Reservoir Description and Static Model build in Heterogeneous Mauddud Carbonates: Raudhatain Field, North Kuwait

Azim, Shaikh Abdul; Al-Ajmi, Hussain Zuyed; Rice, Craig; Bond, Deryck; Abdullah, Shehab; Laughlin, B.A.

doi:10.2118/81524-ms

Cited by 14 publications

(4 citation statements)

References 8 publications

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“…Prior to start-up of full-field waterflood in the Mauddud reservoirs, water injection was tested in pilot schemes in both fields in order to assess the displacement and sweep efficiencies of water Abdul Azim et al, 2003). From the start of the pilots, a comprehensive static and dynamic dataset was collected with which to monitor actual water movement between the injecting and producing wells.…”

Section: Field Historymentioning

confidence: 99%

“…From the start of the pilots, a comprehensive static and dynamic dataset was collected with which to monitor actual water movement between the injecting and producing wells. The directions and rates of water movement have provided valuable information on Mauddud reservoir anisotropy and has significantly improved understanding of internal lateral and vertical reservoir connectivity and of the role played by fractures and high-permeability layers in reservoir performance (Abdul Azim et al, 2003).…”

Section: Field Historymentioning

confidence: 99%

“…Fracture permeability, and the role which fractures play in reservoir performance, is also often underestimated (see e.g. Abdul Azim et al, 2003). This often complicates recovery during water or gas flood by promoting early breakthrough of injection fluids and, if not predicted, necessitating shut-in of producing wells or the "premature" introduction of water or gas-handling capabilities.…”

Section: Application To Other Middle Eastern Reservoirsmentioning

confidence: 99%

“…Despite this long production history, these reservoirs are still at a relatively immature stage of development. As with many similar carbonate reservoirs in the Arabian Gulf, which have poor aquifers, it has eventually been necessary to implement water injection for pressure support (Abdul Azim et al, 2003). Under such circumstances, a detailed and accurate static description of the reservoir is a prerequisite for reservoir modelling and performance prediction, development planning, and effective reservoir management.…”

Section: Introductionmentioning

confidence: 99%

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Reservoir description of a mid-Cretaceous siliciclastic-carbonate ramp reservoir: Mauddud Formation in the Raudhatain and Sabiriyah fields, North Kuwait

Cross¹,

Goodall²,

Hollis³

et al. 2010

GeoArabia

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The mid-Cretaceous Mauddud Formation is the main producing carbonate reservoir in the Raudhatain and Sabiriyah fields of northern Kuwait. Historical field information and results from waterflood pilots indicate that reservoir performance in these reservoirs is controlled by geological complexity at several scales. A detailed, integrated sedimentological and biostratigraphic investigation of the reservoirs, combined with dynamic reservoir data, have provided an understanding of Mauddud reservoir heterogeneity and of the principle controls on reservoir matrix behaviour. The largely carbonate Mauddud Formation overlies the Upper Burgan Member, a thick succession of fluvio-deltaic deposits, and consists of a diverse suite of carbonate facies deposited in low to high-energy, shallow-marine ramp settings. The basal part of the reservoir comprises mixed carbonate and siliciclastic sediments and reflects the establishment of a carbonate-dominated regime during waning supply of Burgan siliciclastic sediment. This system was eventually drowned and covered by the Wara Formation, a shaly offshore succession that is also the reservoir seal. Sedimentary facies associations and microfossil assemblages within the reservoir are organised in a broadly upward-shallowing succession constructed of several transgressive-regressive cycles, which are defined by prominent, widely-correlatable flooding surfaces. Each cycle exhibits a characteristic internal stacking pattern of minor depositional cycles. Field-wide mapping and interpretation of facies within each cycle reveals a SW to NE, proximal to distal, trend consistent with regional seismic and palaeogeographic interpretations. The high-energy, inner to mid-ramp carbonate succession in the lower portion of the Mauddud reservoir is punctuated by siliciclastic incursions. Abrupt lateral facies changes, thickness variations, and local intra-reservoir erosion surfaces in this section suggest that deposition was influenced by subtle syndepositional tectonism. The upper part of the reservoir, in contrast, lacks significant siliciclastic influence and is made up of widely-correlatable, lower-energy carbonate facies, although local subtle facies variations show that the Raudhatain-Sabiriyah structures continued as palaeohighs during deposition. The contrast in quality between grain-dominated facies at the crests of the two structures and less grainy facies along their flanks was accentuated by carbonate cementation in the water legs of the reservoirs, largely in the form of calcite concretions of variable abundance. Cementation is most pronounced in low-energy wackestone facies, particularly in proximity to flooding surfaces where nodules may be amalgamated to form laterally continuous, cemented layers which are commonly fractured. Another significant, but contrasting, diagenetic modification within the reservoir was the generation of secondary macroporosity through dissolution of aragonitic skeletal components in a shallow to intermediate burial environment. The stratigraphic evolution of the Mauddud reservoir, and its diagenetic overprint, in addition to post-depositional fracturing and faulting, created reservoir heterogeneities, which are critical to reservoir performance; one of the most significant of these is the relationship between horizontal and vertical permeability. Parasequences dominated by high-energy inner ramp grainstones, thin inner ramp rudist-bearing tempestites, and vuggy and fractured rudist floatstones and rudstones constitute thief zones that represent major challenges to reservoir management. In contrast, some cemented layers and flooding surfaces support pressure differentials of up to several hundred pounds/square inch (psi), thus complicating sweep and promoting reservoir compartmentalisation. The strong facies, diagenetic and stratigraphic controls on the distribution of thief zones and intra-reservoir baffles demonstrates how important it is to comprehensively understand reservoir sedimentology and stratigraphy when devising long-term development plans for reservoirs of this deceptively simple character. More recent 3-D seismic data, production surveillance, and horizontal development wells show faults and fractures to be important heterogeneities in both reservoirs. Due to the immaturity of the water flood in the Mauddud reservoirs, the impact of these features on field and well behaviour is as yet unclear, but it is anticipated that the impact of such features on well and field performance will become more pronounced during later development.

