b) With examples from academic literature, explain how the deposition environment impact reservoir heterogeneity?
Reservoir heterogeneity is the definition of the geological complexity description of reservoirs and relating the complexity to the flow of fluid in it. The reservoirs are able to exhibit different facial and subfacial depositions which have different and common characteristics in terms of texture, stratification types and bedding architecture (Harris, & American Association of Petroleum Geologists 2005). The reservoir heterogeneity is a wellbore which is affected by matrix permeability, distribution of residual materials, distribution of flow of fluid, fluid-layer interactions and formation damages of the reservoirs. Hydrocarbon volumes in the reservoirs as well as the distribution in their productions are able to determine the reservoir heterogeneity.
The reservoir heterogeneity is highly affected by the deposition environment conditions. Pore network of the deposition environment is able to affect the reservoir heterogeneity in different ways including the formation and flow of the fluids. Pore and pore throats are some of the key characteristics which affect the reservoir heterogeneity (Sydansk, & Romero-Zero?n 2011). The flow of the fluids in the reservoir will be determined the sizes of the grains which dictate the pore sizes. The reservoir heterogeneity flow depends on the grains sizes, grain packing formulation and composition of the grains and therefore determine the amount of flow which will be experienced. In addition, the formation of the deposition environment is able to determine the flow which will be experienced on the reservoirs. The bedding style of the deposition layers will determine the formation type of the reservoir layers (Nader 2017). The stratification of the deposition environment will therefore able to impact the reservoir heterogeneity through the control of packaging of the layers. The deposition formula of the deposition layers is able to affect the porosity, permeability and fluid saturations which are characteristics of the reservoir heterogeneity. There are major characteristics of the deposition environments and which will affect the fluid flow in reservoir heterogeneity.
The reservoir quality is impacted by different characteristics of stratigraphic environment which are related to different parameters. The compaction impact is a key stratigraphic environment which is present during the stratification process and high impacts the reservoir quality. Compaction forces play a critical layer in the physical characteristics of the layers and thus affecting the fluid movement within the layers. Compaction environment and forces play a critical role in pore formation which are essential element in the reservoir quality (Campbell, & Southern Methodist University 2016). Hydrocarbon extraction depend on the compaction of the layers for the reservoir and the pores sizes available. The movement of the hydrocarbons will be related to the pores characteristics which are determined by the compaction impact of the layers. The storage capacity and deliverability of the hydrocarbons are able to determine the quality of the reservoir quality. The deliverability factor, which also affect the reservoir quality is a function of the permeability and also affected by the compaction forces during the stratification process. Effective porosity of the reservoir is defined as the percentage of the interconnected pores within the rock surface (International Association for Mathematical Geosciences., & In Raju 2016). These pores are able to influence the flow and filtration of the fluid in the reservoir and thus affecting the final quality of the reservoir. The final characteristics of the layers which allow the movement of the fluids are dependent on the compaction forces applied during the stratification process.
The stratification process determines the sizes and amount of the pores which will be achieved at the end of formation. The pore sizes are important in the determination of the fluid flow within the reservoir. Additionally, these pores determines the amount of hydrocarbons which will be carried during the flow. The quality of the reservoir will be depended on the filtration process which the layers will be able to offer. The permeability which is defined by the ability of the layers to transmit the fluid is depended on the pore sizes and amount of pores present. (Beigi, Jafarian, Javanbakht, Wanas, Mattern, & Tabatabaei 2017, p.182). The pore formation will be able to affect layers permeability and thus affecting the fluid flow within the layers. The permeability level will in turn affect the quality of filtration process and therefore determine the final level of reservoir quality. Permeability depend on the compaction forces applied. High compaction forces reduce the amount of pores and thus reducing the permeability rate of the layers. The pores determine the flow rate of the fluid present along the section of the layer (International Association for Mathematical Geosciences, & In Raju 2016). The reservoir quality is dependent on the fluid movement and filtrations process of the same. High filtration rate can be achieved with high level of efficiency on the compaction process. The compaction impact determines the arrangement of the grains and therefore dictating the pores sizes and structures.
