1. Supervisor：Pro. Chen qinghua China University of Petroleum
The Application of Architectural Elements Analysis in Characterizing Complex Reservoir
: A case study of Yong’an town oil field, Dongying Sag, Bohai Bay Basin, China
Presenter：Dr. Sun ke
Supervisor：Pro. Chen qinghua
China University of Petroleum

2. OUTLINE 3 5 1 2 4 Research review Three advantages Three problems
Application example 4
Conclusion 5

3. Continuous distribution
1、Research overview
Origin
The concept of fluvial architecture originated from the studies of fluvial outcrops (Allen, 1983). And then, A.D. Miall systematically defined and graded the elements of fluvial facies, and proposed a method of architectural elements analysis（A.D. Miall, 1985, 1988, 1996）.
Developing trend
Single
channelization
Multi-type
Delta、alluvial fan、 carbonate bank-dam ect.
Meandering river, Braided river etc.
Sedimentary types
Surface outcrop
Covered area
Continuous distribution
(Easy to identify and track)
Discrete
distribution
(Difficult to identify and track)
Research area

4. Application condition
1、Research overview
Application condition
Whether the method can be applied in covered area？
Exploration stage：wide well spacing
(Difficult to control distribution of architectural elements)
Development stage：close well spacing
( low level architectural elements can be predicted between wells)
DATA

5. OUTLINE 3 5 1 2 4 Research review Three advantages Three problems
Application example 4
Conclusion 5

6. 1、 Dividing high frequency layers of reservoirs
Three advantages
1、 Dividing high frequency layers of reservoirs
Vertical ：periodicity
Cyclicity
（ Temporal and spatial
distribution of sediment ）
Tectonic movement
Sedimentation
climate change…
Hierarchy
of reservoir
Plane：zonational
Hierarchy of bounding surface
Hierarchy of architectural elements
(A.D Miall, 1988)

7. Three advantages
Problem： The high frequency range is not defined detailedly in the traditional method.
Classification scheme comparison of bounding surface and reservoir unit
Bounding surface hierarchy of positive sequence
（A.D Miall, 1988, 1996）
Bounding surface hierarchy of reverse sequence
（Ji youliang et al, 2012）
Architectural elements
（e.g. meandering stream）
Sequence Stratigraphy
High Resolution Sequence Stratigraphy
Subsurface Geology of Gas and Oil
Level 1
Composite basin filling complex
Megasequence
Level 2
Basin filling complex
Supersequence
Level 8
Level 3
Basin filling
Sequence
Long-term
Oil-bearing series
Level 7
Level 4
System tract
Quasi sequence set
Metaphase
pay zone
Level 6
Level 5
Superimposed channel complexes
Subsequence
Short period
Sands group
Single channel
Bed set
Single layer
Meander belt
Super short-term
Single sand layers
Single point bar
Layer
Level 9
Accretion
Level 10
Group formation
Lamina groups
Level 11
Bed series
Level 0
Level 12
Lamina
 Lamina
Sequence architecture
Facies architecture
Bedding architecture
Advantage one： Dividing the level of reservoir in high frequency, that is, the method of architectural elements analysis defines the high frequency interval of reservoir in detail .

8. 2、 Analyzing complex reservoir architecture
Three advantages
2、 Analyzing complex reservoir architecture
Reservoir architecture ：the geometric shape of a single reservoir sand body and its distribution in three dimensions
Problem： The reservoir analysis of one dimension (drilling section) or two-dimension (seismic and even well section) coarsens the reservoir architecture, making it difficult to correctly characterize the reservoir architecture, and some complex reservoirs are simplified as " Layer cake reservoir type" （Weber and Geuns, 1990）.
Simple reservoir architecture
Complex reservoir architecture

9. 2、 Analyzing complex reservoir architecture
Three advantages
2、 Analyzing complex reservoir architecture
Characterization content of architectural elements (A.D Miall, 1988):
Property of bounding surfaces;
Scale of the architectural elements;
External and internal geometry of architectural elements.
Characterization parameters : thickness, length, area, dip et al.
Advantage two ： Analyzing complex reservoir architecture, that is to say, to analyze the fine genesis of reservoir at specific level by the method of architectural elements analysis.