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Section: Field Historymentioning

confidence: 99%

Section: Field Historymentioning

confidence: 99%

Section: Application To Other Middle Eastern Reservoirsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Reservoir description of a mid-Cretaceous siliciclastic-carbonate ramp reservoir: Mauddud Formation in the Raudhatain and Sabiriyah fields, North Kuwait

Cross¹,

Goodall²,

Hollis³

et al. 2010

GeoArabia

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Thief zone identification based on transient pressure analysis: a field case study

Yang

2015

J Petrol Explor Prod Technol

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Thief zones are generally a channel with high absolute permeability. However, a not very strict theory analysis shows that neglecting the effect of variant of water saturation on formation of thief zone in mature reservoirs cannot explain some thief zones in mature reservoirs. This paper focuses on the effect of water saturation on thief zone development for wells in mature reservoirs with areal permeability heterogeneity. The water saturation increases in high permeable channel with water passing through, which gradually leads to higher value of water phase relative permeability, and thus leads to higher value of effective permeability kÁk rw in the high permeable channel than that in surrounding reservoir. The gradually increasing difference of effective permeability kÁk rw between permeable channel and surrounding reservoir would be the main reason for formation of thief zones in mature reservoir. The oil-water two-phase numerical model based on PEBI (perpendicular bisection) gridding is used to study effect of variant of water phase saturation on formation of thief zone. We find that relatively small pressure change and not obvious bump in pressure derivative curves during shut-in are indicators of thief zones in mature reservoirs. This finding provides a further understanding for the thief zone development and also gives us a guidance to interpret the buildup pressure data in the mature sandstone reservoirs. A field case study verifies the effectiveness of the new explanation.

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Middle Eastern carbonate reservoirs – the critical impact of discrete zones of elevated permeability on reservoir performance

Cross,

Burchette

2024

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Middle Eastern carbonate petroleum reservoirs exhibit a range of heterogeneities which consist of variable combinations of primary stratigraphic and secondary diagenetic and structural characteristics. These produce diverse permeability architectures which can exert a profound influence on reservoir performance during secondary recovery. Of particular importance are laterally persistent discrete zones of elevated permeability (DZEP) that typically make up a volumetrically minor proportion of the reservoir yet show disproportionately high fluid inflow or outflow. The stratigraphic, diagenetic, and structural origins of elevated permeability in Middle Eastern carbonate reservoirs are considered here and the consequences of such features for reservoir performance are discussed. The term DZEP denotes geological sources of elevated permeability at least an order of magnitude greater than background reservoir properties. Stratigraphically organised DZEP comprise coarse-grained layers, event beds or parasequence tops or bases in neritic or platform interior settings. Other origins include bioturbated layers, grainy clinothems, and bed-scale, grain-size variations in shoal deposits. Diagenetic DZEP are typically dissolution horizons with mouldic and touching-vug pore networks or dolomitized intervals which often overprint stratigraphic DZEP. Structural DZEP include individual faults, fracture corridors, and fracture concentrations related to mechanical stratigraphy. During production through natural pressure depletion, DZEP may dominate well productivity. Under secondary recovery, the same intervals may dominate inter-well fluid flow, causing flood conformance issues, cross-zone fluid movement, bypassed pay, and earlier-than-expected water or gas breakthrough to production wells. Optimisation of production and ultimate recovery relies on collecting the correct kinds of data at a sufficiently early stage in the reservoir characterisation process to permit their inclusion in static and dynamic reservoir models.

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Reservoir Description and Static Model build in Heterogeneous Mauddud Carbonates: Raudhatain Field, North Kuwait

Cited by 14 publications

References 8 publications

Reservoir description of a mid-Cretaceous siliciclastic-carbonate ramp reservoir: Mauddud Formation in the Raudhatain and Sabiriyah fields, North Kuwait

Reservoir description of a mid-Cretaceous siliciclastic-carbonate ramp reservoir: Mauddud Formation in the Raudhatain and Sabiriyah fields, North Kuwait

Thief zone identification based on transient pressure analysis: a field case study

Middle Eastern carbonate reservoirs – the critical impact of discrete zones of elevated permeability on reservoir performance

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