The Triassic Yanchang Formation in the Ordos Basin is one of main exploration targets. Based on detailed outcrop at southern margin Basin, combined with previous results, a systematic analysis lithology, rock assemblage, sedimentary facies characteristics and temporal evolution carried out. results show that Changchang 9 oil-bearing group can be divided into lithofacies types, three types facie...

Low-permeability reservoirs, especially ultralow-permeability usually show a problem of ineffective water injection which leads to low pressure with high injection-production ratio. It is urgent determine the direction and proportion injection, so as guide adjustment development. Based on theory percolation mechanics combined modern well test analysis method, determination method effective rati...

Abstract: The Nenjiang Formation, south of Songliao Basin, has many hydrocarbon bearing units, but currently the understanding distribution viable reservoir sandstones is too limited to support a development strategy. Therefore, detailed study on sedimentary microfacies and properties been completed in order reduce uncertainty improve subsurface predictions. Nine lithofacies five associations w...

Abstract The conditions in ancient evaporative environments conducive to authigenic carbonate (especially dolomite [CaMg(CO 3 ) 2 ]) formation are still insufficiently understood. Insights from microfacies analysis can help constrain the these environments. We provide a brief overview of association and carbon oxygen isotope compositions beds intercalated claystone-rich succession Norian Arnsta...

The Fatha Formation, formerly known as the Lower Fars was deposited in a shallow basin, southern Iraq during Middle Miocene. By using description of cores, we found large heterogeneity lithology; contains mixing limestones, mudstone, marl, marly limestone, sandstone, and gypsum, or anhydrite. In this study, Formation divided into three main units according to lithofacies, namely, marl-anhydrite...