Fracture Properties and Their Impacts on Performance in Carbonate Reservoir, Central Block B on the Right Bank of Amu Darya

AbstractThe Callovian-Oxfordian carbonate reservoir in central Block B on the right bank of Amu Darya is composed of different mechanical and petrophysical layers, where the tectonic fractures have major influences on both the performance and production of the low-permeability reservoir. The development of the tectonic fractures is mainly controlled by the mechanical properties of rocks (e.g., lithology, rock texture, porosity, and shale volume), and the differences in the development of tectonic fractures leading to the high production intervals are restricted preferentially due to fractured mechanical layers. Our study results show that the three main tectonic fracture systems are developed in the Callovian-Oxfordian Stage, including the fracture systems caused by extension movement, compression movement, and fold deformation. Specifically, high-angle extensional fractures and conjugate shear fractures are generally caused by extension movement, which are of small apertures and are mostly fully mineralized and have little impact on fluid flow. Medium- and low-angle extensional fractures as well as conjugate shear fractures are generally caused by compression movement where the strike is nearly parallel to the present-day maximum horizontal stress. These fractures have large aperture and good connectivity with strong flow conductivity of the fluid. However, fewer tectonic fractures are caused by fold deformation. The main properties of natural fractures, such as fracture length, fracture density, fracture aperture, fracture porosity, and stress sensitivity as well as their impacts on the Callovian-Oxfordian reservoir performances, are described herein. We conclude that the tectonic fractures have slight impacts on porosity albeit significant impacts on permeability. Hence, the well placement and well type are optimized under the guidance of the study results

Analysis of Mechanical Characteristics of Accumulation Body in Post-disaster Roadway

Aiming at the problem of boundary force of the accumulation body in the post-disaster roadway, on the basis of the site investigation and on the premise of slip effect in the process of fragment accumulation, the calculation formula of boundary force of the accumulation body is derived, and the experimental verification is carried out. The results show that the collapse of roadway section in fault fracture zone is mainly filled with rock fragments, and the adjustment mode of “self-organization” in the process of fragment accumulation is divided into transverse movement adjustment, longitudinal movement adjustment and self-rotation adjustment. The force acting on the boundary of the accumulation body originates from the slip effect in the process of fragment accumulation, and the calculation formula of the passive resisting force in accumulation body boundary is derived, which is related to the bulk density of the block, the buried depth, the horizontal distance from the highest point of the accumulation body to the boundary and the stopping angle. The experimental results verify the correctness of the calculation formula, but the applicable condition of the formula depends on the ratio of particle size to the horizontal size of the accumulation body. The smaller the K value is, the more suitable the formula is

Depositional and Diagenetic Controls on Reservoir Quality of Callovian-Oxfordian Stage on the Right Bank of Amu Darya

Based on the detailed analysis of sedimentology, diagenesis, and petrophysics, this study characterized the Middle-Lower Jurassic Callovian-Oxfordian carbonate reservoirs of 68 key wells in the Amu Darya Basin and assessed the controlling factors on the quality of the target intervals. We identified 15 types of sedimentary facies developed in seven sedimentary environments using sedimentary facies analysis, such as evaporative platform, restricted platform, open platform, platform margin, platform fore-edge upslope, platform fore-edge downslope, and basin facies. The target intervals went through multiple diagenetic stages, including the syndiagenetic stage, early diagenetic stage, and middle diagenetic stage, all of which had a significant impact on the reservoir quality. Main diagenetic processes include dissolution and fracturing which improve the reservoir quality as well as cementation, compaction, and pressure solution that reduce the reservoir quality. By analyzing the reservoir quality, we identified nine fluid flow units and five types of reservoir facies. Among them, the dissolved grain-dominated reservoir facies is of the highest quality and is the best storage and flow body, while the microporous mud-dominated reservoir facies of platform fore-edge downslope and open marine facies is of the lowest quality and could not become the flow unit unless it was developed by fracturing

A Series of New Ligustrazine-Triterpenes Derivatives as Anti-Tumor Agents: Design, Synthesis, and Biological Evaluation

