Eventos Anais de eventos
ENCIT 2018
Brazilian Congress of Thermal Sciences and Engineering
Effects of solubility on kick detection and pressure transmission
Submission Author:
Jonathan Galdino , PR
Co-Authors:
Jonathan Galdino, Gabriel Merhy de Oliveira, Admilson Franco, Cezar Otaviano Ribeiro Negrao
Presenter: Jonathan Galdino
doi://10.26678/ABCM.ENCIT2018.CIT18-0533
Abstract
Blowout is the most dangerous situation during well drilling operations and it only occurs when the kick, the phase that precedes a blowout, is not detected and controlled properly. Early kick detection is crucial for rig safety and is usually performed by observing the pit gain. Gas solubility reduces the pit gain. Kick control initiates by shutting-in the well and waiting for pressure stabilization. The closing pressures (SICP and SIDPP) measured at surface are used to determine the pore pressure. However, drilling fluid yield stress reduces the pressures measured. Consequently, the pore pressure and the necessary density of the drilling fluid to cease the influx may be underestimated. The purpose of this work is to develop a mathematical and numerical model to investigate the effects of gas solubility on kick detection and on pressure transmission after the well closure. The flow is assumed as transient, one-dimensional, laminar and compressible. Bingham model is employed to represent the drilling fluid behavior. Empirical correlations are used for gas solubility. The method of characteristics is employed to solve the balance equations of mass and momentum. The results indicate that gas solubility reduces considerably the pit gain and that the pressure transmission must be taken into account for a proper estimative of the pore pressure
Keywords
kick detection, pressure transmission, Yield-stress, solubility, Method of characteristics
