This paper presents the experience brought from the oil-water subsea separatorproject developed for the Marlim field, known as SSAO Marlim. Here, it will beaddressed the inherent arising challenges from a project of a subsea separationequipment, from the subsea mechanical design perspective, with special focus tothe additional requirements to the normally presented in conventional subseaequipment for oil and gas production. It will be part of the discussion the architecture selected for the system andthe main challenges imposed by:–Separation process (gas-liquid, liquid-liquid and sand removal system);–Requirements for modularization, installation and retrieval of subseacomponents;–Installation concept. Introduction The oil-water subsea separator is installed in a water depth of approximately870m in the Marlim field, located in the Campos basin, Brazil. The subseaseparation station has an envelope of 29m length, 10.8m width, 8.4m height andan overall assembly weight in-air of 392ton, and it will receive productionfrom selected well, separate produced water from oil and sand and re-inject itinto Marlim production reservoir via a centrifugal pump. The water separationhappens into a Pipe SeparatorTM based on a gravitational concept, while waterpolishment to meet quality requirements, i.e. reduce oil content in water toacceptable levels for the re-injection into reservoir, is performed by cyclonicequipment. The equipment also has a sand management system which the main aimis to minimize the operational impact induced by solids production. Figure 1 illustrates the oil-water subsea separation system of Marlim.

The use of biogas generated in landfills has gained importance in developing countries like Colombia. Taking into account that this biogas presents poor combustion properties that make interchangeability with other combustible gases difficult, the elimination of gases and vapors, such as CO2 and H2O, through a cleaning process, in which the biogas is converted to biomethane, improves the biogas properties as a fuel gas for general use. In this work, we simulated the generation of biogas at El Carrasco sanitary landfill in Bucaramanga, using the US EPA (United States Environmental Protection Agency) landfill gas emissions model. Additionally, we simulated the biogas cleaning process to extract the remaining moisture using the ProMax software; for this, we used three different amines (MDEA, MEA, and DEA), followed by a glycol dehydration process. The results showed that the amine MEA produced the largest increase in the concentration of CH4 (90.37 %) for the biogas generated in the landfill. Furthermore, dehydration with glycol was an efficient process to obtain a gas with a high percentage of methane (91.47 %) and low water presence (1.27 %); this would allow the use of biomethane in conventional industrial combustion processes and power generation.

Historically, deepwater offshore Brazil underreaming operations in large hole sizes (bigger than 20 in.) were always considered a significant challenge due to the presence of hard, abrasive interbeded formations in these sections. These challenges were typically associated with premature underreamers cutting structure damage and with bottomhole assembly (BHA) or drillstring catastrophic failures. These situations have caused extra costs to operators to implement remedial solutions, such as enlarging a pre-drilled hole or performing expensive fishing operations.Downhole vibrations, along with underreamers' cutting structure durability had been the main villains in this type of operation. Recently, many options have been tried by operators and service companies including the selection of various drill bit types to improve drilling dynamics, and the use of nonconventional BHAs with underreamers in tandem to enhance the system's longevity. In spite of these efforts, the problems have remained.A total systems approach was implemented to overcome these problems in a particularly challenging application offshore Brazil, where in the closest offset seven underreamer runs were needed to enlarge 850 meters. As the goal was maximizing the likelihood of drilling and underreaming the entire section in a single run, the under-reamer was equipped with a specialized heavy-duty cutting structure design. The design consisted of an optimized blade profile with increased cutter density and the latest newest technology in PDC cutters with improved impact and abrasion resistance. Along with the fit-for-purpose underreamer design, it also utilized a concentric expandable stabilizer on top of the underreamer to reduce downhole vibrations and a real-time drilling dynamics service to monitor downhole torque, weight on bit and vibrations to adjust drilling parameters as needed during the operation.This concept was introduced for the first time in a big-bore project in Brazil. Proper planning and integration between the operator and service company resulted in drilling and underreaming 1,164 meters in a single run, with a total of 304 circulating hours. This accomplishment finalized the 18 1 8 -in. ϫ 22-in. section twenty days ahead of the planned AFE.

The paper focuses on the field life cycle and how new technology (including digital) and proactive, collaborative workflows can significantly optimize a field's production, with a focus on Brazil. Specifically, we discuss how, in the presalt, it is important to monitor casing integrity to identify salt creep and deformation as soon as possible. Proactive early identification of issues can accelerate the plugging and abandonment (P&A) decision at a stage where costs are reduced by avoidance of a more complex P&A caused by deformation of major completion components. Considering the complexity of a deepwater intervention, an innovative approach of through-tubing well surveillance was implemented, based on the third interface echo measurement provided by an advanced ultrasonic tool. The technique was deployed in some wells where the casing stress analysis indicated there was a risk of collapse, providing valuable information about casing and tubing integrity, as well as precise identification of annulus content. The paper intends to present local examples of the logs run, collaboration among technical experts, and the decisions made. The scope extends beyond the initial production period to maximizing production, when it is necessary to consider production issues as well as well integrity issues. The paper proposes that conventional KPIs may not measure the real intervention performance and can indeed detract from an optimal outcome. Most of the wells assessed were found with their integrity preserved, and therefore the production and/or injection, could continue. Where integrity issues were identified, the data gathered were used to redefine the intervention, allowing a safe temporary well suspension, assertive P&A planning, reducing the uncertainties, and facilitating communication with the regulatory agency. The paper will then discuss, during the barrel chasing phase of the field's life, how a better, collaborative alignment of the interests of all shareholders to the outcome of increased production can be achieved. Case studies reflect application of the technique in Brazil. The study demonstrates how to achieve the optimized field life cycle. New technology, including advanced digital workflows, has been applied to the challenge of well integrity assessment to examine casing deformation in Brazil. This has proven extremely important in early identification of issues to enable the most cost-effective remediation. New collaborative workflows initiated after well integrity optimization optimize production from existing well infrastructure to extend the field life cycle.