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High-entropy alloys (HEAs) present unique advantages in surface modification due to their stable mixed-state structures and resistance to intermetallic compound formation. This study investigates the surface modification behavior of equiatomic TiNbHfZnZr HEA components in Ti6Al4V alloy using friction stir processing (FSP). The aim is to enhance the mechanical properties and structural stability of Ti6Al4V by incorporating HEA elements. It was found that the introduction of high-entropy alloys forms shear bands with distinctive micro and nano gradient structures on the surface of the Ti6Al4V alloy. These shear bands not only significantly refine the grains but also promote β phase and β twin formation. The HEA-induced shear bands enhance the strength and stability of the alloy by creating bcc twins and dislocation networks that suppress martensitic transformation and maintain superelasticity. Concurrently, the introduction of HEA components leads to the formation of stable dual-phase (α + bcc) microstructures within the α matrix, significantly improving hardness and modulus.

The FⅠ17 fault is a prominent strike-slip fault in the central Tarim basin, notable for its hydrocarbon abundance and intricate tectonic attributes, characterized by several deflections in its planar trajectory. Analyzing the FⅠ17 fault offers crucial insights into the role of basement structures on the evolution and formation of intracratonic strike-slip fault systems. This study utilizes the latest seismic data and integrating the foundation of previous research to conduct a detailed investigation into the spatial distribution, deformation intensity, activity phases, and formation mechanisms of the fault. The fault can be divided into three structural layers based on deformation features. The deep layer, situated beneath the TЄ3 interface (the bottom of the Upper Cambrian), shows basement rifts and weak strike-slip activity. The middle layer, spanning from TЄ3 to TO3 (the bottom of the Upper Ordovician), exhibits pronounced deformation with flower-like structures. The upper layer, extending from the TO3 to TP (the bottom of the Permian), is marked by three groups of en-echelon normal faults. Controlled by Precambrian basement heterogeneity, the fault evolved through three stages: weak compressive stress during the Middle -Late Cambrian led to rupture along basement rifts and weak zones that formed the fault’s embryonic shape; strong compressive stress from Middle-Late Ordovician activated and propagated the fault upwards; during the Silurian-Carboniferous, the fault experienced episodic reactivation and result in the emergence of en-echelon normal faults. Hydrocarbon enrichment at the FⅠ17 fault is influenced by source rock distribution, reservoir characteristics, and fault reactivation. Its positioning above the source rock center ensures an ample supply of hydrocarbon. The intense fault activity has created favorable conditions for large-scale fracture-cavity reservoir development, and the reactivation period corresponds with the hydrocarbon accumulation phase, significantly boosts hydrocarbon charging.

Objective As a newly discovered source rock in the Fuman area of the Tarim Basin, the source rock of the Tumuxiuke Formation has good petroleum exploration prospects, and the geochemical evaluation of the source rock is conducive to guiding exploration. Methods The qualitative and quantitative characterization of drill cuttings from the Tumuxiuke Formation in the Fuman area was carried out by means of total organic carbon (TOC) content, Rock-Eval pyrolysis, and GC-MS analysis of saturated and aromatic hydrocarbons. Results The results show that the source rock of the Tumuxiuke Formation is a good to excellentsource rock, with an average TOC content of 3.4%. The highest hydrogen index (HI) is 590 mg/g, and the kerogen type is mainly type Ⅱ. According to the molecular geochemical characteristics, the source rock was formed in a marine sedimentary environment with weakly reducing brackish water, with aquatic algae as the primary hydrocarbon-generating organisms.Based on the peak temperature (Tmax) of Rock-Eval, saturated hydrocarbon biomarker compounds, and aromatic hydrocarbon thermal maturity parameters, the source rock of the Tumuxiuke Formation is generally in the mature-medium mature evolution stage and has good hydrocarbon generation potential. Conclusion As the sedimentary center of the Huanman Depression, the southern Fuman area may have thicker and higher-quality Tumuxiuke source rock with a greater degree of thermal evolution, whose contribution to the oil and gas resources in the Ordovician cannot be ignored.

Gradient porous structures based on triply periodic minimal surfaces offer exceptional specific strength and multi-functionality. However, strain heterogeneity complicates their deformation mechanisms and fracture modes. In this study, we fabricated a series of gradient porous NiTi alloys based on gyroid (G), diamond (D), and I-WP (I) unit cells, with porosities ranging from 50% to 70%. Surprisingly, the I structure exhibited an abnormally high compressive strength of nearly 600 MPa at around 50% porosity, more than twice that of the G and D structures. This performance gap was attributed to the activation of mixed deformation mechanisms and distinct fracture modes. While the G structure showed a uniform radial strain distribution, the D and I structures displayed pronounced radial strain gradients with concentrated central strains. The D structure deformed through relative sliding of oblique struts, while the I structure maintained macrostructural stability, with thick edge struts providing continuous strain hardening until monolithic fracture. This unique deformation behavior results from the synergistic effects of its intrinsic macrostructural stability, significant radial strain gradients, and sufficiently thicker edge struts. The integration of metallurgical and architectural design principles represents a novel approach to tailoring the mechanical properties of gradient porous metals for advanced applications.

