Fiber Optics Application for Downhole Monitoring and Wellbore Surveillance; SAGD Monitoring, Flow Regime Determination and Flow Loop Design

Authors: Soroush, Mohammad & Mohammadtabar, Mohammad & Roostaei, Morteza & Hosseini, Seyed Abolhassan & Fattahpour, Vahidoddin & Mahmoudi, Mahdi & Keough, Daniel & Tywoniuk, Matthew & Cheng, Li & Moez, Kambiz. (2020).

Effective Steam Assisted Gravity Drainage (SAGD) operation relies on subcool management to reduce the risk of steam breakthrough. Monitoring of several parameters is performed to assure uniform development of steam chamber and heating of reservoir. This paper discusses the application of Distributed Acoustic Sensing (DAS), a monitoring platform to achieve reliable reservoir and wellbore surveillance in SAGD projects.

In this study, a comprehensive review of DAS deployment in oil and gas industry was performed including vertical seismic profiling, hydraulic fracturing, well/pipe integrity and flow profiling applications. Then, SAGD flow monitoring was investigated in detail. To utilize DAS in SAGD projects, knowing completion designs are necessary. Therefore, various SAGD completion designs and corresponding flow regimes were discussed as well. Finally, four flow loop designs were proposed to accurately simulate the complex wellbore hydraulics of the SAGD producer using DAS recordings.

This work started with an overview of DAS systems in downhole monitoring including real time high resolution vertical seismic profiling, hydraulic fracturing characterization and optimization, well and pipe integrity, leak detection and assessing completion effectiveness. Then, flow profiling including flow rate, flow fractions and flow regimes determinations using DAS were discussed with focus on SAGD monitoring. Completion designs directly impact on SAGD monitoring and DAS recordings, more specifically on flow regimes inside the tubing and annulus. Therefore, various completion designs with their tubing and screen sizes were presented and corresponding flow regimes were determined in both tubing and annulus. It was observed that flow regimes vary with type of completion design, liquid flow rate, steam breakthrough locations and tubing/screen sizes. Eventually, four flow loop designs were proposed based on the discussions for future DAS application.

This paper discusses existing completion designs and possible flow regimes in SAGD projects. Consequently, novel designed flow loops are introduced for DAS deployment to better understand the complex wellbore hydraulic of the well and measure the key parameters in optimizing the production operation. This study is a design stage for future quantitative measuring of flow profiling using DAS systems.

Download paper

Advances in Understanding the Scaling Potential for Thermal Wells: A Mechanistic Study

Authors: Ali Habibi (University of Alberta) | Charles Fensky (Blue Spark Energy) | Morteza Roostaei (RGL Reservoir Management Inc.) | Mahdi Mahmoudi (RGL Reservoir Management Inc.) | Vahidoddin Fattahpour (RGL Reservoir Management Inc.) | Hongbo Zeng (University of Alberta) | Mohtada Sadrzadeh (University of Alberta)

Scale deposition and its treatment are crucial part of any thermal recovery method. High temperature variation, phase change associated with steam condensation and flashing, and complex flow dynamics of the wells make the thermal wells more susceptible to scale deposition. Several studies evaluated the type of scales collected from plugged sand screens; however, more investigation is required to address the reservoir conditions and wellbore hydraulics affecting the scaling potential of minerals at downhole conditions.

A laboratory workflow combined with a predictive modeling toolbox to evaluate scaling tendency of minerals for different downhole conditions has been developed. First, saturation indices (SI) for different minerals were calculated at reservoir temperature and pressure using water chemistry analysis and the Pitzer theory. Then, the mineral composition of deposited materials collected from thermal wells in Athabasca and Cold Lake area were characterized using Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectrometry (EDS), Total Organic Carbon (TOC) and Inductively Coupled Plasma Mass Spectrometry (ICP-MS) analyses. Finally, a comparison analysis was performed between predictive and characterization results.

The results of SI calculations showed that Mg-based silicates and Fe-based minerals are positive (SI>5) even at high temperatures (T>430 K). This indicates that the possibility of deposition for these minerals is high. Carbonates (calcite and aragonite) minerals are the most common depositing minerals. However, the extent of scaling index of carbonates is controlled by the concentration of Ca, HCO₃, and CO₃ in the water sample. The characterization results confirm the results of modeling part. The results of SEM/EDS, ICP-MS analyses showed that carbonates, Mg-based silicates, and Fe-based corrosion products are the most common depositing materials among all minerals.