10. Three advantages 3、 Explaining the fine genesis of reservoir
Numerous studies show that：Sedimentary genesis is the main factor causing the internal
architecture and complex contact relationship of different reservoirs.
How to finely characterize the genesis of complex reservoirs ?
Traditional method ：
（1）Sequence stratigraphy（Vail et al., 1977）
Principle ： Sea level change
Research level ： Allogenetic cycle above the 4th order sequence
Problem： Can not explain high-frequency intervals and the genesis of autogenetic cycle.
（2）High-resolution sequence stratigraphy（ Cross et al., 1993）
Principle ：Principle of base level cycle change, Principle of accommodation space change,
Principle of volume distribution, Principle of facies differentiation.
Research level ： Ultra short term cycle （ Equivalent to the 5th level architectural elements in Miall’s plan）
Problem ： It is impossible to explain the genesis of architectural elements below 5th level , and lack of credibility in explaining autogenetic cycle. .

11. Three advantages 3、 Explaining the fine genesis of reservoir
（3） Underground geology of oil and gas fields
Principle ： Stratigraphy 、 Reservoir geology 、 Tectonic geology 、 Sedimentology
Research level ：Small layer (single sand layer or single layer)
Problem ： The research units do not have a single cause of formation, and can not explain the
sedimentary origin of complex reservoirs finely.
Reservoir architectural elements analysis
（1） Fine hierarchy ： High level to low level , complex to simple
Genesis of mouth bar complex
Genesis of single mouth bar
Genesis of accretion body of mouth bar

12. 3、 Explaining the fine genesis of reservoir
Three advantages
3、 Explaining the fine genesis of reservoir
（2） Detailed analysis ： Multi content, multi angle
Lithofacies genetic analysis ：Lithology, architecture, grain size, sedimentary structure and so on, for example, silty mudstones and mudstones with horizontal bedding in the fluvial facies can be interpreted as fine-grained deposits in flood plains（Fsm）.
architectural elements analysis
Bounding surfaces genetic analysis ： Properties of bounding surfaces, cross cut relation of interface and so on, for example, fluvial facies erode interfaces and cut off early bounding surfaces .
Advantage three： Explain the fine genesis of reservoir, that is to say, analysis of fine genesis of reservoir at specific level by element analysis of reservoir configuration .

13. OUTLINE 3 5 1 2 4 Research review Three advantages Three problems
Application example 4
Conclusion 5

14. 1、 Applicable conditions of the method
Three problems
1、 Applicable conditions of the method
whether the data meets the requirements of the analysis of architectural elements？
The evaluation includes two aspects: well spacing density and data resolution.
Well spacing density：
Usually depending on the extent of oil and gas field development, the higher the development level is, the higher the density of the well pattern is.
The scale of architectural elements at different levels varies greatly, and the lower architectural elements (below 5th order level) of complex reservoirs can be effectively represented under the condition of dense well network (average well spacing < 400m).
Data resolution：
The lateral distribution of seismic data is continuous, but the vertical resolution is too low, and the distinguishable thickness is usually above tens meters. Therefore, the boundaries of reservoir architectural elements can be identified only at higher levels (5 or more).
logging data: reaches 0.5m or even smaller, but it can not recognize the architectural elements under 3rd order level.
Core logging data: identify the lowest architectural elements (laminae), but they are limited by the number of coring wells, so it is difficult to achieve horizontal comparison and tracking.

15. 2、 Selection of basic research units
Three problems
2、 Selection of basic research units
Problem ： What level of architectural elements are selected as basic research unit?
Over complication ：If the lower architectural elements(such as laminae) are the basic research units, the bounding surface is difficult to identify and trace, and the sedimentary genesis and the distribution characteristics of oil and water will be difficult to characterize;
Over simplification ： If the senior architectural elements (such as the superposition of the river complex) are the basic research unit of the architectural elements analysis, the internal architecture characteristics of the reservoir can not be characterized, the sedimentary genesis is too rough, and the oil and water distribution is contradictory.
Miall has also defined the level of architectural elementsanalysis at 3-5 levels in practical work, the choice of basic research units should be combined with information and research needs.
For example, Zhao Xiaoming et al. (2012) in the study of deepwater turbidite channel, the reservoir architectural elements of turbidite channel was divided into three levels by means of well seismic data under the condition of thin well pattern;
First levels ( Waterway system ) , Used to study the subfacies distribution of sand formation
Second levels (channel complex) , Used to solve the distribution of sublayer and microfacies
Third levels (Single channel), Used to solve the distribution of elements within microfacies .

