DESIGNS OF OIL-AND-GAS WELLS AND THEIR INFLUENCE ON THE DRILLING RESULTS

Abstract

The definition of the term “well” is provided in the article. The design of an oil-and-gas well in the Transcarpathian depressionis given as an example; the article contains explanations on which casing strings should be sunk, for what reason and how deep it should be done in order to get a positive result. This article demonstrates a scheme of equipping oil-and-gas wellheads with Christmas trees. Essential designs of project wells that ensure high-quality drilling resultsunder different geological conditions are shown in the article’s second part. The wells’ design on the territory of deposits with simple geological structure may be unsophisticated and include a conductor casing at a shallow depth and a flow string before overlaying of a payout bed. The deposits overlaid by sediments not during drilling require high density of drilling fluid; those sediments should be overlaid by a liner and continue to be drilledtillpayout beds and using fluids with low density. Multiple casing string designs are used under complex geological conditions and in case of extremely deep wells.