Mansir, Hassan (COREteQ Systems Limited) | Rimmer, Michael (COREteQ Systems Limited) | Waldner, Leon (CNOOC International) | Graham, John (Suncor Energy) | Hong, Claire (Cenovus Energy) | Wycislik, Kerry (Cenovus Energy) | Duong, Bruce (Alberta Innovates)
The development of a High-Temperature Permanent Magnet Motor (PMM) was initiated with the main objective to bring forth a technical solution to significantly increase temperature capability and run life of ESPs in Steam Assisted Gravity Drainage (SAGD) beyond current technology. This is in response to operators needs for improved safety margins and increased production rates. Existing ESP motor technologies are limited to approximately 300 C internal motor winding temperatures, driven by the available motor electrical insulation systems. The use of PMMs in SAGD was also prohibited by the availability of magnet materials capable of operating in such temperatures, without partial or full demagnetization. The project's aim is to break this barrier and extend internal temperatures to 350 C and beyond, allowing well ambient temperatures to be pushed beyond the 260 C downhole environment. In addition, for assurance of motor reliability, rigorous and methodical design validation and qualification testing of basic materials, components, sub-assemblies were undertaken.
Zhu, Ziming (Colorado School of Mines) | Fang, Chao (Virginia Polytechnic Institute and State University) | Qiao, Rui (Virginia Polytechnic Institute and State University) | Yin, Xiaolong (Colorado School of Mines) | Ozkan, Erdal (Colorado School of Mines)
In nanoporous rocks, potential size/mobility exclusion and fluid-rock interactions in nano-sized pores and pore throats can turn the rock into a semi-permeable membrane, blocking or hindering the passage of certain molecules while allowing other molecules to pass freely. In this work, we conducted several experiments to investigate whether CO2 can mitigate the sieving effect on the hydrocarbon molecules flowing through Niobrara samples. Molecular dynamics simulations of adsorption equilibrium with and without CO2 were performed to help understand the trends observed in the experiments. The procedure of the experiments includes pumping of liquid binary hydrocarbon mixtures (C10 C17) of known compositions into Niobrara samples, collecting of the effluents from the samples, and analysis of the compositions of the effluents. A specialized experimental setup that uses an in-line filter as a mini-core holder was built for this investigation. Niobrara samples were cored and machined into 0.5-inch diameter and 0.7-inch length mini-cores. Hydrocarbon mixtures were injected into the mini-cores and effluents were collected periodically and analyzed using gas chromatography (GC). After observing the membrane behavior of the mini-cores, CO2 huff-n-puff was performed at 600 psi, a pressure much lower than the miscibility pressure. CO2 was injected from the production side to soak the sample for a period, then the flow of the mixture was resumed and effluents were analyzed using GC. Experimental results show that CO2 huff-n-puff in several experiments noticeably mitigated the sieving of heavier component (C17). The observed increase in the fraction of C17 in the produced fluid can be either temporary or lasting. In most experiments, temporary increases in flow rates were also observed. Molecular dynamics simulation results suggest that, for a calcite surface in equilibrium with a binary mixture of C10 and C17, more C17 molecules adsorb on the carbonate surface than the C10 molecules. Once CO2 molecules are added to the system, CO2 displaces C10 and C17 from calcite. The experimentally observed increase in the fraction of C17 thus can be attributed to the release of adsorbed C17. This study suggests that surface effects play a significant role in affecting flows and compositions of fluids in tight formations. In unconventional oil reservoirs, observed enhanced recovery from CO2 huff-n-puff could be partly attributed to surface effects in addition to the recognized gas-liquid interaction mechanisms.
Ghanavati, Mohsen (Global New Petro Tec Corp.) | Volkov, Maxim (TGT Oilfield Services) | Nagimov, Vener (TGT Oilfield Services) | Ali Mohammadi, Hamzeh (University of Calgary, Global New Petro Tec Corp.)
