Application Analysis and Stress Sensitivity Experiment for a Gas Reservoir in Daqing Oil Field

2013 ◽  
Vol 634-638 ◽  
pp. 3577-3581
Author(s):  
Li Li ◽  
Gao Ning Zhou
Keyword(s):  
Confining Pressure ◽  
Stress Sensitivity ◽  
Oil Field ◽  
Gas Reservoirs ◽  
Gas Reservoir ◽  
Sensitivity Experiment ◽  
Rock Hardness ◽  
Application Analysis ◽  
Daqing Oil Field ◽  
The Impact

By measuring the change of confining pressure penetration on sandstone samples of a gas reservoir in Daqing Oil Field, it has been proven that stress sensitivity existed in this gas reservoirs. The measuring results also show that the stress sensitivity levels of mafic is from weak to medium weak due to the better glutinosity and the greater rock hardness. However, some sandstone samples generally do not have stress sensitivity. The impact of stress sensitivity should be thoroughly considered during the development of natural gas, because the existence of cracks which often result in stronger stress sensitivity.

Stress-sensitive permeability of matrix cores and artificially fractured cores with non-proppant-filled fractures under high-pressure conditions

Geophysics ◽  
2021 ◽  
pp. 1-102
Author(s):  
Ren-Shi Nie ◽  
Zheng Wang ◽  
Zhangxin Chen ◽  
An-Cheng Wang ◽  
Chang-Hong Zhou ◽  
...  
Keyword(s):  
High Pressure ◽  
Internal Pressure ◽  
Confining Pressure ◽  
Stress Sensitivity ◽  
Curve Analysis ◽  
Test Method ◽  
Gas Reservoirs ◽  
Gas Reservoir ◽  
Permeability Damage ◽  
Fractured Sandstone

Stress-sensitive permeability (SSP) influences gas well productivity and is a crucial element influencing gas reservoir development. SSP for high-pressure fractured gas reservoirs with an initial reservoir pressure of more than 20 MPa has never been comprehensively evaluated to the best of our knowledge. SSP experiments with special procedures were designed by adopting the variable confining pressure (VCP) and variable internal pressure (VIP) methods. VCP is a test method in which confining pressure is altered and a constant internal pressure is maintained for the experimental core holder. VIP is a test method in which internal pressure is changed and a constant confining pressure is maintained. A four-stage curve analysis method was developed to perform regressions on semi-logarithmic curves and exponential curves of experimental data. A method to evaluate the SSP was presented using stress sensitivity coefficients obtained via regressions. A calculation approach for determining the degrees of permeability damage and permeability recovery was also proposed. Six matrix cores and six cores with artificial fractures from a high-pressure fractured sandstone gas reservoir were tested using the two methods. The SSP curves for high-pressure reservoirs were characterized by four-stage variation trends, which differentiated with low-pressure reservoirs with an initial reservoir pressure less than 20 MPa. The stress sensitivity of the VCP method was stronger than that of the VIP method. The core samples mainly showed a “Medium” / “Medium-Strong” stress sensitivity under low/high effective stress conditions. Compared with matrix cores, fractured cores showed stronger stress sensitivity owing to its strong plasticity and weak elasticity. The maximum permeability damage degree reached 99.67% and the minimum permeability recovery was only 6.9%. The presented method of experimental design, four-stage curve analysis, stress sensitivity evaluation and the summarized findings in this paper can provide references for future studies on SSP in high-pressure fractured sandstone gas reservoirs.

Stress Sensitivity of Low Permeable and Water-Bearing Gas Reservoir without Gas Slippage Effect

2014 ◽  
Vol 962-965 ◽  
pp. 570-573
Author(s):  
Jian Yan ◽  
Xiao Bing Liang ◽  
Qian Wu ◽  
Qing Guo
Keyword(s):  
Water Saturation ◽  
Stress Sensitivity ◽  
Testing Methods ◽  
Gas Reservoirs ◽  
Gas Reservoir ◽  
Gas Well ◽  
Well Production ◽  
Gas Slippage ◽  
Slippage Effect ◽  
Function Relationship

Because of the gas slippage, the testing methods of stress sensitivity for gas reservoir should be different from that for oil reservoir. This text adopts the method that imposing back pressure on the outlet of testing core to weaken the gas slippage effect and tests the stress sensitivity of low permeability gas reservoirs, then analyzes the influence of permeability and water saturation on stress sensitivity. The results show that: low permeable and water-bearing gas reservoirs have strong stress sensitivity; the testing permeability has the power function relationship with net stress, compared to the exponential function, the fitting correlation coefficient is larger and more suited to the actual; the lower the permeability is and the higher water saturation is, the stronger the stress sensitivity is. The production of gas well is affected when considering the stress sensitivity, so the pressure dropping rate should be reasonable when low permeable gas reservoirs are developed. The results provide theoretical references for analyzing the well production and numerical simulation.

