Wireline Formation Tester (WFT) technologies are well known in oil field industry as a major crucial answers provider for formation evaluation especially during appraisal and exploration stages. Meanwhile, their applications are also very useful in the development period of complex brownfields such in the Caspian Sea offshore Turkmenistan to optimize production and increase cost-efficiency. The main challenges caused by geologic conditions including but are not limited as following: multi-layered sandstones with different hydrocarbons types (gas, gas condensate, oil) masked by shales, varying depletion due to heterogeneity and reservoir connectivity uncertainties, some of formations has a low H2S content, increasing water production, gas breakthrough and wax deposition. WFT provides current pressure measurements and this is important parameter for completion strategy as it defines perforation intervals, packer setting depths and type of screens for reservoir production inflow profile management. Multiwell analyses of pressures survey complimented by reservoir fluids geodynamic study are affording understanding about reservoir connectivity. Downhole fluid analysis allows to get in real-time information about reservoir saturation with formation fluids typing to control in future undesirable gas and water increasing issues. In order to qualify and quantify the wax related issues and manage them in flow assurance workflow laboratory test should be carried out on PVT sample acquired at reservoir conditions. H2S presence is varying across the field and identifying potentially soured layers is required special sampling technique to confirm and exclude them from production. More advanced WFT application such as pressure transient and vertical interference tests provide in situ measurements of effective permeabilities with anisotropy magnitude. Modern WFT tools were run for years on Djeitun (LAM) and Dzhigalybeg (Zhdanov) fields for production and flow assurance optimization purposes and main applications of this technologies will be discussed here. The benefits of pinpoint pressure measurements and subsequent gradient analysis are vital for analyzing reservoir connectivity. Real time fluid analysis with laboratory accuracy and a wide variety of packer and probe interfaces allow the acquisition of valuable fluid data and representative fluid samples down to quite low permeabilities with preserving reservoir conditions and capturing even extremely low H2S content. Also, years of pressure transient experience has been transported to the WFT environment enabling to derive a rich dataset of permeability what can be used to estimate interval productivity index. Cased hole WFT application allows to obtain information about fluid and reservoir properties in conditions where it was previously impossible in open hole due to technical or geological constraints.

In Western Kazakhstan, post-salt high porosity clastic reservoirs of the Caspian Basin of Jurassic and Triassic age are represented by multilayer and multi-contact deposits having several gas-oil (GOC) and oil-water contacts (OWC), formed by channel deposits. Reservoirs have good formation properties. Application of advanced logging suite allows to delineate all the key reservoir properties, such as effective oil-saturated thicknesses, all the types of contacts (GOC, GWC, OWC) along with some other properties. However, in such type of reservoirs, it is important to determine a connectivity of individual lobes/lenses – different small parts of deposits. This can only be achieved via well testing and fluid sampling. Traditional well testing has long been a must during the exploration stage to obtain vital information on reservoir dynamic properties. Usually, it is rather a tedious and time-consuming process, especially when there are many uncertainties on reservoir fluid saturations that can lead to increased well construction costs. This paper will discuss an example on how to optimize and accelerate well testing stage using advanced wireline formation tester and extended logging methods in an open hole, which, in turn, allows for faster commissioning of reservoirs into production. It is important to note that wireline formation testers cannot fully replace traditional well testing of wells and reservoirs; however, they significantly expand and improve the capabilities traditional well testing has to offer. Therefore, the most optimal solution proposed by Embamunaigas was the joint use of results of wireline formation tester and traditional well test data in green fields. This workflow has successfully been tested in its license areas in recent years.

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