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Events such as hydraulic gradients in the horizontal completion, geologic and fluid variations in the reservoir and well placement issues can produce very poor steam conformance in the Steam Assisted Gravity Drainage (SAGD) process. Operators have implemented many strategies in an effort to address the issue. Simultaneous injection in inner tubing and annulus space or dual-tubing completions are commonly used in SAGD wells to provide controllable injection and production from the heel and toe regions of the horizontal well pair but this does not guarantee both uniform and efficient performance. This paper presents a study of a hybrid of two technologies to improve both conformance and economics of this thermal process. Recent work suggests that using Proportional-Integral-Derivative (PID) feedback to control the steam injection can lead to improvements in SAGD performance and conformance. The feedback control is applied to each steam injection point in the horizontal well pair. Injection at these control points is regulated by a PID feedback controller monitoring temperature differences between injected and produced fluids in order to both enforce a specified subcool and to achieve uniform production along the entire length of the producer. PID feedback control can be practically and inexpensively implemented in the field with current technology. Inflow or injection control devices (ICDs) can also improve SAGD performance. ICDs (or FCDs) can be incorporated in the horizontal completion as restrictive elements to modify the pressure distribution along the length of the wellbore. Among other benefits, properly sized and distributed ICDs can create a more uniform flow profile along the horizontal section of the well, regardless of permeability, formation damage and wellbore location. Furthermore, ICDs on the producer can provide a self-regulating effect to prevent live steam from entering the sand control screen. This paper examines detailed wellbore simulations of a SAGD process in which wells are equipped with a combination of ICD completions and feedback control in order to (i) determine the physical mechanisms (including the dynamic flow paths inside the well and in the near wellbore region), and (ii) outline practical procedures to determine an improved ICD completion and feedback control design. A novel aspect of this work is the inclusion of a revised flow-regime-independent multiphase flow correlation that can predict the pressure drop in horizontal and near-horizontal wells. Results presented in this paper should aid reservoir simulation engineers in both the design and optimization of steam injection in a SAGD well pair.

An investigation is presented on the use of Flow Control Valves (ICVs, FCVs) to control steam placement in the early stages of a Steam Assisted Gravity Drainage (SAGD) process. The two parts of this process that are examined in this paper are the steam circulation preheating period and the early stages up to one year of injection/production in which the steam chamber is beginning to form. Steam injection and production in this and other thermal processes can be difficult to control because steam has a high mobility ratio and tends to establish flow paths that may be difficult to break once established. This is especially pronounced in heterogeneous reservoirs. Two SAGD case studies have been designed that accurately model the initial preheating period in which both wells circulate steam through an inner tubing and outer annulus in order to conductively and, to a lesser extent convectively, heat the region around the well pair in order to establish communication. After this initial circulation period, the wells switch to injection and production. Both cases have the same base configuration but differ in the degree of reservoir heterogeneity. In the injection well, ICV devices are placed to control steam/water flow through the outer screens. In the producer, FCV valves are used to flatten the production profile along the well. Two methods are examined to change valve apertures. One uses proportional-integral-derivative (PID) controllers while the second applies an optimization algorithm directly on each individual connection productivity index. A preliminary investigation is presented here into using feedback controllers and optimization with instantaneous reservoir parameters to improve a SAGD process in the presence of reservoir heterogeneity.

Developing an automated framework for real-time optimization (RTO) of the Steam Assisted Gravity Drainage (SAGD) process has significant potential because of the large number of parameters that must be monitored at a high frequency. However, the industry has not yet adopted a standard RTO framework for SAGD because of the intrinsic complexity of the process, the large number of parameters that must be monitored, harsh operating conditions, the lack of integration between various data acquisition systems, and the complex criteria required to optimize SAGD performance.In this paper, a real-time monitoring workflow for SAGD is proposed that streams field data from multiple sources, including fiber optic distributed temperature sensing (DTS) directly into an engineering desktop application that has artificial intelligence (AI) and data mining capabilities. This system is used to derive advanced criteria to make decisions in a timely manner to improve the performance of the SAGD process.It also demonstrates how subcool calculations can be effectively performed along the length of the horizontal well in real time and how the results are used to improve SAGD operation. Observations are compared "live" against simulated predictions from a multisegmented wellbore model that is fully coupled to a thermal/compositional reservoir simulator. Real-Time Production OptimizationThe term "real-time" can be used to refer to as an interaction with any generic event happening in a short time scale. In our industry, depending on the objective function to optimize it may be seconds, minutes, or even days. A generic diagram of a closed-loop RTO system is presented on Firgure 1. This closed loop begins with measuring the operational changes (measure), continuous well and reservoir model updating (analyze), detecting underperforming conditions and defining the optimal production strategy (detect/optimize), and changing operating parameters for surface equipment and wells (control). This was developed based on the series of papers published by the Society of Petroleum Engineers (SPE) Real-Time Optimization Technical Interest Group (TIG) covering the technical and business-relevant aspects of RTO systems in the oil and gas industry (Ref. 1, 2, 3).Many different closed-loops RTO classifications for a hydrocarbon producing system can be found in the literature. One typical example is provided on Figure 2 (Ref. 4).The first level, surveillance, is about installing the right sensors, systems and instruments to collect sufficient real or near real-time data to support decisions. One important component of this level is the communications infrastructure needed to get the data from the sensors back to the key decision makers.Once the information is received at the engineer's desktop, a variety of engineering tools can be used to process the data into meaningful information by integrating it with existing models and providing real-time analysis. Use of intelligent tools to manage, visualize and analyze data is another key aspect of implementation, ...