Water-Production Diagnosis Using Transient Test With Multiphase Flowmeter

Abstract

Accurate determination of oil, water, and gas production rates is an important element of oilfield management and optimization. Multiphase flow meters (MPFM) are being accepted more and more for well testing, reservoir management, production allocation, production monitoring, and fiscal metering. In addition to common MPFM applications, this study shows how a multiphase flow meter may be used as a valuable tool to evaluate water production problems of the well by imposing transient flowing conditions to the well and tracking characteristic parameters such as flowrates, water cut and gas oil ratio with the equipment during the test. Representative curves are shown in this study in order to identify some common wellbore problems associated with water conformance. The curves were obtained through numerical reservoir simulation using a number of cases related to the most important problems: water channeling in stratified formations, mechanical wellbore integrity, water conning, and oil-water contact advance. The flowrate at the well should be shortened to a half of the current flowrate with a choke for several hours then, the dimensionless pattern curves of the water cut and gas oil ratio gathered in this study should be matched with the measurement of the MPFM on site in order to characterize the nature of the water problem. This application represents a new tool used to identify the sources of water production. The tool is easy and quick to apply, and complements other analytical techniques being used like diagnostics plots based on production history, water-oil ratio performance and production logs. All of them are used to differentiate between the different mechanisms of water invasion, so that an appropriate treatment may be selected to control undesirable water production. IntroductionDuring the petroleum exploitation, the production of water can come from an aquifer or from injector wells in a waterflooding process. When excess of water production exists, the costs associated to surface facilities, artificial lift systems, corrosion and scale problems increases. Besides, the recovery factor decreases as oil is left behind the displacement front. These factors reduce the economic indicators. The drastic influence of water production must be soon detected and the source of such problem must be identified in order to apply effective and suitable techniques to control this production.

Diagnosing and Controlling Excessive Water Production: State-of-the-Art Review

“…Analytical and empirical procedures in view of production information make up the second category. In view of the characteristics of the reservoir and the fluid, other authors have developed less prevalent WPM diagnostic strategies [28][29][30][31]. Traditionally, the production logging tool (PLT) is used to identify water inflow zones when the water cut rises excessively at extreme levels.…”

Excess Water Production Diagnosis in Oil Fields Using Ensemble Classifiers

“…The second group consists of various analytical and empirical techniques based on production data. There are also other less common techniques proposed by different authors for WPM diagnostics based on reservoir and fluid characteristics (Novontny 1995;Egbe and Appah 2005;Gasbarri et al 2008;Ayeni 2008), which we will discuss in brief later in section 2.2.3.…”

“…They concluded that wells with coning problem represented periodic spectrums with narrow spectral width. Gasbarri et al (2008) proposed a diagnosis technique using transient test and multiphase flow meters. They used reservoir simulations to build three base cases of WPM models of coning, water channelling and flow behind casing.…”

Comparison Between Homogenous and Heterogeneous Reservoirs: A Parametric Study of Water Coning Phenomena

“…Therefore, the locus of the balance point is a stable cone shaped water oil interface. At this stable situation oil flows above the interface while water remains stationary below the interface (Gasbarri et al, 2007).…”

“…source of such problems must be identified in order to apply effective and suitable techniques to control water production (Gasbarri et al, 2007). The cause of water coning is an imbalance between the viscous and gravitational forces around the completion interval.…”