The Feasibility Analysis of an Underground Natural Gas Storage Using a Depleted Offshore Gasfield

2021 ◽  
Author(s):  
Hongbo Huo ◽  
Jinman Li ◽  
Zhong Li ◽  
Xiaocheng Zhang ◽  
Shiming He ◽  
...  
Keyword(s):  
Natural Gas ◽  
Gas Storage ◽  
Feasibility Analysis ◽  
Bohai Bay ◽  
Gas Reservoir ◽  
Gas Field ◽  
Offshore Engineering ◽  
Well Pattern ◽  
The Impact ◽  
Depleted Gas Reservoir

Abstract Objectives/Scope Compared with the underground nature gas storage (UNGS) onshore, the offshore UNGS is further from residential areas and industrial areas, which can shave the peak of natural gas more safely. However, the investment of offshore engineering is higher. Offshore UNGS with reusing offshore depleted gas reservoir construction can not only solves the problems of offshore engineering structure and wells abandonment but also greatly reduces the investment. Methods, Procedures, Process According to the experience of UNGS onshore, the following factors were considered: reservoir buried depth, working gas volume, distance from land, etc. Based on one depleted gasfield in Bohai Bay, the feasibility analysis of an UNGS was carried out, the impact of the offshore UNGS on the environment, the sealing of the underground gas trap and the integrity of the wellbore were evaluated, and the result proves that the sealing of the underground gas trap of the gas field was good. The natural gas pipeline network subsea can provide transportation for the UNGS and compatible to be transformed into the offshore UNGS. However, for one thing, the poor wellbore integrity conditions and imperfect well pattern constraint the reusing, for another, the capacity of offshore facilities need to be improved. Results, Observations, Conclusions According to the economic evaluation, the investment of offshore depleted gas reservoir reusing as UNGS can be reduced by 56% compared with the construction of a new onshore UNGS, and 32% compared with the offshore gas field abandon. A new idea is provided for peak shaving of natural gas, greatly reducing the investment in gas storage construction. Experience has been accumulated by the feasibility analysis of offshore depleted gas field UNGS and that has a bright future. Novel/Additive Information The limitation of natural conditions on project construction, contingency plans for force majeure such as sea ice, storm and earthquake, etc are necessary to be considered, and its implementation still needs the support of the government and relevant non-governmental organizations

Inventory Verification in Underground Gas Storage Rebuilt from Depleted Gas Reservoir: A Case Study from China

2021 ◽  
Author(s):  
Lina Song ◽  
Hongcheng Xu ◽  
Qiqi Wanyan ◽  
Wei Liao ◽  
Shijie Zhang ◽  
...  
Keyword(s):  
Natural Gas ◽  
Winter Season ◽  
Gas Storage ◽  
Experimental Result ◽  
Operating Pressure ◽  
Underground Gas Storage ◽  
Gas Reservoir ◽  
Well Pattern ◽  
Geological Conditions ◽  
Depleted Gas Reservoir

Abstract Inventory verification is one of vital tasks in underground gas storage (UGS) management process. For one reason, it is possible to know exactly how much natural gas is actually in the gas storage and ensure that it can be produced and supplied to the market in winter season when needed. For another, possible natural gas leakage can be discovered in time by inventory verification, to ensure the safe and economic operation of the gas storage. HTB UGS is a gas storage facility rebuilt from a depleted gas reservoir in China, which has been commissioning in June 2013. After 7 years injection-withdrawal cycles, we calculated and analyzed the inventory of this gas storage. First and foremost, we analyzed the data of 13 observation wells, including monitoring of gas-water interface, caprocks, and faults of the HTB UGS. In addition, we carried out core experiments in the laboratory to simulate the multi-cycle injection and withdrawal of gas storage, and analyzed the microscopic pore seepage characteristics of the reservoir during the UGS operation. Next, based on the operating pressure test data of the gas storage, we corrected the formation pressure and calculated the effective inventory. Furthermore, combined with the simulation results that we have carried out in the previous period, the effective inventory of HTB UGS was comprehensively evaluated. The result shows that: 1) The complete monitoring system indicates that the HTB UGS has no gas escaping from the storage field through faults, caprocks or wellbore. 2) The experimental result shows that in the process of gas withdrawal, various forms of natural gas such as jams and bypasses in some areas of the reservoir cannot participate in the flow, leading to this part of natural gas cannot be used. 3) Inventory calculation shows that as of the end of gas withdrawal in March 2020, the book inventory of HTB UGS is 99.8×108m3，while the effective inventory is 91.8×108m3 and the working gas is 39.9×108m3. 4) By acidification or other measures to improve the geological conditions, intensifying the well pattern and extending the gas production time, HTB UGS can increase its effective inventory. With the great efforts in constructing underground gas storage in China and the market-oriented operation of UGS, inventory verification of gas storage will become increasingly important. The inventory analysis method established in this article can provide a certain reference.