A series of novel ligustrazine-triterpenes derivatives was designed, synthesized and screened for their cytotoxicity against five cancer cell lines (Bel-7402, HepG2, HT-29, Hela, and MCF-7) and Madin-Darby canine kidney (MDCK). Current study suggested that most of the ligustrazine-triterpenes conjunctions showed better cytotoxicity than the starting materials. In particular, compound 4a exhibited better cytotoxic activity (IC50 < 5.23 μM) against Bel-7402, HT-29, MCF-7, Hela, and HepG2 than the standard anticancer drug cisplatin (DDP). The cytotoxicity selectivity detection revealed that 4a exhibited low cytotoxicity (IC50 > 20 μM) towards MDCK cells. A combination of fluorescence staining observation and flow cytometric analysis indicated that 4a could induce HepG2 cell apoptosis. Further studies suggested that 4a-induced apoptosis is mediated through depolarization of the mitochondrial membrane potential and increase of intracellular free Ca2+ concentration. In addition, the structure-activity relationships of these derivatives were briefly discussed

Water producing mechanisms of carbonate reservoirs gas wells: A case study of the Right Bank Field of Amu Darya, Turkmenistan

The mechanisms of carbonate gas reservoirs were systematically studied with the Right Bank Field of Amu Darya Gas Field, Turkmenistan, as an example. Water produced from the reservoirs has three sources, condensate water, engineering fluids and formation water. The fluid physical property and water-gas ratio (WGR) method for the single component conditions and the chloridion conservation method for the multi-components conditions were established to identify the components contained in the production fluids. A water production diagnosing curve, which refers to the degree of reserve recovery as a function of the water-gas ratio in the log-log coordinate curve, was then established and the formation water producing wells were divided into three patterns, i.e. Type 1, Type 2, and Type 3. Through in-depth studies of the static and dynamic reservoir characteristics of each pattern, the following understandings were attained: The reservoirs of Type 1 are mainly porous, and the water producing mechanism is bottom water coning along matrix pores; the reservoirs of Type 2 are mainly fractured-porous, and the bottom water produces basically through the natural fracture system; the reservoirs of Type 3 are mainly fractured-cavity, and the bottom water produces basically through large-scale fractures and caves. Key words: Turkmenistan, Amu Darya Basin, carbonate gas reservoir, water production source, diagnosing curve, water producing mechanis

Water Intrusion Characterization in Naturally Fractured Gas Reservoir Based on Spatial DFN Connectivity Analysis

In this study, the non-intrusive embedded discrete fracture model (EDFM) in combination with the Oda method are employed to characterize natural fracture networks fast and accurately, by identifying the dominant water flow paths through spatial connectivity analysis. The purpose of this study is to present a successful field case application in which a novel workflow integrates field data, discrete fracture network (DFN), and production analysis with spatial fracture connectivity analysis to characterize dominant flow paths for water intrusion in a field-scale numerical simulation. Initially, the water intrusion of single-well sector models was history matched. Then, resulting parameters of the single-well models were incorporated into the full field model, and the pressure and water breakthrough of all the producing wells were matched. Finally, forecast results were evaluated. Consequently, one of the findings is that wellbore connectivity to the fracture network has a considerable effect on characterizing the water intrusion in fractured gas reservoirs. Additionally, dominant water flow paths within the fracture network, easily modeled by EDFM as effective fracture zones, aid in understanding and predicting the water intrusion phenomena. Therefore, fracture clustering as shortest paths from the water contacts to the wellbore endorses the results of the numerical simulation. Finally, matching the breakthrough time depends on merging responses from multiple dominant water flow paths within the distributions of the fracture network. The conclusions of this investigation are crucial to field modeling and the decision-making process of well operation by anticipating water intrusion behavior through probable flow paths within the fracture networks

Ferritinophagy mediates adaptive resistance to EGFR tyrosine kinase inhibitors in non-small cell lung cancer

Abstract Osimertinib (Osi) is a widely used epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI). However, the emergence of resistance is inevitable, partly due to the gradual evolution of adaptive resistant cells during initial treatment. Here, we find that Osi treatment rapidly triggers adaptive resistance in tumor cells. Metabolomics analysis reveals a significant enhancement of oxidative phosphorylation (OXPHOS) in Osi adaptive-resistant cells. Mechanically, Osi treatment induces an elevation of NCOA4, a key protein of ferritinophagy, which maintains the synthesis of iron-sulfur cluster (ISC) proteins of electron transport chain and OXPHOS. Additionally, active ISC protein synthesis in adaptive-resistant cells significantly increases the sensitivity to copper ions. Combining Osi with elesclomol, a copper ion ionophore, significantly increases the efficacy of Osi, with no additional toxicity. Altogether, this study reveals the mechanisms of NCOA4-mediated ferritinophagy in Osi adaptive resistance and introduces a promising new therapy of combining copper ionophores to improve its initial efficacy