Predictive permeability variations in a Hermod sand reservoir, Stine Segments, Siri Field, Danish North Sea

Stokkendal, Jesper; Friis, Henrik; Svendsen, Johan B.; Poulsen, Mette Lise K.; Hamberg, Lars

doi:10.1016/j.marpetgeo.2008.03.004

Cited by 40 publications

(29 citation statements)

References 15 publications

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“…2.1. Lack of silica cementation: At first, the marginal parts of the reservoir may have received a major flux of silica from the Sele Formation located in the Siri Canyon in the North Sea (Stokkendal et al, 2009). The silica flux did not influence all parts of the greensand reservoir.…”

Section: Discussionmentioning

confidence: 99%

“…Microcrystalline-quartz coating on detrital grains is located at the grain contacts. As a result, this quartz cement acts to stiffen the rock (Stokkendal et al 2009). Hence, the presence of the microcrystalline quartz cement should have a major effect on the elastic properties of greensand.…”

Section: Silica and Pore-filling Berthierine Cementationmentioning

confidence: 99%

“…The main mineralogical difference between these two types of diagenetic phases is in that microcrystallinequartz-cemented samples may contain more SiO 2 than berthierine-cemented samples (Stokkendal et al, 2009). Our next step is to understand the effects of these pore-filling minerals on the elastic properties and porosity of the rock.…”

Section: Silica and Pore-filling Berthierine Cementationmentioning

confidence: 99%

“…Porosity in this sediment is found at two scales: macroporosity between grains and microporosity within grains (Figure 1). Greensand petroleum reservoirs occur world-wide, e.g., the mid-Cretaceous Safaniya Sandstone Member in Saudi Arabia (Cagatay et al, 1996), the Lower Cretaceous Glauconitic sandstone in Alberta, Canada (Tilley and Longstaffe, 1984), the Upper Cretaceous Shannon sandstone in Wyoming, USA (Ranganathan and Tye, 1986), a Lower Cretaceous Greensand offshore Ireland (Winn, 1994) and a late Paleocene Greensand in central part of the North Sea (Solymar, 2002;Solymar et al, 2003;Hossain et al, 2009;Hossain et al, 2011a, b;Stokkendal et al, 2009). However, evaluation of greensand reservoirs has challenged geologists, engineers and petrophysicsts.…”

Section: Introductionmentioning

confidence: 99%

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Rock physics model of glauconitic greensand from the North Sea

et al. 2011

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The objective of this study was to establish a rock physics model of North Sea Paleogene greensand. The Hertz-Mindlin contact model is widely used to calculate elastic velocities of sandstone as well as to calculate the initial sand-pack modulus of the soft-sand, stiff-sand, and intermediate-stiff-sand models. When mixed minerals in rock are quite different, e.g., mixtures of quartz and glauconite in greensand, the Hertz-Mindlin contact model of single type of grain may not be enough to predict elastic velocity. Our approach is first to develop a Hertz-Mindlin contact model for a mixture of quartz and glauconite. Next, we use this Hertz-Mindlin contact model of two types of grains as the initial modulus for a soft-sand model and a stiff-sand model. By using these rock physics models, we examine the relationship between elastic modulus and porosity in laboratory and logging data and link rock-physics properties to greensand diagenesis. Calculated velocity for mixtures of quartz and glauconite from the Hertz-Mindlin contact model for two types of grains are higher than velocity calculated from the HertzMindlin single mineral model using the effective mineral moduli predicted from the Hill's average. Results of rock-physics modeling and thin-section observations indicate that variations in the elastic properties of greensand can be explained by two main diagenetic phases: silica cementation and berthierine cementation. These diagenetic phases dominate the elastic properties of greensand reservoir. Initially, greensand is a mixture of mainly quartz and glauconite; when weakly cemented, it has relatively low elastic modulus and can be modeled by a Hertz-Mindlin contact model of two types of grains. Silica-cemented greensand has a relatively high elastic modulus and can be modeled by an intermediate-stiff-sand or a stiff-sand model. Berthierine cement has different growth patterns in different parts of the greensand, resulting in a soft-sand model and an intermediate-stiff-sand model.

