scholarly journals Numerical modelling of the cooling effect in geothermal reservoirs induced by injection of CO2 and cooled geothermal water

2020 ◽  
Vol 75 ◽  
pp. 15
Author(s):  
Hejuan Liu ◽  
Qi Li ◽  
Yang Gou ◽  
Liwei Zhang ◽  
Wentao Feng ◽  
...  
Keyword(s):  
Injection Pressure ◽  
Geothermal Water ◽  
Geothermal Reservoir ◽  
Cooling Effect ◽  
Reservoir Pressure ◽  
Temperature Decrease ◽  
Water Production ◽  
Production Well ◽  
Production Wells ◽  
Thermal Breakthrough

The utilization of geothermal energy can reduce CO2 emissions into the atmosphere. The reinjection of cooled return water from a geothermal field by a closed loop system is an important strategy for maintaining the reservoir pressure and prolonging the depletion of the geothermal reservoir by avoiding problems, e.g., water level drawdown, ground subsidence, and thermal pollution. However, the drawdown of water injectivity affected by physical and chemical clogging may occur in sandstone aquifers, and the reservoir temperature may be strongly affected by the reinjection of large amounts of cooled geothermal water, thus resulting in early thermal breakthrough at production wells and a decrease in production efficiency. In addition to the injection of cooled geothermal water, the injection of CO2 can be used to maintain the reservoir pressure and increase the injectivity of the reservoir by enhancing water–rock interactions. However, the thermal breakthrough and cooling effect of the geothermal reservoir may become complex when both CO2 and cooled geothermal water are injected into aquifers. In this paper, a simplified small-scale multilayered geological model is established based on a low-medium geothermal reservoir in Binhai district, Tianjin. The ECO2N module of the TOUGH2MP simulator is used to numerically simulate temperature and pressure responses in the geothermal reservoir while considering different treatment strategies (e.g., injection rates, temperatures, well locations, etc.). The simulation results show that a high injection pressure of CO2 greatly shortens the CO2 and thermal breakthrough at the production well. A much lower CO2 injection pressure is helpful for prolonging hot water production by maintaining the reservoir pressure and eliminating the cooling effect surrounding the production wells. Both pilot-scale and commercial-scale cooled water reinjection rates are considered. When the water production rate is low (2 kg/s), the temperature decrease at the production well is negligible at a distance of 500 m between two wells. However, when both the production and reinjection rates of cooled return water are increased to 100 m3/h, the temperature decrease in the production well exceeds 10 °C after 50 years of operation.

scholarly journals A Study on the CO2-Enhanced Water Recovery Efficiency and Reservoir Pressure Control Strategies

Geofluids ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-17 ◽  
Author(s):  
Zhijie Yang ◽  
Tianfu Xu ◽  
Fugang Wang ◽  
Yujie Diao ◽  
Xufeng Li ◽  
...  
Keyword(s):  
Saline Water ◽  
Control Strategies ◽  
Production Capacity ◽  
Junggar Basin ◽  
Pressure Control ◽  
Reservoir Pressure ◽  
Water Recovery ◽  
Water Production ◽  
Well Spacing ◽  
Production Wells

CO2 geological storage (CGS) proved to be an effective way to mitigate greenhouse gas emissions, and CO2-enhanced water recovery (CO2-EWR) technology may improve the efficiency of CO2 injection and saline water production with potential economic value as a means of storing CO2 and supplying cooling water to power plants. Moreover, the continuous injection of CO2 may cause a sharp increase for pressure in the reservoir system, so it is important to determine reasonable reservoir pressure control strategies to ensure the safety of the CGS project. Based upon the typical formation parameters of the China Geological Survey CO2-EWR test site in the eastern Junggar Basin, a series of three-dimensional (3D) injection-extraction models with fully coupled wellbores and reservoirs were established to evaluate the effect of the number of production wells and the well spacing on the enhanced efficiency of CO2 storage and saline production. The optimal key parameters that control reservoir pressure evolution over time are determined. The numerical results show that a smaller spacing between injection and production wells and a larger number of production wells can enhance not only the CO2 injection capacity but also the saline water production capacity. The effect of the number of production wells on the injection capacity and production capacity is more significant than that of well spacing, and the simulation scenario with 2 production wells, one injection well, and a well spacing of 2 km is more reasonable in the demonstration project of Junggar Basin. CO2-EWR technology can effectively control the evolution of the reservoir pressure and offset the sharp increase in reservoir pressure caused by CO2 injection and the sharp decrease of reservoir pressure caused by saline production. The main controlling factors of pressure evolution at a certain spatial point in a reservoir change with time. The monitoring pressure drops at the beginning and is controlled by the extraction of water. Subsequently, the injection of CO2 plays a dominant role in the increase of reservoir pressure. Overall, the results of analysis provide a guide and reference for the CO2-EWR site selection, as well as the practical placement of wells.

