Late Paleozoic intracratonic shortening in southwestern Laurentia during the Ancestral Rocky Mountains (ARM) orogeny resulted in the formation of uplifted basement-cored fault blocks and flexural subsidence of adjacent basins. ARM deformation occurred during the final closure of the Rheic Ocean and the amalgamation of western equatorial Pangea, culminating in the Ouachita-Marathon-Sonora (OMS) orogeny. While the two orogenic events have long been linked kinematically, the temporal relationship and the geodynamic linkage between ARM and OMS deformation have become debated in recent years. This study investigates the syntectonic deposition and provenance evolution of the late Paleozoic Orogrande Basin and the tectonic unroofing of the basement-cored Pedernal faulted block in response to the ARM shortening in south-central New Mexico. Detailed detrital zircon (DZ) U−Pb ages (n = 3966 from 30 samples) and zircon (U−Th)/He double dating (n = 50 from five samples) help document a three-stage depositional history for the proximal Orogrande Basin in relation to reverse faulting along the western margin of the Pedernal block. The basal clastic section, represented by incised channels in the lower Gobbler Formation (Morrowan−Atokan), exhibits a pre-ARM Appalachian-type provenance signature, characterized by recycled Grenville (950−1300 Ma) and subordinate early Paleozoic DZ U−Pb ages. Upsection, these DZ components become diluted by locally derived Yavapai−Mazatzal and Granite−Rhyolite sources, signaling the early stages of the Pedernal unroofing. DZ provenance signatures rapidly shifted to a synorogenic unroofing signature linked to the Pedernal fault block, dominated by Yavapai−Mazatzal and Granite−Rhyolite and Grenvillian De Baca Group, defined by an age mode of ca. 1.25 Ga. This dominant DZ age signature derived from the Pedernal block remains uniform from the upper Gobbler (Desmoinesian) through the lower Abo formations (lower Wolfcampian) and constrains the timing of ARM shortening in the Sacramento Mountains from the Early Pennsylvanian to the earliest Permian. The upper part of the Abo Formation is marked by a sharp shift to a unimodal ca. 1.25 Ga DZ age signature, implying early Permian burial of the Pedernal block and cessation of ARM reverse faulting. DZ (U−Th)/He (DZHe) double dating of selected samples tracks the tectonic exhumation of the Pedernal fault block. While DZHe ages broadly scatter from the Pennsylvanian to the Mesoproterozoic, a young Carboniferous age mode (ca. 323 Ma) at the base of the section suggests rapid exhumation of a ca. 1.67 Ga ARM basement source. Upsection, the DZHe ages define a trend of progressively older cooling ages, typical of a reverse unroofing sequence of a sedimentary cover succession, characterized by the progressive erosion of un-reset lower Paleozoic strata followed by Pedernal crystalline basement. Overall, these DZ UPb and He ages from the proximal Orogrande Basin constrain the unroofing of the ARM-related Pedernal uplift from the Early Pennsylvanian to the earliest Permian, predating the Marathon fold-and-thrust belt deformation, the more proximal segment of the OMS orogen. Hence, these new constraints support a late Paleozoic transpressional margin in southwestern Laurentia as the driving mechanism for the synchronous ARM midcontinent deformation that largely predates shortening in the proximal Marathon fold-and-thrust belt.