The workflow presented in this study will help the industry to evaluate the scaling potential for thermal wells at different downhole conditions to make a proper decision to prevent plugging of the completion tools.

Download paper

Characterization and corrosion behavior of electroless Ni-Mo-P/Ni-P composite coating in CO2/H2S/Cl− brine: Effects of Mo addition and heat treatment

Authors: Jiankuan Li, Chong Sun, Morteza Roostaei, Mahdi Mahmoudi, Vahidoddin Fattahpour, Hongbo Zeng, Jing-Li Luo

The electroless Ni-Mo-P/Ni-P composite coating was applied on N80 carbon steel, and the effects of Mo addition and heat treatment on the corrosion resistance enhancement in CO₂/H₂S/Cl⁻ brine were studied by electrochemical measurements and surface analysis techniques. The Mo addition in the as-deposited Ni-P coating causes the microstructural transformation from amorphous to crystalline due to the reduced P content, thereby suffering severe corrosion. The impaired corrosion performance of as-deposited Mo-incorporated coating is also originated from the absence of the oxide film on the coating surface. Nonetheless, the heat-treated Ni-Mo-P/Ni-P coating exhibits desirable corrosion resistance, which is reflected by the outstanding corrosion inhibition efficiency (η = 96.1%). Heat treatment facilitates the formation of Ni₄Mo phase and more importantly, the growth of an oxide film consisting of nickel and molybdenum oxides (H₂S-immuned MoO₃) with better passivation properties, which accounts for the remarkable corrosion resistance improvement.

Download paper

Unplugging Standalone Sand Control Screens with High-power Shock Waves: An Experimental Study

Authors: Ali Habibi (University of Alberta) | Charles Fensky (Blue Spark Energy) | Mike Perri (Blue Spark Energy) | Morteza Roostaei (RGL Reservoir Management Inc.) | Vahidoddin Fattahpour (RGL Reservoir Management Inc.) | Mahdi Mahmoudi (RGL Reservoir Management Inc.) | Ali Ghalambor (Oil Center Research International) | Mohtada Sadrzadeh (University of Alberta) | Hongbo Zeng (University of Alberta)

Previous studies showed that different parameters influence the plugging of completion tools. These parameters include (i) rock mineralogy, (ii) reservoir fluids properties, and (iii) type of completion tools. Although different methods have been used for unplugging these tools, there is still debate regarding performance of these methods on damage removal.

In this study, we assessed the performance of high-power shockwaves generated from an electro-hydraulic stimulation (EHS) tool on cleaning completion tools plugged during oil production. These devices were extracted from different wells in Canada, Europe, and the US. First, we evaluated the extent of cleaning for the plugged completion tools using an EHS tool at the lab-scale. We examined the slots/screens before and after the treatment to show the performance of the EHS tool. Next, we analyzed the mineral composition and morphology of the plugging materials removed after the treatment by conducting X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Energy Dispersive X-Ray Spectroscopy (EDS) analyses. Finally, we reviewed the pulsing stimulation treatment results applied to several field case studies.

The results of unplugging sand control devices at the lab-scale showed that more than 50% of plugged slots/screens were cleaned after 45 pulses of shockwaves. The characterization results showed that the main plugging materials are calcite, silicate, and iron-based components (corrosion products). The results of field case studies showed an improved oil production rate after the pulsing stimulation treatment.

This paper provides a better understanding of the performance of shockwaves on damage removal from plugged completion tools. The results could provide a complementary tool for production engineers to select a proper method for treating the plugged tools.

Download paper

Insights into the Electrochemical Corrosion Behavior and Mechanism of Electroless Ni-P Coating in the CO2/H2S/Cl− Environment

Authors: Jiankuan Li; Chong Sun; Morteza Roostaei; Mahdi Mahmoudi; Vahidoddin Fattahpour; Hongbo Zeng; Jing-Li Luo

The electrochemical corrosion behavior of Ni-P coating in 3.5 wt% NaCl solution-containing CO₂ and H₂S was investigated using electrochemical methods and surface characterization techniques. The results show that the presence of H₂S can enhance the CO₂ corrosion of Ni-P coated carbon steel by affecting both anodic and cathodic processes. The H₂PO₂ adsorbed layer only exists in the very early stage of corrosion and barely improves the anticorrosion performance of the coating. The formation of corrosion products (NiO and Ni₃S₂) renders temporary protection during immersion, but the addition of H₂S accelerates the diffusion process at the electrolyte/coating interface and promotes the electrolyte penetration through the coating, causing severe localized corrosion and coating disbondment. A corrosion model is proposed to illustrate the corrosion and degradation process of Ni-P coated steel in the CO₂/H₂S/Cl⁻ environment.