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.

scholarly journals A productivity prediction method for condensate gas reservoir

2020 ◽  
Vol 213 ◽  
pp. 02001
Author(s):  
Quan Hua Huang ◽  
Hong Jun Ding ◽  
Xing Yu Lin
Keyword(s):  
Pressure Gradient ◽  
Stress Sensitivity ◽  
Water Production ◽  
Gas Wells ◽  
Gas Reservoir ◽  
Gas Well ◽  
Well Productivity ◽  
Inclined Angle ◽  
The Impact ◽  
Starting Pressure Gradient

At present, multiphase flow productivity calculation requires many parameters, and most of them only consider oil and gas two-phase flow, which is complicated and limited. Therefore, a reasonable productivity formula of condensate gas reservoir with producing water is needed. The three-zone model of condensate gas reservoirs is generally applied to the physical model for inferring productivity. On this basis, an improved model is established, which includes that different seepage characteristics are considered for different zones. Moreover, the effects of inclined angle and water production on gas wells are regarded as pseudo-skin factors and additional-skin factors. In addition, Zone I considers the effects of high-speed nonDarcy effect(HSND), starting pressure gradient, stress sensitivity, inclined angle and water production; Zone II is the same way excepting starting pressure gradient and stress sensitivity ; Zone III only considers the effects of inclined angle and water production. As a result, a productivity equation with multiple factors for condensate gas wells is established. Through analysing cases and influences in H gas reservoir X1 well, the HSND, starting pressure gradient, stress sensitivity and water production have a negative impact on gas well productivity, but the inclined angle is opposite. Founded that the starting pressure gradient impacts on productivity is less than the HSND because of the limited radius of Zone I; the impact of the HSND on productivity increases with the decreasing of bottom hole pressure; the impact of water production on gas well productivity is much higher. When the angle is over 60°, the effect of gas

Sandstone Stress Sensitivity Experiment and Stress Sensitivity Evaluation

2014 ◽  
Vol 962-965 ◽  
pp. 526-530
Author(s):  
Tao Gao ◽  
Xiao Guo ◽  
Hong Mei Yang ◽  
Hai Tao Li ◽  
Zheng Zhu
Keyword(s):  
Pore Pressure ◽  
Effective Stress ◽  
Oil And Gas ◽  
Confining Pressure ◽  
Stress Sensitivity ◽  
Differential Method ◽  
Gas Field ◽  
Sensitivity Experiment ◽  
Stress Coefficient ◽  
Pressure Experiment

Change confining pressure experiment or pore pressure experiment is one of the commonly used method to evaluate the reservoir core stress sensitivity. However, a large number of studies have shown that core net stress is not equal to the effective stress,the drawdown pore pressure experiment are consistent with the characteristics of oil and gas field real development process. The pressure stability of drawdown pore pressure experiment is bad, so, a reliable modified method of change confining pressure stress sensitivity experiment is eagerly expected. On the basis of the differential method principle, effective stress coefficient can be determined through core experiments,and with the use of effective stress coefficient , change confining pressure experiment is modified. Main conclusions are as follows:For sandstone core,at reservoir original stress condition with the pore pressure from 15MPa to 11MPa effective stress coefficient from 0.436 to 0.415;Based on Terzaghi effective stress exaggerate stress sensitivity, ontology effective stress can weaken the stress sensitive; Based on effective stress coefficient in this paper correction stress sensitivity is medium weak,impacts on production results almost coincident with the drawdown pore pressure test results.

The Impact of Irreducible Water on Stress-Sensitivity of Gas Reservoir Rocks

2012 ◽  
Vol 246-247 ◽  
pp. 472-475
Author(s):  
Hao Xu ◽  
Zhi Ping Li ◽  
Hua Jun Hu
Keyword(s):  
Stress Sensitivity ◽  
Core Sample ◽  
Effective Pressure ◽  
Value Change ◽  
Gas Reservoir ◽  
Reservoir Rocks ◽  
The Impact ◽  
Made In

According to many researches, the presence of stress-sensitivity has been confirmed in reservoir rocks. Because it will create huge damage to the permeability of reservoirs, sufficient attention should be made. In this paper, through the experiment, the permeability value change with effective pressure in the condition of saturated with irreducible water and dry environment were compared. The study showed that the stress-sensitivity of core sample was more obvious in the condition of saturated with irreducible water.

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.