The Shunbei 5 (SB5) strike-slip fault, situated in the central Tarim basin, is distinguished by its considerable length, significant variations in planar orientation, and intricate multi-stage tectonic evolution. This study delves into the geometric, kinematic, and dynamic features of both the southern and northern parts of the SB5 fault, utilizing the latest seismic data from the Fuman Oilfield, and examines the factors influencing the fault’s planar deflection. The fault can be categorized into three structural deformation layers based on lithological features and fault features: the deep structural deformation layer (below TЄ3), characterized by basement rifting and limited strike-slip activity; the middle structural deformation layer (TЄ3-TO3), marked by vigorous strike-slip movements and the dominance of flower structures; and the shallow structural deformation layer (TO3-TP), featuring echelon-type normal faults and boundary graben faults, specifically in the southern SB5 fault. The fault activity is more pronounced in its southern SB5 fault compared to the northern, with the weakest activity at the TЄ3 interface and the peak at the TO3 interface. The southern SB5 fault transitions to sinistral slip at the TO3 interface, while the northern SB5 fault shifts from dextral to sinistral slip at the TC interface, highlighting variable slip directions across different interfaces. Rifts are extensively distributed within the Precambrian basement along the SB5 fault. The initial strike-slip fault rupture, which is primarily localized in these areas, exerts a significant influence on the formation of the S-shaped fault plane. This process involves four distinct evolution stages: the embryonic stage of strike-slip activity during the Middle-Late Cambrian; the intense strike-slip fault activity stage during the Middle-Late Ordovician; the reactivation stage of deep strike-slip fault in the Silurian; and the connection and reactivation stage during the Devonian-Carboniferous.

In the central Tarim Basin, numerous hydrocarbon deposits were found along ultra-deep strike-slip faults, and its evolving progress and formation mechanism are research hotspots. The Paleozoic small-angle X-type strike-slip fault in the Tabei Uplift is the research subject in this article. Based on high-precision three-dimensional seismic data, three structural deformation layers were revealed: the rift system, weak strike-slip deformation and salt tectonics in the deep structural layer (Sinian–Middle Cambrian), the strong strike-slip deformation and karst-dissolution structure in the middle structural layer (Upper Cambrian–Middle Ordovician), and echelon normal faults in the shallow structural layer (Upper Ordovician–Carboniferous). The formation and evolution of strike-slip faults is jointly controlled by the distribution pattern of basement rift and the activities of surrounding orogenic belts, which can be divided into three stages. In the Middle to Late Cambrian, the initial subduction of the Paleo-Asian and Proto-Tethyan oceans precipitated the emergence of two sets of small-angle X-type strike-slip faults, striking NW and NE above the grooves of Precambrian rifts, influenced by local weak compressive stress. Affected by the closure of peripheral paleo-ocean, strike-slip faults deformed considerably in the Middle–Late Ordovician and were reactivated in the Silurian–Carboniferous, forming en-echelon normal faults in the shallow layer. The layered deformation structure of the strike-slip faults significantly affects the accumulation of hydrocarbons. The differential hydrocarbon enrichment of faults in the Tabei Uplift is collectively influenced by the distribution of source rocks and the migration of oil and gas. The topographical features of the Tabei Uplift, along with the distribution of strike-slip faults across tectonic units, have rendered the NE direction the preferential pathway for hydrocarbon migration. Additionally, impacted by the development of en echelon faults, the NE-trending faults offer superior conditions for hydrocarbon preservation and charging condition, compared to the NW-trending faults.

