scholarly journals Deformation Bands and Associated FIP Characteristics From High-Porous Triassic Reservoirs in the Tarim Basin, NW China: A Multiscale Analysis

2021 ◽  
Vol 9 ◽  
Author(s):  
Wenyuan Yan ◽  
Ming Zha ◽  
Jiangxiu Qu ◽  
Xiujian Ding ◽  
Qinglan Zhang
Keyword(s):  
Thin Section ◽  
Oil And Gas ◽  
Fluid Dynamic ◽  
Shear Bands ◽  
Raman Laser ◽  
Homogenization Temperature ◽  
High Porosity ◽  
Porous Rocks ◽  
Deformation Bands ◽  
Porosity And Permeability

Deformation bands are widely formed and distributed in Triassic high-porous rocks as a result of multistage tectonic movement. In this research, core observation, the rock thin section (fluorescence and casting thin section), FIB-SEM, X-ray diffraction, Raman laser, and thermometry of fluid inclusions were employed to describe the macro- and micro characteristics of deformation bands and their associated relationship with microfractures. Results indicate that the main types of deformation bands formed in the Lunnan Triassic high-porosity sandstone during the Yanshanian and Himalayan periods under different temperature and pressure conditions are compaction shear bands, and their quantity increases evidently with the distance of thrust faults. The density of deformation bands near the fault is about 15/m; porosity and permeability decrease sharply compared with those of the host rock. Microscopically, two obtained fluid-inclusion planes (FIPs) can be distinguished as 51 samples collected from 12 wells by the cutting relationship and mechanical characteristics. The homogenization temperature of associated aqueous inclusion is generally characterized by two peaks, mainly 70–80°C and 110–120°C, which were formed in the Late Yanshanian and Late Himalayan periods. The formation period of deformation bands induced by the intragranular microfractures improved the reservoir seepage capacity. In the later stage, as the interlayer and barrier with low porosity and low permeability affects the distribution of oil and gas, which is an important factor in this study of the local fluid dynamic field and high-quality reservoir evolution distribution.

scholarly journals Structural control on fluid flow and shallow diagenesis: insights from calcite cementation along deformation bands in porous sandstones

Solid Earth ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 2169-2195
Author(s):  
Leonardo Del Sole ◽  
Marco Antonellini ◽  
Roger Soliva ◽  
Gregory Ballas ◽  
Fabrizio Balsamo ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Structural Control ◽  
Control Flow ◽  
Porous Rocks ◽  
Deformation Bands ◽  
Seismic Resolution ◽  
Porous Sandstone ◽  
Reservoir Compartmentalization ◽  
Porosity And Permeability ◽  
And Control

Abstract. Porous sandstones are important reservoirs for geofluids. Interaction therein between deformation and cementation during diagenesis is critical since both processes can strongly reduce rock porosity and permeability, deteriorating reservoir quality. Deformation bands and fault-related diagenetic bodies, here called “structural and diagenetic heterogeneities”, affect fluid flow at a range of scales and potentially lead to reservoir compartmentalization, influencing flow buffering and sealing during the production of geofluids. We present two field-based studies from Loiano (northern Apennines, Italy) and Bollène (Provence, France) that elucidate the structural control exerted by deformation bands on fluid flow and diagenesis recorded by calcite nodules associated with the bands. We relied on careful in situ observations through geo-photography, string mapping, and unmanned aerial vehicle (UAV) photography integrated with optical, scanning electron and cathodoluminescence microscopy, and stable isotope (δ13C and δ18O) analysis of nodules cement. In both case studies, one or more sets of deformation bands precede and control selective cement precipitation. Cement texture, cathodoluminescence patterns, and their isotopic composition suggest precipitation from meteoric fluids. In Loiano, deformation bands acted as low-permeability baffles to fluid flow and promoted selective cement precipitation. In Bollène, clusters of deformation bands restricted fluid flow and focused diagenesis to parallel-to-band compartments. Our work shows that deformation bands control flow patterns within a porous sandstone reservoir and this, in turn, affects how diagenetic heterogeneities are distributed within the porous rocks. This information is invaluable to assess the uncertainties in reservoir petrophysical properties, especially where structural and diagenetic heterogeneities are below seismic resolution.

