Control of Scaling in the South Brae Field

Hardy, Jeff; Barthorpe, R.T.; Plummer,; Rhudy, J.S.

doi:10.4043/7058-ms

Cited by 14 publications

(3 citation statements)

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“…Sulphate removal technology (SRT) has been used in the petroleum industry for sulphate scale prevention since the early 1990's. 16 Sulphate removal for prevention of souring was first investigated in 1994. 17 It is reasonable to expect that decreasing the sulphate concentration in seawater will decrease the mass of sulphide generated by SRB activity.…”

Section: Sulphate Removalmentioning

confidence: 99%

Adoption of a Process to Prevent Souring Associated with Seawater Waterflooding in the Ursa-Princess Fields, Deepwater Gulf of Mexico

McElhiney

Burger²,

Maxwell

et al. 2008

All Days

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A comprehensive evaluation of the potential for preventing reservoir souring through the use of Sulphate Rejection Membranes (SRM) was made for the Ursa-Princess Waterflood (UPWF), deepwater Gulf of Mexico. The operator, Shell Exploration and Production Company (SEPCO) has long believed that injection of seawater is a precursor to souring; the question is not 'if' but 'when' souring would occur. 1 Metallurgy of the producer well tubing, casing, safety valves and topsides is not consistently sour safe and retrofitting would have rendered the waterflood project economics unviable. Therefore, prevention of souring by SRM was investigated, evaluated and adopted in order to avoid retrofitting the metallurgy. This is the first time that an SRM has been selected by a major operator for a seawater waterflood project based primarily on prevention of souring, while accepting SRM as proven for scale control.

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Section: Sulphate Removalmentioning

confidence: 99%

Adoption of a Process to Prevent Souring Associated with Seawater Waterflooding in the Ursa-Princess Fields, Deepwater Gulf of Mexico

McElhiney

Burger²,

Maxwell

et al. 2008

All Days

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“…The removal of sulfate from seawater by nanofiltration has been employed as a means of scale control in several seawater waterfloods around the world (17). Historically, the sulfate removal units (SRU) were able to decrease the sulfate concentration to around 100 mg per L. Improvements in nanofilter technology now allow sulfate concentrations of 20m to 40 mg per L to be guaranteed (18).…”

Section: Sulfate Removalmentioning

confidence: 99%

Souring of Reservoirs by Bacterial Activity During Seawater Waterflooding

Maxwell¹,

Spark²

2005

Proceedings of SPE International Symposium on Oilfield Chemistry

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TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractWaterflooding with seawater for pressure support is to be employed in many of the deepwater Gulf of Mexico fields. Seawater flooding has been employed in the North Sea oilfields for over thirty years and, therefore, this region serves as a valuable source of case histories of the problems that can be encountered. It is now accepted that due to inadequate control of sulfate-reducing bacteria (SRB) the majority of the North Sea seawater floods resulted in souring of the reservoir.In some cases, hydrogen sulfide concentrations in the production wells have risen to the point where either the well has had to be shut-in or sulfide scavenging chemicals have had to be applied in order to prevent excessive corrosion. Where souring was not predicted, some production systems have had to be upgraded for sour service materials. These remedial actions have resulted in very significant unplanned costs. Although there is no formal published economic data, it is clear that over the history of the North Sea, the cost of lost production and remedial action has been $ 100's millions. This paper reviews the North Sea experience and discusses the models developed in an attempt to predict reservoir souring. The paper discusses the application of chemical biocides attempted to kill the SRB; the injection of nitrate to stimulate other bacterial populations to compete with the SRB for essential nutrients; and the potential for sulfate removal technologies to reduce sulfate and minimise sulfide production. A strategy for the development of future models to help predict and avoid reservoir souring in future seawater floods is also discussed.

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“…Modification of existing nanofiltration membranes to be sulphate specific in their rejection characteristics provided the capability to lower sulphate concentrations to the 100 mg/l concentration level. 8,9 Development of a new polyvinylsulfonate inhibitor provided endurance at high temperatures and was effective at high barium concentrations once sulphate concentrations were lowered into a manageable range. 10 At S. Brae an additional problem was encountered early-on before SRT was developed; raw seawater had to be injected to keep the reservoir above the bubble-point in some regions/layers.…”

Section: Introductionmentioning

confidence: 99%

Design of Low-Sulfate Seawater Injection Based Upon Kinetic Limits

McElhiney¹,

Tomson²,

Kan³

2006

Proceedings of SPE International Oilfield Scale Symposium

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TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractReliance on low sulphate seawater as sole protection against sulphate scale may be discomforting to some operators when such expensive subsea wells are at stake. Normal methods such as bullheading squeeze chemicals are nearly impossible to implement due to the long and sometimes multiple flow lines connecting injection wells. Subsea intervention to place squeeze inhibitors is prohibitively expensive due to the requirement of utilizing a service boat over the well for many days. 1 Calculations of scaling index from formation and injected seawater mixtures are routinely based upon the thermodynamics of the mixed brines. Although some mixing does occur in the interwell distance, the most vigorous mixing occurs in the vicinity of the production wellbore where water from multiple layers and streamlines impinge. These near wellbore mixtures have short residence times before being produced therefore reaction kinetics must be considered, and it is not clear how low the sulphate concentration in injected water needs to be to delay scaling downhole. This work offers a fresh look at this scaling problem by examining the kinetics of the mixed brines. Using data from existing field projects that currently inject desulphated seawater, the induction times required for non-scaling fluid transit up production wellbores are chosen, and the sulphate concentrations necessary to provide these induction times are computed from a software program. 2 The software algorithms are based on a broad, robust database of barite kinetics that span large variations in sulphate and barium concentrations, temperatures and salinities. 3 This protocol is compared to scaling index results computed from a thermodynamic approach at both bottomhole and wellhead conditions. A tandem role in which inhibitors can be utilized in conjunction with low sulphate seawater is described.

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Control of Scaling in the South Brae Field

Cited by 14 publications

References 0 publications

Adoption of a Process to Prevent Souring Associated with Seawater Waterflooding in the Ursa-Princess Fields, Deepwater Gulf of Mexico

Adoption of a Process to Prevent Souring Associated with Seawater Waterflooding in the Ursa-Princess Fields, Deepwater Gulf of Mexico

Souring of Reservoirs by Bacterial Activity During Seawater Waterflooding

Design of Low-Sulfate Seawater Injection Based Upon Kinetic Limits

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