Production casings of Cyclic Steam Stimulation (CCS) or steam-assisted gravity drainage wells are exposed to significant temperature variations which in many cases resulted in casing breaks in the weakest part which are typically connection joints. The paper focuses on the new downhole logging approach, in monitoring and detecting production casing connection breaks through tubing without requirement for tubing retrieval.
The metal well barriers can be assessed by utilizing electromagnetic (EM) pulse defectoscopy. This is done by running multiple coaxial sensors downhole in tandem. Each sensor generates EM pulse and then records EM decay from surrounding metal tubes. Modeling of recorded EM decay enables precise assessment of metal loss or metal gain in up to four concentric barriers. However, the tool had never been used previously to detect minor defect features as casing breaks through the tubing. To identify casing breaks several yard and field tests have been conducted and new methodologies were developed. The last one included the recognition of specific patterns of raw EM responses, analysis of hole sensors and utilization of data from all coaxial sensors utilized during the downhole survey.
The new approach including downhole EM pulse tools and new data analysis have been implemented to detect casing connection breaks in over a hundred Cyclic Steam Stimulation (CCS) and SteamAssisted Gravity Drainage (SAGD) wells. The paper demonstrates the testing of the application feasibility in a comprehensive yard test and extends to real field examples. All detected breaks were confirmed after tubing removal and were successfully repaired. Paper highlights detection challenges due to different casing connection break types: minor breaks, partial breaks (contrary to fully circumferential), and casing breaks aligned with tubing connections. The technology has helped Operators to fulfil the objectives of connection break detection without tubing removal through a non-intrusive, safe, quick and economical approach.
Today, CSS and SAGD Operators should confirm casing integrity repeatedly prior to each subsequent steam cycle through the time and resource consuming approach of tubing removal and checking the casing integrity mechanically. Utilizing through tubing electromagnetic diagnostics, enables Operators to pick up multiple casing connection breaks in a single run without tubing retrieval.
Banack, Ben (Halliburton) | Burke, Lyle H. (Devon Canada Corporation) | Booy, Daniel (C-FER Technologies 1999 Inc.) | Chineme, Emeka (Cenovus Energy) | Lastiwka, Marty (Suncor Energy) | Gaviria, Fernando (Suncor Energy) | Ortiz, Julian D. (ConocoPhillips Canada) | Sanmiguel, Javier (Devon Canada Corporation) | Dewji, Ayshnoor (Halliburton)
It is becoming common to install inflow control devices (ICDs) along steam-assisted gravity drainage (SAGD) production liners to enhance temperature conformance and accelerate depletion. Additionally, some operators advocate the installation of similar outflow control devices (OCDs) along the injection well of the SAGD well pair. Collectively, these inflow and outflow devices are often referred to as FCDs. Industry adoption of flow control devices (FCDs) has increased, and several devices are commercially available for use in SAGD.
In an effort to optimize FCD design and selection, a joint industry partnership (JIP) was formed (
Fiber-optic-based instrumentation was deployed within FCD-equipped wells using permanently installed coiled tubing. Well architecture design changes to a typical completion were not required because fiber-optic sensors are used for most non-FCD wells to collect distributed temperature sensing (DTS) data. Although DTS is a common tool for optimizing SAGD production, it has certain limitations; specifically, temperature changes along production wells do not typically allow a detailed definition or quantification of the inflow distribution along the wellbore.
In addition to DTS, distributed acoustic sensing (DAS) was periodically performed on the FCD wells. DAS logging of SAGD producers has several potential uses, including flow profiling, steam breakthrough and/or noncondensable gas (NCG) detection, multiphase flow characterization, electric submersible pump (ESP) performance, completion failure analysis, and four-dimensional seismic analysis. Although FCD characterization with DAS appears promising, a knowledge gap exists as to how to move beyond qualitative analysis to more quantitative analysis of FCD performance and the lateral emulsion inflow distribution. Pending satisfactory results, DAS logging on active wells can potentially be completed to accelerate improvements of SAGD FCD performance and design as well as increase the efficiency of SAGD recovery through improved steam/oil ratio (SOR) and an associated reduction in greenhouse gases.
