Integrated risk management: a Petrobras application in offshore well construction safety to minimize critical emergency disconnections

In order to avoid mistakes and to save a great deal of time in analysis, an innovative methodology was developed that can analyze the well operations and rig characteristics involved to define the best emergency disconnect sequence （EDS） available. A solution was developed based on the characteristics of the rigs and blowout preventers （BOPs）, and six variables were considered that directly affect the choice of EDS. All possible combinations of 64 scenarios were analyzed, and the priority of choice of the EDS was defined empirically. This paper presents an approach to EDS risk management and examples of exposure time （time without riser safety margin and shear capability） for the same well, which can be lowered from 13% to 0.1%. The impact of this reduction is related to the ability of the BOP to cut some of the heavy casings, in addition to improved availability of EDS modes. This implementation opened up many possibilities for the performance of risk exposure analysis, enabling comparison of several BOP configurations of contracted rigs and selection of the best options. This innovative approach allowed a better management of the rig schedules, prioritizing safety aspects and making it possible to allocate the fleet in a systematic way.

Geostatistical seismic inversion and 3D modelling of metric flow units,porosity and permeability in Brazilian presalt reservoir

Flow units(FU)rock typing is a common technique for characterizing reservoir flow behavior,producing reliable porosity and permeability estimation even in complex geological settings.However,the lateral extrapolation of FU away from the well into the whole reservoir grid is commonly a difficult task and using the seismic data as constraints is rarely a subject of study.This paper proposes a workflow to generate numerous possible 3D volumes of flow units,porosity and permeability below the seismic resolution limit,respecting the available seismic data at larger scales.The methodology is used in the Mero Field,a Brazilian presalt carbonate reservoir located in the Santos Basin,who presents a complex and heterogenic geological setting with different sedimentological processes and diagenetic history.We generated metric flow units using the conventional core analysis and transposed to the well log data.Then,given a Markov chain Monte Carlo algorithm,the seismic data and the well log statistics,we simulated acoustic impedance,decametric flow units(DFU),metric flow units(MFU),porosity and permeability volumes in the metric scale.The aim is to estimate a minimum amount of MFU able to calculate realistic scenarios porosity and permeability scenarios,without losing the seismic lateral control.In other words,every porosity and permeability volume simulated produces a synthetic seismic that match the real seismic of the area,even in the metric scale.The achieved 3D results represent a high-resolution fluid flow reservoir modelling considering the lateral control of the seismic during the process and can be directly incorporated in the dynamic characterization workflow.

Petroleum exploration and production in Brazil:From onshore to ultra-deepwaters

The Santos Basin in Brazil has witnessed significant oil and gas discoveries in deepwater pre-salt since the 21^(st)century.Currently,the waters in eastern Brazil stand out as a hot area of deepwater exploration and production worldwide.Based on a review of the petroleum exploration and production history in Brazil,the challenges,researches and practices,strategic transformation,significant breakthroughs,and key theories and technologies for exploration from onshore to offshore and from shallow waters to deep-ultra-deep waters and then to pre-salt strata are systematically elaborated.Within 15 years since its establishment in 1953,Petrobras explored onshore Paleozoic cratonic and marginal rift basins,and obtained some small to medium petroleum discoveries in fault-block traps.In the 1970s,Petrobras developed seismic exploration technologies and several hydrocarbon accumulation models,for example,turbidite sandstones,allowing important discoveries in shallow waters,e.g.the Namorado Field and Enchova fields.Guided by these models/technologies,significant discoveries,e.g.the Marlim and Roncador fields,were made in deepwater post-salt in the Campos Basin.In the early 21^(st)century,the advancements in theories and technologies for pre-salt petroleum system,carbonate reservoirs,hydrocarbon accumulation and nuclear magnetic resonance(NMR)logging stimulated a succession of valuable discoveries in the Lower Cretaceous lacustrine carbonates in the Santos Basin,including the world-class ultra-deepwater super giant fields such as Tupi(Lula),Mero and Buzios.Petroleum development in complex deep water environments is extremely challenging.By establishing the Technological Capacitation Program in Deep Waters(PROCAP),Petrobras developed and implemented key technologies including managed pressure drilling(MPD)with narrow pressure window,pressurized mud cap drilling(PMCD),multi-stage intelligent completion,development with Floating Production Storage and Offloading units(FPSO),and flow assurance,which remarkably improved the drilling,completion,field development and transportation efficiency and safety.Additionally,under the limited FPSO capacity,Petrobras promoted the world-largest CCUS-EOR project,which contributed effectively to the reduction of greenhouse gas emissions and the enhancement of oil recovery.Development and application of these technologies provide valuable reference for deep and ultra-deepwater petroleum exploration and production worldwide.The petroleum exploration in Brazil will consistently focus on ultra-deep water pre-salt carbonates and post-salt turbidites,and seek new opportunities in Paleozoic gas.Technical innovation and strategic cooperation will be held to promote the sustainable development of Brazil's oil and gas industry.