The stability of the gas displacing oil front (i.e., gas–oil interface) is of the utmost importance for the success of the immiscible gas flooding project under crestal gas injection. However, the preceding gas flooding assessment models are deficient in their description of the gas flooding mechanism, and they do not take into account the critical influencing factors in a comprehensive manner. Utilizing theoretical derivation, oilfield justifications, criterion and experiment validation, and dimensional analysis on crestal gas injection for stable flooding, this study presents an innovative theory and technique for artificial CO2 gas cap immiscible rigid stable gas flooding under CO2 injection, which could not only greatly improve crude oil recovery but also realize CO2 geological storage on a large scale, and new insights into displacement mechanism on the gas–oil interface through artificial CO2 gas cap immiscible rigid stable gas flooding process. Based on the multiphase filtrate theory, considering the influencing factors such as crude oil density, crude oil viscosity, density of injected gas, gas injection rate, strata dip, liquid phase relative permeability, air permeability in formation direction, viscosity of injected gas, gas phase relative permeability and the acting forces such as buoyancy, gravity, driving pressure, capillary pressure, viscous force and additional resistance in multiphase flow during the artificial CO2 gas cap immiscible rigid stable gas flooding process under CO2 injection, A simple quantified artificial CO2 gas cap immiscible rigid stable gas flooding assessment model ({N_{{text{GOI}}}}) was established. The results indicate the artificial CO2 gas cap immiscible rigid stable gas flooding process has the theory and field feasibility of greatly enhancing crude oil recovery and realizing CO2 geological storage on a large scale. And the oil reservoirs with strata dip, which have large oil and gas density difference, small oil and gas viscosity ratio, large oil and gas relative permeability ratio, large strata dip, and large air permeability in the direction are easy to exert gravity and buoyancy, reduce the influence of capillary pressure, viscosity and additional resistance, benefit to maintain the stability of gas displacing oil front and improve microscopic oil displacement efficiency, and facilitate the implementation of artificial CO2 gas cap immiscible rigid stable gas flooding development. In addition, the theoretical deduction, field and experimental validation indicate that artificial CO2 gas cap immiscible rigid stable gas flooding under CO2 injection can be realized when {N_{{text{GOI}}}} is greater than 1. The proposed {N_{{text{GOI}}}} model can be used as a creterion to assess the stablity and efficiency of the crestal gas injection for stable flooding such as artificial CO2 gas cap immiscible rigid stable gas flooding, artificial CO2 gas cap immiscible stable gas flooding, GAGD, gravity assisted gas injection, and crestal gas injection for stable gravity flooding for theoretical investigation, numerical simulation, laboratory test and field trial project design or operation.

The South Aegean Sea hosts two ENE–WSW rift zones with sedimentary basins of 500–700 m depth: the Christiana–Santorini–Kolumbo–Amorgos (CSKA) and the Astypalaea–Nisyros–Kos (ANK) zones. These form discontinuous graben structures with sediment thicknesses of 600–700 m from the Late Pliocene to Quaternary. Both rift zones comprise active volcanic centres: Santorini–Kolumbo in the CSKA and Nisyros in the ANK. Segmented by transverse NW–SE fault lines, these zones produce 25–40 km fault blocks, limiting maximum earthquake sizes per segment. High seismic activity includes the 7.4 magnitude 1956 Amorgos earthquake in the CSKA and several ∼6.5 events near Kos in the ANK (1933, 2017). Volcanic activity is stronger in the southwestern CSKA, with eruptions in Santorini continuing from the Minoan event (∼3.6 ka) to 1950, while Nisyros last erupted in 1878–85. The CSKA rift is also marked by a dyke system along the Santorini caldera and aligned submarine domes extending NE from Kolumbo. Both rifts are slightly oblique to the Aegean volcanic arc, with NW–SE crustal extension confirmed by Global Positioning System, showing 4–5 mm a −1 extension between the eastern Cycladic and southern Dodekanese islands. These rift geometries reflect deep tectonic processes related to magma generation and shallow crustal deformation above the East Mediterranean subducted slab.

We investigated the Wood Mountain fault and the Show Goat formation in the northern Chiricahua Mountains in southeast Arizona, USA, to resolve the timing, style, and distribution of Late Cretaceous to Paleogene contractional deformation in the southern U.S. portion of the North American Cordillera. The Wood Mountain fault is a thin-skinned, low-angle to subhorizontal thrust fault that places Upper Paleozoic carbonate rocks structurally over the Upper Cretaceous to Paleocene Show Goat formation. The Show Goat formation is an ∼420-m-thick succession of syntectonic clastic and volcanic strata that overlie a prominent angular unconformity above steeply dipping mid-Cretaceous−age rocks of the Bisbee Group. The angular unconformity records initial uplift and erosion related to the onset of regional contractional deformation. New zircon U-Pb data indicate deformation started at ca. 90−73 Ma. The lower Show Goat formation consists of alluvial-fan deposits that formed adjacent to uplifted fault blocks. The upper Show Goat formation records the development of a local volcanic center and primarily consists of lithic tuffs, ash-rich mudstones interpreted as volcanic mudflows, and andesitic lava flows and ash-flow tuffs. New detrital and igneous zircon U-Pb geochronology data constrain deposition of the Show Goat formation between 73 Ma and 63 Ma. New zircon U-Pb data from volcaniclastic deposits of the Bobcat Hill Formation in the Peloncillo Mountains, New Mexico, USA, located ∼30 km east of the Chiricahua Mountains, indicate regional volcanism and syntectonic sedimentation started ca. 80 Ma. A compilation of regional syntectonic deposits suggests that Late Cretaceous to Paleogene contractional deformation cannot be characterized by a single deformation front propagating toward the foreland. Locally, deformation may have been out-of-sequence or episodic. Syntectonic basins in southeast Arizona and southwest New Mexico were relatively small and localized, formed within an actively deforming orogenic wedge, and were not part of a spatially continuous basin or depocenter.

