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oa Increasing the Efficiency of Drilling Intervals of wells Composed of Unstable Rocks
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 18th International Conference Monitoring of Geological Processes and Ecological Condition of the Environment, Apr 2025, Volume 2025, p.1 - 5
Abstract
The experience of drilling wells of «Ukrburgaz» shows that at different depths, including over 5000m, in intervals composed of clays, siltstones and mudstones, complications almost always occur that adversely affect the pace of well construction. The most common complications are rock caving and collapse; wellbore narrowing in intervals of unstable rocks; excessive dispersion of clays, etc. The most common and severe complications are those that lead to changes in the configuration of the wellbore walls, namely their collapse and caving. The occurrence and course of these complications are influenced by two groups of factors: objective and subjective. The former are related to the lithological characteristics of the rocks in question and the presence of fractures in them, while the latter are related to incorrect technological solutions required for drilling such well intervals. Complications caused by the loss of well wall stability are most often observed in clay deposits, which are found in almost every well constructed in Ukraine. To solve these problems, it is advisable to apply a comprehensive approach that includes the selection of the type and properties of the drilling fluid, as well as new technologies, namely the use of pulsed fluid flow during well flushing.