Stochastic seismic inversion and Bayesian facies classification applied to porosity modeling and igneous rock identification

We apply stochastic seismic inversion and Bayesian facies classification for porosity modeling and igneous rock identification in the presalt interval of the Santos Basin. This integration of seismic and well-derived information enhances reservoir characterization. Stochastic inversion and Bayesian classification are powerful tools because they permit addressing the uncertainties in the model. We used the ES-MDA algorithm to achieve the realizations equivalent to the percentiles P10, P50, and P90 of acoustic impedance, a novel method for acoustic inversion in presalt. The facies were divided into five: reservoir 1,reservoir 2, tight carbonates, clayey rocks, and igneous rocks. To deal with the overlaps in acoustic impedance values of facies, we included geological information using a priori probability, indicating that structural highs are reservoir-dominated. To illustrate our approach, we conducted porosity modeling using facies-related rock-physics models for rock-physics inversion in an area with a well drilled in a coquina bank and evaluated the thickness and extension of an igneous intrusion near the carbonate-salt interface. The modeled porosity and the classified seismic facies are in good agreement with the ones observed in the wells. Notably, the coquinas bank presents an improvement in the porosity towards the top. The a priori probability model was crucial for limiting the clayey rocks to the structural lows. In Well B, the hit rate of the igneous rock in the three scenarios is higher than 60%, showing an excellent thickness-prediction capability.

The roll damping assessment via decay model testing (new ideas about an old subject)

The methodology to obtain the non-linear roll damping from decay tests is very old. It has been proposed by Froude in the 19th century and used from then on. Behind it there is a quadratic model [θ｜θ｜] for the damping and a subsequent equivalent linearization. Probably all model basin in the world follows this approach to assess the damping from a methods to get the P1-P2 coefficients. This is very applied to any kind of hull. However, it has become decay test. This is well documented and so is the general in the sense that in principle, it could be clear that for hull with a flat bottom such as a very large crude carrier （VLCC）, this approach may lead to confusing results such as negative P2. Faced with this, the work presents a completely new idea. Avoiding the polynomial approximation, the basic attitude is to devise two regions from the decaying test response. The first, called the large amplitude response region yields a larger damping, probably due to the large bilge keel vortices that are attracted to the hull flat bottom. The second is the small amplitude response region where the vortices are not attracted to the bottom but travels approximately 45° sidewise. These observations has led to a new approach called the bi-linear approach as discussed in the work after analyzing several （many） model test results. In fact, a new modified bi-linear approach is ultimately proposed after the understanding of a transition region instead of a transition angle.

Application of Molecular Distillation Process to Extend the True Boiling Point Curve of Petroleum Residues 400 ℃ ＋

True Boiling Point （TBP） distillation is one of the most common experimental techniques for determination of petroleum properties. The methods for performing TBP distillation experiments are described by ASTM D2892 and by ASTM D5236. However, these methods are established for petroleum fractions that reach temperatures up to 565 ~C. In this work, two petroleum residues were distilled in a falling film molecular distillation prototype and the data were used to obtain the extension of the TBP curve above a temperature of 565 ~C. It was possible to extend the TBP curve of both petroleum up to temperatures close to 700 ~C with consistency and continuity in comparison to the standard curve. In addition, an amount of raw material that was been treated as residue could be reused.