16. 3、 Relationship between architectural element sand oil reservoir units
Three problems
3、 Relationship between architectural element sand oil reservoir units
The division and correlation of oil reservoir units are important basic work of complex reservoir characterization. It is very important to make the relationship between architectural elements and reservoir units clear.
Architectural elements ： The geometry, size, direction and mutual configuration of the units in the reservoir are composed of lithofacies and bounding surfaces.
Small layer ： Consisting of one or more single sand layers, having a definite distribution in the same field, lithology and physical properties are basically the same , the interlayer is separated by an interlayer, and the separating area is larger than the communicating area.
Same point ： Pay attention to the division of lithology and bounding surface (interlayer or interlayer) .
Different： The difference is that the reservoir architectural elements pay more attention to the spatial form of reservoir units ，occurrence and deposition relationship.

17. Three problems
According to the distribution of mudstone interlayer between fluvial sand bodies, it can be divided into three small layers, marked as 1、2、3（Figure 2）；four stages of channel sand body （CH）, marked as ①、②、③、④（Figure 2）, within the scope of the graphic section, the 1 and 3 small layers correspond to the sand bodies of the two channels, the small layers 1 and 3 correspond to the sand bodies of the ① and ④channels, The small layers 2 are superposed by ② and ③ channel sand bodies.
The relationship : Not a simple correspondence or contained relationship, but a complex interleaving relationship, Therefore, we can not divide and correlate the architectural elements on the basis of the division of sand groups or small layers, which is necessary for the characterization of complex reservoirs .

18. OUTLINE 3 5 1 2 4 Research review Three advantages Three problems
Application example 4
Conclusion 5

19. Application example 1、Sedimentary bounding surface division
Taking the reservoir of the mouth bar of Es26in Yongan oilfield as an example , the bounding surface of mouth bar complex is defined as Level 5 , and the bounding surface of the single mouth bar is Level 4, and the bounding surface of the accretion body is Level 3.
（1）5th level bounding surface
The thickness of mudstone (4-9m) is stable above or under the mouth bar complex, connected the interface between thick mudstone and the mouth bar complex of each well , Two 5th level bounding surfaces are obtained, marked as 5-①和5-②.
SP large negative anomaly , Sandstone purity 、 well-sorted 、 Good porosity and permeability
SP small negative anomaly , High shale content , Poor porosity and permeability

20. 1、Sedimentary bounding surface division
SP large negative anomaly , Sandstone purity 、 well-sorted 、 Good porosity and permeability
SP small negative anomaly , High shale content , Poor porosity and permeability
（2） 4th level bounding surfaces
A stable mudstone is developed in the mouth bar complex, but the thickness varies greatly , 0.5-4m. The top and bottom of the set of mudstone are respectively connected , two 4th level bounding surfaces are obtained, marked as 4-① and 4-②.
（3） 3rd level bounding surfaces
The 3rd level bounding surfaces is small in thickness, fast in change and limited in distribution, so it is easy to identify in cores. But logging data usually shows low return or no obvious return point . Connect a, b, c, d, e five points to get a 3rd level bounding surface 3- ④.

