Identification Method for Shallow Gas Layers in Cased Well

2014 ◽  
Vol 508 ◽  
pp. 146-149
Author(s):  
Xiao Min Tang ◽  
Xin Deng ◽  
Jian Fu ◽  
Lin Hou
Keyword(s):  
Gas Production ◽  
Production Testing ◽  
Neutron Lifetime ◽  
Gas Reservoirs ◽  
Gas Reservoir ◽  
Shallow Gas ◽  
Identification Methods ◽  
Identification Method ◽  
Gas Formation

In this paper, based on log response in gas formation, effective identification curves for shallow gas reservoirs are preferred from casedhole compensated neutron log, neutron lifetime log and openhole logs, and 4 parameters and 5 overlap curves are developed for identification of shallow gas reservoirs in cased wells. A gas reservoir in cased wells is interpreted with proposed identification methods. The gas production testing results shows that the proposed methods can determine shallow gas reservoirs in cased wells accurately.

scholarly journals Analysis of the Influence of Different Fracture Network Structures on the Production of Shale Gas Reservoirs

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Ming Yue ◽  
Xiaohe Huang ◽  
Fanmin He ◽  
Lianzhi Yang ◽  
Weiyao Zhu ◽  
...  
Keyword(s):  
Finite Element ◽  
Shale Gas ◽  
Flow Direction ◽  
Fracture Network ◽  
Gas Production ◽  
Low Flow ◽  
Gas Reservoirs ◽  
Gas Reservoir ◽  
Shale Gas Reservoir ◽  
Gas Seepage

Volume fracturing is a key technology in developing unconventional gas reservoirs that contain nano/micron pores. Different fracture structures exert significantly different effects on shale gas production, and a fracture structure can be learned only in a later part of detection. On the basis of a multiscale gas seepage model considering diffusion, slippage, and desorption effects, a three-dimensional finite element algorithm is developed. Two finite element models for different fracture structures for a shale gas reservoir in the Sichuan Basin are established and studied under the condition of equal fracture volumes. One is a tree-like fracture, and the other is a lattice-like fracture. Their effects on the production of a fracture network structure are studied. Numerical results show that under the same condition of equal volumes, the production of the tree-like fracture is higher than that of the lattice-like fracture in the early development period because the angle between fracture branches and the flow direction plays an important role in the seepage of shale gas. In the middle and later periods, owing to a low flow rate, the production of the two structures is nearly similar. Finally, the lattice-like fracture model is regarded as an example to analyze the factors of shale properties that influence shale gas production. The analysis shows that gas production increases along with the diffusion coefficient and matrix permeability. The increase in permeability leads to a larger increase in production, but the decrease in permeability leads to a smaller decrease in production, indicating that the contribution of shale gas production is mainly fracture. The findings of this study can help better understand the influence of different shapes of fractures on the production in a shale gas reservoir.

Development of a New Correlation of Gas Compressibility Factor (Z-Factor) for High Pressure Gas Reservoirs

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
Mohamed Mahmoud
Keyword(s):  
High Pressures ◽  
Compressibility Factor ◽  
Gas Reservoirs ◽  
Gas Reservoir ◽  
Gas Formation ◽  
New Correlation ◽  
Gas System ◽  
Data Points ◽  
New Formula ◽  
Gas Compressibility

Gas compressibility factor or Z-factor for natural gas system can be determined from Standing-Katz charts using the pseudocritical gas pressure and temperatures. These charts give accurate values for Z-factors. Reservoir simulation softwares need accurate correlations to estimate the values of Z-factor; one of the well-known correlations is Dranchuk and Abou-Kassem (DAK) Correlation. This correlation gives large errors at high gas reservoir pressures, this error could be more than 100%. The error in estimating Z-factor will lead to big error in estimating all the other gas properties such as gas formation volume factor, gas compressibility, and gas in place. In this paper a new accurate Z-factor correlation has been developed using regression for more than 300 data points of measured Z-factor using matlab in addition to other data points at low pressure and temperature from Standing-Katz charts and DAK correlation. Old correlations give good estimation of Z-factor at low gas reservoir pressures below 41.37 MPa (6000 psia), at high pressures the error started to appear. The developed correlation is a function of pseudoreduced pressure and temperature of the gas which makes it simpler than the existing complicated correlations. The new correlation can be used to determine the gas compressibility factor at any pressure range especially for high pressures the error was less than 3% compared to the measured data. The developed correlation is very simple to be used, it just needs the gas specific gravity that can be used to determine the pseudocritical properties of the gas and at last the Z-factor can be determined. A new formula of reduced gas compressibility was developed based on the developed Z-factor correlation which in turn can be used to determine the gas compressibility.

