scholarly journals Reserve Estimation from Early Time Production Data in Geopressured Gas Reservoir: Gas Production of Cumulative Unit Pressure Drop Method

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Hongfeng Wang ◽  
Xiaoping Li ◽  
Hedong Sun ◽  
Guangren Meng ◽  
Wen Cao ◽  
...  
Keyword(s):  
Pressure Drop ◽  
Natural Gas ◽  
Gas Production ◽  
Correction Coefficient ◽  
Formation Pressure ◽  
Gas Reservoirs ◽  
Reserve Estimation ◽  
Straight Line ◽  
Deviation Factor ◽  
Unit Pressure

There is high uncertainty in reserve estimation during the early development of deep ultrahigh pressure gas reservoirs, largely because it remains challenging in accurately determining the formation compressibility. To overcome this, starting from the definition of compressibility, a novel gas production of cumulative unit pressure drop analysis method was established, of which the effectiveness was proven by applications in calculating the reserves of three gas reservoirs. It has been found that, in the limiting case, i.e., when the formation pressure dropped to the normal atmospheric pressure, the dimensionless gas production of the cumulative unit pressure drop was the reciprocal of the initial formation pressure. Besides, the relationship curve of the dimensionless gas production of the cumulative unit pressure drop and pressure drop was a straight line in the medium term, extending the straight line and intersecting the vertical line passing through the original formation pressure point, and the reserves can be determined according to the intersection point and the initial formation pressure. However, due to the influence of natural gas properties, the value needs further correction, and the correction coefficient depends on the pseudocritical temperature of natural gas. Specifically, when the pseudocritical temperature is given, the correction coefficient would be close to the minimum value of the natural gas deviation factor. When the pseudocritical temperature is more than 1.9 and less than 3.0, the minimum deviation factor would be between 0.90 and 1.0, and the higher the pseudocritical temperature, the closer the ratio is to 1.0.

The Method of Dynamic Reserves Prediction for a Constant Volume Gas Reservoir

2013 ◽  
Vol 275-277 ◽  
pp. 456-461
Author(s):  
Lei Zhang ◽  
Lai Bing Zhang ◽  
Bin Quan Jiang ◽  
Huan Liu
Keyword(s):  
Pressure Drop ◽  
Material Balance ◽  
Production Method ◽  
Gas Production ◽  
Constant Volume ◽  
Phase Method ◽  
Gas Reservoirs ◽  
Two Phase ◽  
Material Balance Method ◽  
Unit Pressure

The accurate prediction of the dynamic reserves of gas reservoirs is the important research content of the development of dynamic analysis of gas reservoirs. It is of great significance to the stable and safe production and the formulation of scientific and rational development programs of gas reservoirs. The production methods of dynamic reserves of gas reservoirs mainly include material balance method, unit pressure drop of gas production method and elastic two-phase method. To clarify the characteristics of these methods better, in this paper, we took two typeⅠwells of a constant volume gas reservoir as an example, the dynamic reserves of single well controlled were respectively calculated, and the results show that the order of the calculated volume of the dynamic reserves by using different methods is material balance method> unit pressure drop of gas production method >elastic two-phase method. Because the material balance method is a static method, unit pressure drop of gas production method and elastic two-phase method are dynamic methods, therefore, for typeⅠwells of constant volume gas reservoirs, when the gas wells reached the quasi-steady state, the elastic two-phase method is used to calculate the dynamic reserves, and when the gas wells didn’t reach the quasi-steady state, unit pressure drop of gas production method is used to calculate the dynamic reserves. The conclusion has some certain theoretical value for the prediction of dynamic reserves for constant volume gas reservoirs.

Calculation Methods of the Dynamic Reserves for Gas Wells in a Low-Permeability Gas Reservoir

2013 ◽  
Vol 295-298 ◽  
pp. 3243-3248
Author(s):  
Lei Zhang ◽  
Lai Bing Zhang ◽  
Jun Jie Zhang ◽  
Feng Lan ◽  
Pan Deng
Keyword(s):  
Pressure Drop ◽  
Material Balance ◽  
Production Method ◽  
Gas Production ◽  
Phase Method ◽  
Low Permeability ◽  
Gas Reservoir ◽  
Two Phase ◽  
Material Balance Method ◽  
Unit Pressure

Accurately calculating dynamic reserves for single well in a low-permeability gas reservoir has an important guiding significance to high efficiency development of the gas reservoir. During the development of the gas reservoir, dynamic analysis methods were often used to calculate dynamic reserves. Dynamic analysis methods mainly include the material balance method, the gas production method in unit pressure drop, the flexible two-phase method and the production unstable method. Dynamic reserves for four types of gas wells in a low-permeability gas field were calculated using these four methods. Calculation results show that dynamic reserves from big to small are respectively obtained using material balance method, gas production method in unit pressure drop, flexible two-phase method and production unstable method. Calculating dynamic reserves obtained by flexible two-phase method and production unstable method are utilized to production dynamic data of gas well, and those obtained by material balance method and gas production method in unit pressure drop are utilized to the reservoir parameters of different state. Therefore, the values of dynamic reserves obtained using flexible two-phase method and production unstable method in the low-permeability gas reservoir may be more accurate than those obtained using the other methods.

