Multilayer Gas Reservoirs Research Articles

Research on Numerical Simulation Methods for Water Invasion Dynamics in Fractured Gas Reservoirs with Water Content

Abstract Fractured gas reservoirs with water have complex gas-water relationship, large permeability difference between matrix and fracture, complex gas-water percolation mode, rapid production decline, short stable production period and large reduction of recovery factor due to water production of gas wells, which poses great challenges to efficient development of gas fields. The fracture system is the main channel for the edge and bottom water channeling of gas reservoirs. It is the core issue to understand the water invasion dynamic characteristics of such gas reservoirs to accurately depict the fracture geometry occurrence and truly simulate the gas-water two-phase flow mechanism in the fracture-matrix dual media. Taking the Jia-2 gas reservoir in Moxi gas field as an example, a discrete fracture model construction method that explicitly characterizes the fracture system is proposed. Based on the discrete fracture model, a mathematical model of gas-water two-phase flow in the fracture-matrix dual system is constructed and numerically solved. The influence mechanism of fracture opening, length, density and occurrence on the water invasion performance of multi-layer gas reservoirs is discussed, and the main control factors of the water invasion and water channeling law of fractured water gas reservoirs are identified. The application shows that the water invasion dynamics of gas reservoirs based on the discrete fracture model are more consistent with the actual conditions of the mine, providing a theoretical basis for deepening the understanding of water invasion dynamics of this type of gas reservoirs, optimizing the gas well working system, and formulating targeted water control countermeasures..

Efficient development technology of Upper Paleozoic Lower Shihezi tight sandstone gas reservoir in northeastern Ordos Basin

Abstract The Lower Shihezi Formation of the Upper Paleozoic at the northeastern margin of the Ordos Basin develops widely distributed thick massive and multilayer gas reservoirs. How to formulate an effective development policy is a difficult and hot spot. In this article, reservoir characteristics and production capacity influencing factors of the tight gas sandstone in Lower Shihezi Formation in this area are systematically studied, and optimization schemes of development measures for massive and multilayer gas reservoirs are proposed. The results show that the petrophysical characteristics of the small pore–mesopore type gas reservoir in the target layer are the best, with the average porosity, permeability, and coordination number of 7.6%, 0.74 mD, and 3.3, respectively. Thick sand body, high structural position, good petrophysical properties, and high drilling rate of sandstone are all conducive to drilling high production gas wells. Development policies for massive and multilayer gas reservoirs have been formulated: (1) the preferred well type for massive gas reservoir is vertical well + horizontal well, while the preferred well type for multilayer gas reservoir is horizontal well + stepped horizontal well; (2) the reasonable horizontal segment length of massive gas reservoir is 1,000 m, and the reasonable horizontal segment length of multilayer gas reservoir is 1,250 m; (3) similar to massive and multilayer gas reservoirs, the more the fracture stages, the higher the cumulative gas production, and the optimal fracture stage number of both gas reservoirs is 8; (4) the optimal fracture half-length and the angle between the fracture and the horizontal section are 140 m and 90°, respectively; and (5) the reasonable well spacing of vertical wells is 600 m and that of horizontal wells is 750 m. The development policy proposed in this study is suitable for the efficient development of complex tight sandstone gas reservoirs in similar areas.

A Coupling Model of Gas–Water Two-Phase Productivity for Multilateral Horizontal Wells in a Multilayer Gas Reservoir

A series of complex horizontal wells have been implemented in challenging gas reservoirs. Multilateral horizontal well technology can be used in multilayer gas reservoirs, facilitating the expansion of the gas drainage area and enhancing productivity. Accurate productivity calculations for multilateral wells in multilayer reservoirs are essential for effective reservoir development. However, there have been few studies in this area. This paper introduces a coupling model for calculating the gas–water two-phase productivity of multilateral wells in multilayer reservoirs, based on the principles of conformal transformation and superposition of potential functions. The accuracy of the model is validated by obtaining the distribution of flow along the horizontal wellbore through numerical simulation cases. The results from the field case and sensitivity analysis indicate that the pressure difference increases nonlinearly from the toe to the heel, and the productivity of multilateral wells decreases as the gas–water ratio increases. The method proposed in this paper is applicable for calculating the productivity of multilateral wells in multilayer reservoirs.

