Removal of Wax Deposits in Flexible Pipelines by Electrical Heating

2000 ◽  
Author(s):  
Marcelo de Albuquerque Lima Gonçalves ◽  
Carlos Henrique da Silva Dittz
Keyword(s):  
Electrical Current ◽  
Electrical Heating ◽  
Heating Process ◽  
Southern Brazil ◽  
Oil Pipeline ◽  
Flexible Pipes ◽  
Campos Basin ◽  
Offshore Oil Production ◽  
Wax Deposits ◽  
Offshore Oil

In offshore oil production, sometimes unexpected situations may occur, resulting in full blockage of a subsea oil pipeline. The blockage is often due to wax freezing in cold sea. In such cases the solution is to remove the blocked oil pipeline from the subsea. In Campos Basin, Brazil, the launcher ship brings the pipelines to the Vitória Harbor, E.S (southern Brazil). The solution adopted there for blockage removal is the application of differential pressure to promote block displacement. The maximum allowed pressure is equal to the rating pressure for the pipeline, but sometimes it is not enough to move the wax core. A new solution has been developed to allow the recovery of those flexible pipes. It consists of an electrical heating process to melt the wax residues. The electrical current circulates through a metallic layer of the flexible pipeline. This solution was accomplished with success and more than 20 km of pipelines have already been recovered. This paper presents the numerical simulation and the experimental results of a flexible pipeline reel electrical heating operation and the method to control it.

Flexible Pipe Integrity Management

2003 ◽  
Author(s):  
Luiz Souza ◽  
Salvador Filho ◽  
Marcos Carpigiani ◽  
Jeter Freitas
Keyword(s):  
Composite Structures ◽  
Production Systems ◽  
Flexible Pipe ◽  
Oil Companies ◽  
Long Period ◽  
Flexible Pipes ◽  
Offshore Oil Production ◽  
Integrity Management ◽  
Offshore Oil ◽  
Production Industry

At present, flexible pipes are used worldwide to conduct several fluids within the offshore oil production industry. These flexible pipes are complex composite structures made up of several plastic and steel layers. They are intended to work for a long period of time, something around 20 years. Although the flexible pipes behavior is satisfactory in most applications, they are susceptible to simple damages, for example on the external sheath, which much reduces their service life. The offshore inspection activities are extremely expensive and, given that, these activities need to be very well oriented in order to be effective. This paper describes the Risk Based Inspection Methodology, which is a helpful applicable tool in the integrity management of several flexible pipe systems, allowing to concentrate the efforts where they are really needed. This methodology may be used by the oil companies to reduce overall costs and enhance safety and integrity of the production systems.

FPSO: Tanks Optimization Design Approach

2005 ◽  
Author(s):  
Jose M. Vasconcellos ◽  
Antonio C. Fernandes ◽  
Alberto Santos ◽  
Marcos D. A. S. Ferreira
Keyword(s):  
Optimization Design ◽  
Load Condition ◽  
Optimization Procedure ◽  
Oil Fields ◽  
Design Approach ◽  
Campos Basin ◽  
Offshore Oil Production ◽  
New Ideas ◽  
Offshore Oil ◽  
Stress Minimization

Brazil Campos Basin is under large offshore oil production activity. Many new giant oil fields are under development. Brazil has been using tankers ship converted as FPSO platform vessel. At this moment three FPSO are in final construction phase to be installed in Campos Basin. Many oil cargo tankers are transformed to work as FPSO. Although they are showing good characteristics, some problems are having been emerging. The turret design approach was used in the primary FPSO’s but recently the spread mooring system with rigid risers is also under installation in Campos Basin. New ideas about Floating Production Storage and Offloading (FPSO) system have been in focus since some projects started working in an appropriately FPSO design direction. This paper spotlights one of these ideas: the FPSO tankers arrangement as a possible optimization procedure. MARPOL rule is followed but an alternative procedure is suggested to consider vessel control under wave’s action and at the same time looking for stress minimization. The aim in this procedure is increase the operator capability. The idea is allow the FPSO operator change the load condition using ballast in segregated tanks assuring a more suitable vessel condition in waves. Stability, wave response, stresses and operation ability should be also merit functions in any optimization process. A box shape FPSO-BR is used to highlight the procedure application. Results are presented and conclusion pointed out.

Development and Application of Electrical-Joule-Heating Simulator for Heavy-Oil Reservoirs

SPE Journal ◽  
2016 ◽  
Vol 21 (01) ◽  
pp. 87-100 ◽  
Author(s):  
Hamid R. Lashgari ◽  
Mojdeh Delshad ◽  
Kamy Sepehrnoori ◽  
Eric de Rouffignac
Keyword(s):  
Electrical Conductivity ◽  
Joule Heating ◽  
Water Saturation ◽  
Saline Water ◽  
Electrical Potential ◽  
Electrical Energy ◽  
Electrical Current ◽  
Electrical Heating ◽  
Heating Process ◽  
Reservoir Simulator

