Performance Analysis of Infill Wells Adjacent to SAGD Well Pair: Non-Condensable Gas NCG Breakthrough

2021 ◽  
Author(s):  
Mazda Irani ◽  
Aubrey Tuttle ◽  
Jesse Stevenson
Keyword(s):  
Hot Spot ◽  
Pressure Effects ◽  
Productivity Index ◽  
First Year ◽  
Steam Chamber ◽  
Steam Assisted Gravity Drainage ◽  
Flow Control Devices ◽  
Fit For Purpose ◽  
The Common ◽  
The Impact

Summary Late in the life of the Steam Assisted Gravity Drainage (SAGD) process, it has become common practice to drill a single, horizontal infill well (called a “Wedge Well™” by some) in the oil bank located between two mature SAGD well pairs to produce the bitumen that has been heated and mobilized but is unable to be effectively drained by gravity given the largely lateral location relative to that of the SAGD producers. Since this oil bank is surrounded by the large, depleted steam chamber created by the existing well pairs, it requires little heat to mobilize bitumen. One of the challenges, however, in producing infill wells is that non-uniform drainage and local hot spots can be readily created in the first year of their operation, that in many cases require completion retrofits, such as with Flow Control Devices (FCDs), to improve the drainage profile. Installation of FCDs in these wells is quite challenging since the dynamics of the infill wells is changing with time and there is limited time to achieve conformance. To maintain pressure in SAGD chambers the common practice is to inject non-condensable gas (NCG). NCGs, such as methane, which is most common, do not condense in the steam chamber. Some of these NCG can short-cut into the infill through the existing hot-spot. The main reason is that the hot sections of infills are locations that are closer to the SAGD steam chamber, and due to steam condensate encroachment and higher mobility create a pathway for NCG breakthrough. FCDs are designed to promote a more uniform flux distribution along the producer, and exposure to NCG can change the impact of the FCDs. The true hot-spot temperature after NCG injection is decreasing and this can be mistaken as FCD efficiency and steam blocking. In reality, this temperature reduction is due to partial pressure effects associated with NCG encroachment. In this study, a new thermodynamic model is created to explain the NCG encroachment into infill wells, and a new temperature profile along the producer as a function of NCG breakthrough is calculated. The purpose of this work is to create a productivity index (PI) relationship that is fit for purpose for infill wells adjacent to SAGD well-pairs with NCG breakthrough that can primarily be used for analysis and optimization of SAGD FCD completions. This model can also be used to evaluate FCD performance in infill wells pre- and post- NCG breakthrough.

Liner Deployed Flow Control Devices in SAGD Infill Producers

2021 ◽  
Author(s):  
Michael Hardcastle ◽  
Ryan Holmes ◽  
Frank Abbott ◽  
Jesse Stevenson ◽  
Aubrey Tuttle
Keyword(s):  
Flow Control ◽  
Oil And Gas ◽  
Distributed Temperature Sensing ◽  
Steam Assisted Gravity Drainage ◽  
Well Production ◽  
Flow Control Devices ◽  
Control Devices ◽  
The Impact ◽  
Mobility Variable

Abstract Connacher Oil and Gas has deployed Flow Control Devices (FCDs)on an infill well liner as part of a Steam Assisted Gravity Drainage (SAGD) exploitation strategy. Infill wells are horizontal wells drilled in between offsetting SAGD well pairs in order to access bypassed pay and accelerate recovery. These wells can have huge variability in productivity, based on several factors: variable initial temperature due to variable steam chamber development and initial mobility variable injectivity from day one limiting steam circulation and stimulation significant hot spots during production that limit drawdown of the well and oil productivity FCDs have shown great value in several SAGD schemes and are becoming common throughout SAGD applications to manage similar challenges in SAGD pairs, but their application in infill wells is less prevalent and presents a novel challenge to design and evaluate performance. This case study will examine the theory, operation, and early field results of this field trial. Density-based FCDs designed for thermal operations were selected to minimize the impact of viscous fluids commonly encountered early in cold infill well production. The design also limited steam outflow during the stimulation phase, where steam is injected in order to initiate production of the well. Distributed Temperature Sensing (DTS) data, pressures and rates are utilized to analyze the impact of the FCDs towards conformance of the well in the early life. The value of FCDs has led to further piloting of this technology in a second group of nine infill wells, where further value is to be extracted using slimmer wellbores.

