No abstract

A number of articles were published in the journal "Bulletin of the Oil and Gas Industry of Kazakhstan" in 202022 with the participation of the authors, , in which the experience of prospecting and exploration and development of deposits at ultra-deep depths (more than 6000 m) was analyzed. Since the industry has accumulated a significant number of successfully implemented ultra-deep projects, it may seem that such projects, in principle, have an increased chance of success. This is not so: when they are implemented, geological, technological and, most importantly, organizational and commercial problems arise even more often than when developing more traditional reserves. The several non-commercial projects considered in this paper cover almost the entire spectrum of possible cases of various structural and tectonic conditions: foothill depressions and intracraton basins, coasts, offshore and deep-water offshore areas. Stratigraphically, the time interval covers deposits from the Miocene to the Lower Paleozoic (Silurian) and a wide variety of lithofacial complexes. Based on the generalization, a list of possible reasons for making unsuccessful decisions is derived.

This paper discusses specific facies associated with Cretaceous deep‐water slumps and sandstone intrusions in the West Siberian Basin. The slumps were formed during sea‐level falls when storms caused sediment masses to be discharged into deep‐water areas where they imposed a significant load on the underlying semi‐consolidated black shales, deforming and partially destroying them. Multiple slump / avalanche events are observed at the boundary between the Lower Cretaceous (Neocomian) and Upper Jurassic (Tithonian) sequences and form potential targets for oil exploration. High‐resolution sequence stratigraphic analyses show that both slump and distal fans are genetically related to lower slope/basin floor sediments and were deposited during regressions and subsequent lowstands. Two key depositional environments are recognized: the proximal parts of fans, where the most prospective potential reservoirs are found; and the more distal parts of slumps, which are principally composed of deformed shale clasts in a silt‐mudstone matrix. A third facies (“slump head”) is only observed on seismic profiles and is probably related to horizontally displaced “shingled” semi‐consolidated black shales.

The second part of the article on deep-water deposits in the Norflet formation in the Gulf of Mexico discusses the history of discoveries as a result of the implementation of the largest geological exploration project as well as the project for the development of discovered fields implemented by Shell. The history of the Appomattox field discovery is discussed in more detail. This discovery played a key role in the entire history of this project, becoming the trigger for the transition to an unprecedented pace of exploration for ultradeep horizons in ultra-deep water (in total over 10 km). Prospects for further EA activity for Norflet formation in the Gulf of Mexico considered in the final part.

This article continues a series of reviews of the worlds oil and gas basins, where active exploration and development of hydrocarbon deposits in superdeep (6 km +) horizons are taking place, as probable analogues of projects in the Caspian megabasin, primarily the Eurasia project. In this regard the Gulf of Mexico is of great interest, since this region is very well studies over such a long history of its development and thus makes it possible to analyze a huge amount of data collected during this time. The Gulf of Mexico includes the deep-water, offshore and coastal parts of three countries the United States, Mexico and Cuba, and is one of the most important oil and gas provinces in the world. Its deposits are represented by various complexes from the Middle Jurassic to modern sediments, with a total thickness of 14,000 m and more. Exploration for hydrocarbons has been going on here for almost 100 years. During this time, various new technologies have been developed and successfully applied, such as forecasting abnormally high reservoir pressure, cyclostratigraphy and seismic facies analysis, characterization of low-resistivity productive reservoirs and the search for ultra-deep hydrocarbon deposits. Of all the variety of objects developed in the Gulf, in the context of the study of deep deposits, the main interest and possible associations with the Caspian megabasin are the deposits of the Norflet Formation of the Upper Jurassic, which are discussed in the main part of this article. Of course, we are not talking about a direct comparison; in particular, the aeolian origin of part of the section makes this object significantly different. Nevertheless, according to the authors, studying it, as well as understanding how a successful project for its development is being implemented right before our eyes, can provide a lot of important information for working in the deep horizons of the Caspian region. The article is divided into two parts. The first examines the geological history of the formation of the Gulf of Mexico Basin, the features of the deep-lying productive complex of the Norflet Formation. The second part provides information about the history of exploration of the Norflet productive complex, characteristics of the main discoveries, as well as the prospects for discoveries of new superdeep deposits in the Norflet Formation within the Gulf of Mexico (sectors of the United States and Mexico). Analysis of the history of the development of this complex by the global player Shell, is very important, as one of the scenarios for the development of deep horizons in other oil and gas basins, incl. Caspian. International Oil Companies are able to mobilize the necessary resources and technology to effectively address this challenge.