Titanium and its alloys are promising materials for engine production, special pump manufacturing, and bone implants. However, the abrasion resistance and fracture toughness of Ti alloys are insufficient to withstand extreme high loading conditions and harsh environments. Surface modification is an effective way to improve the performance of Ti alloys. In this study, Ag and Cu were added to Ti6Al4V alloy through friction stir processing to modify its surface. The different ratios of the Ag/Cu powder mixture were designed to optimize the surface modification of Ti6Al4V, and the relationship between intermetallic compounds and martensitic transformation was analyzed. The martensitic transformation was induced by AgCuTi phases. The submicron-size martensite was distributed outside the AgCuTi particle, while the nano-laminar martensitic band was generated inside the AgCuTi particle. Under the co-modification of Ti alloy using Ag and Cu, the surface of Ti6Al4V alloy exhibited higher hardness (4.3 GPa) values and lower modulus (100.6 GPa), which gave the credit to the formation of AgCuTi and martensitic transformation. The alloy specimen was subjected to short heat treatment at 600 °C for 30 min to further modify the gradient structure. After the short heat treatment of the Ag/Cu co-modified specimen, a lower modulus (88.8 GPa) and a high level of hardness (4.1 GPa) were achieved. In addition, superelastic strain recovery was also enhanced, showing the further induced martensitic transformation. This work provides new insight into the surface modification of titanium alloys using the FSP method to achieve the ideal hardness and elastic modulus balance.

Intracratonic strike-slip faults have been recognized as a major factor controlling the formation of fracture-cave carbonate reservoirs in deep buried basins, yet which properties and how the strike-slip faults influence reservoir distribution and their connectivity are still ambiguous. This uncertainty significantly restricts hydrocarbon exploration and development, such as in the Fuman oilfield, northern Tarim Basin, NW China. Using a high-resolution 3D seismic reflection survey and borehole data, we investigated the geometry and kinematic evolution of the FI17 fault zone in the Fuman oilfield. This fault zone is characterized by a single fault zone, pop-up or pull-apart structures, right-stepping en echelon normal faults, and much smaller displacement (

A giant fault-controlled oilfield has been found in the ultra-deep (greater than 6000 m) Ordovician carbonate strata in the northern Tarim Basin. It is of great significance for hydrocarbon accumulation study and oil exploitation to determine the key oil accumulation periods. Based on detailed petrographic analysis, fluid inclusion association (FIA) in calcite samples filling in fractures from 12 wells were analyzed, and key accumulation periods of the strike-slip fault-controlled oilfield was studied by combining oil generation periods of the source rocks, formation periods of the fault and traps, and the fluid inclusion data. (1) There are multiple types of FIA, among them, two types of oil inclusions, the type with yellow fluorescence from the depression area and the type with yellow-green fluorescence from the uplift area with different maturities indicate two oil charging stages. (2) The homogenization temperature of the brine inclusions in FIA is mostly affected by temperature rises, and the minimum temperature of brine inclusions symbiotic with oil inclusions is closer to the reservoir temperature during its forming period. (3) FIA with yellow fluorescence all have homogenization temperatures below 50 °C, while the FIA with yellow-green fluorescence have homogenization temperatures of 70–90 °C tested, suggesting two oil accumulation stages in Middle–Late Caledonian and Late Hercynian. (4) The Middle–Late Ordovician is the key formation period of the strike-slip fault, fracture-cave reservoir and trap there. (5) The oil generation peak of the main source rock of the Lower Cambrian is in the Late Ordovician, and the oil accumulation stage is mainly the Late Ordovician in the depression area, but is mainly the Early Permian in the uplift area. The key oil accumulation period of the strike-slip fault-controlled reservoirs is the Late Caledonian, the depression area has preserved the primary oil reservoirs formed in the Caledonian, while the uplift area has secondary oil reservoirs adjusted from the depression area during the Late Hercynian. Oil reservoir preservation conditions are the key factor for oil enrichment in the strike-slip fault zone of northern Tarim, and the Aman transition zone in the depression is richer in oil and gas and has greater potential for exploration and development.

The largest carbonate condensate field in China has been found in the central Tarim Basin. Ordovician carbonate reservoirs are generally attributed to reef-shoal microfacies along a platform margin. However, recent production success has been achieved along the NE-trending strike-slip fault zones that intersect at the platform margin. For this contribution, we analyzed the strike-slip fault effects on the reef-shoal reservoirs by using new geological, geophysical, and production data. Seismic data shows that some NE-trending strike-slip faults intersected the NW-trending platform margin in multiple segments. The research indicated that the development of strike-slip faults has affected prepositional landforms and the subsequent segmentation of varied microfacies along the platform margin. In addition, the strike-slip fault compartmentalized the reef-shoal reservoirs into multiple segments along the extent of the platform margin. We show that fractured reef-shoal complexes are favorable for the development of dissolution porosity along strike-slip fault damage zones. In the tight matrix reservoirs (porosity < 6%, permeability < 0.5 mD), the porosity and permeability could be increased by more than 2–5 times and to 1–2 orders of magnitude in the fault damage zone, respectively. This suggests that high production wells are correlated with “sweet spots” of fractured reservoirs along the strike-slip fault damage zones, and that the fractured reservoirs in the proximity of strike-slip fault activity might be a major target for commercial exploitation of the deep Ordovician tight carbonates.