scholarly journals Geothermal Boreholes in Poland—Overview of the Current State of Knowledge

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3251
Author(s):  
Tomasz Sliwa ◽  
Aneta Sapińska-Śliwa ◽  
Andrzej Gonet ◽  
Tomasz Kowalski ◽  
Anna Sojczyńska
Keyword(s):  
Heat Exchangers ◽  
Oil And Gas ◽  
Produced Water ◽  
Geothermal Water ◽  
Laboratory System ◽  
Water Production ◽  
Injection Wells ◽  
Geological Conditions ◽  
Geothermal Wells ◽  
Borehole Heat Exchangers

Geothermal energy can be useful after extraction from geothermal wells, borehole heat exchangers and/or natural sources. Types of geothermal boreholes are geothermal wells (for geothermal water production and injection) and borehole heat exchangers (for heat exchange with the ground without mass transfer). The purpose of geothermal production wells is to harvest the geothermal water present in the aquifer. They often involve a pumping chamber. Geothermal injection wells are used for injecting back the produced geothermal water into the aquifer, having harvested the energy contained within. The paper presents the parameters of geothermal boreholes in Poland (geothermal wells and borehole heat exchangers). The definitions of geothermal boreholes, geothermal wells and borehole heat exchangers were ordered. The dates of construction, depth, purposes, spatial orientation, materials used in the construction of geothermal boreholes for casing pipes, method of water production and type of closure for the boreholes are presented. Additionally, production boreholes are presented along with their efficiency and the temperature of produced water measured at the head. Borehole heat exchangers of different designs are presented in the paper. Only 19 boreholes were created at the Laboratory of Geoenergetics at the Faculty of Drilling, Oil and Gas, AGH University of Science and Technology in Krakow; however, it is a globally unique collection of borehole heat exchangers, each of which has a different design for identical geological conditions: heat exchanger pipe configuration, seal/filling and shank spacing are variable. Using these boreholes, the operating parameters for different designs are tested. The laboratory system is also used to provide heat and cold for two university buildings. Two coefficients, which separately characterize geothermal boreholes (wells and borehole heat exchangers) are described in the paper.

Development of efficiency increase methods for water injection

2020 ◽  
pp. 57-60
Author(s):  
K.I. Mustafaev ◽  
◽  
◽  
Keyword(s):  
Water Injection ◽  
Cost Effective ◽  
Current Interest ◽  
Residual Oil ◽  
Production Well ◽  
Field Development ◽  
Oil Reserves ◽  
Production Wells ◽  
Efficiency Increase

The production of residual oil reserves in the fields being in a long-term exploitation is of current interest. The extraction of residual oil in such fields was cost-effective and simple technological process and is always hot topic for researchers. Oil wells become flooded in the course of time. The appearance of water shows in production wells in the field development and operation is basically negative occurrence and requires severe control. Namely for this reason, the studies were oriented, foremost, to the prevention of water shows in production well and the elimination of its complications as well. The paper discusses the ways of reflux efficiency increase during long-term exploitation and at the final stages of development to prevent the irrigation and water use in production wells.

Multifrequency full-waveform sonic logging in the screened interval of a large-diameter production well

Geophysics ◽  
2013 ◽  
Vol 78 (5) ◽  
pp. B243-B257 ◽  
Author(s):  
Majed Almalki ◽  
Brett Harris ◽  
J. Christian Dupuis
Keyword(s):  
Phase Velocity ◽  
Velocity Dispersion ◽  
Large Diameter ◽  
Low Frequency ◽  
Production Well ◽  
Frequency Wave ◽  
Full Waveform ◽  
Phase Velocity Dispersion ◽  
Production Wells ◽  
Sonic Logging

