Similarity measure of sedimentary successions and its application in inverse stratigraphic modeling

This paper presents a unique and formal method of quantifying the similarity or distance between sedimentary facies successions from measured sections in outcrop or drilled wells and demonstrates its first application in inverse stratigraphic modeling. A sedimentary facies succession is represented with a string of symbols, or facies codes in its natural vertical order, in which each symbol brings with it one attribute such as thickness for the facies. These strings are called attributed strings. A similarity measure is defined between the attributed strings based on a syntactic pattern-recognition technique. A dynamic programming algorithm is used to calculate the similarity. Inverse stratigraphic modeling aims to generate quantitative 3D facies models based on forward stratigraphic modeling that honors observed datasets. One of the key techniques in inverse stratigraphic modeling is how to quantify the similarity or distance between simulated and observed sedimentary facies successions at data locations in order for the forward model to condition the simulation results to the observed dataset such as measured sections or drilled wells. This quantification technique comparing sedimentary successions is demonstrated in the form of a cost function based on the defined distance in our inverse stratigraphic modeling implemented with forward modeling optimization.

A Climatic Sequence Stratigraphic Model in the Terrestrial Lacustrine Basin:A Case Study of Green River Formation,Uinta Basin,USA

In recent years, with the development of terrestrial sequence stratigraphy, more attention has been focused on the study of the terrestrial lacustrine sequence stratigraphic model globally. Different viewpoints are preferred by researchers. Under the guidance of the theory of sequence stratigraphy, the findings of this paper indicate that climate is a major factor controlling the formation of the fourth-order sequence, based upon the study of the sequence stratigraphy in the Green River Formation of the Uinta basin in the USA. It also divides the fourth-order sequence in the terrestrial lacustrine basin into two system tracts： the wet （rising） half-cycle and the dry （falling） half- cycle, establishing a new-style fourth-order sequence stratigraphic model for the terrestrial lacustrine basin, that is, the climate-genetic sequence stratigraphic model. As a result, the theory of sequence stratigraphy is greatly enriched.

Estimating stratal completeness of carbonate deposition via process-based stratigraphic forward modeling

Hiatuses are ubiquitous in stratigraphic records at various temporal scales,but they cannot be easily identified and quantified owing to the lack of adequate methods in determining the duration of hiatuses or stratal completeness.Here a processbased stratigraphic forward modeling(SFM)approach was used to effectively estimate the completeness of carbonate strata in three dimensions and at basin-scale.By using information derived from both spatial and temporal domains in the SFM outputs for five grid locations(pseudo wells)under different depositional settings,we were able to delineate basin-wide hiatuses of various temporal scales and determine their durations and stratal completeness quantitatively.The stratal completeness appears to be controlled by sea level changes,depositional environments,carbonate growth rates and tectonic subsidence patterns in various ways.

Study on Carbonate Sequence Stratigraphy of Ordovician in Northern Ordos Basin

The formation of carbonates is different from that of siliciclastics. The controlling factors, such as the in-situ production of carbonates the transport, local variation in depositional processes and the way of dispersal are unique to carbonates systems, and have resulted in the formation of a wide variety of stratal patterns. The authors believe that all the factors influencing the formation of carbonates, such as the evolution of carbonate platform, transgression and regression, drowning and exposing of the platform, should be taken into consideration during the study of carbonate sequence stratigraphy.This paper attempts to summarize the study procedure in outcrop sequence stratigraphy and to describe the integrated identification of condensed section, first flooding surface and maximum flooding surface, so that the framework of high-resolution sequence stratigraphy can be constructed. During the Sandokan in early Ordovician, a carbonate-siliciclastic ramp was developed in northern Ordos, which changed into a carbonate rimmed shelf or a distally steepened ramp during the Zhuozishan and Kelimoli. It was the break in the Wulalike and Middle Ordovician,changing the sedimentary setting into an aulacogen According to the basin evolution, the authors have established some different idealized models for depositional sequences and systems tracts.