桑托斯盆地R油田辉绿岩对盐下碳酸盐岩储层接触热变质影响

针对岩浆侵入接触热变质作用对超深水环境盐下碳酸盐岩储层的影响问题,以桑托斯盆地R-油田为例,对6口井中不同厚度辉绿岩侵入对盐下灰岩储层的重结晶程度、影响厚度、物性变化等进行统计分析。研究表明,R-油田盐下的灰岩受巨厚层辉绿岩的接触热烘烤变质作用显著,普遍发生大理岩化重结晶,颗粒变粗大,颜色白化,但不均匀性也较强;储层物性急剧降低,一般降低幅度4~8倍,孔隙度越高降低幅度也越大;接触变质带厚度与侵入体厚度具有正相关关系,符合二项式y = 0.001x2 + 0.0801x + 0.2426变化规律,但明显低于塔里木盆地辉绿岩影响灰岩的幅度。研究认为,接触变质带高度重结晶和胶结作用是导致储集空间降低的主要原因;超深水环境较低的围岩温度以及侵入体上覆巨厚导热性好的膏盐岩是造成接触变质影响厚度偏低的主要原因。

An Adaptive Load Stepping Algorithm for Path-Dependent Problems Based on Estimated Convergence Rates

A new adaptive(automatic)time stepping algorithm,called RCA(Rate of Convergence Algorithm)is presented.The new algorithm was applied in nonlinear finite element analysis of path-dependent problems.The step size is adjusted by monitoring the estimated convergence rate of the nonlinear iterative process.The RCA algorithm is relatively simple to implement,robust and its performance is comparable to,and in some cases better than,the automatic load incrementaion algorithm existent in commercial codes.Discussions about the convergence rate of nonlinear iterative processes,an estimation of the rate and a study of the parameters of the RCA algorithm are presented.To show the capacity of the algorithm to adjust the increment size,detailed discussions based on results for different limit load analyses are presented.The results obtained by RCA algorithm are compared with those by ABAQUS?,one of the most powerful nonlinear FEA(Finite Element Analysis)commercial software,in order to verify the capability of RCA algorithm to adjust the increment size along nonlinear analyses.

Biodiesel production by hydroesterification of microalgal biomass using heterogeneous catalyst

This paper assesses the hydroesterification process for the production of Biodiesel from Monoraphidium contortum (MORF-1) microalgae biomass, as it is a sustainable alternative not only economically, but also environmentally and ecologically to replace petroleum diesel fuel. The Biodiesel studied in this work was obtained from fatty acid esterification, a product of microalgae and methanol biomass hydrolysis reaction. CBMM’s (HY-340) niobium oxide powder was used as catalyst. The reactions were carried out in a properly closed autoclave reactor (batch), where the reagents were mixed under constant stirring at 500 rpm for hydrolysis and esterification. The products generated were submitted to gas chromatography and oxidative stability analysis. The hydroesterification process showed itself to be a promising alternative to the conventional biodiesel production process (transesterification) as it favors the use of feedstocks with any acidity and moisture content and may be performed with acid catalyst, which favors high conversions in a small range of time (30 minutes).

A Novel Approach for Inferring the Proportion of Terrestrial Organic Matter Input to Marine Sediments on the Basis of TOC:TN and δ¹³C_orgSignatures

The ratio of total organic carbon to total nitrogen (TOC:TN) and the stable carbon isotope ratio of organic matter (δ13Corg) are widely applied for inferring the origin of organic matter (OM) in Quaternary marine sediments. A plot of TOC:TN vs. δ13Corg is useful for such studies but is strongly based on qualitative constraints. This study is based on the qualitative characterization of the source of Quaternary OM via analysis of TOC:TN and δ13Corg signatures, but also proposes a probability parameter, which combines both signatures, to infer the amount of Terrestrial OM Input (TOMI). This index provides a method for quantifying the proportion of terrestrial OM vs. marine OMin a more comprehensive manner. The TOMI index concept was applied to a study area in theJoetsuBasin, eastern margin of theJapanSea, where previous studies have characterized theOMfrom the Last Glacial Maximum (LGM) to the present. The upwards increase in TOC indicates thatOMproduction during the Holocene was higher than during the LGM. The enriched δ13Corg signature upwards and decrease in TOC:TN suggest predominantly marine phytoplankton OM during the Holocene. Throughout the LGM, low OM production with depleted δ13Corg values and high TOC:TN values in the sediments suggest a predominantly C3 terrestrial plant source for the OM. Using these data, it was possible to calculate a proxy for a sea level variation curve during that period and to investigate the influence of the proximity of the coastal line to the continental slope on the input of terrestrial material to the basin. The proposal provides information for the application of sequence stratigraphic concepts. The TOMI index could confirm that the proximity to the shoreline and shelf break has a strong influence on the input of terrestrial material during lowstand periods.

