Dynamic Surveillance Templates for Reservoir Management: Diagnostic Tools Oriented to Production Optimization

Abstract

Abstract The huge number of available data imposes the use of finest tools to be shared by several stakeholders avoiding time consumption and repetition of same tasks1. This paper presents the use of dynamic templates developed on well known concepts in the literature, other than those frequently used for reservoir and production monitoring. This study proposes few tools developed on different fields that have proven useful in the surveillance and monitoring phases as well as the further optimization activity. The first recommended template is a key performance tool applied to gas/oil field named ‘Warning Index’ (WI). This index accounts for several crucial components for a given well such as draw down, Water Cut (WC), Gas Oil Ratio (GOR). It offers a quick snapshot of well production efficiency and the most critical wells in the fields. It can be extremely helpful in the well performance tracking, in the identification of field areas and wells that require a deep depth analysis. In the optimization activity for two deep water oil and gas fields an analysis has been performed through the ‘Dimensionless Productivity Index’2 (JD). A dynamic tool calculates this indicator for each well and compares it with the benchmark estimated for vertical no damaged well. The use of ‘Dimensionless Productivity Index’ template allows defining the level of damage, the effectiveness of stimulation activities, the minimum elapsed time among operations, the sudden changes in the well behaviour and performances. For an off shore gas field with high level of water production a dynamic template has been implemented in order to quickly define the critical gas rate for liquid loading. In this case the use of well head pressure regularly monitored day by day and PVT data coming from gas and water analysis allowed developing a dynamic plot that can track the critical gas rate and as a consequence define the best time for some interventions such as acid stimulation or nitrogen lifting. A further proposed template enables to evaluate the total drained area for an oil field with a huge number of producer wells. By tracking the variation of total drainage area is possible to define interference among wells, less drained area for infilling wells, effect of injection wells on producers, variation in time for a given well related to production conditions, damage or pressure support. Introduction Nowadays real time monitoring systems are becoming a standard set up for oil and gas fields. The increased efficiency in the raw data acquisition involves an enhancement in their processing and interpretation aimed at obtaining reservoir parameters. These properties are now analyzed not only by absolute value but by track, trend, regularity and impact to other related variables, defining a closed circle in the reservoir management and production optimization stream. Hereafter some applications for different fields and environments are presented. The current study consists in searching, collecting, checking and integrating reservoir and production data then carrying out a detailed analysis. The main goal is the implementation of new surveillance and diagnostic templates to be widely employed in the day by day reservoir management activity as a standard best practice. These new tools allow carrying out analysis on how field and wells are performing, if there are any critical conditions, moreover they can assist specialists in suggesting what kind of remedial job to perform and with which time interval. As a consequence these templates enable performing a dynamic diagnosis of field and well status offering an additional decision - making instrument to the engineer in the reservoir and production management activities.