Challenges of D-SAGD Completion

2021 ◽  
Author(s):  
John Graham ◽  
Cody Hollohan
Keyword(s):  
Traditional Approach ◽  
Pressure Fluctuations ◽  
Temperature Drop ◽  
Steam Injection ◽  
Heat Energy ◽  
Large Temperature ◽  
Production Well ◽  
Distribution Profile ◽  
Injection Wells ◽  
Steam Chamber

Abstract In the production well of a Steam Assisted Gravity Drainage (SAGD) injector-producer well-pair, Direct-to-SAGD (D-SAGD) reservoir steam chamber development and electrical submersible pump (ESP) deployment requires only a single workover, effectively performing the jobs in parallel. This is an improvement over the traditional approach where reservoir steam chamber development and ESP deployment occur sequentially, each requiring a dedicated workover. The D-SAGD completion not only eliminates all costs associated with one workover, but also minimizes the heat energy dissipation that would otherwise occur over several days of steam injection downtime associated with pulling the completion string and installing the artificial lift system, along with decreased time, and increased safety, among other attendant benefits. Traditionally, an initial completion is performed on the production well to install monitoring instrumentation and a steam injection string, then steam injection occurs through both the injection and production wells for approximately 90 to 120 days. Once the reservoir temperature has reached a predetermined midpoint temperature between the wells, a fall-off test is performed by halting steam injection in both the production and injection wells and monitoring the completion's heat energy distribution profile throughout the length of the liner from heel to toe as the well cools back down toward its steady state temperature. If the results of the fall-off test are satisfactory, then subsequently a second workover is performed to install the ESP into the production well. Lastly, steam injection in the injector well is resumed, and the ESP operation begins. Given that the single D-SAGD workover achieves both the deployment of instrumentation and the ESP prior to steam chamber development, this implies that the ESP is required to withstand the large temperature and pressure fluctuations inherent to the combination of steam chamber development and fall off testing, all prior to being powered on for production to begin. This represents an unprecedented challenge for ESP seal sections. Among several other novel challenges, if the internal oil volume contraction induced by the deep temperature drop of the fall off test exceeds the capacity of the seal section to compensate for it, then the seal and motor may flood with wellbore fluid prior to the first attempt at turning it on. This paper discusses the unique challenges associated with the D-SAGD completion as it relates to ESP reliability. A SAGD-spec ESP remaining downhole for several months at unprecedented bottom hole pressure and temperature, and withstanding the associated fall-off test is a meaningful deviation from the conventional SAGD application, and this paper will detail the considerations associated with achieving ESP reliability in a D-SAGD completion that is comparable to that achieved in the conventional SAGD completion.

Mathematical Modeling of Steam Assisted Gravity Drainage

2005 ◽  
Vol 8 (05) ◽  
pp. 372-376 ◽  
Author(s):  
Serhat Akin
Keyword(s):  
Mathematical Model ◽  
Heavy Oil ◽  
Steam Injection ◽  
Viscosity Reduction ◽  
Gravity Drainage ◽  
Heavy Oils ◽  
Production Well ◽  
Steam Chamber ◽  
Steam Assisted Gravity Drainage ◽  
Wide Range

Summary A mathematical model for gravity drainage in heavy-oil reservoirs and tar sands during steam injection in linear geometry is proposed. The mathematical model is based on the experimental observations that the steam-zone shape is an inverted triangle with the vertex fixed at the bottom production well. Both temperature and asphaltene content dependence on the viscosity of the drained heavy oil are considered. The developed model has been validated with experimental data presented in the literature. The heavy-oil production rate conforms well to previously published data covering a wide range of heavy oils and sands for gravity drainage. Introduction Gravity drainage of heavy oils is of considerable interest to the oil industry. Because heavy oils are very viscous and, thus, almost immobile, a recovery mechanism is required that lowers the viscosity of the material to the point at which it can flow easily to a production well. Conventional thermal processes, such as cyclic steam injection and steam-assisted gravity drainage(SAGD), are based on thermal viscosity reduction. Cyclic steam injection incorporates a drive enhancement from thermal expansion. On the other hand, SAGD is based on horizontal wells and maximizing the use of gravity forces. In the ideal SAGD process, a growing steam chamber forms around the horizontal injector, and steam flows continuously to the perimeter of the chamber, where it condenses and heats the surrounding oil. Effective initial heating of the cold oil is important for the formation of the steam chamber in gravity-drainage processes. Heat is transferred by conduction, by convection, and by the latent heat of steam. The heated oil drains to a horizontal production well located at the base of the reservoir just below the injection well. Based on the aforementioned concepts, Butler et al. derived Eq. 1 assuming that the steam pressure is constant in the steam chamber, that only steam flows in the steam chamber, that oil saturation is residual, and that heat transfer ahead of the steam chamber to cold oil is only by conduction. One physical analogy of this process is that of a reservoir in which an electric heating element is placed horizontally above a parallel horizontal producing well.

