additionally, we analyse a series of outcrops, seismic data, and structures to characterize the spatial geometry of these major faults and their surrounding fractures in detail. Most of these are strike-slip faults, and their subsequent reservoirs can be divided into three categories based on their development, including dendritic, sandwich and slab reservoirs. Recent studies demonstrate that karstic fault reservoirs are most common traps in the study area. Although various types of carbonate karstic fault reservoirs are represented in this region, the dendritic karstic fault reservoir is the most hydrocarbon-rich.Guided by these initial results, 108 wells were drilled from 2013 to 2014, producing 485 thousand tons of oil and yielding success ratios greater than 89%. The average production of dendritic reservoirs is 37.4 tons per day (t/d), while those of sandwich and slab types are 20.2 t/d and 14.0 t/d, respectively. These results represent significant references for future hydrocarbon exploration and the development of similar deeply buried karstic fault reservoirs in the Tarim Basin and elsewhere.