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Section: Discussionmentioning

confidence: 99%

Section: Silica and Pore-filling Berthierine Cementationmentioning

confidence: 99%

Section: Silica and Pore-filling Berthierine Cementationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Rock physics model of glauconitic greensand from the North Sea

et al. 2011

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“…Chlorite may form by (i) the alteration of eogenetic, grain-coating berthierine or odinite (Hillier & Velde 1992;Humphreys et al, 1989;Kugler & McHugh, 1990), kaolinite and smectite precursor in deltaic deposits (Ehrenberg, 1993;Ryan, 1997;Stokkendal et al, 2009);(ii) by the dissolution of Fe-and Mg-rich detrital grains (Anjos et al, 2000;Blackbourn & Thomson, 2000;Ros et al, 1994;Remy, 1994;Valloni et al, 1991). Diagenetic chlorites in Chang 7 sandstones were most probably formed by (i) massive biotite alteration, (ii) the transformation of precursor clay, and (iii) direct precipitation from pore fluids.…”

Section: Paragenetic Sequencementioning

confidence: 99%

Diagenetic controls on reservoir quality of tight sandstone: A case study of the Upper Triassic Yanchang formation Chang 7 sandstones, Ordos Basin, China

et al. 2018

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Through a range of petrological techniques, the petrology, diagenesis, pore characteristics, and controlling factors on the regional variations of reservoir quality of the Chang 7 sandstones were studied. These sandstones, mainly arkoses, lithic arkoses, and feldspathic litharenites, were deposited in a delta front and turbidites in semi-deep to deep lacustrine. The detrital constituents were controlled by the provenance and sedimentary condition, which resulted in a spatially variable composition; e.g., high biotite and feldspar contents in the northeast (NE) of the study area, and high contents of rock fragments, especially dolomite, matrix, and quartz in the southwest (SW). Diagenesis includes intense mechanical compaction, cementation, and dissolution of unstable minerals. Diagenetic minerals which were derived internally include quartz, ankerite, ferrous calcite, albite, illite, kaolinite, and chlorite. Thus the original sandstone composition hadfirm control over the development and distribution of cement. Mechanical compaction and late-stage cementations contribute to the porosity loss of sandstones of Chang7 member. The dissolution porosity in major sandstone, slightly higher than primary porosity is principally dependent on the accessibility of acid fluid. The high content of plastic component facilitated the reduction of primary porosity and limited the mineral dissolution. The best reservoir sandstones are found in W, and partly from NE, M districts, with porosity are primary. The relatively high textural maturity of these sandstones reduces the impact of compaction on primary pores, and commonly existed chlorite rims limited the precipitation of pore filling quartz and carbonate cementation in late stage. A través de una gama de técnicas petrológicas se estudió la petrología, la diagénesis, las características de poro y los factores que controlan las variaciones regionales de la calidad del yacimiento de las areniscas Chang 7. Estas areniscas, principalmente arcosas, arcosas líticas y arenitas líticas feldespáticas, se depositaron en un frente deltáico mientras las turbiditas se depositaron en ambientes lacustres profundos y semi-profundos. Los componentes detríticos dependen de la procedencia y la condición sedimentaria, lo que resultó en una composición variable en el espacio; por ejemplo, altos contenidos de biotita y feldespato en el noreste (NE) del área de estudio, y altos contenidos de fragmentos de roca, especialmente dolomita, matriz y cuarzo en el suroeste (SW). La diagénesis incluye compactación mecánica intensa, cementación y disolución de minerales inestables. Los minerales diagenéticos que se derivaron internamente incluyen cuarzo, ankerita, calcita ferrosa, albita, illita, caolinita y clorita. Por lo tanto, la composición original de arenisca tenía un firme control sobre el desarrollo y la distribución del cemento. La compactación mecánica y las cementaciones de la última etapa contribuyen a la pérdida de porosidad de las areniscas del miembro Chang7. La porosidad de disolución en la pi...

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Diagenetic differences in tight sandstone reservoirs in two delta fronts: an example from the Chang 4 and 5 members of the Yanchang Formation in the Longdong area, Ordos Basin, China

Zhu

Yang

et al. 2018

Arab J Geosci

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Predictive permeability variations in a Hermod sand reservoir, Stine Segments, Siri Field, Danish North Sea

Cited by 40 publications

References 15 publications

Rock physics model of glauconitic greensand from the North Sea

Rock physics model of glauconitic greensand from the North Sea

Diagenetic controls on reservoir quality of tight sandstone: A case study of the Upper Triassic Yanchang formation Chang 7 sandstones, Ordos Basin, China

Diagenetic differences in tight sandstone reservoirs in two delta fronts: an example from the Chang 4 and 5 members of the Yanchang Formation in the Longdong area, Ordos Basin, China

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