scholarly journals Numerical Modeling and Performance Evaluation of Standing Wave Thermoacoustic Refrigerators with a Multi-Layered Stack

Energies ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 4360
Author(s):  
Umar Nawaz Bhatti ◽  
Salem Bashmal ◽  
Sikandar Khan ◽  
Rached Ben-Mansour
Keyword(s):  
Standing Wave ◽  
Numerical Study ◽  
Temperature Drop ◽  
Acoustic Power ◽  
Heat Energy ◽  
Coefficient Of Performance ◽  
Material Layer ◽  
And Performance ◽  
Stacked Material ◽  
Thermoacoustic Refrigerators

Thermoacoustic refrigerators have huge potential to replace conventional refrigeration systems as an alternative clean refrigeration technology. These devices utilize conversion of acoustic power and heat energy to generate the desired cooling. The stack plays a pivotal role in the performance of Standing Wave Thermoacoustic Refrigerators (SWTARs), as the heat transfer takes place across it. Performance of stacks can be significantly improved by making an arrangement of different materials inside the stack, resulting in anisotropic thermal properties along the length. In the present numerical study, the effect of multi-layered stack on the refrigeration performance of a SWTAR has been evaluated in terms of temperature drop across the stack, acoustic power consumed and device Coefficient of Performance (COP). Two different aspects of multi-layered stack, namely, different material combinations and different lengths of stacked layers, have been investigated. The combinations of four stack materials and length ratios have been investigated. The numerical results showed that multi-layered stacks produce lower refrigeration temperatures, consume less energy and have higher COP value than their homogeneous counterparts. Among all the material combinations of multi-layered stack investigated, stacks composed of a material layer with low thermal conductivity at the ends, i.e., RVC, produced the best performance with an increase of 26.14% in temperature drop value, reduction in the acoustic power consumption by 4.55% and COP enhancement of 5.12%. The results also showed that, for a constant overall length, an increase in length of side stacked material layer results in an increase in values of both temperature drop and COP.

Field Implementation of In-Depth Conformance Gel Treatment Prior to Starting an ASP Flooding Pilot

2021 ◽  
Author(s):  
Mohammed T. Al-Murayri ◽  
Abrahim Hassan ◽  
Naser Alajmi ◽  
Jimmy Nesbit ◽  
Bastien Thery ◽  
...  
Keyword(s):  
Polymer Solution ◽  
Injection Pressure ◽  
High Viscosity ◽  
Production Well ◽  
Sweep Efficiency ◽  
Injection Wells ◽  
Appreciable Change ◽  
Well Pattern ◽  
Gel Treatment ◽  
Viscosity Polymer

Abstract Mature carbonate reservoirs under waterflood in Kuwait suffer from relatively low oil recovery due to poor volumetric sweep efficiency, both areal, vertically, and microscopically. An Alkaline-Surfactant-Polymer (ASP) pilot using a regular five-spot well pattern is in progress targeting the Sabriyah Mauddud (SAMA) reservoir in pursuit of reserves growth and production sustainability. SAMA suffers from reservoir heterogeneities mainly associated with permeability contrast which may be improved with a conformance treatment to de-risk pre-mature breakthrough of water and chemical EOR agents in preparation for subsequent ASP injection and to improve reservoir contact by the injected fluids. Each of the four injection wells in the SAMA ASP pilot was treated with a chemical conformance improvement formulation. A high viscosity polymer solution (HVPS) of 200 cP was injected prior to a gelant formulation consisting of P300 polymer and X1050 crosslinker. After a shut-in period, wells were then returned to water injection. Injection of high viscosity polymer solution (HVPS) at the four injection wells showed no increase in injection pressure and occurred higher than expected injection rates. Early breakthrough of polymer was observed at SA-0561 production well from three of the four injection wells. No appreciable change in oil cut was observed. HVPS did not improve volumetric sweep efficiency based on the injection and production data. Gel treatment to improve the volumetric conformance of the four injection wells resulted in all the injection wells showing increased of injection pressure from approximately 3000 psi to 3600 psi while injecting at a constant rate of approximately 2,000 bb/day/well. Injection profiles from each of the injection well ILTs showed increased injection into lower-capacity zones and decreased injection into high-capacity zones. Inter-well tracer testing showed delayed tracer breakthrough at the center SA-0561 production well from each of the four injection wells after gel placement. SA-0561 produced average daily produced temperature increased from approximately 40°C to over 50°C. SA-0561 oil cuts increased up to almost 12% from negligible oil sheen prior to gel treatments. Gel treatment improved volumetric sweep efficiency in the SAMA SAP pilot area.

scholarly journals A Numerical Model for Investigating the Steam Conformance along the Dual-String Horizontal Wells in SAGD Operations