Online Modeling of CO2 Storage Systems

2021 ◽  
Author(s):  
Dale Douglas Erickson ◽  
Greg Metcalf
Keyword(s):  
Co2 Storage ◽  
Free Water ◽  
Oil Field ◽  
Management Tool ◽  
Carbon Dioxide Injection ◽  
Injection Wells ◽  
Internal Corrosion ◽  
Injection Process ◽  
Corrosion Risk ◽  
The Impact

Abstract This paper discusses the development and deployment of a specialized online and offline integrated model to simulate the CO2 (Carbon Dioxide) Injection process. There is a very high level of CO2 in an LNG development and the CO2 must be removed in order to prepare the gas to be processed into LNG. To mitigate the global warming effects of this CO2, a large portion of the CO2 Rich Stream (98% purity) is injected back into a depleted oil field. To reduce costs, carbon steel flowlines are used but this introduces a risk of internal corrosion. The presence of free water increases the internal corrosion risk, and for this reason, a predictive model discussed in this paper is designed to help operations prevent free water dropout in the network in real time. A flow management tool (FMT) is used to monitor the current state of the system and helps look at the impact of future events (startup, shutdowns etc.). The tool models the flow of the CO2 rich stream from the outlet of the compressor trains, through the network pipeline and manifolds and then into the injection wells. System behavior during steady state and transient operation is captured and analyzed to check water content and the balance of trace chemicals along with temperature and pressure throughout the network helping operators estimate corrosion rates and monitor the overall integrity of the system. The system has been running online for 24/7 for 2 years. The model has been able to match events like startup/shutdown, cooldowns and blowdowns. During these events the prediction of temperature/pressure at several locations in the field matches measured data. The model is then able to forecasts events into the future to help operations plan how they will operate the field. The tool uses a specialized thermodynamic model to predict the dropout of water in the near critical region of CO2 mixtures which includes various impurities. The model is designed to model startup and shutdown as the CO2 mixture moves across the phase boundary from liquid to gas or gas to liquid during these operations.

Experiment on Mechanical Properties and Seepage Capability of Deep Tight Sandstone Under True-Triaxial Stresses Environment

2021 ◽  
Author(s):  
Jiaying Li ◽  
Chunyan Qi ◽  
Ye Gu ◽  
Yu Ye ◽  
Jie Zhao
Keyword(s):  
Mechanical Properties ◽  
In Situ Stress ◽  
Stress Sensitivity ◽  
Stress Conditions ◽  
Tight Sandstone ◽  
Gas Reservoir ◽  
True Triaxial ◽  
Strain Behavior ◽  
Triaxial Stresses

Abstract The characteristics of seepage capability and rock strain during reservoir depletion are important for reservoir recovery, which would significantly influence production strategy optimization. The Cretaceous deep natural gas reservoirs in Keshen Gasfield in Tarim Basin are mainly buried over 5000 m, featuring with ultra-low permeability, developed natural fractures and complex in-situ stress states. However, there is no comprehensive study on the variation of mechanical properties and seepage capability of this gas reservoir under in-situ stress conditions and most studies on stress-sensitivity are conducted under conventional triaxial or uniaxial stress conditions, which cannot truly represent in-situ stress environment. In this work, Cretaceous tight sandstone in Keshen Gasfield was tested under true-triaxial stresses conditions by an advanced geophysical imaging true-triaxial testing system to study the stress-sensitivity and anisotropy of rock stress-strain behavior, porosity and permeability. Four groups of sandstone samples are prepared as the size of 80mm×80mm×80mm, three of which are artificially fractured with different angle (0°,15°，30°) to simulate hydraulic fracturing. The test results corresponding to different samples are compared to further reveal the influence of the fracture angle on rock mechanical properties and seepage capability. The samples are in elastic strain during reservoir depletion, showing an apparent correlation with fracture angles. The porosity decreases linearly with stress loading, where the decrease rate of effective porosity of fracture samples is significantly higher than that of intact samples. The permeabilities decrease exponentially and show significant anisotropy in different principal stress directions, especially in σH direction. The mechanical properties and seepage capability of deep tight sandstone are successfully tested under true-triaxial stresses conditions in this work, which reveals the stress-sensitivity of anisotropic permeability, porosity and stress-strain behavior during gas production. The testing results proposed in this paper provides an innovative method to analyse rock mechanical and petrophysical properties and has profound significance on exploration and development of tight gas reservoir.

Study the effect of casting temperature on details from thermo-plastic materials

2020 ◽  
pp. 42-45
Author(s):  
J.A. Kerimov ◽  
Keyword(s):  
Oil And Gas ◽  
Oil And Gas Industry ◽  
Mold Temperature ◽  
Quality Parameters ◽  
Oil Field ◽  
Casting Temperature ◽  
Gas Industry ◽  
Field Equipment ◽  
Wide Range ◽  
The Impact

The implementation of plastic details in various constructions enables to reduce the prime cost and labor intensity of machine and device manufacturing, decrease the weight of design and improve their quality and reliability at the same time. The studies were carried out with the aim of labor productivity increase and substitution of colored and black metals with plastic masses. For this purpose, the details with certain characteristics were selected for further implementation of developed technological process in oil-gas industry. The paper investigates the impact of cylinder and compression mold temperature on the quality parameters (shrinkage and hardness) of plastic details in oil-field equipment. The accessible boundaries of quality indicators of the details operated in the equipment of exploration, drilling and exploitation of oil and gas industry are studied in a wide range of mode parameters. The mathematic dependences between quality parameters (shrinkage and hardness) of the details on casting temperature are specified.

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