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.

scholarly journals Development of a prmA genes quantification technique and assessment of the technique’s application potential for oil and gas reservoir exploration

2018 ◽  
Vol 36 (5) ◽  
pp. 1172-1188 ◽  
Author(s):  
Zhuo Ning ◽  
Ze He ◽  
Sheng Zhang ◽  
Miying Yin ◽  
Yaci Liu ◽  
...  
Keyword(s):  
Oil And Gas ◽  
Quantitative Polymerase Chain Reaction ◽  
Oil Field ◽  
Gas Reservoirs ◽  
Gas Reservoir ◽  
Gas Field ◽  
Detection Range ◽  
Gene Copies ◽  
Application Potential ◽  
Sensitivity Specificity

Propane-oxidizing bacteria in surface soils are often used to indicate the position of oil and gas reservoirs. As a potential replacement for the laborious traditional culture-dependent counting method, we applied real-time fluorescent quantitative polymerase chain reaction detection as a quick and accurate technology for quantification of propane-oxidizing bacteria. The propane monooxygenase gene was set as the target and the assay is based on SYBR Green I dye. The detection range was from 9.75 × 108 to 9.75 × 101 gene copies/µl, with the lowest detected concentration of 9.75 copies/µl. All coefficient of variation values of the threshold cycle in the reproducibility test were better than 1%. The technique showed good sensitivity, specificity, and reproducibility. We also quantified the propane-oxidizing bacteria in soils from three vertical 250 cm profiles collected from an oil field, a gas field, and a nonoil gas field using the established technique. The results indicated that the presence of propane monooxygenase A genes in soils can indicate an oil or gas reservoir. Therefore, this technique can satisfy the requirements for microbial exploration of oil and gas.

Research Progress in Calculation Methods for Single-Well Dynamic Reserves of Gas Reservoirs

2014 ◽  
Vol 1044-1045 ◽  
pp. 401-405
Author(s):  
Hai Dong Shi
Keyword(s):  
High Efficiency ◽  
Research Progress ◽  
Calculation Methods ◽  
Gas Wells ◽  
Gas Reservoirs ◽  
Gas Field ◽  
Well Spacing ◽  
Well Pattern ◽  
Single Well ◽  
Gas Fields

Dynamic reserves are the important basis for determining the reasonable deliverability of gas wells and well spacing density and also the foundation for the overall development plan of a gas field. Therefore, the evaluation of dynamic reserves of gas wells is crucially important to developing gas fields with high efficiency, optimizing well pattern and shortening development period. For this reason, this paper arranges and analyzes systematically a series of calculation methods for dynamic reserves of single gas well, which have arisen in recent years, and identifies the calculation methods for different types of gas reservoirs.

scholarly journals Effect of Geological Heterogeneity on the Production Performance of a Multifractured Horizontal Well in Tight Gas Reservoirs

Lithosphere ◽  
2021 ◽  
Vol 2021 (Special 1) ◽  
Author(s):  
Yue Peng ◽  
Tao Li ◽  
Yuxue Zhang ◽  
Yongjie Han ◽  
Dan Wu ◽  
...  
Keyword(s):  
Horizontal Well ◽  
Horizontal Wells ◽  
Gas Production ◽  
Production Performance ◽  
Tight Gas ◽  
Gas Reservoirs ◽  
Gas Reservoir ◽  
Tight Gas Reservoirs ◽  
Reservoir Permeability ◽  
Half Length

Abstract Multifractured horizontal wells are widely used in the development of tight gas reservoirs to improve the gas production and the ultimate reservoir recovery. Based on the heterogeneity characteristics of the tight gas reservoir, the homogeneous scheme and four typical heterogeneous schemes were established to simulate the production of a multifractured horizontal well. The seepage characteristics and production performance of different schemes were compared and analyzed in detail by the analysis of streamline distribution, pressure distribution, and production data. In addition, the effects of reservoir permeability level, length of horizontal well, and fracture half-length on the gas reservoir recovery were discussed. Results show that the reservoir permeability of the unfractured areas, which are located at both ends of the multifractured horizontal well, determines the seepage ability of the reservoir matrix, showing a significant impact on the long-term gas production. High reservoir permeability level, long horizontal well length, and long fracture half-length can mitigate the negative influence of heterogeneity on the gas production. Our research can provide some guidance for the layout of multifractured horizontal wells and fracturing design in heterogeneous tight gas reservoirs.