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.

scholarly journals Production Data Analysis and Practical Applications in the Sulige Tight Gas Reservoir, Ordos Basin, China

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Minhua Cheng ◽  
Wen Xue ◽  
Meng Zhao ◽  
Guoting Wang ◽  
Bo Ning ◽  
...  
Keyword(s):  
Data Analysis ◽  
Ordos Basin ◽  
Gas Production ◽  
Production Data ◽  
Gas Reservoirs ◽  
Tight Sandstone ◽  
Gas Reservoir ◽  
Well Pattern ◽  
Tight Gas Reservoir ◽  
Wellbore Pressure

Successful exploitation of tight sandstone gas is one of the important means to ensure the “increasing reserves and production” of the oil and gas initiative and also one of the important ways to ensure national energy security. To further improve the accuracy of historical matching of field data such as gas production and bottom-hole pressure during the production process of this type of gas reservoir, in this study, a new expression of wellbore pressure for the uniform flow of vertical fractured wells in Laplace space based on the point sink function model of vertical fractures in tight sandstone gas reservoirs is constructed. This innovation is based on a typical production data analysis plot of the Blasingame type that uses the numerical inversion decoupling mathematical equation. After analyzing the pressure and pressure derivative characteristics of each flow stage in the typical curves, a new technique of type-curve matching was proposed. In order to verify the correctness of the model and the application value of the field, based on the previous production data of Sulige Gas Field in China, a new set of production data diagnostic chart of tight sandstone gas reservoir was formed. A case analysis showed that the application of the production data analysis method and data diagnosis plot in the field accurately evaluated the development effect of the tight sandstone gas reservoirs, clarified the scale of effective sand bodies, and provided technical support for optimizing and improving the well pattern and realizing the efficient development of gas fields.

Method for Calculating Dynamic Reserves of Water Drive Gas Reservoir with Considering of Water-Sealing Gas

2014 ◽  
Vol 522-524 ◽  
pp. 1542-1546
Author(s):  
Xu Zhang ◽  
Wei Hua Liu
Keyword(s):  
Material Balance ◽  
Least Square Method ◽  
Gas Production ◽  
Least Square ◽  
Gas Reservoirs ◽  
Gas Reservoir ◽  
Gas Recovery ◽  
Water Influx ◽  
Calculation Results ◽  
Large Water

When research the behavior of water drive gas reservoirs, especially with large water influx, the first concerned is, how many gas is sealed, how many water seals the gas? Therefore, it is very important to study the amount of water-sealing gas, unsealed gas, and water influx. The amount of unsealed gas influences the Recovery Efficiency, and the water influx influences the drainage intensity, when we take the measures of Strong Drainage Gas Recovery, in the future. In this paper, we analysis Material Balance Equation; establish objective functions with Formation Pressure and gas production data; auto-match by Least-square Method; directly calculate the dynamic reserves of water drive gas reservoir, and the amount of water-sealing gas and water influx. The example calculation of well HB1, proved that the calculation results of this method is more accurate and reliable than in the past, and it is simple and practical as well.

scholarly journals Simulation Study to Evaluate the Impact of Fracture Parameters on Shale Gas Productivity

2020 ◽  
Vol 39 (2) ◽  
pp. 432-442
Author(s):  
Abdul Majeed Shar ◽  
Waheed Ali Abro ◽  
Aftab Ahmed Mahesar ◽  
Kun Sang Lee
Keyword(s):  
Shale Gas ◽  
Gas Production ◽  
Simulation Software ◽  
Production Performance ◽  
Gas Reservoirs ◽  
Gas Reservoir ◽  
Shale Gas Reservoir ◽  
Fracture Parameters ◽  
Shale Gas Reservoirs ◽  
The Impact

The production from shale gas reservoirs has significantly increased due to technological advancements. The shale gas reservoirs are very heterogeneous and the heterogeneity has a significant effect on the quality and productivity of reservoirs. Hence, it is essential to study the behavior of such reservoirs for accurate modelling and performance prediction. To evaluate the impact of fracture parameters on shale gas reservoir productivity using CMG (Computer Modelling Group) stars simulation software was the main objective of this study. In this paper, a comprehensive analysis considering an example shale gas reservoir was conducted for production performance analysis considering uniform and non-uniform fractures configurations. Several simulations were performed by considering the multi-stage hydraulically fractured reservoir. The sensitivities conducted includes the different cases of moderate and severe heterogeneity along with variable fractures half-length, effect of changing fracture spacing, variable fracture conductivities. The simulation results showed that by increasing conductivity of fracture increases the gas production rate significantly. Moreover, cases of reservoir permeability heterogeneity were analyzed which show the significant effect on gas rate and on cumulative gas production. The results of this study can be used to improve the effectiveness in designing and developing of shale gas reservoirs and also to improve the accuracy of analyzing heterogeneous shale gas reservoir performance.