Summary Offshore low-permeability oil reservoirs are an important component of global energy reserves, yet the drilling and fracturing costs are significantly higher than those onshore. Thus, offshore development typically requires fewer wells with higher production, which leads to larger well spacing, wider low-pressure gradient areas, and more obvious low-velocity nonlinear flow. Therefore, there is an urgent need to investigate the nonlinear flow on the well and the fracture design in offshore low-permeability reservoirs. Here, we first establish a reservoir simulation method with multimechanism, including low-velocity nonlinear flow, fracture conductivity reduction, matrix stress sensitivity, complex fault block, and fracture. A grid preprocessing technology is developed to implement embedded discrete fracture on corner point grid. Then, the nonlinear flow parameters are fitted based on experimental data. Finally, the optimal design of well and fracture is investigated. The results show that the staggered well pattern is first recommended, followed by opposite well pattern. As the matrix permeability increases, the recommended well spacing gradually increases, and the fracture penetration ratio and conductivity gradually decrease. The lower the matrix permeability, especially below 10×10−3 μm2, the more significant the nonlinear flow characteristics in the target reservoir block. When the matrix permeability is 2×103 μm2, compared with Darcy flow, the optimal well spacing, fracture penetration ratio, and conductivity differ by 50%, 17%, and 13.6%, respectively.

Research on the principal reservoir architecture of lacustrine delta-front: A case from the second member 7-8 sand groups of Shahejie formation (Es27-Es28) in Liang 60 fault block

Study on the Distribution Characteristics of Remaining Oil of Typical Fault Block Reservoir in Ordos Basin

Rich Oil Regularity and Rolling Development Technology in Complex Fault Block Reservoirs

To enhance the oil recovery of the Ha-34 fault block reservoir in the A'nan depression of the Erlian Basin (a low-permeability heavy oil reservoir), a novel composite nano-oil-displacing agent (CNODA) was formulated, several indoor experiments (stability, wettability, interfacial tension, emulsion state, oxygen-17 nuclear magnetic resonance (¹⁷O NMR), dynamic light scattering, zeta ( ζ ) potential and core flooding) were performed and outdoor well group flooding projects were conducted. The following results were obtained: (1) visual observations (no precipitation) and a higher ζ potential (>±30 mV) demonstrated the exceptional stability of the nanofluid system; (2) the CNODA increased the contact angle of the oil droplets on the glutenite surface from 29.3° to 151.1°; (3) the CNODA had a solid capacity to reduce the oil–water interfacial tension (IFT) (0.065 mN m −1 , ultralow IFT) and could let the oil pass through the capillary throats; (4) the CNODA increased the sweep efficiency of the reservoir and decreased the mobility ratio of the injection fluid to the formation fluid; (5) the SiO 2 nanoparticles dispersed in the fluid, weakened the hydrogen bonds and formed small water clusters, which is the essence of oil-displacement agents entering low porosity; (6) the CNODA could detach the oil droplets from rock surfaces through structural disjoining pressure; and (7) outdoor two-well and five-well group flooding projects increased oil production by 1269.55 t (enhanced oil recovery (EOR) of 59.1%) and 3376.22 t (EOR of 53.3%), respectively. In other words, the CNODA could peel off the oil droplets in the Ha-34 fault block reservoir by creating stronger oil‒rock (water) interactions, a higher sweep coefficient, a reduced pore throat limit for oil-displacement agents to enter and a greater structural disjoining pressure.