Summary In the electrical-Joule-heating process, the reservoirs are heated in situ by dissipation of electrical energy to reduce the viscosity of oil. In principle, electrical current passes through the reservoir fluids mostly because of the electrical conductivity of saturated fluids such as saline water. The flow of electrical current through the reservoir raises the heat in the reservoir and thereby dramatically reduces the oil viscosity. In this process, electrical current can flow between electrical-potential sources (electrodes) in wells, and then electrical energy is dissipated to generate the heat. Therefore, the regions around the electrodes in (or around) the wells are extremely heated. Because the wells act as line sources for the electrical potential, greater heating takes place near the wellbore, causing possible vaporization of water in that region. Because steam has very-low electrical conductivity, it can reduce the efficiency of this process significantly. In this process electrical conductivity plays a very important role. To increase efficiency of this type of heating process, the presence of optimum saline-water saturation is an essential factor. To model the electrical Joule heating in the presence of multiphase-fluid flow, we use three Maxwell classical electromagnetism equations. These equations are simplified and assumed for low frequency to obtain the conservation of the electrical-current equation and Ohm's law. The conservation of electrical current and Ohm's law are implemented by use of a finite-difference method in a four-phase chemical-flooding reservoir simulator (UTCHEM 2011.7). The Joule-heating rate caused by dissipation of electrical energy is calculated and added to the energy equation as a source term. The formulation and implementation of electrical heating are validated against a reference analytical solution and verified with a reservoir simulator. A typical-reservoir model is built, and constant electrical potential with alternating current is applied to the model to study the efficiency of the electrical-heating process properly. The efficiency of this process is evaluated in the presence of water-saturated fractures and evaporation effect. Results illustrate that water saturation in the presence of fractures and electrical conductivity of saturated rock have an important effect on the Joule-heating process. The importance of the fractures saturated by saline water and operation of such processes below the boiling point are key findings in this paper to obtain high recovery in comparison with other conventional-thermal-recovery methods.

Optimization of well product pumpless transportation under offshore oil production conditions

2017 ◽  
pp. 140-142
Author(s):  
A.G. Akhmadeev ◽  
◽  
Pham Thanh Vinh ◽  
Bui Trong Han ◽  
Le Huu Toan ◽  
...  
Keyword(s):  
Oil Production ◽  
Offshore Oil Production ◽  
Offshore Oil ◽  
Production Conditions

scholarly journals A Lagrange Relaxation Based Decomposition Algorithm for Large-Scale Offshore Oil Production Planning Optimization

Processes ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 1257
Author(s):  
Xiaoyong Gao ◽  
Yue Zhao ◽  
Yuhong Wang ◽  
Xin Zuo ◽  
Tao Chen
Keyword(s):  
Production Planning ◽  
Large Scale ◽  
Oil Production ◽  
Original Model ◽  
Decomposition Algorithm ◽  
Scale Model ◽  
Lagrange Relaxation ◽  
Planning Optimization ◽  
Offshore Oil Production ◽  
Offshore Oil

In this paper, a new Lagrange relaxation based decomposition algorithm for the integrated offshore oil production planning optimization is presented. In our previous study (Gao et al. Computers and Chemical Engineering, 2020, 133, 106674), a multiperiod mixed-integer nonlinear programming (MINLP) model considering both well operation and flow assurance simultaneously had been proposed. However, due to the large-scale nature of the problem, i.e., too many oil wells and long planning time cycle, the optimization problem makes it difficult to get a satisfactory solution in a reasonable time. As an effective method, Lagrange relaxation based decomposition algorithms can provide more compact bounds and thus result in a smaller duality gap. Specifically, Lagrange multiplier is introduced to relax coupling constraints of multi-batch units and thus some moderate scale sub-problems result. Moreover, dual problem is constructed for iteration. As a result, the original integrated large-scale model is decomposed into several single-batch subproblems and solved simultaneously by commercial solvers. Computational results show that the proposed method can reduce the solving time up to 43% or even more. Meanwhile, the planning results are close to those obtained by the original model. Moreover, the larger the problem size, the better the proposed LR algorithm is than the original model.

Tacit knowledge and risk perceptions: Tullow Oil and lay publics in Ghana’s offshore oil region

2017 ◽  
Vol 27 (2) ◽  
pp. 197-213 ◽  
Author(s):  
Sylvester Senyo Ofori-Parku
Keyword(s):  
Risk Perceptions ◽  
Practical Knowledge ◽  
Petroleum Industry ◽  
Risk Process ◽  
Theoretical Contribution ◽  
The Social ◽  
Offshore Oil Production ◽  
Local Residents ◽  
Fish Harvest ◽  
Offshore Oil

This study examines how local residents make sense of offshore oil production risks in Ghana’s nascent petroleum industry. From a naturalistic-interpretive perspective, it is primarily based on in-depth interviews with community residents: 8 opinion leaders, 15 residents, and 1 journalist. Residents associate Tullow’s oil activities with health concerns (e.g. conjunctivitis), environmental challenges (e.g. the emergence of decomposed seaweeds along the shore), and socio-economic concerns (e.g. loss of livelihoods, decline in fish harvest, and increased rent and cost of living). Focusing on how the local, practical knowledge of interviewees manifest in their sense of offshore oil risks, the study identifies two strategies—scapegoating and tacit knowing—underlying how residents construe offshore oil risks and benefits. Beyond its theoretical contribution to the social construction of risk process, the study illustrates the challenge the expert-lay publics dichotomy poses (and the potential bridging this dichotomy has) for corporate and societal risk management.

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