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Steam generation for the purposes of thermal recovery includes facilities to treat the water (produced water or fresh water), generate the steam, and transport it to the injection wells. A steamflood uses high-quality steam injected into an oil reservoir. The quality of steam is defined as the weight percent of steam in the vapor phase to the total weight of steam. The higher the steam quality, the more heat is carried by this steam. High-quality steam provides heat to reduce oil viscosity, which mobilizes and sweeps the crude to the producing wells.
The objective of scaleup is to take the behavior predicted from detailed, fine-grid reference models that at best represent only a few wells and a tiny part of the reservoir and transfer it to a model that attempts to represent many wells and the integrated behavior of the entire compositionally enhanced solvent flood (or at least a significant portion of it). Jerauld is a good example of the application of this method. Several reference models describe different areas of the field. Water/oil, solvent/oil, and solvent/water pseudorelative permeability relations are developed, along with pseudotrapped-solvent and solvent-flood residual oil values, so that the relevant behavior of the reference models is reproduced by corresponding models that have the same coarse grids as the full-field model. The coarse-grid models, of course, represent the same parts of the full-field model that the reference models represent.
Tracers are used in geothermal reservoir engineering to determine the connectivity between injection and production wells. Because injected fluids are much cooler than in-situ fluids, knowledge of injectate flow paths helps mitigate premature thermal breakthrough. As in other applications of tracer testing, the goal of the tracer test is to estimate sweep efficiency of a given injection pattern. Because geothermal systems tend to be open, tracer tests can also be used to estimate the extent of recharge/discharge or total pore volume. Currently, however, the primary use of geothermal tracers is to estimate the degree of connectivity between injectors and producers.
A successful well to well tracer test is more than selecting the right tracer. It involves determining the appropriate timing, designing the field test, and collecting and analyzing the samples. A well designed sampling program will produce high quality tracer-response curves for further interpretation. The timing for tracer injection depends on the information that is requested. Normally, it is desirable to inject the tracer early in the injection process to obtain information as soon as possible and be able to take the necessary actions to optimize the production strategy.
Gohari, Kousha (Baker Hughes) | Ortiz, Julian (ConocoPhillips) | Nespor, Kristian (ConocoPhillips) | Sanchez, Javier (ConocoPhillips) | Betancur, Andres (University of Calgary) | Irani, Mazda (Ashaw Energy) | Bashtani, Farzad (Ashaw Energy) | Sabet, Nasser (Ashaw Energy) | Ghannadi, Sahar (Ashaw Energy) | Abraham, Anson (CMG) | Bilic, Jeromin (Baker Hughes) | Becerra Moreno, Oscar (Baker Hughes)
Abstract ConocoPhillips operates Surmont, which is the first Steam-Assisted Gravity Drainage (SAGD) project to implement Flow Control Devices (FCDs) in producer wells. This study was conducted to evaluate the production performance of different liner completion strategies. The analysis compared well pairs completed with slotted liners (SL) to producers completed with FCDs, both liner deployed (LD-FCD) and tubing deployed (TD-FCD), and investigated the impact of FCDs in injectors. An extensive analysis was conducted using available production and temperature data along the wells. The wells were completed using various fixed-resistance FCD settings, while some wells were completed using variable setting designs. As time went on, several of the slotted liner producer wells were retrofitted with tubing-deployed FCD completions. One of the key objectives of the study was to determine the success rate of tubing-deployed FCDs and their performance relative to liner-deployed FCD wells. Another objective was to evaluate the impact of retrofitting slotted liner SAGD injectors with tubing-deployed FCD completions. In this study, a grading system was established based on the reservoir quality along the well for both injector and producer. For similar graded well pairs, LD-FCDs had better production performance than TD-FCDs. Considering similar graded reservoir quality, FCDs consistently performed better than slotted liners, in both conformance and production acceleration. The production analysis showed that the FCD flow restriction was a major controller of the conformance, but considering the self-choking phenomenon of the reservoir, most FCDs can perform positively in different circumstances. In this study, the self-choking effect of the liquid pool is discussed and explained for different reservoirs and variable subcool. Generally, if erosion is not a factor, FCDs can create a more controlling system than liquid-pool dominant systems. In these cases, both conformance and production acceleration is enhanced if operators yield lower subcools and greater draw-down pressures.
The design of a waterflood has many phases. First, simple engineering evaluation techniques are used to determine whether the reservoir meets the minimum technical and economic criteria for a successful waterflood. If so, then more-detailed technical calculations are made. These include the full range of engineering and geoscience studies. The geologists must develop as complete an understanding as possible of the internal character of the pay intervals and of the continuity of nonpay intervals.