Due to strong compression in the later stage, multiple rows of positive structural zones were formed in southern Sichuan. The Dengjingguan structure is a high and steep structure with a complete anticline morphology, which develops from bottom to top and has favorable overall structural conditions. There are many drilling wells in the Jialingjiang Formation of the Dengjingguan structure, with drilling concentrated in the 1950s and 1960s. There are only three wells with complete drilling curves, and the faults within the structural zone are developed and fragmented as a whole. It is difficult to accurately identify the structural traps of the fault blocks within the structural zone, making it difficult to evaluate exploration potential and affecting subsequent well site deployment. In response to this issue, this article uses newly acquired 3D seismic data to carry out fine structural interpretation, combined with the actual drilling situation of production dynamic data, and combines static and dynamic to complete the evaluation of the Dengjingguan structural block. Dynamically leveraging the advantages of the new 3D, we can sort out the development patterns of faults from regions to blocks, and then from blocks to local systems, and use coherent attributes to determine the distribution of faults. Dynamically utilize the pressure coefficient of drilling and the production data of gas wells to validate the static interpretation plan, conduct well to well comparisons, and repeatedly revise the static interpretation results. The evaluation of fault block traps through the combination of static and dynamic gas reservoirs effectively reduces the ambiguity of complex high steep structural fault block interpretation, improves the rationality between wells, and provides reliable basis for the subsequent exploration and well location deployment of oil fields. It has good guidance and reference significance for the potential evaluation of complex high steep structural fault blocks in southern Sichuan in the future.

The research on formation water injection, gas injection, and mixed injection media is too complicated, especially for fault block oil and gas reservoirs, which lacks systematic reports from experimental demonstration to field practice. Aiming at a characteristic block, we have carried out a systematic study on the evaluation of nitrogen immiscible flooding in the early stage → engineering adaptability evaluation → engineering verification. We use a shorter research process and combine the advantages of experiment and software simulation, and finally put forward the screening standard of nitrogen immiscible flooding reservoir suitable for the study area. The results show that gas injection from high position in this study area is effective and the recovery factor reaches 46.75%. When the gas injection reaches 200 min, the nitrogen front begins to break through. The gas injection rate of this well group is 40 ∼ 80 m/d, and the reasonable gas injection rate is 2 × 104 ∼ 3 × 104 m3/d. Nitrogen can change the wettability of rocks under certain conditions, so as to improve the seepage channel or reduce the viscosity of crude oil. At the same time, nitrogen gas molecules are easier to enter micro-fractures and matrix pores than water molecules, which can displace crude oil in smaller matrix pores and fractures and increase the oil displacement sweep volume.

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 222836, “Compartmentalization, Complex Filling History and Operational Oil Alteration Caused by EOR Processes Revealed Using State-of-the-Art Multivariate Geochemical Fingerprinting in a Mature Abu Dhabi Oilfield, UAE,” by Tamer Koksalan, SPE, Karem A. Khan, SPE, and Andi A. Salahuddin, ADNOC, et al. The paper has not been peer reviewed. _ The studied Abu Dhabi onshore field, characterized by over 60 producing horizontal wells, has undergone extensive hydrocarbon recovery through miscible techniques for more than 15 years. The field’s recent expansion includes delineation wells drilled to appraise potentially separate oil pools to the west and confirm structural integrity and reservoir continuity. This study leverages oil-fingerprinting technology and geochemical data to evaluate fluid connectivity between the main field and stepout wells. Field Background The main field’s horizontal-well production is assisted by water-alternating-gas (WAG), CO2-WAG, and CO2 enhanced oil recovery. The WAG has been operational for 15 years. Recently, the operator has drilled delineation wells beyond the main oil pool. For instance, Well X-194 was drilled approximately 9 km to the west to confirm structure and appraise the presence of a potentially separate oil pool west of the proven oil pool (Fig. 1). Well X-196 is another stepout well approximately 6.5 km to the southeast of Well X-195 and 4.5 km to the west of Well X-3. Well X-196 is in a different fault block, which is separated by the N45W fault system from the main proven area and which has a different pressure datum and regime and free water level. All wells are perforated in the same reservoir in the upper subzones, and only Well X-28 is perforated in the lowest subzone. The wells are drilled off-structure, and their perforations were completed only in upper subzones. Well X-194 is an updip trap with a sealing fault on the west side. Well X-196 was drilled in the downdip extent of the upper subzone to delineate the fringe of the main field. The upper subzone is a much thinner pay zone close to the basal aquifer with potentially lower overall oil saturation. The objective of this study was to assess the fluid connectivity at the reservoir level by using geochemical oil-fingerprinting technology on separator-produced oil samples from the onshore main Field X wells and stepout Wells X-196 and X-194. Nine produced oils were analyzed. Those oils were from the two western stepout areas (Wells X-194 and X-196), the crest of the main field (Well X-28), wells adjacent to Well X-196 across the fault (Wells X-90 and X-154) and four additional wells across the main field. All these oils are moderate-maturity, black oils with gravity values ranging from 37 to 39 °API. High-resolution gas chromatography (HRGC) was used to characterize these oils for this reservoir-connectivity study.

