Liquid loading in wellbores and its effect on cleanup period and well productivity in tight gas sand reservoirs

2010 ◽  
Vol 50 (1) ◽  
pp. 559
Author(s):  
Hassan Bahrami ◽  
M Reza Rezaee ◽  
Vamegh Rasouli ◽  
Armin Hosseinian
Keyword(s):  
Numerical Simulation ◽  
Gas Production ◽  
Production Performance ◽  
Tight Gas ◽  
Gas Reservoirs ◽  
Liquid Loading ◽  
Performance Modelling ◽  
Well Productivity ◽  
Tight Gas Reservoirs ◽  
Tight Gas Reservoir

Tight gas reservoirs normally have production problems due to very low matrix permeability and significant damage during well drilling, completion, stimulation and production. Therefore they might not flow gas to surface at optimum rates without advanced production improvement techniques. After well stimulation and fracturing operations, invaded liquids such as filtrate will flow from the reservoir into the wellbore, as gas is produced during well cleanup. In addition, there might be production of condensate with gas. The produced liquids when loaded and re-circulated downhole in wellbores, can significantly reduce the gas production rate and well productivity in tight gas formations. This paper presents assessments of tight gas reservoir productivity issues related to liquid loading in wellbores using numerical simulation of multiphase flow in deviated and horizontal wells. A field example of production logging in a horizontal well is used to verify reliability of the numerical simulation model outputs. Well production performance modelling is also performed to quantitatively evaluate water loading in a typical tight gas well, and test the water unloading techniques that can improve the well productivity. The results indicate the effect of downhole liquid loading on well productivity in tight gas reservoirs. It also shows how well cleanup is sped up with the improved well productivity when downhole circulating liquids are lifted using the proposed methods.

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.

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.

A Reservoir Simulation Study of Naturally Fractured Lenticular Tight Gas Sand Reservoirs

1990 ◽  
Vol 112 (4) ◽  
pp. 231-238 ◽  
Author(s):  
R. D. Evans ◽  
S. D. L. Lekia
Keyword(s):  
Gas Flow ◽  
Gas Production ◽  
Department Of Energy ◽  
Natural Fracture ◽  
Tight Gas ◽  
Gas Reservoirs ◽  
Tight Gas Reservoirs ◽  
Reservoir Performance ◽  
Tight Gas Reservoir ◽  
Naturally Fractured

The results of parametric studies of two naturally fractured lenticular tight gas reservoirs, Fluvial E-1 and Puludal Zones 3 and 4, of the U.S. Department of Energy Multi-Well Experiment (MWX) site of Northwestern Colorado are presented and discussed. The three-dimensional, two-phase, black oil reservoir simulator that was developed in a previous phase of this research program is also discussed and the capabilities further explored by applying it to several example problems. The simulation studies lead to the conclusion that 1) at early times the reservoir performance does not depend on lenticularity; 2) the initial reservoir performance does not depend on natural fracture concentration, although at later times the performance predictions of systems with lower natural fracture concentrations begin to fall below the ones with higher concentrations; 3) porosity change with time and pressure leads to double performance prediction reversals when comparing gas flow rates and cumulative gas production from naturally fractured and non-naturally fractured tight gas reservoirs; 4) the assumption of zero capillary pressure in the fractures can lead to erroneous predictions in the simulation of naturally fractured tight gas reservoir performance; and 5) the simulator developed in a prior phase of this project is capable of handling a reservoir block that is blanket sand, lenticular, completely fractured, partially fractured or completely unfractured and is amenable to an anisotropic heterogeneous reservoir whether the reservoir is fractured or not.

scholarly journals Modified Horizontal Well Productivity Model for a Tight Gas Reservoir Subjected to Non-Uniform Damage and Turbulence

Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8334
Author(s):  
Samuel O. Osisanya ◽  
Ajayi Temitope Ayokunle ◽  
Bisweswar Ghosh ◽  
Abhijith Suboyin
Keyword(s):  
Flow Rate ◽  
Horizontal Well ◽  
Horizontal Wells ◽  
Total Production ◽  
Tight Gas ◽  
Gas Reservoirs ◽  
Well Productivity ◽  
Tight Gas Reservoirs ◽  
Skin Factor ◽  
Tight Gas Reservoir

Tight gas reservoirs are finding greater interest with the advancement of technology and realistic prediction of flow rate and pressure from such wells are critical in project economics. This paper presents a modified productivity equation for tight gas horizontal wells by modifying the mechanical skin factor to account for non-uniform formation damage along with the incorporation of turbulence effect in the near-wellbore region. Hawkin’s formula for calculating skin factor considers the radius of damage as a constant value, which is less accurate in low-permeability tight gas reservoirs. This paper uses a multi-segment horizontal well approach to develop the local skin factors and the equivalent skin factor by equating the total production from the entire horizontal well to the sum of the flow from individual segmented damaged zones along the well length. Conical and horn-shaped damaged profiles are used to develop the equivalent skin used in the horizontal well productivity equation. The productivity model is applied to a case study involving the development of a tight gas field with horizontal wells. The influence of the horizontal well length, damaged zone permeability, drainage area, reservoir thickness, and wellbore diameter on the calculated equivalent skin (of a non-uniform skin distribution) and the flow rate (with turbulence and no turbulence) are investigated. The results obtained from this investigation show significant potential to assist in making practical decisions on the favorable parameters for the success of the field development in terms of equivalent skin factor, flow rate, and inflow performance relationships (IPR).

scholarly journals A Novel Dynamic Splitting Method for Production Based on Material Balance Theory and Catastrophe Theory in Tight Gas Reservoirs

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Shengye Hao ◽  
Xinyu Qiu ◽  
Pengcheng Liu ◽  
Xiaoxia Chen
Keyword(s):  
Numerical Simulation ◽  
Production Process ◽  
Catastrophe Theory ◽  
Scale Effects ◽  
Splitting Method ◽  
Material Balance ◽  
Splitting Methods ◽  
Tight Gas ◽  
Gas Reservoirs ◽  
Tight Gas Reservoirs

Splitting methods play a significant role in the coproduction of tight reservoirs which are characterized by vertical multilayer superimposition. It directly affects the accuracy of reservoir performance analysis and detailed descriptions. However, conventional splitting methods are limited to a few factors and static factors without considering the effect of layer parameter change. In this study, sensitivity analysis was carried out on five factors that affect the production splitting in coproduction wells. The research shows that in the production process, multiple parameters have a direct impact on the production of layers. Different parameters, which have to be included to split production, have different scale effects on layer production. Comparing the results of the KH method with the numerical simulation results, the limitation of the KH method for yield splitting is illustrated. A novel dynamic splitting method for production (DPSM) was proposed. This method is based on two primary methods, which are the multifactor static method for production splitting of gas (GPSM) and water (WPSM) and use the catastrophe theory and material balance equation (MBE) and obtain the final results by iterative method. The advantage of this method is that more accurate results in the production process are obtained by selecting eight factors, which contain 6 static factors and 2 dynamic factors, for research. It is more in line with the production practice that the ultimate results of production splitting vary with the production process. The accuracy and practicality of the results had been verified by numerical simulation. This method has practical significance for production splitting in tight gas reservoirs.

scholarly journals Experimental Study on the Effective Utilization of Reserves in Tight Sandstone Gas Reservoirs and Their Applications

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Jie Zhang ◽  
Feifei Fang ◽  
Weijun Shen ◽  
Huaxun Liu ◽  
Shusheng Gao ◽  
...  
Keyword(s):  
Pressure Distribution ◽  
Moving Boundary ◽  
Production Performance ◽  
Tight Gas ◽  
Gas Reservoirs ◽  
Tight Sandstone ◽  
Effective Utilization ◽  
Tight Gas Reservoir ◽  
Water Cut ◽  
Field Production

