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During the development of a sand-conglomerate reservoir, there is a huge variation in rock grain size and different åmineral compositions of different-sized sand grains. The mineral composition and microstructure of the rock both have an impact on the characteristics of the remaining oil in the reservoir. The stripping mechanism of a surfactant system on sand-conglomerate surface crude oil with varied grain size minerals was explored in this paper. Sand-conglomerate was classified and analyzed to determine their wettability and stripping oil effects. The optimization of the surfactant solution system and molecular dynamics simulation revealed the surfactant stripping mechanism on crude oil on distinct sandstone minerals. The results of the study showed that montmorillonite minerals are more readily adsorbed by surfactants. The crude oil within them is more likely to compete for adsorption and to be stripped off, and then extracted with the recovery fluid. The surfactant solution system can increase the hydrophilicity of the rock surface, make the crude oil on the rock surface shrink and gather, and enhance the transportation ability of the displacement fluid. And the emulsification seals part of the pore in the reservoir, increases the displacement pressure, and improves the overall wave volume. The results of this paper are of great significance for the efficient development of sand-conglomerate reservoirs.

This study investigates the mechanisms behind strong water sensitivity in some low-clay-mineral-content tight conglomerate reservoirs in China’s Mahu Sag. Using core-scale water sensitivity tests, mineral analysis, in situ micro-CT scanning, and digital core techniques, we analyzed how water sensitivity alters pore structures across cores of varying permeability. Key findings include the following: (1) Water sensitivity damage increases as initial gas permeability decreases. (2) Despite low clay content, significant water sensitivity arises from the combined effect of water and velocity sensitivity, driven mainly by illite and kaolinite concentrated in gravel-edge fractures and key flow channels. (3) Water sensitivity causes non-uniform pore structure changes—some macropores and throats enlarge locally, reflecting heterogeneity. (4) Structural responses differ by permeability: medium–low permeability cores suffer from clay mineral swelling and particle migration, whereas high-permeability cores resist overall damage and may even have main flow paths enhanced by flushing. (5) Water sensitivity mainly degrades smaller pores but can improve larger ones, with the critical pore-size threshold between macro- and micro-pores inversely related to permeability. This work clarifies the pore-scale mechanisms of water sensitivity in some low-clay-mineral-content tight conglomerates, and can provide guidance for the optimization of water types injected into similar conglomerate reservoirs.

We examine the organizational choice and innovative activity of technology conglomerates—firms that explore different technology fields with heated inventive activity. We develop a measure of firm-to-economy technological proximity to capture the extent of a firm’s technology conglomeration. We show that technology conglomerates are more likely to form alliances and that these alliances lead to higher patent output. In terms of underlying mechanisms, we show that after alliance formation, there are significant knowledge pooling and cross-fertilization between technology conglomerates and their alliance partners. Moreover, technology conglomerates produce more patents that are novel and/or with greater impact. Our findings suggest that both synergy and tolerance for failure are important motives for technology conglomerates to use alliances to accelerate corporate innovation.

We argue and demonstrate that resource allocation within firms' internal capital markets provides an important force countervailing financial market dislocation. We estimate a structural model of internal capital markets to separately identify and quantify the forces driving the reallocation decision and illustrate how these forces interact with external capital market stress. The weaker (stronger) division obtains too much (little) capital, as though it is 12% (9%) more (less) productive than it really is. Out-of-sample simulated data are consistent with the actual data showing that internal capital markets offset financial market stress during the recent financial crisis by 16%–30%.

The microstructure of rock plays a vital role in the deformation and fracturing process when subjected to external loading. Conglomerate, being a pivotal part of unconventional reservoir, is characterized by a distinct composition structure and high degree of heterogeneity. Thus, a proper understanding of the impact of microstructure on the mechanical properties of conglomerate is crucial. We conduct uniaxial and triaxial compression tests on conglomerate samples, accompanied by monitoring acoustic emission events and ultrasonic wave velocity. Experimental results show that: (1) conglomerate fails in tension under uniaxial compression, but in shear fracture or cataclastic flow with volume expanding under triaxial compression; (2) the deformation transforms from brittle to ductile with increasing confining pressure. Two failure modes may exist in the brittle–ductile transition regime, namely, shear fracture and cataclastic flow; (3) the relationship between the mechanical characteristics and average gravel size is consistent with the “Hall–Petch” empirical relationship. The confining pressure required for brittle–ductile transformation reduces with larger average gravel size. Microscopic observation demonstrates that two gravels contacting with each other may fail in Hertzian fractures. Shear slip and rotation of gravel occurs under triaxial compression. We propose a conceptual model to describe the deformation of conglomerate under different confining conditions and compare the deformation properties of conglomerate with sandstone.HighlightsThe effects of microstructural and micromechanical properties on the deformation of conglomerate deformation are studied.Both the peak strength and the brittle–ductile transition pressure reduce with higher average gravel size.Discrepancy between gravel and matrix deformation dominates the cracks initiation, while the location of gravel affects the propagation.

Conglomerate reservoirs are important oil and gas resources that require hydraulic fracturing for stimulation. However, the heterogeneity of conglomerate rocks causes fractures to propagate irregularly, complicating the fracturing design. To provide insight into the complex fracture behavior in conglomerate rocks, a three-dimensional (3D) hydromechanical numerical model based on the discrete element method (DEM) was proposed in this study. Besides, a novel approach combining the grain-based DEM with Voronoi tessellation was adopted to depict the geometrical characteristics of conglomerate rocks. Considering the rock matrix-interface-gravel structure, the effects of various influencing factors including the strength and permeability, in situ stress difference, fluid properties and injection scheme on the fracture propagation and induced microseismic events were investigated. Two fracture behaviors, penetration and deflection, were summarized. Finally, the mechanisms of different fracture behaviors were discussed, revealing the joint effects of various factors on the fracture behavior. To predict the fracture behavior in conglomerate rocks, an explainable machine learning framework comprising the extreme gradient boosting and the shapley additive explanations was adopted, which attained high accuracy on the testing set. It can also provide comprehensive explanations for the predicted results, offering support for practical decisions.