scholarly journals Utilization of CO2 as Cushion Gas for Depleted Gas Reservoir Transformed Gas Storage Reservoir

Energies ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 576 ◽  
Author(s):  
Cheng Cao ◽  
Jianxing Liao ◽  
Zhengmeng Hou ◽  
Hongcheng Xu ◽  
Faisal Mehmood ◽  
...  
Keyword(s):  
Natural Gas ◽  
Production Rate ◽  
Water Saturation ◽  
Gas Storage ◽  
Periodic Change ◽  
Residual Water ◽  
Reservoir Pressure ◽  
Gas Reservoir ◽  
Reservoir Permeability ◽  
Depleted Gas Reservoir

Underground gas storage reservoirs (UGSRs) are used to keep the natural gas supply smooth. Native natural gas is commonly used as cushion gas to maintain the reservoir pressure and cannot be extracted in the depleted gas reservoir transformed UGSR, which leads to wasting huge amounts of this natural energy resource. CO2 is an alternative gas to avoid this particular issue. However, the mixing of CO2 and CH4 in the UGSR challenges the application of CO2 as cushion gas. In this work, the Donghae gas reservoir is used to investigate the suitability of using CO2 as cushion gas in depleted gas reservoir transformed UGSR. The impact of the geological and engineering parameters, including the CO2 fraction for cushion gas, reservoir temperature, reservoir permeability, residual water and production rate, on the reservoir pressure, gas mixing behavior, and CO2 production are analyzed detailly based on the 15 years cyclic gas injection and production. The results showed that the maximum accepted CO2 concentration for cushion gas is 9% under the condition of production and injection for 120 d and 180 d in a production cycle at a rate of 4.05 kg/s and 2.7 kg/s, respectively. The typical curve of the mixing zone thickness can be divided into four stages, which include the increasing stage, the smooth stage, the suddenly increasing stage, and the periodic change stage. In the periodic change stage, the mixed zone increases with the increasing of CO2 fraction, temperature, production rate, and the decreasing of permeability and water saturation. The CO2 fraction in cushion gas, reservoir permeability, and production rate have a significant effect on the breakthrough of CO2 in the production well, while the effect of water saturation and temperature is limited.

scholarly journals Phase Behavior Identification and Formation Mechanisms of the BZ19-6 Condensate Gas Reservoir in the Deep Bozhong Sag, Bohai Bay Basin, Eastern China

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-19
Author(s):  
Zhenliang Wang ◽  
Shengdong Xiao ◽  
Feilong Wang ◽  
Guomin Tang ◽  
Liwen Zhu ◽  
...  
Keyword(s):  
Critical Temperature ◽  
Natural Gas ◽  
Phase Behavior ◽  
Oil And Gas ◽  
Eastern China ◽  
Bohai Bay ◽  
Bohai Bay Basin ◽  
Gas Reservoir ◽  
Gas Field ◽  
Gaseous Hydrocarbons

Significant developments have been observed in recent years, in the field of deep part exploration in the Bozhong Sag, Bohai Bay Basin in eastern China. The BZ19-6 large condensate gas field, the largest gas field in the Bohai Bay Basin, was discovered for the first time in a typical oil-type basin. The proven oil and gas geological reserves in the deeply buried hills of the Archean metamorphic rocks, amount to approximately 3 × 10 8 tons of oil equivalent. However, the phase behavior and genetic mechanisms of hydrocarbon fluids are still unclear. In this study, the phase diagram identification method and various empirical statistical methods, such as the block diagram method, φ 1 parameter method, rank number method, and Z -factor method were implemented to comprehensively identify the phase behavior types of the BZ19-6 condensate gas reservoir. The genetic mechanism of the BZ19-6 condensate gas reservoir was investigated in detail through analyses of physical properties of the fluid at high temperatures and pressures, organic geochemical characteristics of condensate oil and gas, and regional tectonic background. Consequently, this study is shown as follows: (1) The BZ19-6 condensate gas reservoir is a part of a secondary condensate gas reservoir with oil rings, formed synthetically since the Neogene period due to multiple factors, such as retrograde evaporation from deep burial and high temperature, inorganic CO2 charging from the deep mantle, and late natural gas invasion. (2) The hydrocarbon accumulation process of the BZ19-6 condensate gas reservoir is as follows: First, a large amount of oil is accumulated at the end of the lower Minghuazhen deposition (5 Ma BP); second, a large amount of natural gas is generated in the deep-source kitchen and mantle-derived inorganic CO2 charged into the early formed oil reservoirs at the end of the upper Minghuazhen deposition (2 Ma BP). As a result, the content of gaseous hydrocarbons in the hydrocarbon system of the reservoir increased, which led to large amounts of liquid hydrocarbons dissolved in gaseous hydrocarbons and significantly reduced the critical temperature of the hydrocarbon system. Therefore, existing secondary condensate gas reservoirs are formed when the critical temperature is lower than the formation temperature and it enters the critical condensate temperature range.