Challenges from Well Shut-in Amid the Oil Downturn: Long Term Impacts on Near Wellbore Skin Buildup and Sand Control

2021 ◽  
Author(s):  
Mohammad Soroush ◽  
Mahdi Mahmoudi ◽  
Morteza Roostaei ◽  
Hossein Izadi ◽  
Seyed Abolhassan Hosseini ◽  
...  
Keyword(s):  
Hot Spot ◽  
Oil Production ◽  
Well Performance ◽  
Well Completion ◽  
Flow Control Devices ◽  
Sand Control ◽  
Control Devices ◽  
Inflow Problem ◽  
The Impact

Abstract In wake of the biggest oil crash in history triggered by the COVID-19 pandemic; Western Canada in- situ production is under tremendous price pressure. Therefore, the operators may consider shut in the wells. Current investigation offers an insight into the effect of near-wellbore skin buildup because of such shut-in. A series of simulation studies was performed to quantitatively address the impact of well shut-in on the long-term performance of well, in particular on key performance indicators of the well including cumulative steam to oil ratio and cumulative oil production. The long-term shut-in contributes to three main modes of plugging: (1) near-wellbore pore plugging by clays and fines, (2) scaling, and (3) chemical consolidation induced by corrosion. A series of carefully designed simulations was also utilized to understand the potential of skin buildup in the near-wellbore region and within different sand control devices. The simulation results showed a higher sensitivity of well performance to shut-in for the wells in the initial stage of SAGD production. If the well is shut in during the first years, the total reduction in cumulative oil production is much higher compared to a well which is shut-in during late SAGD production life. As the induced skin due to shut-in increases, the ultimate cumulative oil production drops whose magnitude depends on well completion designs. The highest effect on the cumulative oil production is in the case of completion designs with flow control devices (liner deployed and tubing deployed completions). Therefore, wellbore hydraulics and completion design play key roles in the maintenance of uniform inflow profile, and the skin buildup due to shut-in poses a high risk of inflow problem and increases the risk of hot-spot development and steam breakthrough. This investigation offers a new understanding concerning the effect of shut-in and wellbore skin buildup on SAGD operation. It helps production and completion engineers to better understand and select candidate wells for shut-in and subsequently to minimize the skin buildup in wells.

scholarly journals Impact of geomechanical effects during SAGD process in a meander belt

2018 ◽  
Vol 73 ◽  
pp. 17
Author(s):  
Iryna Malinouskaya ◽  
Christophe Preux ◽  
Nicolas Guy ◽  
Gisèle Etienne
Keyword(s):  
Reservoir Simulation ◽  
Pressure Effects ◽  
Productivity Index ◽  
Petrophysical Properties ◽  
Steam Assisted Gravity Drainage ◽  
Reservoir Simulations ◽  
Fluvial Reservoir ◽  
Current State ◽  
Productivity Estimation ◽  
Pressure And Temperature Effects

In the reservoir simulations, the geomechanical effects are usually taken into account to describe the porosity and the permeability variations. In this paper, we present a new method, patented by authors, which allows to model the geomechanical effects also on the well productivity index. The Steam Assisted Gravity Drainage (SAGD) method is widely used for the heavy oil production. A very high variation in pressure and temperature play a significant role on the petrophysical properties and may impact the productivity estimation. In this paper we develop a new simplified geomechanical model in order to account for the thermal and pressure effects on the porosity, permeability and the productivity index during the reservoir simulation. At the current state, these dependencies are defined using semi-analytical relationships. The model is applied to a meandering fluvial reservoir based on 3D outcrop observations. The productivity is found underestimated if the pressure and temperature effects on the petrophysical properties are ignored in the reservoir simulation. Moreover, this study shows an important impact of thermal effects on the productivity estimation. The results of this work show that it is essential to properly take into account the geomechanical effects on the petrophysical properties and also on the productivity index for a better productivity estimation.

On Subcool Control in SAGD Producers—Part II: Localized-Hot-Spots Effects and Optimization of Flow-Control Devices

SPE Journal ◽  
2019 ◽  
Vol 24 (04) ◽  
pp. 1613-1629 ◽  
Author(s):  
Mazda Irani
Keyword(s):  
Flow Control ◽  
Hot Spots ◽  
Hot Spot ◽  
Large Fraction ◽  
Liquid Pool ◽  
Gas Production ◽  
Differential Pressure ◽  
Steam Chamber ◽  
Flow Control Devices ◽  
Control Devices