Energies ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3981
Author(s):  
Peng Li ◽  
Yanyu Zhang ◽  
Xiaofei Sun ◽  
Huijuan Chen ◽  
Yang Liu
Keyword(s):  
Pressure Drop ◽  
Horizontal Wells ◽  
Pressure Profile ◽  
Steam Injection ◽  
Steam Pressure ◽  
Optimization Method ◽  
Injection Time ◽  
Reservoir Model ◽  
Landing Position ◽  
Steam Chamber

Non-uniformity of the steam-assisted gravity drainage (SAGD) steam chamber significantly decreases the development of heavy oil reservoirs. In this study, to investigate the steam conformance in SAGD operations, a wellbore model is developed for fluid flow in dual-string horizontal wells. Then, a three-dimensional, three-phase reservoir model is presented. Next, the coupled wellbore and reservoir model is solved with a fully implicit finite difference method. Finally, the effects of the injector wellbore configuration, steam injection ratio and injection time on the steam conformance are investigated. The results indicate that under different injector wellbore configurations, the closer the differences between the pressure drop from the landing position of the short string to the heel of the wellbore and the pressure drop from the landing position of the short string to the toe of the wellbore, the better is the steam conformance. The smaller the difference in the steam injection rate between the long and short injection strings, the higher is the uniformity of the steam chamber. The injector annular pressure profile uniformity is consistent with the steam conformance. Creating a more uniform steam pressure in the annulus of the injector improves the uniformity of the steam chamber. The steam conformance decreases with increasing injection time, so the optimization method of steam chamber uniformity should be adjusted according to different injection times.

scholarly journals A steam rising model of steam-assisted gravity drainage production for heavy oil reservoirs

2019 ◽  
Vol 38 (4) ◽  
pp. 801-818
Author(s):  
Ren-Shi Nie ◽  
Yi-Min Wang ◽  
Yi-Li Kang ◽  
Yong-Lu Jia
Keyword(s):  
Production Rate ◽  
Horizontal Well ◽  
Oil Production ◽  
Steam Injection ◽  
Injection Rate ◽  
Gravity Drainage ◽  
Model Parameters ◽  
Steam Quality ◽  
Steam Chamber ◽  
Steam Assisted Gravity Drainage

The steam chamber rising process is an essential feature of steam-assisted gravity drainage. The development of a steam chamber and its production capabilities have been the focus of various studies. In this paper, a new analytical model is proposed that mimics the steam chamber development and predicts the oil production rate during the steam chamber rising stage. The steam chamber was assumed to have a circular geometry relative to a plane. The model includes determining the relation between the steam chamber development and the production capability. The daily oil production, steam oil ratio, and rising height of the steam chamber curves influenced by different model parameters were drawn. In addition, the curve sensitivities to different model parameters were thoroughly considered. The findings are as follows: The daily oil production increases with the steam injection rate, the steam quality, and the degree of utilization of a horizontal well. In addition, the steam oil ratio decreases with the steam quality and the degree of utilization of a horizontal well. Finally, the rising height of the steam chamber increases with the steam injection rate and steam quality, but decreases with the horizontal well length. The steam chamber rising rate, the location of the steam chamber interface, the rising time, and the daily oil production at a certain steam injection rate were also predicted. An example application showed that the proposed model is able to predict the oil production rate and describe the steam chamber development during the steam chamber rising stage.

Sensitivity of Thermal Transport in Uranium Dioxide to Fission Gas

2019 ◽  
Author(s):  
Katherine Mitchell ◽  
Hunter Horner ◽  
Alex Resnick ◽  
Jungkyu Park ◽  
Eduardo B. Farfán ◽  
...  
Keyword(s):  
Thermal Resistance ◽  
Uranium Dioxide ◽  
Thermal Transport ◽  
Temperature Drop ◽  
Phonon Transport ◽  
Interfacial Thermal Resistance ◽  
Large Temperature ◽  
Gas Bubble ◽  
Gas Generation ◽  
Fission Gas

Abstract Understanding the effect of fission gas generation on thermal resistance in various nuclear fuels is critical for managing fuel performance. Fission gas in the fuels degrades its thermal properties by altering the lattice vibrations. It results in thermal expansion that increases the thermal resistance and decreases the structural stability of the fuels. In this research, thermal transport in uranium dioxide is studied at a microscopic level when Xe and Kr gasses interact with uranium and oxygen atoms. Reverse non-equilibrium molecular dynamics (RNEMD) is used to calculate the thermal resistances and provide an understanding about the effect of the fission gas release on phonon transport. The results show that the thermal conductivity of uranium dioxide is decreased nearly by 78% by the presence of only one fission gas bubble. The thermal transport in uranium dioxide is shown to become highly diffusive by a single fission gas bubble and a large temperature drop in temperature profiles are observed in all simulation structures with fission gas bubbles. The average interfacial thermal resistance across a fission gas bubble is estimated to be 2.1 × 10−9 Km2/W.

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