The formation process involves the layers compaction which affects the porosity of the layers. The porosity determines the flow which essential for the distribution of flow of other materials and reservoir quality (Kordi 2013). Less compaction will lead to high distribution and large sizes of the pores. These will have poor filtration rate and therefore lead to poor quality of the reservoir. Increasing the compaction force will reduce the sizes of the pores and increase their distribution over the layers. This will ensure increased filtration rate which will help to increase the quality of reservoir. Residues will be highly filtered when there is high distribution of the pores and small sizes. The pressure of the compaction is able to determine the grain forms suturing and the stylolitization (Dey, & Sen, 2017 p.465). Grains shape during the layer formation is important to the filtration process. The configuration of the pores will be depended on the grain shapes and thus affecting the porosity and permeability of the independent layers. High compacted layers with irregular grain shapes will have small pores with pores on different directions. These will increase the efficiency of the filtration process for the reservoir and therefore able to increase the reservoir final quality.
The compaction impact is a clear stratigraphic environment which affects the quality of the reservoirs. The grain arrangement is also dependent on the environment compaction during the stratification process. The arrangement process is a critical process which helps to determine the final filtration rate of the fluid and thus determining the reservoir quality. Porosity and permeability will be affected by the grains arrangement and which is dependent on the compaction of the layers (Campbell, & Southern Methodist University 2016). The impact of the compact is therefore a critical environment which need to be controlled to define the specific characteristics of the strata. The compaction force is able to determine the physical parameters of the strata which is an important part for the filtration and reservoir quality. As seen, the matching of the analogues is dependent on the compaction of the layers.
In conclusion, the compaction impact plays a critical role in the reservoir quality. The compaction forces are found during the stratification process and helps to determine the physical properties of the layers. First, the pores sizes are directly related with the amount of compact impact is applied to the layer. The sizes determine the fluid flow within the layers and thus a factor in determining the reservoir quality. The compaction impact also plays a critical role in the pores distribution and therefore affecting the fluid flow rate within the layer. The compaction impact for the stratigraphic environment helps to provide a critical filtration process which helps to come out with reservoir quality. The pore characteristics helps to control the residue filtration resulting to the final quality of the reservoir. The compaction impact will determine the sizes of the pores, their arrangement and structure of the layers which will affect the fluid flow within the stratigraphic environment and therefore affecting the reservoir quality.
Beigi, M., Jafarian, A., Javanbakht, M., Wanas, H. A., Mattern, F., & Tabatabaei, A. (May 01, 2017). Facies analysis, diagenesis and sequence stratigraphy of the carbonate-evaporite succession of the Upper Jurassic Surmeh Formation: Impacts on reservoir quality (Salman Oil Field, Persian Gulf, Iran). Journal of African Earth Sciences, 129, 179-194.
Campbell, R., & Southern Methodist University,. (2016). Stratigraphic architecture and reservoir characteristics of slumped distributary mouth bar deposits, Cretaceous Ferron Sandstone, Utah: An analysis of sedimentary fabric and facies utilizing outcrop and core data. (Masters Abstracts International, 55-5.).
Dey, J., & Sen, S. (April 01, 2017). Impact of bioturbation on reservoir quality and production - A review. Journal of the Geological Society of India, 89, 4, 460-470.
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Kordi, M. (2013). Characterization and prediction of reservoir quality in chlorite-coated sandstones: Evidence from the Late Cretaceous Lower Tuscaloosa Formation at Cranfield Field, Mississippi, U.S.A. [Austin, Tex.]: [University of Texas]
Nader, F. H. (2017). Multi-scale Quantitative Diagenesis and Impacts on Heterogeneity of Carbonate Reservoir Rocks. Cham: Springer International Publishing.
Sydansk, R. D., & Romero-Zero?n, L. (2011). Reservoir conformance improvement. Richardson, TX : Society of Petroleum Engineers.