Open AccessRozwiązania techniczne i technologiczne końcowego wyposażenia odwiertów z odcinkiem odchylonym i horyzontalnym w odwiertach na Niżu Polskim
Author(s) -
Marian Wolan
Publication year - 2021
Publication title -
nafta gaz
Language(s) - English
Resource type - Journals
ISSN - 0867-8871
DOI - 10.18668/ng.2021.08.04
Subject(s) - completion (oil and gas wells) , workover , borehole , geology , high pressure , hydrostatic pressure , petroleum engineering , computer science , engineering , geotechnical engineering , physics , engineering physics , thermodynamics
The article covers typical problems during realization of completion projects in the Polish Lowlands. It also presents harsh reservoir conditions encountered at the time of completion. Very high pressure gradient (over 0.021 MPa/m), relatively small thickness of cap rock layer, small differences between hydrostatic pressure and fracture pressure and high concentrations of CO2 and H2S require experience and knowledge when completing the wells. The article discusses the main functions and most common elements of completion assembly. Only a few sample completion assemblies that are used in boreholes in the Polish Lowlands are presented. Each element is described with emphasis placed on its tasks and advantages during completion, production phase of the well, as well as during workover and abandonment operations in the well. Some completion schemes common in the Polish Lowlands are presented together with their advantages and capabilities depending on final equipment used for completion and its location in the completion assembly. Selection of materials and elastomers used in completion assembly is shown depending on reservoir conditions. The article also presents a brief analysis of stresses that can occur in completion assembly during stimulation treatments, e.g. during acidizing of carbonate reservoir rocks, killing the well, operation of the well. Tools and equipment necessary for completing the well, determined by well construction and well conditions are described. Wells have been divided into two types depending on the trajectory of the well, up to 30° and above 30°, which influences the selection of equipment used to perform the operations of controlling the elements of the final completion assembly of the wells. It was emphasized that the selection of equipment to control the above-mentioned elements also depends on other conditions, such as the parameters of the fluid in which these operations are performed or the depth. The article also outlines the procedures necessary before and during the installation of the completion assembly.