Evidence of An Early Cretaceous Giant Dyke Swarm in Northeast Brazil(South America):A Geodynamic Overview

The Mesozoic break-up and drifting of the Equatorial Atlantic margin in the northeast Brazil(South America)is characterized by a modest magmatic activity compared with the Southern Atlantic margin,where the Paraná-

Alternative System of Industrial Paint Applied to Spherical Mount for Liquefied Petroleum Gas

The present article reports the application of zinc ethyl silicate paint and the use of internal and external paint schemes on carbon steel spheres for the storage of liquefied petroleum gas. The new paint scheme eliminates the steps of blasting in the field and minimizes the collection of waste generated and the environmental impact, reducing the service time onsite and therefore providing a productivity gain and better health and cleanliness at work. The results were obtained through test runs and qualified in bodies-of-proof made with the same characteristics as the sphere, that is, using the same material (carbon steel), thickness, and mechanical formation and subject to the same conditions of design and implementation process. The paint scheme was approved, qualified, and committed to the supplier’s warranty with the paint manufacturer and assembler of the storage spheres for liquefied petroleum gas.

Process Temperature Profile and Rheological Properties of Greases from Vegetable Oils

Greases are composed by lubricating oil dispersed in a thickener that can be a metal soap, polymers or clays. Grease production using vegetable oils is increasing due to biodegradability requirements. Since vegetable oils present a worse oxidation and hydrolysis stability than mineral oils, it is usually difficult to produce a neutral grease using them. Four greases were produced using soybean oil as lubricating oil and lithium 12-hydroxy- stearate as thickener. The maximum temperature of reaction ranged from 230°C to 120°C in a bench process and a reduction in the final product acidity was observed (from 8.2% acid to 0.05% alkaline). Traditional tests to evaluate thickener structure resistance like 10,000-time worked penetration, roll stability and dropping point were performed and results compared. In addition, rheological tests were performed and the results were also compared. Results indicate that it is possible to produce a quite neutral grease using vegetable oils with good thickener structure properties.

Characterization of the Lipid Components in <i>Desmodesmus</i>and <i>Scenedesmus</i>Strains: Lipid Content, Lipid Classes and Fatty Acid Profile

The lipid composition in terms of the amount of neutral lipids, free fatty acids and polar lipid content is of great importance to make full use possible of this fraction and to define the suitability of its application, either as a raw material for fuel production, nutraceutical purposes or feed. In addition to the fatty components present in the lipid extract, other components may be included, such as: carotenoids, pigments and sterols. The microalgae studied in this work, Scenedesmus sp. and Desmodesmus sp., were subjected to the same growth conditions and evaluated for lipid content, quantification and diversity of lipid components as well as its fatty acid profile. For lipid determination two extraction methods were compared: the J: Schmid-Bondzynski-Ratzlaff and Bligh & Dyer method. For Desmodesmus sp. 5.43% ± 0.41% and 9.18% ± 0.33% of lipids were obtained on an ash-free dry weight basis and for Scenedesmus sp. 12.46% ± 0.38% and 8.16% ± 0.42% of lipids were obtained on an ash-free dry weight basis using for both methods J: Schmid-Bondzynski-Ratzlaff and Bligh & Dyer, respectively. For the identification of the main lipid components present in the extracts, the Thin layer chromatography (TLC) technique was used. This made it possible, using a simple and inexpensive method, to identify the compounds extracted by different extraction methods, that is, it was possible to verify the selectivity of the different extraction methods. In addition, it has been shown that using these methods, widely described in the literature as methods of extracting lipids in practice, extracts a wide diversity of compounds. The major lipid class for both microalgae was fatty acids with amounts between 23.62% - 38.02%. The triglycerides percentage in biomasses without chemical treatment did not exceed 18.26%. In the lipid extract obtained with Bligh & Dyer, the microalgae Desmodesmus sp. presented 55.26% of unsaponifiable material, higher than the amount present using the same extraction method for Scenedesmus sp. 49.06%. Among the main unsaponifiables identified are hydrocarbons (carotenes) and sterols esters. The acid treatment of biomass, method J: Schmid-Bondzynski-Ratzlaff, showed selectivity of 72.84% and 76.66% for obtaining fatty material from the microalgae Desmodesmus sp. and Scenedesmus sp., respectively. The results showed that depending on the method used for extraction, the lipid fraction will be different in relation to the percentage of fatty components.