Abstract In case of giant brown fields, a proper water injection management can result in a very complex process, due to the quality and quantity of data to be analysed. Main issue is the understanding of the injected water preferential paths, especially in carbonate environment characterized by strong vertical and areal heterogeneities (karst). A structured workflow is presented to analyze and integrate a massive data set, in order to understand and optimize the water injection scheme. An extensive Production Data Analysis (PDA) has been performed, based on the integration of available geological data (including NMR and Cased Hole Logs), production (allocated rates, Well Tests, PLT), pressure (SBHP, RFT, MDT, ESP) and salinity data. The applied workflow led to build a Fluid Path Conceptual Model (FPCM), an easy but powerful tool to visualize the complex dynamic connections between injectors-producers and aquifer influence areas. Several diagnostic plots were performed to support and validate the main outcomes. On this basis, proper actions were implemented to optimize the current water injection scheme. The workflow was applied on a carbonate giant brown field characterized by three different reservoir members, hydraulically communicating at original conditions, characterized by high vertical heterogeneity and permeability contrast. Moreover, dissolution phenomena, localized in the uppermost reservoir section, led to important permeability enhancement through a wide network of connected vugs, acting as water preferential communication pathways. The geological analysis played a key role to investigate the reservoir water flooding mechanism in dynamic conditions. The water rising mechanism was identified to be driven by the high permeability contrast, hence characterized by lateral independent movements in the different reservoir members. The integrated analysis identified room for optimization of the current water injection strategy. In particular, key factor was the analysis and optimization at block scale, intended as areal and vertical sub-units, as identified by the PDA and visualized through the FPCM. Actions were suggested, including injection rates optimization and the definition of new injections points. A detailed surveillance plan was finally implemented to monitor the effects of the proposed actions on the field performances, proving the robustness of the methodology. Eni workflow for water injection analysis and optimization was previously successfully tested only in sandstone reservoirs. This paper shows the robustness of the methodology also in carbonate environment, where water encroachment is strongly driven by karst network. The result is a clear understanding of the main dynamics in the reservoir, which allows to better tune any action aimed to optimize water injection and increase the value of mature assets.
Martinez, Maryvi (Adnoc Onshore) | Ortiz, Jhon (Adnoc Onshore) | Alshehhi, Fatmah (Adnoc Onshore) | Bethapudi, Bhanu (Adnoc Onshore) | Permana, Krisna (Adnoc Onshore) | Ismail, Ahmed (Adnoc Onshore) | Al Qubais, Faisal (Adnoc Onshore)
Abstract With the aim to fulfil a more comprehensive and effective water injection optimization strategy in a giant carbonate reservoir, the asset carried out a dedicated study for a giant carbonate unit (Unit-M) to evaluate the specific challenges and define mitigation actions to improve the reservoir performance. This paper outlines the experience of the successful integration and strong collaborative environment between Reservoir Management Surveillance-Studies, Water Handling, Optimization and Production Operations teams through the project execution leading to optimal solutions in a short period, in accordance with a long-term plan oriented to effectively manage future injection requirements. These actions allowed a favorable impact on the operating costs associated to the new and more efficient water balancing. Water injection, oil production, and reservoir pressure performance in addition to surveillance data for Unit-M have been analyzed at region and well scale. A better-detailed understanding about Peripheral and pattern injection Balance using streamline simulation and material balance analysis provided the support to implement actions that include: reactivation of the pilot pattern WI wells, redistribution of Water Injection in the periphery, maximize the efficiency of the Water injectors (Roll Up, re-utilization in other units, P&A) and Optimize clusters utilization. Moreover, the reservoir simulation was used to verify the impact of the new Water Injection strategy in pressure maintenance, sweep efficiency and the ultimate recovery expected. The conformation of a dedicated task force team between Water Handling Operations and Development teams enable the alignment to common goals and a successful integration that led to define short term actions and mitigate present challenges of waterflood reservoir management. Effective and timely application of these solutions resulted in significant reduced maintenance cost (+/-30%) of the wells and clusters involved.
Often when evaluating waterfloods, the focus is on issues at the well level: pumping fluid off a producer or making sure an injector doesn't have plugged perforations. These are important issues that need to be addressed to optimize a waterflood, but focusing solely on the wells makes it easy to forget that each well is only one part of a bigger system. Losing sight of the reservoir means losing sight of other influencing factors that are affecting each well's individual performance. Everything is connected and each change made on a single well affects all wells across the field. For this reason it is important to diagnose a waterflood from multiple viewpoints: the field, pattern, and well levels. At the field level, the goal is to understand the reservoir as a whole.
You must log in to edit PetroWiki. Content of PetroWiki is intended for personal use only and to supplement, not replace, engineering judgment. SPE disclaims any and all liability for your use of such content. In the context of injectors, tracers are chemicals placed in the flow stream of an injector to determine that the water takes from an injector to the producing wells.