scholarly journals THE INFLUENCE OF SEDIMENTATION AND POST-SEDIMENTATION TRANSFORMATIONS ON THE RESERVOIR PROPERTIES OF THE ROCKS

2019 ◽  
pp. 14-19
Author(s):  
V. Khomyn ◽  
M. Maniuk ◽  
O. Maniuk ◽  
A. Popluiko ◽  
N. Khovanets
Keyword(s):  
Oil And Gas ◽  
Scientific Evidence ◽  
Gas Content ◽  
High Porosity ◽  
Reservoir Properties ◽  
Quartz Content ◽  
Positive Correlation ◽  
Median Diameter ◽  
Porosity And Permeability ◽  
Cover Thickness

The topicality of the research is proved by the scientific evidence of the peculiarities of the sedimentation and post-sedimentation transformations of the rocks in relation to their possible oil and gas content. The productive sediments of the deposits of the interior of the Precarpathian Depression were thoroughly and lithologically researched. The objective implied the study and recognition of the reservoir properties within primary (sedimentation) and secondary (post-sedimentation) factors. The primary ones are as follows: granulity (grains median diameter), sorting, and rock maturity. Consequently, a positive correlation between the grains median diameter and rock porosity has been determined; the very coefficient equals 0.56. Evidently, unlike the well-sorted sandstones, the badly graded ones are marked by poor porosity and permeability. The positive correlation between porosity and clastic quartz content is revealed: should the latter increase, the former will go up as well. Apparently, more mature sandstones are characterized by dramatically high porosity; this factor positively affects the reservoir properties of the rocks. After studying the secondary transformations of the sandy rocks, we have determined that the diagenesis stage is defined by the change of mineral composition. This alteration is mainly caused by organic material decomposition and the appearance of reducing environment. Considering the cover thickness, we have graded the transformations of the fragments of the sandy-aleuritic rocks of the depression. The pattern of the catagenetic changes at various depths has been introduced. In the end, we have inferred that the increasing depth starts influencing the three types of the structures, i.e. incorporating, reclaiming and microstilolite rather gradually. In addition, the declining importance of the conformal structures has been identified. The stress pattern of the catagenetically transformed solid rocks promotes the microfracture within the late catagenesis zones; this factor predetermines the development of decompression zones at the depths exceeding 4 km characterised by good reservoir properties.

Prospects, Challenges and Way Forward in the Use of Hydraulic Fracturing For Oil and Gas Production From Igneous Rocks

2021 ◽  
Author(s):  
Agnes Anuka ◽  
Celestine Udie ◽  
Grace Aquah
Keyword(s):  
Hydraulic Fracturing ◽  
Energy Demand ◽  
Oil And Gas ◽  
Gas Production ◽  
Commercial Production ◽  
Igneous Rocks ◽  
High Porosity ◽  
Global Energy ◽  
Oil And Gas Production ◽  
Porosity And Permeability

Abstract Commercial accumulation of hydrocarbons occurs mostly in sedimentary rocks due to their high porosity and permeability. Increased global energy demand has necessitated the need for unconventional methods of oil production. The world is gradually moving away from reliability on conventional oils. The need to ensure global energy sustainability has necessitated an urgent diversion to unconventional oils. In recent times, hydrocarbon accumulations have been found in igneous rocks. Their low porosity and permeability however prevents commercial production as oil and gas found in these rocks will not flow. Hydraulic fracturing is useful in increasing rock porosity as it involves the breaking of rocks to allow oil and gas trapped inside to flow to producing wells. This method is useful in developing unconventional resources such as oil and gas found in igneous rocks. This research explores the prospects, challenges and way forward in the use of hydraulic fracturing to increase the porosity of igneous rock for commercial production of oil and gas.