A set of field experiments using multiple transmitter center frequencies was completed to test the application potential of low-frequency full-waveform sonic logging in large-diameter production wells. Wireline logs were acquired in a simple open drillhole and a high-yield large diameter production well completed with wire-wound sand screens at an aquifer storage and recovery site in Perth, Western Australia. Phase-shift transform methods were applied to obtain phase-velocity dispersion images for frequencies of up to 4 kHz. A 3D representation of phase-velocity dispersion was developed to assist in the analysis of possible connections between low-frequency wave propagation modes and the distribution of hydraulic properties. For sandstone intervals in the test well, the highest hydraulic conductivity intervals were typically correlated with the lowest phase velocities. The main characteristics of dispersion images obtained from the sand-screened well were highly comparable with those obtained at the same depth level in a nearby simple drillhole open to the formation. The sand-screened well and the open-hole displayed an expected and substantial difference between dispersion in sand- and clay-dominated intervals. It appears that for clay-dominated formations, the rate of change of phase velocity can be associated to clay content. We demonstrated that with appropriate acquisition and processing, multifrequency full-waveform sonic logging applied in existing large-diameter sand-screened wells can produce valuable results. There are few wireline logging technologies that can be applied in this setting. The techniques that we used would be highly suitable for time-lapse applications in high-volume production wells or for reassessing formation properties behind existing historical production wells.

scholarly journals Studying of changes in the interaction of well during the water injection process

2019 ◽  
pp. 81-85
Author(s):  
Damir K. Sagitov
Keyword(s):  
Correlation Coefficient ◽  
Pair Correlation ◽  
Water Injection ◽  
Reservoir Pressure ◽  
Maintenance System ◽  
Displacement Front ◽  
Injection Process ◽  
Production Wells

The study of the causes of changes in the effectiveness of the reservoir pressure maintenance system in terms of the interaction of injection and production wells is an important and insufficiently studied problem, especially in terms of the causes of the attenuation of stable connections between the interacting wells. Based on the results of the calculation of the Spearman pair correlation coefficient, the reasons for the change in the interaction of wells during the flooding process at various stages were estimated. Of particular interest are identified four characteristic interactions, which are determined by the periods of formation of the displacement front.

scholarly journals An Approach for Estimating Geothermal Reservoir Productivity under Access Limitations Associated with Snowy and Mountainous Prospects

2021 ◽  
Author(s):  
Mitsuo Matsumoto
Keyword(s):  
Early Time ◽  
Geothermal Field ◽  
Geothermal Reservoir ◽  
Well Testing ◽  
Reservoir Pressure ◽  
New Approach ◽  
Frequency Distributions ◽  
Arbitrary Time ◽  
Active Exploration ◽  
Time Limitations

This chapter describes an approach to estimate reservoir productivity during the active exploration and development of a geothermal prospect. This approach allows a reservoir model to be updated by overcoming the severe time limitations associated with accessing sites for drilling and well testing under snowy and mountainous conditions. Performed in parallel with the conventional standard approach, the new approach enables us to obtain a first estimate of the reservoir productivity at an early time and to make successful project management decisions. Assuming a practical geothermal field, the procedures of the new approach are demonstrated here in detail. Finally, frequency distributions for the expected production rates and changes in the reservoir pressure at an arbitrary time are obtained during an assumed operational period.

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.

Preformed Particle Gels (PPGs) Compressibility Measurements in the Reservoirs Channels

2019 ◽  
Author(s):  
Mahmoud O. Elsharafi
Keyword(s):  
Particle Size ◽  
Injection Pressure ◽  
Gel Strength ◽  
Oil Field ◽  
Particle Sizes ◽  
Water Production ◽  
Load Pressure ◽  
Gel Particles ◽  
Preformed Particle Gels ◽  
Brine Concentration

Abstract Excess water production has become a significant problem to the oil-field operations as reservoirs mature. Preformed particle gels (PPGs) has been used widely to reduce the permeability of the formation channels. Therefore, water production decreases and sweeps efficiency increases in mature oil-fields. The work on this research will help out and determine what factors affect the PPG pack compressibility. It will determine the compressibility of swollen PPGs which could affect the selection and the design of the best PPG treatments in mature reservoirs. A transparent model was designed to observe the compression of gel particles in fluid channels at different injection pressures, and thus to study the effect of different parameters on PPG blocking efficiency. After each injection pressure, PPG compressibility was calculated to study the effect of various particle sizes, gel types, and brine concentrations on the PPG compressibility. Permeable gel packs were formed in fluid channels by gel particles and its compressibility depends on PPG particle size, gel strength, types, brine concentration, and load pressure. Gel pack is compressed and its compressibility is increased as injection pressure increases. A weak PPG with large particle size, low brine concentration, and low gel strength compressed more than a strong PPG with small particle size, high brine concentration, and high gel strength. The increase of the gel compressibility cause more reduction on the gel permeability on the fluid channels. A gel pack which has a desired compressibility can be designed by selecting proper gel strength and particle sizes at reservoir pressures.

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