Widuri field, offshore Southeast Sumatra: sandbody geometries and the reservoir model

Young, Roger A.; Harmony, W. E.; Juniarto, Gunawan; Thomas, Budiyento

doi:10.29118/ipa.2177.385_1991

Cited by 7 publications

(3 citation statements)

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“…The target reservoir was a thin sand body, medium grain size, clean sand, deposited in a fluvial environment (Figure 1). It is characterized by a very high permeability in the order of 1 to 2 Darcy, 29% porosity, moderate consolidation and sand production tendency 15 . This reservoir lies at 3500 -3600 ft TVD and has an original reservoir pressure of 1350 psi.…”

Section: Field Characteristicsmentioning

confidence: 99%

Frac-Packing Openhole Completions: An Industry Milestone

Saldungaray¹,

Juan²,

Sofyan³

et al. 2002

Proceedings of International Symposium and Exhibition on Formation Damage Control

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TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractAlthough frac-packing has been widely and successfully used in cased-hole completions, open-hole frac-packing is not so common. It is well known that the efficiency of cased-hole frac-packs can be limited by the perforations. It can therefore be expected that open-hole frac-packing would provide higher productivity by eliminating a major choke in the flow path. In this paper, we present an open-hole frac-pack case history involving a highly-deviated, challenging well in South East Asia and demonstrate the expected efficiency gains.The well was drilled in a field with a major water-flooding program. Due to extremely low reservoir pressure, low fracture-gradient and high kh formation (100,000 md-ft), very high losses were experienced. The presence of a highpressure, reactive shale above the pay zone made it necessary to prematurely run a 7-in casing in order to isolate the problematic zone. However, due to the collapse of the reactive shale section, the casing was set above the target depth thereby exposing 70-ft of shale zone. Initial attempts to run the completion assembly failed due to the collapsed shales, resulting in a suspension of the well. After 4-months of waterflooding, partial re-pressurization of the reservoir was expected, and consequently a decision was made to complete the well with the open-hole frac-packing technique. In order to address complete coverage in a high kh zone completed as open-hole, the shunt technique was used. In order to prevent reactive shales from collapsing and mixing with the proppant during frac-packing, a cup-type packer was set inside the casing to divert flow through the shunt tubes and thus bypass the shale section. These procedures resulted in a complete pack of the entire, highly deviated open-hole interval, with an optimized tip screen-out as per design. The resulting PI of 13.4 bpd/psi compares favorably to cased-hole frac-packs (average PI of 2.5 with a best PI of 5.8), cased-hole gravel packs (average PI of 2.3 with a best PI of 4.7) and open-hole gravel packs (average PI of 10.0 and best PI of 19.6) in the same field, particularly considering the extremely high losses (thus the extent of damage) experienced during the drilling stage of this well.Detailed procedures are given along with operation execution and production results. An extension of this technique to long open-hole horizontal wells (injectors and producers), using modified tool configurations, is also discussed. IntroductionFrac-packing has been a popular sand control technique since the early 1990's 1, 2 and proven to provide high productivity and reliable completions 3 . The average skin value for these completions was reported to be close to 3 with a range of 2 to 10 (ref. 4), resulting in flow efficiencies 2.5 to 3 times of those obtained with gravel packs 3 . With the introduction of fracturing with water (also referred to as high rate water packs, HRWP) as a sand control technique, emphasis for productivity comparisons switched to performance of ...

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Section: Field Characteristicsmentioning

confidence: 99%

Frac-Packing Openhole Completions: An Industry Milestone

Saldungaray¹,

Juan²,

Sofyan³

et al. 2002

Proceedings of International Symposium and Exhibition on Formation Damage Control

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“…?about 3500 km 2 with a sediment thickness up to 16,000 feet which was formed in the Paleocene to Pleistocene (Sukanto et al, 1998). The oilfields in the Asri Basin are dominated by structural traps and a combination of stratigraphic traps (Young et al, 1991). Kusuma (2010) states that the reservoir in the Gita member, part of Talang Akar Formation, is consist of…”

Section: Introductionmentioning

confidence: 99%

Application of Spectral Decomposition and RGB Blending for Delineation of “S” Channel At Asri Basin

Piranti

Zulivandama²,

Aryanto³

et al. 2020

BoMG

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Gita member is part of Talang Akar Formation is known as hydrocarbon reservoir at Asri Basin, eastern part of South Sumatra. This formation consists of several depositional systems such as braided channel, meandering channel, fluvial-deltaic, and estuarine system. A channel system was an interesting system developed in the Asri Basin, however, to get the channel distribution in Asri Basin is quite challenging because the thickness of the channels caused its appearance is generally close or under seismic resolution, the existence of coal below our target also affects the impression of “S” sand on seismic data. In this study, spectral decomposition and RGB Blending have been successful to identify “S” sand. RGB Blending map is extracted from 15 Hz as low frequency, 45 Hz as middle frequency, and 75 Hz as high frequency. Our interpretation was applied at RGB Blending map and reveal the “S” sand is classified as a meandering channel depositional system with the main direction of the channel is Northeast – Southwest.

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“…The main producers in the Widuri field are the 34-2 and the 35-1 sandstone reservoirs. In these reservoirs, the log porosities average 29% and permeability ranges up to 30 Darcies (Young et al, 1991). The 34-2 sandstone is erosive on top of Coal A, which is an extensive coal layer seen on the seismic over the bulk of the field.…”

Section: Field Descriptionmentioning

confidence: 99%

Time-Lapse Simultaneous AVO Inversion of the Widuri Field, Offshore Southeast Sumatra

Harmony¹,

Eykenhof²,

Harvidya³

et al.

Proc. Indon Petrol. Assoc., 29th Ann. Conv.

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Reservoir characterization of the Widuri field, offshore SE Sumatra, is complicated by complex lithology and difficulties in predicting changes in fluid distribution during production. In 2000, a monitor 3D seismic data set of the Widuri field was acquired and processed to take advantage of seismic AVO effects. The base line 1991 seismic data set was reprocessed in parallel. The primary reason for the monitor data set was to observe the reservoir pressure depletion state around a waterflooding project. Furthermore there was a need to improve the characterization of the reservoir sands and to develop a better understanding of the fluid movement over time. To support AVO based reservoir characterization the base line and monitor seismic data were processed to 3 partial angle stacks. These were subsequently inverted to acoustic and shear impedance using a global, Simultaneous AVO Inversion algorithm. Resultant multi-parameter impedance based reservoir characterization from well log data and the impedance inversion results show that sands and coals in the reservoir interval can now be discriminated. Previously, reliable interpretation of these lithologies away from well control from poststack seismic data was infeasible as the acoustic impedance of these lithologies overlap. To investigate and characterize fluid movement, a novel workflow involving joint Simultaneous AVO Inversion of baseline and monitor seismic data was applied. The results from the time-lapse AVO inversion confirm the hypothesis based on production history analysis that aquifer support comes from the SouthEast. The same technique is successfully used to map more specific features related to depletion. As a result of production, increased water cut was observed at most of the wells. In addition to this, pressure dropped below bubble point with gas coming out of solution, which accumulated at structural highs. Both factors influence production and are potential drilling risks for newly planned wells.

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Widuri field, offshore Southeast Sumatra: sandbody geometries and the reservoir model

Cited by 7 publications

References 0 publications

Frac-Packing Openhole Completions: An Industry Milestone

Frac-Packing Openhole Completions: An Industry Milestone

Application of Spectral Decomposition and RGB Blending for Delineation of “S” Channel At Asri Basin

Time-Lapse Simultaneous AVO Inversion of the Widuri Field, Offshore Southeast Sumatra

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