The largest ultra-deep (>6000 m) strike-slip fault-controlled oilfield in the world is found in the Tarim Basin of Northwestern China. The localized fractured reservoirs are the major production targets along the strike-slip fault zones. Different from its use in the primary porous-type reservoirs, however, the conventional technology is not favorable for use in oil/gas development in Ordovician carbonate reservoirs. For this reason, high-density seismic acquisition and high-resolution seismic processing were carried out to provide high-precision data for fault and fractured reservoir identification. In addition, the multi-filtering process and the maximum likelihood method are typically used to identify small faults and fault segments along a strike-slip fault zone. Further, seismic facies-constrained inversion and amplitude attributes are favorable for large fracture-cave reservoir description. With the advancements in seismic technology, the high and stable production well ratio has been doubled in the “sweet spots” of fractured reservoir optimization, and the first ultra-deep strike-slip fault-controlled oilfield with an annual oil production of over 1 million tons has been realized, achieving economic development in the ultra-deep fractured reservoirs. However, unstable production and high rates of production decline are still significant challenges in the economic exploitation of the ultra-deep fractured reservoirs. Seismic technology requires further improvement for the description of small fractured reservoirs and matrix reservoirs, as well as reservoir connectivity prediction and hydrocarbon detection in the deep subsurface.

A giant strike-slip fault-controlled Fuman Oilfield has been found in the Ordovician fractured carbonates of the Tarim Basin. However, conventional seismic methods are hardly able to distinguish the fractured reservoir and its connectivity in the ultra-depth (>7000 m) carbonate fault zones. We propose thin-likelihood and tensor-thickness process methods to describe the fracture network and large cave reservoir, respectively. Together with the two methods for 3D visualization of fracture-cave reservoirs, we had an application in the ultra-deep well deployment in Fuman Oilfield. The results show that the fracture network and cave reservoir can be 3D-imaged more clearly than conventional methods. The fracture network and cave reservoir show distinct segmentation by the fault assemblage in Fuman Oilfield. Furthermore, 3D modeling is favorable for the reservoir connectivity description along the carbonate fault zones. There are three distinct reservoir models: fault core-, fault damage zone- and overlap zone-controlling fractured reservoirs along the fault zones. This revealed variable fractured reservoirs that are related to fault maturity and segmentation. The method has been widely used in fracture-cave reservoir description and subsequent well optimization, suggesting a favorable method for economic oil exploitation in the ultra-depth reservoirs. This case study is not only useful for the complicated reservoir 3D description and modeling but also helpful for well employment to provide support for the target evaluation and optimization in ultra-depth fractured reservoirs.

A giant, ultra-deep (>7000 m) strike-slip fault-related oilfield has been found in the central depression of the Tarim Basin. However, little research has addressed this discovery to understand the fault effects on the oil migration, which constrains the oil exploitation deployment and well optimization. Based on fault modeling and fluid analysis, we present the effects of fault segment on the oil segmentation and migration in the ultra-deep Fuman Oilfield. The results show a distinct fault segmentation and also subsequent variable fault architecture and non-connected fracture network other than a through-going fault zone. There are fault segment-related isolated fractured reservoirs and fluid variation along the fault strike, which indicates that a large oilfield comprises a series of unconnected small oil reservoirs along the fault segments. The fluid segmentation and molecular indicator of dibenzothiophenes reveal that there is a variable petroleum lateral migration along the strike-slip fault segment. The fault segmentation is a major contribution in the varied oil accumulation along the strike-slip fault zone in Fuman Oilfield. This case study suggests that fault segmentation has variable effects on petroleum migration and accumulation along the strike-slip zone.

The fractured-vuggy carbonate oil resources in the western basin of China are extremely rich. The connectivity of carbonate reservoirs is complex, and there is still a lack of clear understanding of the development and topological structure of the pore space in fractured-vuggy reservoirs. Thus, effective prediction of fractured-vuggy reservoirs is difficult. In view of this, this work employs adaptive point cloud technology to reproduce the shape and capture the characteristics of a fractured-vuggy reservoir. To identify the complex connectivity among pores, fractures, and vugs, a simplified one-dimensional connectivity model is established by using the meshless connection element method (CEM). Considering that different types of connection units have different flow characteristics, a sequential coupling calculation method that can efficiently calculate reservoir pressure and saturation is developed. By automatic history matching, the dynamic production data is fitted in real-time, and the characteristic parameters of the connection unit are inverted. Simulation results show that the three-dimensional connectivity model of the fractured-vuggy reservoir built in this work is as close as 90% of the fine grid model, while the dynamic simulation efficiency is much higher with good accuracy. [ABSTRACT FROM AUTHOR]