Feasibility Analysis of Gas Storage in JB Area Caprock Evaluation

2011 ◽  
Vol 110-116 ◽  
pp. 3117-3124
Author(s):  
Lei Shi ◽  
Shu Sheng Gao
Keyword(s):  
Natural Gas ◽  
Carbonate Platform ◽  
Gas Storage ◽  
High Demand ◽  
Gas Reservoir ◽  
Sealing Capacity ◽  
Important Index ◽  
Long Run ◽  
Cap Rock ◽  
Selection Of

Underground gas storages （UGS） are widely used to store the excess of produced natural gas during periods of low demand, and relieve the pressure during periods of high demand. Depleted natural gas reservoir is generally the best choice against others. Proper selection of a depleted gas reservoir is essential to the succession, steady and reliability of UGS in the long run. Sealing capacity of caprock is an important index for measuring the performance of gas storage reservoir. In order to analysis feasibility of UGS in JB area, the development characteristics of caprock were studied, the sealing gas effectiveness of caprock was evaluated. it was concluded that the main caprock was the formation of evaporative carbonate platform, and the breakthrough pressure of cap rock was high. The cap rocks with good sealing capacity were distributed in the area between S224 well and S39 well. The sealing ability was comprehensively evaluated by use of the development features and sealing capacity of caprock.

Investigation of Underground Gas Storage in a Partially Depleted Gas Reservoir

2008 ◽  
Author(s):  
Reza Azin ◽  
Amir Nasiri ◽  
Ali Jodeyri Entezari ◽  
Gholam Hossein Montazeri
Keyword(s):  
Gas Storage ◽  
Underground Gas Storage ◽  
Gas Reservoir ◽  
Depleted Gas Reservoir

scholarly journals Comparative Study on the Reservoir Characteristics and Development Technologies of Two Typical Karst Weathering-Crust Carbonate Gas Reservoirs in China

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-19
Author(s):  
Haijun Yan ◽  
Ailin Jia ◽  
Fankun Meng ◽  
Qinyu Xia ◽  
Wei Xu ◽  
...  
Keyword(s):  
Carbonate Reservoirs ◽  
Production Performance ◽  
Dynamic Monitoring ◽  
Weathering Crust ◽  
Gas Reservoirs ◽  
Gas Reservoir ◽  
Gas Field ◽  
Reservoir Characteristics ◽  
Reservoir Stimulation ◽  
Well Pattern

Carbonate reservoirs are the main reservoir types in China, which occupy the large ratio of reserves and production at present. The high-efficiency development of carbonate reservoirs is of great significance to assure the stability of national energy supply. The Lower Paleozoic reservoir in Jingbian gas field and the Sinian reservoir in Anyue gas field are two typical carbonate gas reservoirs, and their successful development experiences can provide significant references for other similar carbonate gas reservoirs. For Jingbian gas field, it is a lithological-stratigraphic reservoir developed in a westward monocline and multiple rows of nose-fold structures, and is a stable craton basin with simple palaeognomy distribution and stable connectivity, which has complex gas-water distribution. However, for Anyue gas field, it is a lithological-structural reservoir with multiple tectonic high points and multiple fault systems, and is biological dune beach facies under extensional setting with highly differentiated inside of the block in palaeognomy characteristics, which has limited connectivity and tectonic side water is in a local area. The difference of gas reservoir characteristics leads to the diverse development strategies. For these two gas reservoirs, although there are some similar aspects, such as the screen of enrichment areas, the application of irregular well pattern and reservoir stimulation techniques, the criteria of enrichment areas, the well types, and the means of reservoir stimulation are absolutely different. In addition, due to the differences of control reserves and production capacity for these two kinds of reservoirs, the mode of stable production is also different. The effective development of Jingbian gas field can give some references to the future exploitation on the Sinian gas reservoir. Firstly, the sedimentary characteristics should be studied comprehensively. Secondly, the distribution pattern and distribution characteristics of the palaeognomy should be found and determined. Thirdly, the distribution of fracture system in the reservoir should be depicted finely. Finally, dynamic monitoring on the production performance should be strengthened, and the management for this gas field should be improved further. The findings of this study can help for better understanding of the Karst weathering-crust carbonate gas reservoir formation characteristics and the optimal development technologies that should be taken in practice.

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