Challenges of Gas Wells Killing Operation with Emphasis on Reservoir & Completion Integrity Issues

2021 ◽  
Author(s):  
Zeeshan Ahmad ◽  
Abdullah Alhaj Al Hosini ◽  
Mohammed Ibrahim Al Janahi ◽  
Abdulla Mohammed Al Marzouqi ◽  
Muhammad Ali SIDDIQUI ◽  
...  
Keyword(s):  
Gas Production ◽  
Fluid Loss ◽  
Gas Wells ◽  
Gas Reservoirs ◽  
Gas Reservoir ◽  
Advantages And Disadvantages ◽  
Reservoir Permeability ◽  
Production Wells ◽  
Zonal Isolation ◽  
Fluid Losses

Abstract Well killing always remains a most radical part during the life cycle of gas production wells with reservoir and completion integrity issues. In moderate permeability gas reservoirs, it will be more challenging due to below issues; Low pressure gas reservoir with moderate reservoir permeability where hydrostatic head of water is almost double the formation pressure Well with the sustainable annulus pressures (Production & first cemented annulus) Well with complex layered scale / asphalting deposition Completion jewelry component integrity breached Recycle reservoir with pressure maintenance Noise logs / corrosion logs generally conducted in order to assess the downhole completion jewelry and potential leak source prior any attempt for killing the well. To achieve the desired accessibility extensive scale analysis for better designing of scale clean out operation carried out specially to access the SPM. Variation of reservoir permeability considered for designing of optimized kill fluid for Depleted horizontal gas reservoir to cater challenge of complete losses. Effective fluid loss solutions designed and implemented to avoid abnormal fluid losses. Further more Polymer based gels used to kill and prevent the gas peculation to surface. Wells having completion and reservoir integrity issue isolated by considering cement zonal isolation, salt plugs, thru-tubing bridge plugs and nipple less plugs. All these barriers having their advantages and disadvantages with reference to work over objectives and their application limitations with respect to well conditions and detail study conducted for each candidate prior execution. Depletion Gas well killing and securing operation considered to be complex in nature and may result serious concern of rig intervention or well future objectives in case of improper execution. Gas wells having reservoir integrity issues and in case of 1st cemented Annulus pressure can be isolated by using thru-tubing bridge plugs. For retrieval of dummy from SPM must be done after setting of downhole plug to avoid any heavy suction for wire line operation. Cement plug operation is not suitable for such wells due to severe losses and fluid circulation limitation. Adequate selection of kill gel fluid as per reservoir characteristics will improve the killing efficiency.

scholarly journals Quantitative study on natural gas production risk of Carboniferous gas reservoir in eastern Sichuan

2021 ◽  
Author(s):  
Guo Yu ◽  
Haitao Li ◽  
Yanru Chen ◽  
Linqing Liu ◽  
Chenyu Wang ◽  
...  
Keyword(s):  
Risk Factors ◽  
Risk Factor ◽  
Natural Gas ◽  
Gas Production ◽  
Probability Method ◽  
Gas Reservoir ◽  
Production Risk ◽  
Probability Interval ◽  
Natural Gas Production ◽  
Stable Production

AbstractQuantifying natural gas production risk can help guide natural gas exploration and development in Carboniferous gas reservoirs. In this study, the Monte Carlo probability method is used to obtain the probability distribution and growth curve of each production risk factor and production in a Carboniferous gas reservoir in eastern Sichuan. In addition, the fuzzy comprehensive evaluation method is used to conduct the sensitivity analysis of the risk factors, and the natural gas production and realization probability under different risk factors are obtained. The research results show that: (1) the risk factor–production growth curve and probability distribution are calculated by the Monte Carlo probability method. The average annual production under the stable production stage under different realization probabilities is obtained. The maximum probability range of annual production is $$\left( {43.43 - 126.35} \right) \times 10^{8} {\text{m}}^{3} /{\text{year}}$$ 43.43 - 126.35 × 10 8 m 3 / year , and the probability range is 14.59–92.88%. (2) The risk factor sensitivity analysis is significantly affected by the probability interval. In the entire probability interval, the more sensitive risk factors are the average production of the kilometer-deep well (D) and the production rate in the stable production stage (A). During the exploration and development of natural gas, these two risk factors can be adjusted to increase production.

Well Design Specificities For Shallow Gas Production Of Tunu Field.

2010 ◽  
Author(s):  
Samir Oumer ◽  
Hafidh Taufiqurrachman ◽  
Marie-Pascale Perruchot ◽  
Fata Yunus
Keyword(s):  
Gas Production ◽  
Shallow Gas ◽  
Well Design
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