Pressure Drop Characteristics and Reserves Calculation Method of Gas Reservoir of Multi-Layer Unconsolidated Sandstone

2012 ◽  
Vol 616-618 ◽  
pp. 864-869
Author(s):  
Pang Jin ◽  
Hong Liu ◽  
Xiao Lu Wang
Keyword(s):  
Pressure Drop ◽  
Formation Pressure ◽  
Accurate Calculation ◽  
Gas Wells ◽  
Gas Reservoir ◽  
Gas Field ◽  
Practical Result ◽  
Straight Line ◽  
Sand Control ◽  
Pressure Test

Taking Sebei gas field as an example, this paper sorts hydrostatic pressure test data over the years and summarizes the reasons that the formation pressure drop curve generates a straight line, up-warping and recurvation from the perspective of water invasion, perforation adding, layer adjusting, sand burying, and sand control as well as inter-layer interference and inter-well interference, with typical wells analyzed and explained. On this basis, two kinds of mass balance correction models which have taken the offset of the pressure drop curve into account are proposed to calculate the dynamic reserves of gas wells with different offset shapes of pressure drop curves. Practical result shows the simple concept and strong practicality of this method, which provides an effective method for the accurate calculation of dynamic reserves of such gas reservoir.

scholarly journals A Novel Analytical Method to Calculate the Amounts of Free and Adsorbed Gas in Shale Gas Production

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Qingyu Li ◽  
Peichao Li ◽  
Wei Pang ◽  
Quanfu Bi ◽  
Zonghe Du ◽  
...  
Keyword(s):  
Pressure Distribution ◽  
Shale Gas ◽  
Analytical Method ◽  
Gas Production ◽  
Petroleum Engineering ◽  
Formation Pressure ◽  
Adsorption Model ◽  
Gas Reservoirs ◽  
Free Gas ◽  
Adsorbed Gas

Shale gas has now become an important part of unconventional hydrocarbon resources all around the world. The typical properties of shale gas are that both adsorbed gas and free gas play important roles in gas production. Thus the contributions of free and adsorbed gas to the shale gas production have become a hot, significant, and challenging problem in petroleum engineering. This paper presents a new analytical method to calculate the amounts of free and adsorbed gas in the process of shale gas extraction. First, the expressions of the amounts of adsorbed gas, matrix free gas, and fracture free gas in shale versus the producing time are presented on the basis of Langmuir adsorption model and formation pressure distribution. Next, the mathematical model of multifractured horizontal wells in shale gas reservoirs is established and solved by use of Laplace transform and inversion to obtain the normalized formation pressure distribution. Finally, field case studies of two multifractured horizontal shale gas wells in China are carried out with the presented quantitative method. The amounts of adsorbed and free gas in production are calculated, and the adsorbed-to-total ratio is provided. The results show that the proposed method is reliable and efficient.

scholarly journals Multiphysics coupling study of near-wellbore and reservoir models in ultra-deep natural gas reservoirs

2022 ◽  
Author(s):  
Pengda Cheng ◽  
Weijun Shen ◽  
Qingyan Xu ◽  
Xiaobing Lu ◽  
Chao Qian ◽  
...  
Keyword(s):  
Natural Gas ◽  
Pore Pressure ◽  
Production Rate ◽  
Gas Production ◽  
Permeability Evolution ◽  
Gas Reservoirs ◽  
Reservoir Properties ◽  
Gas Field ◽  
Natural Gas Reservoirs ◽  
Stress Dependent

AbstractUnderstanding the changes of the near-wellbore pore pressure associated with the reservoir depletion is greatly significant for the development of ultra-deep natural gas reservoirs. However, there is still a great challenge for the fluid flow and geomechanics in the reservoir depletion. In this study, a fully coupled model was developed to simulate the near-wellbore and reservoir physics caused by pore pressure in ultra-deep natural gas reservoirs. The stress-dependent porosity and permeability models as well as geomechanics deformation induced by pore pressure were considered in this model, and the COMSOL Multiphysics was used to implement and solve the problem. The numerical model was validated by the reservoir depletion from Dabei gas field in China, and the effects of reservoir properties and production parameters on gas production, near-wellbore pore pressure and permeability evolution were discussed. The results show that the gas production rate increases nonlinearly with the increase in porosity, permeability and Young’s modulus. The lower reservoir porosity will result in the greater near-wellbore pore pressure and the larger rock deformation. The permeability changes have little effect on geomechanics deformation while it affects greatly the gas production rate in the reservoir depletion. With the increase in the gas production rate, the near-wellbore pore pressure and permeability decrease rapidly and tend to balance with time. The reservoir rocks with higher deformation capacity will cause the greater near-wellbore pore pressure.