The Research and Application of Cementing Isolation Technology in High Porosity and Permeability of Developed Clastic Rock Reservoir in Tarim Basin

2021 ◽  
Author(s):  
Hongtao Liu ◽  
Zhengqing Ai ◽  
Jingcheng Zhang ◽  
Zhongtao Yuan ◽  
Jianguo Zeng ◽  
...  
Keyword(s):  
Drilling Fluid ◽  
Water Layer ◽  
High Porosity ◽  
Self Healing ◽  
Cement Slurry ◽  
Clastic Rock ◽  
Pump Rate ◽  
Porosity And Permeability ◽  
Zonal Isolation ◽  
High Pump

Abstract The average porosity and permeability in the developed clastic rock reservoir in Tarim oilfield in China is 22.16% and 689.85×10-3 μm2. The isolation layer thickness between water layer and oil layer is less than 2 meters. The pressure of oil layer is 0.99 g/cm3, and the pressure of bottom water layer is 1.22 g/cm3, the pressure difference between them is as bigger as 12 to 23 MPa. It is difficult to achieve the layer isolation between the water layer and oil layer. To solve the zonal isolation difficulty and reduce permeable loss risk in clastic reservoir with high porosity and permeability, matrix anti-invasion additive, self-innovate plugging ability material of slurry, self-healing slurry, open-hole packer outside the casing, design and control technology of cement slurry performance, optimizing casing centralizer location technology and displacement with high pump rate has been developed and successfully applied. The results show that: First, the additive with physical and chemical crosslinking structure matrix anti-invasion is developed. The additive has the characteristics of anti-dilution, low thixotropy, low water loss and short transition, and can seal the water layer quickly. Second, the plugging material in the slurry has a better plugging performance and could reduce the permeability of artificial core by 70-80% in the testing evaluation. Third, the self-healing cement slurry system can quickly seal the fracture and prevent the fluid from flowing, and can ensuring the long-term effective sealing of the reservoir. Fourth, By strict control of the thickening time (operation time) and consistency (20-25 Bc), the cement slurry can realize zonal isolation quickly, which has achieved the purpose of quickly sealing off the water layer and reduced the risk of permeable loss. And the casing centralizers are used to ensure that the standoff ratio of oil and water layer is above 67%. The displacement with high pump rate (2 m3/min, to ensure the annular return velocity more than 1.2 m/s) can efficiently clean the wellbore by diluting the drilling fluid and washing the mud cake, and can improve the displacement efficiency. The cementing technology has been successfully applied in 100 wells in Tarim Oilfield. The qualification rate and high quality rate is 87.9% and 69% in 2019, and achieve zone isolation. No water has been produced after the oil testing and the water content has decreased to 7% after production. With the cementing technology, we have improved zonal isolation, increased the crude oil production and increased the benefit of oil.

scholarly journals Distribution, microphysical properties, and tectonic controls of deformation bands in the Miocene subduction wedge (Whakataki Formation) of the Hikurangi subduction zone

Solid Earth ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 141-170
Author(s):  
Kathryn E. Elphick ◽  
Craig R. Sloss ◽  
Klaus Regenauer-Lieb ◽  
Christoph E. Schrank
Keyword(s):  
Microstructural Analysis ◽  
Shear Bands ◽  
Normal Faults ◽  
Pore Collapse ◽  
Deformation Bands ◽  
Progressive Deformation ◽  
Compaction Bands ◽  
Microphysical Properties ◽  
Sealing Capacity ◽  
Grain Crushing