Download paper

Insights into the erosion-enhanced corrosion on electroless Ni–P coating from single particle impingement

Authors: Chong Sun, Jiankuan Li, Vahidoddin Fattahpour, Morteza Roostaei, Mahdi Mahmoudi, Hongbo Zeng, Jing-Li Luo

The erosion-enhanced corrosion behavior of electroless Ni–P coating was investigated by single particle impingement coupled with in-situ electrochemical measurements. The transient anodic dissolution of Ni–P coating induced by the single particle impingement is enhanced with the rising impact velocity, followed by a rapid repassivation that obeys a bi-exponential decaying law. The coating demonstrates a good erosion-corrosion resistance due to its strong capability of repassivation that is scarcely affected by the changing hydrodynamics under the test conditions. The erosion-enhanced corrosion rate of Ni–P coating in flowing slurry is well predicted based on the repassivation kinetic parameters determined from single particle impingement.

Download paper

Surface Interactions between Water-in-Oil Emulsions with Asphaltenes and Electroless Nickel-Phosphorus Coating

Authors: Lu Gong, Ling Zhang, Li Xiang, Jiawen Zhang, Vahidoddin Fattahpour, Mahdi Mamoudi, Morteza Roostaei, Brent Fermaniuk, Jing-Li Luo, and Hongbo Zeng

Surface interactions between emulsion drops and substrate surfaces play an important role in many phenomena in industrial processes, such as fouling issues in oil production. Investigating the interaction forces between the water-in-oil emulsion drops with interfacially adsorbed asphaltenes and various substrates is of fundamental and practical importance in understanding the fouling mechanisms and developing efficient antifouling strategies. In this work, the surface interactions between water drops with asphaltenes and Fe substrates with or without an electroless nickel–phosphorus (EN) coating in organic media have been directly quantified using the atomic force microscope drop probe technique. The effects of asphaltene concentration, organic solvent type, aging time, contact time, and loading force were investigated. The results demonstrated that the adhesion between water drops and the substrates was enhanced with higher asphaltene concentration, better organic solvent to asphaltenes, longer aging time, longer contact time, and stronger loading force, which was due to the growing amount and conformational change of asphaltenes adsorbed at the water/oil interface. Meanwhile, the adhesion between the water drop and the EN substrate was much weaker than that with the Fe substrate. The bulk fouling tests also showed that EN coating had a very good antifouling performance, which was in consistence with the force measurement results. Our work sheds light on the fundamental understanding of emulsion-related fouling mechanisms in the oil industry and provides useful information for developing new coatings with antifouling performances.

Download paper

Protocol for sand control screen design of production wells for clayey silt hydrate reservoirs: A case study

Authors: Yanlong Li, Fulong Ning, Nengyou Wu, Qiang Chen, Alireza Nouri, Gaowei Hu, Jiaxin Sun, Zenggui Kuang, Qingguo Meng

The process of extracting natural gas from gas hydrate‐bearing sediments (GHBS) may yield significant sand influx due to the metastable nature of GHBS. Selecting appropriate sand control media is vital to addressing the challenges caused by excessive sand production. This study proposes a protocol called holding coarse expelling fine particles (HCEFP) for sand control design. The protocol aims to provide a new optimization method for screen mesh size selection for clayey silt hydrate reservoirs. Detailed optimizing procedures of proper candidate screen mesh sizes in hydrate exploitation well in clayey silt hydrate reservoirs are depicted based on the HCEFP. Then, the site W18, which is located in the Shenhu area of the northern South China Sea, is taken as an example to illustrate the optimization procedure for screen mesh size selection. The results reveal that complete solid retention via a standalone screen is rarely beneficial as high clay contents can adversely affect wellbore productivity due to excessive plugging. Screen aperture size selection for clayey silt hydrate wells should strike a balance between retaining coarser particles and avoiding screen blockage by the relatively fine particles. Furthermore, longitudinal heterogeneity of the PSDs also increases the difficulties associated with sand control design. Multistage sand control optimization is necessary in hydrate production wells. For Site W18, we recommend that the entire production interval can be divided into two subintervals for multistage sand control operations.