Effect of liquid invasion damage and supercharging on wireline formation tester measurements in tight gas reservoirs

2012 ◽  
Vol 52 (1) ◽  
pp. 627 ◽  
Author(s):  
Joshua Andrews ◽  
Hassan Bahrami ◽  
Reza Rezaee ◽  
Hamid Reza ◽  
Sultan Mehmood ◽  
...  
Keyword(s):  
Capillary Pressure ◽  
Drilling Fluid ◽  
Gas Production ◽  
Tight Gas ◽  
Formation Pressure ◽  
Gas Reservoirs ◽  
Reliable Determination ◽  
Tight Gas Reservoirs ◽  
Tight Gas Reservoir ◽  
Measured Pressure

Wireline formation testing and measurement of true formation pressure can provide essential knowledge about the reservoir dynamic characteristics. In tight formations, a reliable determination of pressure and mobility gradients is challenging because of the tight nature of formation rock. Due to the very low reservoir permeability, the mud cake across wellbore is often ineffective in preventing filtrate invasion, thus causing the measured pressure to be higher than actual formation pressure as a result of supercharging effect. Wireline formation testing measurements are also influenced by the effects of filtrate invasion and capillary pressure, as the measured pressure is pressure of drilling fluid filtrate, the continuous phase present in the invaded region around wellbore. As a result, the measured pressure might be different to true formation pressure. This effect is more noticeable in tight gas reservoirs due to capillary pressure effect. This paper looks into estimation of true formation pressure and evaluates the effect of filtrate invasion damage and supercharging on wireline formation tester measurements in tight gas reservoirs. Numerical simulation approach is used to build the reservoir model based on data acquired from a tight gas reservoir. The model undergoes water injection followed by gas production from different testing points along the wellbore, and the corresponding pressure gradients are plotted to check for pressure matching with that of the formation fluid in the virgin region. The results indicate the significant effects of supercharging, reservoir characteristics, capillary pressure and liquid invasion damage on wireline formation pressure measurements in tight gas reservoirs.

Technology Focus: Gas Production (August 2021)

2021 ◽  
Vol 73 (08) ◽  
pp. 62-62
Author(s):  
Scott J. Wilson
Keyword(s):  
Energy Source ◽  
Natural Gas ◽  
Enhanced Oil Recovery ◽  
Oil Recovery ◽  
Fossil Fuels ◽  
Gas Production ◽  
Step Change ◽  
The Moon ◽  
Gas Reservoirs

The carbon-free future should not be confused with a utopian future. A zero-carbon world will include the difficult realities experienced in Texas in February 2021. As shown in a graph of US EIA data, during the recent extreme cold event in Texas, wind and solar could not hold flat compared with their baseline the week before (4–8 February). Coal and nuclear remained mostly steady, while natural-gas producers ramped up supplies delivered to power plants by a factor of 4, helping people who were struggling to heat their homes. Natural gas may not receive well-deserved recognition from some quarters, and blackouts and loss of life still occurred, but our industry stepped up when people needed us most. Texas generates 25% of the wind power in the US and has more solar potential than 18 northern states combined, yet wind and solar simply failed when called upon. As the world attempts to go carbon-free, this reviewer hopes that more consumers will see the difference between results and public-relations promises. It will take a legitimate technological step-change before an unsubsidized renewable energy source is capable of replacing reliable fossil fuels. Imagine if Sir Isaac Newton, with all his brilliance, had tried to be the first man to land on the moon. In 1720, the cumulative knowledge did not exist to allow that to happen, and, if he had tried, he could have spent the entire British treasury and still failed. By standing upon the shoulders of giants like Newton, others were able to reach the moon 250 years later. Step-change technological breakthroughs happen when their time has come, not when mandated by political pressure. Until you hear that commercial fusion reactors are online or that low-cost, grid-scale electricity storage made from commonplace materials can handle a 10-day cold snap or heat wave, there is no need to hang up your pipe wrenches. Fossil fuels will remain the most energy-dense, cost-effective, reliable energy source until an extraordinary breakthrough creates a better alternative. The three papers selected for this feature demonstrate the continued critical role of gas production, and innovation therein, in the necessary daily role of supplying the world’s energy needs. One discusses means of exploiting stranded offshore gas reservoirs; the second details an Eagle Ford cyclic-gas-injection enhanced-oil-recovery effort; and the third focuses on the fracturing interference of multi-well pads in shale gas reservoirs. Reference Wilson, Scott. 2021. “EIA Texas Power Generation Data, February 2021.” Recommended additional reading at OnePetro: www.onepetro.org. SPE 200468 Hydraulic-Fracturing Test Site Phase-2 Enhanced-Oil-Recovery Pilot: Huff ’n’ Puff Pilot in the Permian Midland Basin by Shadi Salahshoor, Gas Technology Institute, et al. SPE 202448 Unconventional Gas Development in Queensland, Australia: How Well Does It Align With the Golden Rules of Gas? by Katherine Witt, The University of Queensland, et al. SPE 203208 Underbalanced Well Intervention to Re-Enter a Dead Well Changed the Future Dynamics of the Largest Gas Field in Pakistan—A Successful Pilot Project by Qasim Ashraf, Weatherford, et al.

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