Summary At the base of a steam-assisted-gravity-drainage (SAGD) steam chamber, a liquid pool is developed, which is a key component for bitumen production. A producer is placed in the liquid pool, and its production is mainly controlled by its liquid level and the temperature gradient across its depth. A “subcool control” or “thermodynamic steam-trap control” is a typical operating strategy to control steam coning to the producer. Part I of this study (Irani 2018) presented a methodology to evaluate the production rate for a given pressure drawdown and subcool in a SAGD liquid pool; and Part III (Irani and Gates 2018) modified such a formulation for a stability analysis of the Nsolv™ (Nenniger and Nenniger 2000, 2001) process that contained a large fraction of liquid butane. In this study, first, the effect of localized hot spots on well control is formulated as a virtual skin factor in the liquid-pool deliverability equation. The results of this work suggest that a longer hot spot will yield to lower differential pressure and make it more challenging to control the steam breakthrough by choking the well at a given rate. Another key finding is that the steam coning becomes less controllable for higher-permeability reservoirs. Flow-control devices (FCDs) have been used extensively in horizontal wells for conventional oil and gas production to prevent early water breakthrough or gas coning. Although FCDs are commonly installed to prevent steam coning after steam breakthrough and to manage hot spots as retrofit completions by SAGD operators, in recent years, FCDs have been often installed to improve SAGD well-pair performance as part of the initial completion. The benefits associated with this technology in the SAGD industry have been studied with reservoir simulations and validated with field experience, but a theoretical study that discusses the main factors for a correct FCD selection on the basis of operational conditions and reservoir heterogeneity is required. In this study, the liner-deployed FCD and liquid-pool systems are coupled, and two criteria are suggested for a design of liner-deployed FCDs on the basis of the pressure-drop ratio of the FCD relative to the liquid pool (ΔPFCD/ΔPpool) and the coefficient of variation (CoV) of inflow for the liner-deployed-FCD wellbore (CoVFCD). The results of this study show that in higher-permeability reservoirs, the ideal FCD design should have more ports to reduce the differential pressure to flow response. While FCDs will improve inflow conformance relative to completions without FCDs, the effect of permeability in this improvement is minimal. This improvement is larger in applications operating at lower target subcool values. Reducing the target-wellbore subcool value can improve well deliverability twofold: First, FCD-completed wells produce more at lower subcools and, second, reducing the subcool value helps to improve inflow uniformity along the length of the lateral. By effectively removing the fluids available to the producer, the growth of the steam chamber can be maximized through accelerated injection rates.

Limit Load Analysis of a Torispherical Head With Thermal Hot Spot Damage

2018 ◽  
Author(s):  
Amir Mehrizi ◽  
Soheil Nakhodchi ◽  
Reza Adibi-Asl
Keyword(s):  
Hot Spots ◽  
Hot Spot ◽  
Limit Load ◽  
Pressure Vessels ◽  
Load Carrying ◽  
Different Shapes ◽  
Service Degradation ◽  
The Common ◽  
The Impact ◽  
Inside Wall

Vessel dished heads are widely being used in storage tanks or pressure vessels. These heads are available in different shapes including hemispherical, ellipsoidal and torispherical heads. In this paper, pressure limit load of torispherical head with thermal hotspot damage is investigated. Thermal hotspots are one of the common types of in-service degradation in some pressurized components and can be considered as damage. This type of damage is usually caused by the loss of refractory lining on the inside wall of pressure components or due to a misdistribution of the flow within vessels containing catalysts. Hotspot damage potentially jeopardizes the integrity of the components [1]. In the current research, the impact of a thermal hotspot on the load carrying capacity of various shapes of torispherical heads is investigated using numerical simulation. Also, sensitivity analysis has been performed to investigate the effect of location of thermal hot spots and thickness in the torispherical heads, with and without thermal hot spot damage.

Analysis of the Performance of Various Well Liner Completion Strategies in Surmont

2021 ◽  
Author(s):  
Kousha Gohari ◽  
Julian Ortiz ◽  
Kristian Nespor ◽  
Javier Sanchez ◽  
Andres Betancur ◽  
...  
Keyword(s):  
Liquid Pool ◽  
The Self ◽  
Production Performance ◽  
Reservoir Quality ◽  
Steam Assisted Gravity Drainage ◽  
Flow Restriction ◽  
Controlling System ◽  
Flow Control Devices ◽  
The Impact ◽  
Better Than

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.