Partial Availability and RGBI Methods to Improve System Performance in Different Interval of Time: The Drill Facility System Case Study

The main objective of this study is to propose a methodology to define the operational availability for a system in different interval of time based on Monte Carlo simulation. In addition, it is also an objective to identify critical equipment in such interval of time and define when carrying out inspections to detect and prevent failures. Nowadays, many software packages which apply Monte Carlo simulation based on reliability diagram block do not show the operational availability defined by interval of time. In most of cases, there’s no result that shows how system performs in specific interval of time. Depending on situation, it’s important to define the operational availability by different interval of time in order to follow up system performance along time. In order to solve such problem, it is proposed the “partial availability methodology” based on system age. Indeed, such method regards equipment age based in different period of time that will results in Partial Availability. That means, as instance, in case of two years of simulation there will be the cumulative operational availability and partial operational availability results for first and second years for example. Therefore, it is also important to define the inspection time in each interval of time (year) in order to detect possible equipment failure and define preventive maintenance to avoid such failures that will be performed by RGBI method. In order to show such methodologies, it will be carried out a drill facility case study which is required to define operational availability of the system on the first and second years as well as inspection time.

Flywheel and Induction Motor Sizing for Torque Fluctuation Optimization in Reciprocating Compressor

Reciprocating compressors are prone to high cyclic loads. The high required performance relies on a good design focusing a torque oscillation applied by the driver. In the first part of this job, dynamic model of reciprocating is presented. Newton-Euler method is used to get motion equations. In the second part, numerical results are presented. Simulations are used for calculating the driving moment as function of crankshaft motion. These results illustrate the effect of the flywheel and motor on its dynamics and are used for induction motor selection and flywheel sizing for optimizing crankshaft torque fluctuation and power consumption reduction.

Prioritizing Alarms in Real-Time： Intelligent Alarms Advanced System

During the operation of complex process, such as oil production or refming, abnormal situations may occur, leading to an alarm flooding. Alarm flooding is the signalling of a large number of alarms in a few minutes, in such a way that it is impossible for the operator to attend to all alarms. On these occasions, it is usual that the operator leaves the alarm summary list and gets an analysis of the plant through the screens of the DCS （digital control system）, seeking to understand the situation. The alarm summary list ceases to be a useful tool. In such cases, the operator might have the aid of a filter that would present the highest priority alarms and other information associated with them, enabling him to gain a better knowledge of the situation. This paper describes the interface of a system aimed to help the operator to have a more comprehensive knowledge of the process （a better situational awareness） during process upsets that cause alarm flooding, recovering the utility of the alarm layer to the safety of industrial processes.

Performance of Compact Radial Basis Functions in the Direct Interpolation Boundary Element Method for Solving Potential Problems

This study evaluates the effectiveness of a new technique that transforms doma in integrals into boundary integrals that is applicable to the boundary element method.Si mulations were conducted in which two-dimensional surfaces were approximated by inter polation using radial basis functions with full and compact supports.Examples involving Poisson’s equation are presented using the boundary element method and the proposed te chnique with compact radial basis functions.The advantages and the disadvantages are e xamined through simulations.The effects of internal poles,the boundary mesh refinemen t and the value for the support of the radial basis functions on performance are assessed.

Suiting Dynamic Models of Fixed-Bed Catalytic Reactors for Computer-Based Applications

This work investigated the applicability of heterogeneous and pseudo-homogeneous models to predict the dynamic behavior of a fixed-bed catalytic reactor. Some issues concerning the dynamic behavior of the system were discussed, such as the prediction of the inverse response phenomenon. The proposed models (Het- erogeneous I and II and Pseudo-homogeneous) were able to predict with qualitative similarity the main characteristics of the dynamic behavior of a fixed-bed catalytic reactor, including the inverse response. The computational time demanded for the solution of the heterogeneous models was 10 to 50% longer than in the case of the pseudo-homogeneous model, making the use of the former suitable for applications where computational time is not the major restriction (off-line applications). On the other hand, when on-line applications are required, the simplified model (Pseudo-homogeneous model) showed to be a good alternative because this model was able to predict (qualitatively) the dynamics of the reactor using a faster and easier numerical solution.