Download paper

Optimization of Slotted Liner in Rubiales Field: Trade-Off between Sand Control, Flow Performance, and Plugging Tendency

Authors: Morteza Roostaei (RGL Reservoir Management Inc.) | Edgar Alberto Mayorga Cespedes (Ecopetrol) | Alberto A. Uzcátegui (RGL Reservoir Management Inc.) | Mohammad Soroush (RGL Reservoir Management Inc. and University of Alberta) | Seyed Abolhassan Hosseini (RGL Reservoir Management Inc. and University of Alberta) | Hossein Izadi (University of Alberta) | Brad Schroeder (RGL Reservoir Management Inc.) | Mahdi Mahmoudi (RGL Reservoir Management Inc.) | Dionis M. Gomez (Ecopetrol) | Edgar Mora (Ecopetrol) | Javier Alpire (Ecopetrol) | Joselvis Torres (Ecopetrol) | Vahidoddin Fattahpour (RGL Reservoir Management Inc.)

Designing and selecting the proper sand control mechanism for horizontal wells in unconsolidated heavy-oil reservoirs tend to be underlooked in some cases. Standalone completions pose some sand control challenges, which could jeopardize the oil production or even lead to critical problems. Massive sand production, screen/formation plugging, hot spots, and mechanical integrity failures are some of the well-known issues. This study attempts to optimize the slotted liner design for horizontal wells in a heavy-oil field in Colombia.

A careful selection of representative core data was made to study the variation of sand particle-size distribution (PSD) within the development area. Reservoir fluid properties were analyzed. Based on PSD variation and current design criteria in the industry, several seamed slotted-liner configurations were proposed as an alternative completion for testing. Later, a series of large-scale sand retention tests (SRTs) were performed to assess the selected alternatives under typical field production conditions. The effects of aperture size and open-to-flow area were investigated to evaluate flow and sand control performance.

This investigation started with a detailed study of the PSD, particle shape variation, and composition of fines in the development area. The PSD then classified into four distinct minor and major sand facies, ranging from medium to very coarse sand with different fines content. Further investigations have shown that current design is only suitable for a limited number of the PSDs, while the overall PSD classes indicate the requirement for wider slot aperture sizes. The results of the SRTs indicated that the flow performance of the screen is mainly controlled by the slot aperture. Choosing the optimized aperture size avoids unacceptable sanding even for the multiphase flow scenarios with gas. Results also indicated that by increasing the aperture size and application of the seamed slots for the studied formation, plugging could be mitigated.

A comprehensive sand control design workflow for cold primary heavy-oil production in horizontal wells is presented in this work. The current study is one of the first that investigates and compares conventional straight slotted liners with seamed slotted liners at a larger scale for this field. Moreover, this study helps to better understand the effect of design parameters of seamed slotted liners on sand control, flow performance, and plugging tendency.

Download paper

Coupled Hydraulic Fracture and Proppant Transport Simulation

Authors: Morteza Roostaei, Alireza Nouri, Vahidoddin Fattahpour and Dave Chan

This paper focuses on the study of proppant transport mechanisms in fractures during frac-packing operation. A multi-module, numerical proppant, reservoir and geomechanics simulator has been developed, which improves the current numerical modeling techniques for proppant transport. The modules are linked together and tailored to capture the processes and mechanisms that are significant in frac-pack operations. The proposed approach takes advantage of a robust and sophisticated numerical smeared fracture simulator and incorporates an in-house proppant transport module to calculate propped fracture dimensions and concentration distribution. In the development of software capability, the propped fracture geometry and proppant concentration, which are the output of the proppant module, are imported to the hydraulic fracture simulator through mobility modification. Complex issues of proppant transport in fractures that are addressed in the literature and captured by the current model are: hindered settling velocity (terminal velocity of proppant in the injection fluid), the effect of fracture walls, proppant concentration and inertia on settling (due to extra drag forces applied on particles, compared to single-particle motion in Stokes regime in unbounded medium), possible propped fracture porosity and also mobility change due to the presence of proppant, and fracture closure or extension during proppant injection. A sensitivity analysis is conducted using realistic parameters to provide guidelines that allow more accurate predictions of the proppant concentration and fluid flow. The main objective of this study is to link a numerical hydraulic fracture model to a proppant transport model to study the fracturing response and proppant distribution and to investigate the effect of proppant injection on fracture propagation and fracture dimensions.

Download paper