The Miocene succession of the Bakr–Amer–Al Hamd fields, central Gulf of Suez, Egypt, is interpreted using seismic integration and well logs to delineate its structural and sequence stratigraphic framework. Three Tectono-Stratigraphic Megasequences (TSM) of the Miocene rifting phases: pre-Miocene (pre-rift), Oligo-Miocene (syn-rift), and post-Miocene (post-rift) are outlined by forty seismic lines and seven wells. Sequence stratigraphic analysis identifies three third-order depositional sequences: SQ-I (Early Miocene Gharandal Group), SQ-II (Middle Miocene Belayim Formation), and SQ-III Late Miocene (South Gharib and Zeit Formations). A major unconformity at the Middle-Upper Miocene boundary represents a regional depositional hiatus. Structural interpretation reveals a dominant NNW-SSE syn-rift fault system (Clysmic trend) with 50–700 m fault throws, forming half-grabens and horst blocks that have a strong control on reservoir distribution. The Hammam Faraun Member of the Belayim Formation, composed of reefal limestone (Nullipore), is the principal hydrocarbon reservoir with 15–35% porosities. Structural contour maps highlight the compartmentalization of reservoirs and hydrocarbon entrapment by tilted fault blocks. These findings contribute to the knowledge of syn-rift carbonate and clastic reservoirs in extensional basins and provide key analogs for hydrocarbon exploration in rift systems globally, particularly in those characterized by complex fault-controlled deposition and evaporite-sealed traps.

ABSTRACT In this article, the Modular Multilevel Converter (MMC) having a modified mixed-cell Submodule (SM) with improved DC-side fault current blocking capability for the High Voltage Direct Current (HVDC) system is presented. This improved design reduces the number of MMC SMs by one-third times compared to the traditional MMC, yet maintains a high level of output power quality. A mixed cell constitutes a series connected Half-Bridge (HB) and modified Full-Bridge (FB) in an SM. It comprises a power diode, two asymmetrically charged isolated capacitors, and five IGBTs with antiparallel diodes. Isolated capacitors are charged according to the binary Geometry Propagation (GP) ratio in an SM so that it can generate a maximum four-level output voltage. The proposed SM features a reduced device count, lesser converter level faults and losses, higher efficiency, low voltage and current harmonic distortion, DC fault blocking capability, etc. The dimensioning of the proposed MMC converter is discussed in detail. Also, a comparison of the proposed modified mixed-cell SM with other SM topologies in terms of power losses, component count, output voltage level, and DC fault-blocking capability is discussed. Finally, the feasibility of the proposed topology is validated by both simulation and experiments.

The South China Sea (SCS) is located in the region of convergence between the Eurasian, Indo-Australian and Pacific plates. In previous studies, the diachronic movement of these plates led to a complex picture of tectonic evolution of the rifting stage before opening of the SCS. The Yundong Low Uplift (YLU) is a synrift uplift with an asymmetric structure located in the Baiyun Sag in the northern SCS. In this study, the formation process of the YLU is studied on the basis of 3D seismic reflection data. Based on multiple profiles comparing the 3D structures, we determined that the detachment faults controlling the formation of the YLU are composed of several secondary faults. There is significant cross-cutting and uplift on these secondary faults, accompanied by rotation of the fault blocks, denudation of the strata and some synrift magmatism. Therefore, the cross-cutting and merging relationships of multiple faults revealed in the seismic profiles indicate that the formation of the YLU in the northern SCS is consistent with the classical listric normal fault-controlled model proposed for North American metamorphic core complexes. Finally, we determined that the YLU formed during the synrift stage and underwent three uplift processes, and the formation of the YLU corresponded to the Huizhou movement ( c. 43 Ma) defined by previous studies in the Zhu 1 Depression. This study enriches the model for genesis of synrift uplift in the northern SCS margin, and also contributes to our understanding of the regional tectonic evolution.

Abstract In the wind power transmission system via DC under the support of a weak grid, there is a transient process on the same time scale as the fault duration. The existing calculation method of temporary overvoltage based on surplus reactive power does not consider the transient characteristics of the system, and there is a large error in the calculation of temporary overvoltage under a weak grid. In this paper, research is carried out through theoretical derivation and simulation verification. Firstly, the AC grid near the sending end is reasonably simplified and equivalent to a second-order circuit, and the analytical expression of the transient voltage is given. Then, combined with the actual physical process, the physical meanings of the transient component and the steady-state component in the total transient voltage response are respectively discussed. Finally, based on the Matlab/Simulink simulation platform, a typical system model of wind power transmission via DC is built to verify the correctness of the proposed method. The results show that the equivalent second-order transient response method proposed in this paper has high accuracy in describing the short-term temporary overvoltage characteristics and calculating the overvoltage peak value after the DC bipolar blocking fault.

