Surge Pressure Analysis for Bijupira and Salema Water Injection System

Meliande, Patricia; Nascimento, Elson Antonio do; Dandoulakis, Joao Paulo; Massa, Andre Lupinacci

doi:10.4043/19365-ms

Cited by 3 publications

(1 citation statement)

References 2 publications

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“…Techniques for assuring well production have been continuously implemented, and one of them is known as "water injection", which consists of applying water flow in wells to guarantee enough pressure to raise oil and gas flow. In a previous paper [1] the authors described a transient analysis performed on the Bijupirá and Salema oil fields located in Campos Basin, Brazil.…”

Section: Introductionmentioning

confidence: 99%

Methodology for surge pressure evaluation in a water injection system

Meliande

Nascimento

Mascarenhas

et al. 2009

WIT Transactions on the Built Environment

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Predicting transient effects, known as surge pressures, is of high importance for offshore industry. It involves detailed computer modeling that attempts to simulate the complex interaction between flowline and fluid in order to ensure efficient system integrity. Platform process operators normally raise concerns as to whether the water injection system is adequately designed in order to be protected against possible surge pressures during sudden valve closure. This report aims to evaluate the surge pressures in Bijupirá and Salema water injection systems due to valve closure, through a computer model simulation. Comparisons among the results from empirical formulations are discussed and supplementary analysis for the Salema system was performed in order to define the maximum volumetric flow rate that the design pressure was able to withstand. Maximum surge pressure values of 287.76 bar and 318.58 bar, obtained using empirical formulations in Salema and Bijupirá respectively, have surpassed the operating pressure design, while the computer model results have shown the highest surge pressure value to be 282 bar in the Salema system.

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Section: Introductionmentioning

confidence: 99%

Methodology for surge pressure evaluation in a water injection system

Meliande

Nascimento

Mascarenhas

et al. 2009

WIT Transactions on the Built Environment

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Hydrate Blockage in Subsea Water Injection Wells - Causes and Preventive Procedures

Rodrigues

Frota

Loures³

et al. 2009

All Days

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Hydrate blockage has been a problem in Campos Basin subsea producer wells for a long time. Although hydrate formation was not expected in sea water injection wells there were some occurrences in Campos Basin. The formation of hydrate requires the presence of water and gas at low temperature and high pressure condition. As the subsea sea water injection wells always present water at low temperature and high pressure, the missing link to form hydrate is gas. Thus, to explain the occurrence of hydrate blockage in these wells one has to explain how and when gas enters into the well. A study was carried out to determine the causes of gas inflow into the injection strings and to make recommendations on the proper procedures and equipments to avoid hydrate blockage. The literature survey and the Campos Basin occurrences showed initially that gas segregation, water hammer effects and crossflow were the most probable causes for gas inflow during injection plant shutdowns or long time waiting for injection. The crossflow was ignored because the formations are homogeneous in all the cases. The water hammer effects were analyzed with a numerical simulator developed in the study. The final analyses revealed that gas segregation was the cause of hydrate blockage in the water injection wells studied. Other relevant conclusions are that down hole valves, such as deep subsurface safety valves and backflow valves are useless to prevent gas inflow and that water hammer effects can be managed in the sea water injection plant. This paper presents recommendations for water injection wells startups, regarding hydrate prevention, which can be useful for any subsea water injection project. Introduction Natural gas hydrates are solid structures composed of water and gas. Depending on the thermodynamic conditions, water molecules will form a solid cage entrapping gas molecules (Freitas et al. 2002). Hydrate blockage has been a problem in Campos Basin subsea producer wells since 1994. In Campos Basin the sea temperature decreases with WD showing values around 13°C at 300 m WD, 8.5°C at 500 m WD and varies in the range of 3.5°C to 4.5°C from 1,000 m to 2,000 m WD. In this scenario, hydrate may occur in water depth (WD) beyond 300 m (984 ft), even with small amounts of water and gas. The hydrate blockages often occur during operations such as production shutdown/startup. From 1994 to 2006 hydrate blockage was the main cause of rig intervention in the most prolific field of Campos Basin (Figure 1). Their occurrences in completion and workover have decreased in Campos Basin because of the preventive measures adopted. Besides causing production losses and requiring expensive rig interventions, hydrate blockages can put in risk the production system safety and the environment. This is because they can occur in the wet Christmas tree (WCT) valves, and in the subsurface safety valve control lines (Freitas et al. 2002). Analyses have shown that lack of attention to details in planning the operations and not following program and good practices are by far the main causes of the hydrate problems (Rodrigues et al. 2007). The first occurrence of hydrate blockage in water injection wells (WIW) in Campos Basin was in August 2000. Since then there were eight occurrences in seven wells, all requiring costly rig interventions. At the most penalized field it was decided to install downhole valves to prevent gas migration from the formation open zones up to the WCT valves. The recurrence of hydrate blockage in subsea WIW was the reason for this study. There are no publications about hydrate blockage in WIW to the best of our knowledge. However, there are good references about some probable causes of hydrate blockage that were raised in the early phase of this study. This is the case of water hammer (WH) effects.

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New method of predicting surge pressure apply to horizontal well based on casson flow*

Sun¹,

Zhao²

2010

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In order to predict the surge pressure caused in the horizontal well drilling process, a new simple and applicable method has been established. It is based on the general theory of hydrostatic drilling fluid mechanics, and specifically described the flowing physical model towards surge pressure in horizontal well annulus, taking the effect of string eccentricity on the flowing law of drilling fluid into consideration. According to the constitutive equation of casson-mode under one-dimensional steady flow and the equations of annular flow rate under different drill string working conditions, this paper introduced the flow rate computation models of axial laminar flow in eccentric annulus apply to horizontal well, of which the numerical model was calculated by the program called Mathematica, ultimately, a new model for surge pressure prediction towards each interval in horizontal well was put forward. Application examples indicated that it can solve questions easily and precisely, which presents important meaning of guidance to the safety control while horizontal well drilling

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Surge Pressure Analysis for Bijupira and Salema Water Injection System

Cited by 3 publications

References 2 publications

Methodology for surge pressure evaluation in a water injection system

Methodology for surge pressure evaluation in a water injection system

Hydrate Blockage in Subsea Water Injection Wells - Causes and Preventive Procedures

New method of predicting surge pressure apply to horizontal well based on casson flow*

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