Optimization of a Separationless Three-Phase Oil–Water–Gas Flowmeter of Horizontal Orientation with Dual-Isotope Gamma Densitometers

Information on the characteristics of separationless three-phase oil–water–gas flowmeters of horizontal orientation is presented, probably, for the first time; it is related to the optimization of their design based on experimental studies of single-isotope and dual-isotope gamma densitometers (GD) and a combined conical narrowing device (ND), which consists of two sequentially installed cones of various dimensions. The experiments were carried out on both real oil–gas–salt water mixtures at a TUV SUD NEL test bench (Glasgow) and with model exxsol–gas–fresh water flows at the GET195-2011 standard of multiphase flows at the All-Russia Research Institute for Flow Metering (Kazan) using typical flowmeters with a nominal diameter of DN 100. It is shown that it is advisable to install a γ-densitometer in a cross section with an intermediate diameter of D = 70 mm, use a cone of 70/50 mm as the measuring ND, and use a cone of 100/70 mm to preaccelerate the flow in order to reduce the variety of flow regimes of two-phase and three-phase flows in the measuring ND and in the flow part of the γ-densitometer. This significantly improves the characteristics of the prototype flowmeter. Some of the obtained characteristics are compared with those of the well-known Vx Schlumberger vertical analogue, and designs of variants of an advanced horizontal three-phase flowmeter are presented, which also make it possible to increase its service life and raise the operating pressure.