Reservoir heterogeneity is a key geological problem that restricts oil and gas exploration and development of clastic rocks from the early to late stages. Existing reservoir heterogeneity modeling methods such as multiple-point geostatistics (MPS) can accurately model the two-dimensional anisotropic structures of reservoir lithofacies. However, three-dimensional training images are required to construct three-dimensional reservoir lithofacies anisotropic structures models, and the method to use reservoir heterogeneity model of fewer-dimensional to obtain a three-dimensional model has become a much-focused research topic. In this study, the outcrops of the second member of Qingshuihe Formation (K1q2) in the northwestern margin of the Junggar Basin, which are lower cretaceous rocks, were the research target. The three-dimensional reservoir heterogeneity model of the K1q2 outcrop was established based on the unmanned aerial vehicle (UAV) digital outcrops model and MPS techniques, and the “sequential two-dimensional conditioning data” (s2Dcd) method was modified based on a sensitivity parameter analysis. Results of the parametric sensitivity analysis revealed that the isotropic multigrid simulations demonstrate poor performance because of the lack of three-dimensional training images, conditioning data that are horizontally discrete and vertically continuous, and distribution of lithofacies that are characterized by large horizontal continuities and small thicknesses. The reservoir lithofacies anisotropic structure reconstructions performed well with anisotropic multigrids. The simulation sequence of two-dimensional surfaces for generating the three-dimensional anisotropic structure of reservoir lithofacies models should be reasonably planned according to the actual geological data and limited hard data. In additional to this, the conditional probability density function of each two-dimensional training image should be fully utilized. The simulation results using only one two-dimensional section will have several types of noises, which is not consistent with the actual geological background. The anisotropic multigrid simulations and two-dimensional training image simulation sequence, proposed in this paper as “cross mesh, refinement step by step”, effectively reduced the noise generated, made full use of the information from the two-dimensional training image, and reconstructed the three-dimensional reservoir lithofacies anisotropic structures models, thus conforming to the actual geological conditions.

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Calcite‐cemented concretions can reduce reservoir quality and form important low‐permeability baffles for fluid flow in sandstone hydrocarbon carrier beds/reservoirs. Understanding the origin and distribution patterns of concretions has important implications for characterizing reservoir heterogeneity and developing fields. The origin of calcite concretions in non‐marine sandstones lacking detrital carbonate to source the cement is poorly studied. The practical difficulty of obtaining the precipitation temperature of the concretions prevents the precise determination of the source of cement components, solute flux, pore water type and the geochemical microenvironments in which cement precipitated. Carbonate clumped isotope thermometry can give unique constraints to the temperature of concretionary cement precipitation. This study focused on outcrops of the Lower Cretaceous non‐marine Qingshuihe Formation in the Urho area, on the north‐western margin of the Junggar Basin (West China). Four depositional facies associations were recognized, corresponding to channel, mid‐channel bar, abandoned channel and overbank floodplain environments. Calcite concretions occur only in sandstones and include spherical, ellipsoidal and tabular forms. They are isolated and/or mutually aligned in layers that tend to be either at the top, base, or within channel and mid‐channel sand bodies. The clumped isotope temperatures for the concretionary calcite range from 31 to 45°C with a standard error of <3°C. The calcite has highly variable, low δ13C values ranging from −16.91 ± 0.01 to −2.93 ± 0.02‰ (Vienna Pee Dee Belemnite). The 13C‐depleted bicarbonate source was linked to biodegradation of migrated oils at shallow burial owing to tectonic uplift and erosion. Calcite δ18O values are very consistent and fall between −12.30 ± 0.04 to −9.79 ± 0.31‰ (Vienna Pee Dee Belemnite). Introduction of meteoric water was a dominant mechanism for the pronounced 18O‐depletion in the oxygen isotopes of pore water, along with water–rock interaction during alteration of volcaniclastic materials in sandstones. Meteoric groundwater flushed the Qingshuihe sandstones as confined aquifers down the regional palaeo‐slope, biodegrading the migrated oils and enabling a sufficient solute flux for precipitation of concretions.