This paper describes piloting the collection and analysis of DTS and DAS data to help improve understanding of SAGD inflow distribution. Logs were performed on multiple wells during stable and transient flowing conditions. Early surveillance demonstrated suitability and limitations of fiber-optic-based logging to validate FCD performance in active wells. In addition to field logging, acoustic recording using JIP flow loop testing was completed with accelerometers, geophones, and fiber-optic cables during FCD characterization. The goal was to cross reference the acquired acoustic signals for quantification of flow at devices and validation of performance. An overview of the JIP flow loop FCD acoustic characterization program is described.
This paper presents a description of the technology for numerical simulation of thermal gas treatment on Bazhenov formation, taking into account features of Bazhenov formation and thermal gas treatment and assumptions of the simulator.
First of all it is required to determine the following parameters: voidness (porosity), permeability, fracturing, free oil (initial oil saturation), TOC (Total Organic Carbon). And also it is important to establish dependence of the parameters on temperature and pressure. Then, the process of thermal gas treatment can be conditionally divided into several stages: Effective production of light oil from drainable (permeable) zones (miscible displacement in front of the combustion front) Involvement of zones of reservoir containing kerogen during to heat treatment (pyrolysis reaction) and liberation of light oil and gaseous hydrocarbons from "locked" zones of reservoir. Involvement of the initially non-drainable (impermeable) zones of reservoir, named matrix (doesn’t mean the same as in dual porosity/permeability system). Especially these zones are the greatest interest among reservoir engineers because it can contain huge reserves of hydrocarbons.
Effective production of light oil from drainable (permeable) zones (miscible displacement in front of the combustion front)
Involvement of zones of reservoir containing kerogen during to heat treatment (pyrolysis reaction) and liberation of light oil and gaseous hydrocarbons from "locked" zones of reservoir.
Involvement of the initially non-drainable (impermeable) zones of reservoir, named matrix (doesn’t mean the same as in dual porosity/permeability system). Especially these zones are the greatest interest among reservoir engineers because it can contain huge reserves of hydrocarbons.
As a result of the steps described above, a 2D model was created, a numerical realization of the key processes taking place during thermal gas treatment on Bazhenov formation was carried out. Further, the main zones characterizing the process were identified and a physical justification for the individual indicators was given. Calculations of variants involving the matrix in the drainage process were carried out.
The calculated technological effect over a 50-year period of thermal gas treatment on the model (involving the production from matrix) was about 50% of the additional oil production, relative to the thermal gas treatment variant without involvement of matrix.
According to the results of the work, an evaluation of the efficiency of wet combustion was carried out during thermal gas treatment. The results of the calculations clearly demonstrate the advantage of using wet combustion. It is as stimulation of production of reservoir oil, as of additional synthetic oil as a result of kerogen pyrolysis reaction.
Dong, Xiaohu (China University of Petroleum, Beijing) | Liu, Huiqing (China University of Petroleum, Beijing) | Lu, Ning (China University of Petroleum, Beijing) | Zheng, Aiping (Xinjiang Oilfield Company, CNPC) | Wu, Keliu (China University of Petroleum, Beijing) | Xiao, Qianhua (Chongqing University of Science & Technology) | Wang, Kung (University of Calgary) | Chen, Zhangxin (University of Calgary)
Considering the non-uniform steam conformance of conventional horizontal well, dual-pipe steam injection technique has currently demonstrated technical potential for improving heavy oil recovery. It can delay the occurrence of steam fingering and homogenize the steam injection profile along horizontal wellbore. But in some field tests, it is observed that the results were far greater than such an approach would have justified. In addition, the actual physics are still unclear, and not demonstrated. In this paper, first, we built a cylindrical wellbore physical model to experimentally study steam injection profiles of a single pipe horizontal well and a concentric dual-pipe horizontal well. Thus, the heat and mass transfer behavior of steam along horizontal well with a single-pipe well configuration and a dual-pipe well configuration was addressed. Subsequently, considering the effect of pressure drops and heat loss, a semi-analytical model for the gas-liquid two-phase flow in horizontal wellbore was developed to numerically match the experimental observation. Next, a sensitivity analysis on the physical parameters and operation properties of a steam injection process was conducted. The effect of the injection fluid type was also investigated.
