Modeling of optimal parameters that ensure the effective performance of well killing in conditions of abnormally low reservoir pressure

Abstract

Improving the efficiency of well-workover operations under conditions of hydrocarbon production is an urgent task. The object of the study is the process of killing gas wells in conditions of abnormally low formation pressure. In order to control technological parameters during well workover operations it is advisable to develop mathematical models that quantitatively describe the process of killing the well, allowing the calculation and selection of optimal parameters of killing fluid. This will reduce filtration of process fluids into the formation and contamination of the bottom-hole formation zone, which contributes to the restoration of productivity at the pre-repair level and rapid well commissioning. Development of a program combining hydrodynamic and filtration models of bottomhole formation zone blocking processes will allow selecting optimal technical and technological parameters and ensuring efficient workover operations under abnormally low formation pressure conditions. The aim is to improve the efficiency of gas and gas condensate field operations and the effectiveness of well maintenance in conditions of a significant decrease in reservoir pressure due to the development of methods for managing hydrodynamic processes in bottom-hole formation zone. Methods. To achieve the objectives of the study were analyzed and systematized data of scientific, technical and patent literature, conducted laboratory and computational experiments that allowed to study in detail the models of hydrodynamic processes of filtration of liquids into the formation. The developed mathematical models describing the process of well killing were implemented as a set of programs for computers by computer simulation method. Results. The mathematical model of killing process for gas wells with and without packer is developed and described. Analytical dependencies for calculation of aeration coefficient, taking into account the diameter of the nozzle for foam formation, formation pressure and well depth are given. A set of programs for selecting optimal technical and technological parameters ensuring effective killing of a well under abnormally low formation pressure conditions was developed on the basis of a mathematical model and tested. The developed mathematical model is a tool for calculation and selection of optimal technical and technological parameters, providing effective repair works, excluding work on excessive repressions and absorption of process fluids.