Asphaltene Precipitation During Bitumen Extraction With Expanding-Solvent Steam-Assisted Gravity Drainage: Effects on Pore-Scale Displacement

SPE Journal ◽  
2016 ◽  
Vol 21 (02) ◽  
pp. 380-392 ◽  
Author(s):  
Albina Mukhametshina ◽  
Taniya Kar ◽  
Berna Hascakir
Keyword(s):  
High Energy ◽  
Economic Benefits ◽  
Gravity Drainage ◽  
Steam Generation ◽  
Injection Strategy ◽  
Steam Chamber ◽  
Steam Assisted Gravity Drainage ◽  
Asphaltene Fraction ◽  
Solvent Type ◽  
The Impact

Summary Steam-assisted gravity drainage (SAGD) is a proved enhanced-oil-recovery technique for oil-sand extraction. However, the environmental and the economic challenges associated with steam generation limit the application of this technology. To address these issues, we have investigated the effectiveness of expanding-solvent-SAGD (ES-SAGD) over base SAGD on a bitumen sample (8.8 °API). Experimental studies are conducted with a 2D physical model. Different strategies for solvent injection are tested (coinjection and cyclic injection) to examine the impact of the deposition of the asphaltene fraction of the bitumen on porous media and the behavior of the asphaltene fraction in produced oil. Toluene is used as asphaltene-soluble solvent, and n-hexane is selected as asphaltene-insoluble. Steam-chamber development is monitored with temperature profiles from 47 separate positions. The oil rate, recovery factor, and the produced-oil quality are evaluated together. The effectiveness of SAGD and ES-SAGD is discussed by considering the role of asphaltenes and their interactions with clays in both produced- and residual-oil samples. This study reveals that coinjection of hydrocarbon solvents with steam enhances the steam-chamber development with higher oil-production rate. Moreover, ES-SAGD results in recovery of more-upgraded oil and has a lesser environmental impact. We observe that the selections of solvent type and injection strategy are the most crucial parameters for the design of a hybrid SAGD process, and solvent cost and toxicity can be minimized with the recycling of solvent for continuous injection of solvents. High-energy consumption for steam generation during the SAGD process can be reduced by coinjection of proper solvent type with steam at a proper injection strategy. Our study reveals that the ES-SAGD process has environmental and economic benefits that are preferable to those of the base SAGD. However, some solvents can cause undesirable effects because of asphaltene destabilization and precipitation in production or transportation lines. The results of this work show that not only asphaltenes but also the other fractions of oil, along with the reservoir-clay type and the clay amount, affect the ES-SAGD performance.

The Need to Belong and the Relationship Between Loneliness and Health

2014 ◽  
Vol 22 (4) ◽  
pp. 194-201 ◽  
Author(s):  
Freda-Marie Hartung ◽  
Britta Renner
Keyword(s):  
Individual Differences ◽  
Social Isolation ◽  
Social Situation ◽  
First Year ◽  
Health State ◽  
Need To Belong ◽  
First Year University ◽  
Perceived Social Isolation ◽  
The Impact ◽  
The Relationship

Humans are social animals; consequently, a lack of social ties affects individuals’ health negatively. However, the desire to belong differs between individuals, raising the question of whether individual differences in the need to belong moderate the impact of perceived social isolation on health. In the present study, 77 first-year university students rated their loneliness and health every 6 weeks for 18 weeks. Individual differences in the need to belong were found to moderate the relationship between loneliness and current health state. Specifically, lonely students with a high need to belong reported more days of illness than those with a low need to belong. In contrast, the strength of the need to belong had no effect on students who did not feel lonely. Thus, people who have a strong need to belong appear to suffer from loneliness and become ill more often, whereas people with a weak need to belong appear to stand loneliness better and are comparatively healthy. The study implies that social isolation does not impact all individuals identically; instead, the fit between the social situation and an individual’s need appears to be crucial for an individual’s functioning.

Impact of merger on efficiency and productivity : a case study of commercial banks in Malaysia

1970 ◽  
Vol 5 (1) ◽  
pp. 77
Author(s):  
Mahadzir Ismail ◽  
Saliza Sulaiman ◽  
Hasni Abdul Rahim ◽  
Nordiana Nordin
Keyword(s):  
Efficiency Score ◽  
Malmquist Productivity Index ◽  
Productivity Index ◽  
Data Envelopment ◽  
Master Plan ◽  
Before And After ◽  
Domestic Banks ◽  
The Impact ◽  
Efficiency And Productivity

The Financial Master Plan (2001- 2010) aims to enhance the capacity of banking industry so that higher effic iency and productivity can be reaped in the future. This study seeks to determine the impact of merger on the efficiency and productivity ofcommercial banks in Malaysia for the period 1995 until 2005. The study uses a non-parametric approach, nam ely DEA (data envelopment analysis?) to estimate the efficiency scores and to construct the Malmquist productivity index. To enable this estimation, three bank inputs and outputs are used. Amongst the findings are those banks exhibit higher efficiency score after the merger and thefo reign banks are more efficient than the local banks. Productivity of the banks is calculated in both periods, before and after the merger: The results show that, it is the local banks that have improved the most after the merger. The main source of productivity is technical change or innovation. The findings support the existing policy of having larger domestic banks in term of size.

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