As is known, one of the critical challenges in Ukraine's railway transport sector in recent years has been ensuring the reliability of passenger cars. Increasing train speeds, enhancing safety levels, and meeting higher passenger comfort requirements necessitate ensuring high operational reliability of passenger cars. Reducing passenger car downtime and improving their operational readiness can be achieved by minimizing the time required to assess the operability of electronic equipment and locate failures within its electronic components. This issue can be addressed by conducting research, developing, and implementing advanced methods for reliability assessment, as well as technical diagnostic methods and tools for passenger car equipment. The authors of this article have developed a methodology for assessing the design reliability of passenger car electronic equipment. Using this methodology, a study was conducted on the design reliability of automation devices integrated into passenger car control panels. The reliability of the electronic equipment was standardized, and reliability parameters were calculated considering operational coefficients. A modern passenger car is a complex engineering system, consisting of a combination of mechanical, electronic, and electrical systems. Up to 75 % of the total repair time for systems is spent on fault localization in complex radio-electronic systems, including preparation for fault detection. The most critical automation devices include the electronic blocks of the generator voltage regulator, frequency relay, battery charge control, and protection units. Therefore, when troubleshooting and monitoring operability, it becomes crucial to determine the most optimal sequence of operations, ensuring the shortest possible verification time for electrical equipment. The research results can significantly reduce the time required to locate faults in the electronic blocks of passenger cars, thus enhancing their reliability and operational readiness. Based on the calculated reliability parameters of the car’s electronic blocks, a new diagnostic technology has been proposed. This technology considers the calculated reliability parameters, the time required for diagnosing components, and determines the optimal sequence for diagnosing electronic equipment according to a calculated priority criterion.

This study provides a comprehensive analysis of seismic activity and structural characteristics in Shandong Province, China, with a focus on identifying seismic belts and potential epicentral zones critical for regional seismic safety. A detailed database was developed, integrating regional seismicity statistics, earthquake distribution patterns, significant geotectonic movements, and recent neotectonic activities. The results reveal that seismic activity in Shandong is heterogeneously distributed, with moderate to strong earthquakes predominantly associated with active fault zones and exhibiting zonal clustering. Earthquakes are generally shallow, occurring within the middle to upper crust, with historical destructive events averaging a focal depth of 19 km, while recent minor seismic events average 14.9 km in depth. These activities span North China Plain and Tan-Lu Seismic Statistical Areas. Projections indicate sustained or heightened seismic activity over the next century, with the potential for earthquakes up to magnitude 5. The geological framework is dominated by Luxi Fault Block and Tan-Lu Fault Zone, characterized by episodic uplift and subsidence driven by neotectonic movements. The prevailing horizontal tectonic stress regime supports the likelihood of strike-slip faulting as the predominant mechanism.

Abstract In order to identify the main controlling factors affecting the unsteady water drive development, a conceptual model considering planar heterogeneity is established by using numerical simulation software. The main controlling factors affecting the unsteady water drive development are analyzed based on the numerical model. The geological factors mainly analyzed are planar heterogeneity, permeability, and crude oil viscosity. While the development factors are mainly analyzed from the aspects of recovery degree, pressure retention level, and water cut rise rate. The results show that the development effect of an unsteady water drive is better than that of a conventional water drive for reservoirs with strong heterogeneity. Unsteady water drive development is more suitable for reservoirs with strong heterogeneity, low permeability, low oil viscosity, high-pressure retention level, low recovery degree, and high water cut rise rate. Considering the reservoir selecting technical limits for unsteady water drive development, the H34 fault block is suitable for unsteady water drive development, which provides a theoretical basis for subsequent unsteady water drive development.

Fault-fold-block structures of the Earth’s crust play a critical role in the formation of stress states and in controlling seismic processes. These structures, along with the faults that border them, accumulate stresses and are responsible for generating strong earthquakes. A detailed analysis of geological, geophysical, and seismic data, combined with mathematical modeling has allowed the identification of fault structures and blocks of higher ranks. Investigating the stress state of such structures and the patterns of their interaction is allowed essential for predicting the sources of strong earthquakes. This study examines the seismotectonics of similar structures in the Uzbek segment of the Western Tien Shan microplate.