Experimental results indicated that under the same steam injection condition, an application of the dual-pipe well configuration can significantly enhance the oil drainage volume by about 35% than the single-pipe well configuration. During the experiments, both a temperature distribution and liquid production along the horizontal wellbore were obtained. A bimodal temperature distribution can be observed for the dual-pipe well configuration. From this proposed model, an excellent agreement can be found between the simulation results and the experimental data. Because of the effect of variable-mass flowing behavior and pressure drops, the wellbore segment closed to the steam outflow point can have a higher heating radius than that far from the steam outflow point. From the results of sensitivity analysis, permeability heterogeneity and steam injection parameters have a tremendous impact on the steam injection profile along wellbore. Compared with a pure steam injection process, the co-injection of steam and NCG (non-condensable gas) can improve the effective heating wellbore length by over 25%. Furthermore, this model is also applied to predict the steam conformance of an actual horizontal well in Liaohe oilfield. This paper presents some information regarding the heat and mass transfer of a dual-pipe horizontal well, as well as imparts some of the lessons learned from its field operation. It plays an important role for the performance evaluation and remaining reserve prediction in a dual-pipe thermal recovery project.
Lastiwka, Marty (Suncor Energy) | Burke, Lyle H. (Devon Canada Corporation) | Booy, Daniel (C-FER Technologies 1999 Inc.) | Chineme, Emeka C. (Cenovus Energy) | Gaviria, Fernando (Suncor Energy) | Ortiz, Julian D. (ConocoPhillips Canada)
A review of laboratory and field testing of a new flow control device is presented in this paper. The device is designed specifically to limit steam breakthrough in thermal operations.
For the past few years, four companies operating Steam Assisted Gravity Drainage (SAGD) facilities in Alberta's oil sands have come together to study downhole Flow Control Devices (FCDs) in a laboratory setting and to share field data of the application of such devices. Within this collaboration, a new device was designed to address the challenge specific to thermal operations, namely limiting steam breakthrough into production wells. Laboratory tests were undertaken to define the steam-limiting characteristics of this device under field representative SAGD conditions at full scale rates, temperatures and pressures. Tests were performed with oil to gauge viscosity sensitivity, as well as with water and steam at various inflow rates, temperatures and steam qualities. Testing was also performed with Non-Condensable Gas (NCG) to help assess how methane production may affect performance under both low and high Gas Volume Fraction (GVF) conditions. Finally, three-phase erosion testing was performed using water, quartz and air, allowing a realistic, scalable assessment of the device's long-term reliability.
Highlights from these tests are reported and compared to results from testing of conventional, commercially available devices. The new device has shown superior performance relative to other devices designed for non-thermal applications. Thus, it inhibits the influx of steam while allowing the flow of emulsion into a production well. Based on the results of laboratory testing, the device is currently being tested in field operations. Early indications are that the device is performing as expected. Preliminary field data are presented.
Laboratory testing of thermal flow control devices is especially challenging and unique when compared with similar testing for conventional flow control devices. This becomes more evident when testing devices designed specifically to limit steam breakthrough. Furthermore, in thermal operations, the phase change potential that is inherent when operating near the saturation point of water opens new possibilities in the design of flow control devices. A successful, practical implementation of this phase change characteristic was achieved in a collaborative environment.