Abstract. We analyse deformation bands related to horizontal contraction with an intermittent period of horizontal extension in Miocene turbidites of the Whakataki Formation south of Castlepoint, Wairarapa, North Island, New Zealand. In the Whakataki Formation, three sets of cataclastic deformation bands are identified: (1) normal-sense compactional shear bands (CSBs), (2) reverse-sense CSBs, and (3) reverse-sense shear-enhanced compaction bands (SECBs). During extension, CSBs are associated with normal faults. When propagating through clay-rich interbeds, extensional bands are characterised by clay smear and grain size reduction. During contraction, sandstone-dominated sequences host SECBs, and rare CSBs, that are generally distributed in pervasive patterns. A quantitative spacing analysis shows that most outcrops are characterised by mixed spatial distributions of deformation bands, interpreted as a consequence of overprint due to progressive deformation or distinct multiple generations of deformation bands from different deformation phases. As many deformation bands are parallel to adjacent juvenile normal faults and reverse faults, bands are likely precursors to faults. With progressive deformation, the linkage of distributed deformation bands across sedimentary beds occurs to form through-going faults. During this process, bands associated with the wall-, tip-, and interaction-damage zones overprint earlier distributions resulting in complex spatial patterns. Regularly spaced bands are pervasively distributed when far away from faults. Microstructural analysis shows that all deformation bands form by inelastic pore collapse and grain crushing with an absolute reduction in porosity relative to the host rock between 5 % and 14 %. Hence, deformation bands likely act as fluid flow barriers. Faults and their associated damage zones exhibit a spacing of 9 m on the scale of 10 km and are more commonly observed in areas characterised by higher mudstone-to-sandstone ratios. As a result, extensive clay smear is common in these faults, enhancing the sealing capacity of faults. Therefore, the formation of deformation bands and faults leads to progressive flow compartmentalisation from the scale of 9 m down to about 10 cm – the typical spacing of distributed, regularly spaced deformation bands.

scholarly journals Numerical Simulation of Two-Phase Flows in Heterogeneous Porous Media

2020 ◽  
Vol 21 (2) ◽  
pp. 339
Author(s):  
I. Carneiro ◽  
M. Borges ◽  
S. Malta
Keyword(s):  
Porous Media ◽  
Oil Recovery ◽  
Flow Behavior ◽  
Water Injection ◽  
Heterogeneous Porous Media ◽  
Flow In Porous Media ◽  
High Porosity ◽  
Two Phase ◽  
Recovery Method ◽  
Porosity And Permeability

In this work,we present three-dimensional numerical simulations of water-oil flow in porous media in order to analyze the influence of the heterogeneities in the porosity and permeability fields and, mainly, their relationships upon the phenomenon known in the literature as viscous fingering. For this, typical scenarios of heterogeneous reservoirs submitted to water injection (secondary recovery method) are considered. The results show that the porosity heterogeneities have a markable influence in the flow behavior when the permeability is closely related with porosity, for example, by the Kozeny-Carman (KC) relation.This kind of positive relation leads to a larger oil recovery, as the areas of high permeability(higher flow velocities) are associated with areas of high porosity (higher volume of pores), causing a delay in the breakthrough time. On the other hand, when both fields (porosity and permeability) are heterogeneous but independent of each other the influence of the porosity heterogeneities is smaller and may be negligible.

scholarly journals Petrophysical Properties of Nahr Umar Formation in Nasiriya Oil Field

2020 ◽  
Vol 21 (3) ◽  
pp. 9-18
Author(s):  
Ahmed Abdulwahhab Suhail ◽  
Mohammed H. Hafiz ◽  
Fadhil S. Kadhim
Keyword(s):  
Gamma Ray ◽  
Water Saturation ◽  
Oil Field ◽  
Well Logs ◽  
High Porosity ◽  
Reservoir Properties ◽  
Petrophysical Parameters ◽  
Resistivity Logs ◽  
Lithology Prediction ◽  
Porosity And Permeability

   Petrophysical characterization is the most important stage in reservoir management. The main purpose of this study is to evaluate reservoir properties and lithological identification of Nahr Umar Formation in Nasiriya oil field. The available well logs are (sonic, density, neutron, gamma-ray, SP, and resistivity logs). The petrophysical parameters such as the volume of clay, porosity, permeability, water saturation, were computed and interpreted using IP4.4 software. The lithology prediction of Nahr Umar formation was carried out by sonic -density cross plot technique. Nahr Umar Formation was divided into five units based on well logs interpretation and petrophysical Analysis: Nu-1 to Nu-5. The formation lithology is mainly composed of sandstone interlaminated with shale according to the interpretation of density, sonic, and gamma-ray logs. Interpretation of formation lithology and petrophysical parameters shows that Nu-1 is characterized by low shale content with high porosity and low water saturation whereas Nu-2 and Nu-4 consist mainly of high laminated shale with low porosity and permeability. Nu-3 is high porosity and water saturation and Nu-5 consists mainly of limestone layer that represents the water zone.

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