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In many subsurface studies, facies and petrophysical properties are two important reservoir parameters that are closely correlated. They are routinely used in well interpretation, hydrocarbon reserve calculation and production profile prediction. These two parameters have commonly been determined in two separate tasks because of their mathematical differences (facies are discrete, and petrophysical properties are continuous). However, this is incorrect because facies and petrophysical properties are often strongly correlated. Therefore, we propose a new joint inversion method of facies and petrophysical properties based on a bi‐level optimization model. In the bi‐level optimization model, the upper‐level problem is the petrophysical property inversion while the lower‐level problem can identify the facies and add a facies‐related constraint for the upper‐level optimization. We also develop a new genetic algorithm for the discrete‐continuous inversion problem based on the bi‐level optimization model because the inversion problem usually has multiple local solutions. In addition, rock physics and statistics are combined in the inversion process. A rock physics model is used to establish the basic relationships between the petrophysical and elastic parameters, and the statistical approach is used to describe the intrinsic connection among the multiple reservoir parameters based on well log data. The numerical experiments indicate that the traditional separate prediction method and the new joint inversion method can quickly obtain more accurate results. In the application examples of real data, the inversion results can be matched to the well log data within the limits of the input data resolution, which further verifies the reliability and application potential of this new method. [ABSTRACT FROM AUTHOR]

The Cryogenian–Ediacaran strata in the Kuruktag block, northeastern Tarim Craton, are pivotal for deciphering the breakup of Neoproterozoic Rodinia and related peripheral subduction processes. This study reveals previously unidentified Ediacaran strata in the western Kuruktag block, characterized by deltaic plain clastic rocks and channel deposits. Zircon geochronological analyses of basalts and sandstones indicate a maximum depositional age of ~596 Ma, thereby attributing these strata to the Ediacaran Yukengou Formation in conjunction with prior paleontological findings. The prevalence of lithic fragments and two primary detrital zircon age populations within the Yukengou Formation sandstones suggest a rift basin environment, in contrast to a passive continental margin, receiving detrital material from the neighboring Paleoproterozoic basement and Neoproterozoic magmatic activity. As a result, the Cryogenian–Ediacaran strata are posited to have been deposited in an aulacogen basin. The presence of numerous Neoproterozoic zircon grains further implies significant volcanic events preceding and concurrent with Cryogenian rifting, suggesting that continental rifting along the northeastern Tarim margin may have been instigated by subduction-induced extension. [ABSTRACT FROM AUTHOR]

The low-rank matrix completion theory based on nuclear-norm minimization is becoming increasingly popular in practice, and has been applied to seismic data reconstruction of missing traces. In this paper, we investigate the weighted nuclear-norm minimization model on low-rank seismic texture matrix which is obtained with a designed texture-patch pre-transformation. Unlike the previous nuclear-norm model that treats all singular values of the seismic data matrix equally, the weighted nuclear-norm model, based on the idea of iterative reweighting, makes a closer approximation to the ‘counting rank function’ and can promote the low-rank matrices. We apply weighted spectral soft-thresholding iterative scheme and weighted iterative supported detection method to solve the weighted model. Experimental study on synthetic and real seismic data shows that high-quality reconstruction can be obtained by the weighted low-rank methods. [ABSTRACT FROM AUTHOR]