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

scholarly journals Relationship between well pattern density and variation function of stochastic modelling and database establishment

2020 ◽  
Vol 75 ◽  
pp. 84
Author(s):  
Jinkai Wang ◽  
Kai Zhao ◽  
Zhaoxun Yan ◽  
Yuxiang Fu ◽  
Jun Xie
Keyword(s):  
Oil And Gas ◽  
Stochastic Modelling ◽  
Gas Reservoirs ◽  
Gas Field ◽  
Pattern Density ◽  
Vertical Range ◽  
Variation Function ◽  
Well Pattern ◽  
Geological Conditions ◽  
Degree Of Convergence

For 3D geological modelling of oil and gas reservoirs, well pattern density is directly related to the number of samples involved in the calculation, which determines the variation function of stochastic modelling and has great impacts on the results of reservoir modelling. This paper focuses on the relationship between well pattern density and the variogram of stochastic modelling, selects the large Sulige gas field with many well pattern types as the research object, and establishes a variogram database of stochastic models for different well pattern densities. First, the well pattern in the study area is divided into three different types (well patterns A, B, and C) according to well and row space. Several different small blocks (model samples) are selected from each type of well pattern to establish the model, and their reasonable variogram values (major range, minor range and vertical range) are obtained. Then, the variogram values of all model samples with similar well pattern densities are analysed and counted, and the variogram database corresponding to each type of well pattern is established. Finally, the statistical results are applied to the modelling process of other blocks with similar well pattern density to test their accuracy. The results show that the reservoir model established by using the variation function provided in this paper agrees well with the actual geological conditions and that the random model has a high degree of convergence. This database has high adaptability, and the model established is reliable.

scholarly journals Analysis of Gas Flow Behavior for Highly Deviated Wells in Naturally Fractured-Vuggy Carbonate Gas Reservoirs

2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Kongjie Wang ◽  
Lian Wang ◽  
Caspar Daniel Adenutsi ◽  
Zhiping Li ◽  
Sen Yang ◽  
...  
Keyword(s):  
High Efficiency ◽  
Flow Behavior ◽  
Production Performance ◽  
Gas Reservoirs ◽  
Gas Reservoir ◽  
Reservoir Development ◽  
Proposed Model ◽  
Naturally Fractured ◽  
Production Behavior ◽  
Deviated Wells

To improve the carbonate gas reservoir development and production, highly deviated wells (HDW) are widely used in the field. Production decline analysis of HDW is crucial for long-term gas reservoir development. However, it is a new challenge to incorporate the complex pore structure of naturally fractured-vuggy carbonate gas reservoirs and evaluate the production performance of HDW. This paper presents a semianalytical model to analyze the pressure and production behavior of HDW in naturally fractured-vuggy carbonate gas reservoirs, which consist of fractures, vugs, and matrix. The primary flow occurs only through the fracture and the outer boundary is closed. Introducing pseudopressure and pseudotime, the Laplace transformation, Fourier transformation, and its inverse and Stehfest numerical inversion were employed to establish a point source and line source solutions. Furthermore, the validity of the proposed model was verified by comparing a field data from the Arum River Basin in Turkmenistan. Finally, the effects of major parameters on the production decline curves were analyzed by using the proposed model and it was found that they had influences at different stages of gas production history and the sensitivity intensity of each parameter was different. With its high efficiency and simplicity, this semianalytical model will serve as a useful tool to evaluate the well production behavior for the naturally fractured-vuggy carbonate gas reservoirs.

scholarly journals The Researches on Reasonable Well Spacing of Gas Wells in Deep and low Permeability Gas Reservoirs

2018 ◽  
Vol 38 ◽  
pp. 01038
Author(s):  
Yu Bei Bei ◽  
Li Hui ◽  
Li Dong Lin
Keyword(s):  
Pressure Gradient ◽  
Low Permeability ◽  
Well Testing ◽  
Gas Wells ◽  
Gas Reservoirs ◽  
Gas Reservoir ◽  
Gas Field ◽  
Well Spacing ◽  
Start Up ◽  
Starting Pressure Gradient

This Gs64 gas reservoir is a condensate gas reservoir which is relatively integrated with low porosity and low permeability found in Dagang Oilfield in recent years. The condensate content is as high as 610g/m3. At present, there are few reports about the well spacing of similar gas reservoirs at home and abroad. Therefore, determining the reasonable well spacing of the gas reservoir is important for ensuring the optimal development effect and economic benefit of the gas field development. This paper discusses the reasonable well spacing of the deep and low permeability gas reservoir from the aspects of percolation mechanics, gas reservoir engineering and numerical simulation. considering there exist the start-up pressure gradient in percolation process of low permeability gas reservoir, this paper combined with productivity equation under starting pressure gradient, established the formula of gas well spacing with the formation pressure and start-up pressure gradient. The calculation formula of starting pressure gradient and well spacing of gas wells. Adopting various methods to calculate values of gas reservoir spacing are close to well testing' radius, so the calculation method is reliable, which is very important for the determination of reasonable well spacing in low permeability gas reservoirs.

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