21. φ: the dip angle of accretion body bounding surfaces, °.
1、Sedimentary bounding surface division
Problem： The logging response of bounding surface is very weak or there is no response, so dip prediction method can be adopted. Taking mouth bar reservoir as an example, the principle is that the sedimentary environment and hydrodynamic conditions of a single mouth dam are similar, and the accretion interface has similar trend .
According to formula ①, the dip angle of the known bounding surface can be calculated. Then, the dip angle of other similar bounding surfaces in the same mouth bar can be predicted, and the 3 interface of other logging responses is not obvious .
φ = arctan(Δh/L)×π/ ①
In the formula：L:the horizontal distance, m；Δh: the height difference of bounding surfaces between two wells, m；
φ: the dip angle of accretion body bounding surfaces, °.
Δh(m)
L(m)
Φ(°)
6.2
135
2.6
4.9
126
2.2
5.4
115
2.7
4.7
107
2.5
4.2 92
2.9 63
3.2 79
2.3

22. Application example 2、 Sedimentary genetic analysis
problem： The bounding surface description is rough and difficult to describe Sedimentary genesis quantitatively .
（1） Sedimentary microfacies maps are compiled in small layers，in essence, is the dominant sedimentary facies distributional diagram of the composite genetic sedimentary body （Shenghe et al., 2013）
（2 ）Application of high resolution sequence stratigraphy, the unit of ultra short cycle division can not characterize the distribution and scale of accretion bodies in the channel sand bar .

23. Application example 2、 Sedimentary genetic analysis
（1） The facies distribution map is compiled by taking the accretion body of the mouth bar as the unit. In the study area, the mouth bar accretion in 61 small layers can be divided into 6 stages mouth bar accretion bodies
（2） To characterize the appearance, scale and interface position of each stage.
e.g.
Ⅵ1 accretion body thin out near the Y3-5, with an area of 0.18Km2；
Ⅵ2 accretion body thin out between the Y3-86 and Y3-100, with an area of 0.32Km2；
Ⅵ3 accretion body thin out between the Y3-100 and Y3-147, with an area of 0.40 Km2.
（3） According to the relative spatial relation of the accretion bodies of the mouth bar in different periods , the 6 stages mouth bar accretion body retrograde from west to East .

24. Application example 3、 Study on oil-water distribution characteristics
Problem：
（1） On the plane, the effective thickness zero line does not match the top  structure maps
of the small layer ；
（2） There are mutiple oil-water interfaces in the same small layer.
Effective
Thickness
Zero
Line
runout
Architectural elements describe：
（1）The oil-bearing area of Ⅵ1 accretion body is 0.097Km2, average effective thickness is 3.2m, unit reserve factor is 16.8×104t/Km2·m, Using the volume method, the geological reserves are 5.21×104t；
（2）The oil pool area of Ⅵ2 accretion body is 0.176Km2, the average effective thickness is 3.9m, the geological reserves are 11.53×104t.

25. Application example
3、 Study on characteristics of oil-water distribution
Thought：
First, log interpretation thickness of reservoir, water layer and dry layer of each stage on the well point are read, and draw a plan of the small layer of the mouth bar accretion in each period ；
Second, the small layer plan is superposed with the micro architecture drawing of the corresponding accretion body, and the matching relation between the oil-water boundary and the structural contour is contrasted .
Approximately parallelled tectonic lines, the effect of oil-water control is obvious.
The oil-water boundary of the small layer intersects with the structural line, it does not accord with the law of oil-water distribution .

26. OUTLINE 3 5 1 2 4 Research review Three advantages Three problems
Application example 4
Conclusion 5

27. Conclusion
(1)The advantages of architectural elements analysis in complex reservoir characterization are shown in three aspects : first, dividing the high frequency reservoir；Second, analyzing the complex architecture of reservoir; third, explaining the fine genesis of reservoir.
(2) It is necessary to pay attention to several important problems in the analysis of complex reservoirs by using the method of architectural elements analysis:
①The applicable conditions of the method；
②The selection of the basic research units；
③The relationship between the architectural elements and the oil reservoir units.
(3)The original 61 small layers can be divided into 6 stages mouth bar accretion bodies, and the dip angle of mouth bar accretion body is 2~3 degrees; A sedimentary model with an accretion body of mouth bar is established, and it is considered that the mouth bar has the characteristics of retreating from west to East；The distribution characteristics of oil and water in the 61 small layers of Yong 3-1 fault block are controlled by the mouth bar accretion body (3rd order architectural elements ).

28. Thank you！