The effective utilization of reserves in tight sandstone reservoirs is one of the major concerns in terms of the development of tight sandstone gas reservoirs. However, the characteristics of reserve utilization are not fully understood, and many uncertainties still exist in the process. For this purpose, long cores on the Su 6 block of Sulige tight sandstone gas field in China were selected, and a multipoint embedded measurement system was established to study the characteristics of effective reserve utilization. Then, the effects of the related reservoir properties and production parameters were investigated. Based on the similarity theory, the effective conversion relationship between the physical experiment and the actual field production was established. The results showed that the pressure distribution in the exploitation of tight gas reservoir is nonlinear, and water cut in the reservoir will hinder the effective utilization of reserves. The lower the reservoir permeability, the larger the negative effect of water on reservoir utilization. Lower gas production rate and higher original pressure are associated with a smoother drawdown curve, which results in larger reserve utilization. The moving boundary expands with time, and its initial propagation velocity increase and then decrease. Additionally, the water cut in the reservoir can delay the spread of moving boundary propagation. The experimental results are consistent with the actual results of the field production by the similarity criterion, which can reflect and predict the production performance in tight gas reservoirs effectively. These results can provide a better understanding of reservoir pressure distribution and effective utilization of reserves to optimize the gas recovery and development benefit in tight sandstone gas reservoirs.

Induced and natural fracture interaction in tight-gas reservoirs

2012 ◽  
Vol 52 (1) ◽  
pp. 611
Author(s):  
Mohammad Rahman ◽  
Sheik Rahman
Keyword(s):  
Hydraulic Fracture ◽  
Development Planning ◽  
Natural Fracture ◽  
Tight Gas ◽  
Gas Reservoirs ◽  
Differential Stress ◽  
Tight Gas Reservoirs ◽  
Reservoir Development ◽  
Well Spacing ◽  
Tight Gas Reservoir

This paper investigates the interaction of an induced hydraulic fracture in the presence of a natural fracture and the subsequent propagation of this induced fracture. The developed, fully coupled finite element model integrates a wellbore, an induced hydraulic fracture, a natural fracture, and a reservoir that simulates interaction between the induced and natural fracture. The results of this study have shown that natural fractures can have a profound effect on induced fracture propagation. In most cases, the induced fracture crosses the natural fracture at high angles of approach and high differential stress. At low angles of approach and low differential stress, the induced fracture is more likely to be arrested and/or break out from the far-end side of the natural fracture. It has also been observed that the propagation of the induced fracture is stopped by a large natural fracture at a high angle of approach, when the injection rate remains low. At a low angle of approach, the induced fracture deviates and propagates along the natural fracture. Crossing of the natural fracture and/or arrest by the natural fracture is controlled by the shear strength of the natural fracture, natural fracture orientation, and the in situ stress state of the reservoir. In tight-gas reservoir development, the optimum well spacing and induced hydraulic fracture length are correlated. Therefore, fracturing design should be performed during the initial reservoir development planning phase along with the well spacing design to obtain an optimal depletion strategy. This model has a potential application in the design and optimisation of fracturing design in unconventional reservoirs including tight-gas reservoirs and enhanced geothermal systems.

ANALYSIS OF PRESSURE-DEPENDENT RELATIVE PERMEABILITY IN PERMEABILITY JAIL OF TIGHT GAS RESERVOIRS AND ITS INFLUENCE ON TIGHT GAS PRODUCTION

2019 ◽  
Vol 22 (13) ◽  
pp. 1667-1683
Author(s):  
Fei Mo ◽  
Zhimin Du ◽  
Xiaolong Peng ◽  
Baosheng Liang ◽  
Yong Tang ◽  
...  
Keyword(s):  
Relative Permeability ◽  
Gas Production ◽  
Tight Gas ◽  
Gas Reservoirs ◽  
Tight Gas Reservoirs
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