East Brae Research Articles

Sonar Metering Optimizes Production in Liquid-Loading-Prone Gas Wells

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 166652, ’Use of Sonar Metering To Optimize Production in Liquid-Loading-Prone Gas Wells,’ by C.A. Shields and M. Dollard, Marathon Oil UK, and S. Sridhar, G. Dragnea, and M. Illingsworth, Expro Meters, prepared for the 2013 SPE Offshore Europe Oil and Gas Conference and Exhibition, Aberdeen, 3-6 September. The paper has not been peer reviewed. This paper discusses the use of clamp-on sonar flowmeters to minimize losses associated with well testing and to gain the subsequent benefits seen with respect to production optimization and well deliquefication. Clamp-on sonar flowmetering is a nonintrusive technology that measures the flow velocity of the fluid stream. This intensive well-management strategy has assisted in reducing the production decline of the East Brae field in the North Sea. Introduction The East Brae platform (Fig. 1) is located 275 km northeast of Aberdeen in Block 16/3a in a water depth of 110 m. The reservoir comprises high- permeability sands deposited by turbidity currents. The reservoir has an average porosity of 17% and an average permeability of 558. md. The platform initially started producing condensate, while reinjecting the gas, in December 1993. Exporting of the gas began in 1994, and reinjection was phased out. The current topside holds a low- pressure (LP) separator (test separator) operated at 217 psig, a high-pressure (HP) separator (first-stage separator) currently operated at 406 psig, and second- and third-stage separators. It also includes a gas-processing and - dehydration plant, three gas-compression trains, and produced-water-processing facilities for discharge into the sea. There are currently 12 producing monobore wells on the East Brae platform. Former gas-injection wells have now been converted to producing wells. The wells are inclined up to a maximum deviation of 45°. The reservoir fluid is a retrograde gas condensate that exhibits compositional variation with depth. The reservoir has an active aquifer that has encroached into the producing layers as reservoir pressure has depleted through production. Background: Allocation and Well Testing On the East Brae platform, production allocation for the wells has typically been carried out by individual well tests of each well in the test separator on a monthly basis. The well test records the amount of oil and gas produced from a well during the first stage of separation. The oil and gas are then processed further in the plant. Some of the oil is vaporized into the gas phase as it is stabilized in lower-pressure separators, and some of the gas is liquefied as it is cooled and compressed. As a result of these equilibrium changes, the oil and gas rates exported from the platform (known as its “potentials”) that are attributable to a single well are not directly comparable with the oil and gas rates measured at the test separator for that well.

The East Brae Field, Blocks 16/03a, 16/03b, UK North Sea

Abstract The East Brae gas condensate field is the most northern of the four Upper Jurassic fields operated by Marathon Oil UK Limited in the UK North Sea. The field lies at the western margin of the South Viking Graben in UK Blocks 16/03a and 16/03b. The field was discovered in 1980 and commenced production in December 1993 from the East Brae platform. Recoverable reserves are estimated as 242 MMBBL of condensate and 1530 BSCF of sales gas.

The North Brae and Beinn Fields, Block 16/7a, UK North Sea

Abstract North Brae is located in Block 16/07a, and was discovered in 1975 by Pan Ocean Oil Company. The field was purchased by Marathon Oil Company in 1976 and was delineated in the early 1980s. Production by gas recycling was commenced in 1988. Liquid reserves are estimated at 207 MMBBLs with recoverable dry gas of 800 BCF. The North Brae Field is one of three gas/condensate fields in the Brae fields area of the South Viking Graben in the UK Sector of the North Sea. The reservoir is part of a large turbidite and debris flow, submarine fan system that also encompasses the East Brae and Kingfisher fields to the northeast of North Brae. North Brae is located at the proximal end of this fan system, and channelized massive conglomerates and sandstones characterize its reservoirs. The stratigraphy of the fan system was influenced by highly variable changes in relative sea level that controlled sediment input. Structural activity was also important, such as syn-sedimentary normal faulting related to the subsidence of the South Viking Graben, and structural inversion, in a series of regional compressive episodes commencing in the Late Jurassic and Early Cretaceous.

ABSTRACT: 3-D Geologic Model of Permeability in a Deep-Water Sandstone, East Brae Field, North Sea

ABSTRACT: 3-D Geologic Model of Permeability in a Deep-Water Sandstone, East Brae Field, North Sea

ABSTRACT: 3-D Geologic Model of Permeability in a Deep-Water Sandstone, East Brae Field, North Sea

ABSTRACT: 3-D Geologic Model of Permeability in a Deep-Water Sandstone, East Brae Field, North Sea

Abstract: Quantification of Quartz Cement and Pressure Solution Volumes, East Brae Field, Offshore UK 

Abstract: Quantification of Quartz Cement and Pressure Solution Volumes, East Brae Field, Offshore UK 

Abstract:Quantification of Quartz Cement and Pressure Solution Volumes, East Brae Field, Offshore UK

Abstract:Quantification of Quartz Cement and Pressure Solution Volumes, East Brae Field, Offshore UK

WIND VORTEX-INDUCED VIBRATION OF STRUCTURAL MEMBERS IN A STEEL TOWER: A CASE HISTORY.

Gas is flared offshore on the East Brae oil production platform via a 124 m long, inclined flare boom. Each of the tubular elements of the flare boom could, under certain wind conditions, vibrate due to the forces induced when vortices are shed from the member. When members on the flare boom were assessed for wind vortex-induced vibration to Health and Safety Executive (HSE) guidelines, many were predicted to have high levels of vibration leading to low fatigue lives. Selected flare boom members were instrumented. Actual member natural frequencies and damping were measured and accelerometers were fitted to selected members to monitor vibrations. The results showed that narrow-band response was not occuring and broad-band response was significantly less than that predicted by the HSE guide method. The maximum measured broad-band responses were typically of the of 20 tio 30% of the predicted maximum response at the critical velocity. Tentative reasons for this variation in response are offered.

A Revised Hypothesis for the Structural Evolution of the East Brae Region of the South Viking Graben, North Sea : ABSTRACTS

A Revised Hypothesis for the Structural Evolution of the East Brae Region of the South Viking Graben, North Sea : ABSTRACTS