The simulation of the In Situ Combustion (ISC) process is a very challenging process due to the complexity and nonlinear nature of the problem. In this work, we propose an efficient technique to simulate experimental procedures for the ISC process including heterogeneity. The effects of permeability on mass flow and heat transfer were studied through a series of numerical frameworks. Different approaches to model the reactions occurring during combustion were attempted and simulation results were validated using experimental results. We focus on two different key areas: the integration of chemical reaction kinetics obtained through kinetic cell experiments, and the analysis of efficient simulations of combustion tube experiments that account for the flow element. After establishing a robust framework that accurately matches lab-scale results, combustion tube simulation results using a commercial simulator were analyzed to corroborate conclusions. Through observing the propagation of the combustion front and the oil bank in heterogeneous zones, assessments around the effects of permeability on the ISC process were performed. This work provides valuable information that would be instrumental in understanding experimental behavior of in-situ combustion and upgrading results to field scale after matching numerical results with experimental data collected in our future work.
Optimizing steam-assisted gravity drainage (SAGD) performance in oil sands reservoirs relies on the quality of steam allocation decisions made across the well inventory. With finite facility steam generation capacity, SAGD producers are typically challenged with identifying the true opportunity cost of allocating steam volumes based on well performance. This paper presents a novel technique to inform steam allocation decisions and managing SAGD reservoir pressures in service of optimizing production and consequently improving the economic performance of the asset through smarter SAGD field development planning.
The concept of marginal steam-oil-ratio (mSOR) is introduced as a method of guiding steam allocation decisions. Marginal SOR is defined as the cold-water equivalent volume of steam required to produce the next marginal barrel of bitumen from the production system in a steam constrained environment. The metric represents the opportunity cost of deploying a barrel of steam to the next best alternative in steam allocation decisions. Dynamic quantification of mSOR over the plausible range of operating pressures for each producing entity (PRDE) in the inventory (such as a well group or drainage area) is critical to optimally allocating steam when faced with reservoir challenges such as reservoir complexity and heterogeneity and transient reservoir behaviors such as thief zone interaction.
This paper prescribes methodologies to analytically and empirically quantify mSOR for a SAGD production system. Additionally, application of the concept if field production optimization is discussed under the context of integrated production modeling and constrained flow network optimization problems. A case example of applying mSOR to guide steam allocation decisions at ConocoPhillips' Surmont SAGD asset is presented under a steam constrained environment. The mSOR guided solution is validated using brute-force enumeration of steam allocation outcomes in the production system to prove production optimality. The results from this dynamic steam allocation strategy guided by mSOR characterization show significant improvements in field oil rates, field steam management efficiency and consequently the economic value of the SAGD asset.
One of the main challenges in Steam Assisted Gravity Drainage (SAGD) wells is steam breakthrough in producer wells, which can result in inefficient bitumen recovery due to high Steam Oil Ratio (SOR). Flow Control Devices (FCDs), also known as Inflow Control Devices (ICDs), have been developed for several years to balance the oil inflow along the horizontal wells and consequently delay or mitigate the unwanted fluid breakthrough. The newest generation of FCDs is a truly Autonomous Inflow Control Valve (AICV) which can optimize oil production, reduce SOR and significantly restrict the inflow of unwanted fluids such as water, steam and Non-condensable Gases (NCGs).
This novel AICV design was tested in a full-scale high temperature laboratory flow loop that replicates the downhole operating temperatures, fluid conditions and flow rates of a SAGD production well. The full-scale tests were conducted to determine how the AICV could optimize SAGD production by restricting the production of NCGs and steam and favor the production of oil.
Both single-phase and multi-phase flow performance behavior of the AICV are presented. Furthermore, the results are compared with a conventional passive ICD to illustrate the significant potential of the AICV in enhancing oil production, total recovery and overall project economics.
The results show that the production of lower temperature, relatively high viscosity oil can be increased by approximately 90% for the situation of deploying AICVs. Additionally, gas production is dramatically reduced from approximately 1200 L/h for the ICD, to 180 L/h with the AICV, corresponding to an 85% reduction. These results show that a considerable reduction in steam use is possible by using the AICVs, which would result in reduced energy usage for steam generation, reduced water usage, and reduced greenhouse gas emissions for each barrel of oil produced, thus improving the economics of SAGD projects.