The Production Splitting Method of Offshore Multilayer Combined Water Flooding Gas Wells with Gas Dissolving.

Offshore gas reservoirs are characterized by thin interlayers, high production, few wells, etc., and are often exploited by multilayer combined mining, whereas the production dynamics of multilayer gas reservoirs are very different from those of single-layer gas reservoirs. Therefore, clarifying the gas production contribution of each layer in multilayer combined gas reservoirs is an important prerequisite for analyzing the potential of gas reservoirs and realizing efficient development. In this paper, unlike the past method of evaluating the gas production contribution of each layer by using the KH attribute of the reservoir, we combined the modified B-L equation considering CO2 dissolution and the multilayer multizone seepage equation to establish a dynamic split model of the production dynamics of multilayer water-driven gas reservoirs, verified the reliability of the model through the numerical model and the results of the production well logging, quantitatively analyzed the degree of influence of each parameter on the contribution of the layered gas production, and designed the orthogonal experiments. The main controlling factors of the gas production contribution of each layer were determined. The results of the study show that (1) the main controlling factors for the gas production contribution of each layer in the early stage of WDG are, in order, permeability, thickness, outer boundary distance, porosity, CO2 content, and total gas production rate; however, the main controlling factors for the gas production contribution of each layer in the late stage of WDG are, in order, thickness, permeability, outer boundary distance, porosity, CO2 content, and total gas production rate; and the combined view shows that the permeability and thickness have the greatest influence. (2) In multilayer production, the conditions of high permeability, close gas-water boundary, poor gas content, and low CO2 content will reduce the gas production contribution of the layer with the increase of production time. (3) Compared with the results of production logging and numerical simulation, the split model can better predict the gas production of each layer, and the prediction error is no more than 10%. (4) By comparing with the numerical simulation results, the model can realize the prediction of the time of seeing water in the layer with stronger water body capability. (5) The model takes into account the effect of the CO2 content, better reflects the actual gas composition of each layer, and can improve the production prediction accuracy by up to 4%. Considering the high cost of production logging in offshore oil and gas fields, the inability of the KH method to reflect the dynamic changes of gas production in each layer, the poor application of stratified sampling to dry gas reservoirs, and other limitations, the model in this paper can be utilized to simulate the multilayer water-driven gas drive process when the energy of the water body is strong by using the geological parameters of the reservoir and the fluid parameters, and the simulation results of this model provide directions for offshore multilayer water-driven gas reservoirs to improve the recovery rate, and for plugging and regulating the water and exploiting the potential of gas wells that have seen water.

Inter-layer interference for multi-layered tight gas reservoir in the absence and presence of movable water

Due to the dissimilarity among different producing layers, the influences of inter-layer interference on the production performance of a multi-layer gas reservoir are possible. However, systematic studies of inter-layer interference for tight gas reservoirs are really limited, especially for those reservoirs in the presence of water. In this work, five types of possible inter-layer interferences, including both absence and presence of water, are identified for commingled production of tight gas reservoirs. Subsequently, a series of reservoir-scale and pore-scale numerical simulations are conducted to quantify the degree of influence of each type of interference. Consistent field evidence from the Yan'an tight gas reservoir (Ordos Basin, China) is found to support the simulation results. Additionally, suggestions are proposed to mitigate the potential inter-layer interferences. The results indicate that, in the absence of water, commingled production is favorable in two situations: when there is a difference in physical properties and when there is a difference in the pressure system of each layer. For reservoirs with a multi-pressure system, the backflow phenomenon, which significantly influences the production performance, only occurs under extreme conditions (such as very low production rates or well shut-in periods). When water is introduced into the multi-layer system, inter-layer interference becomes nearly inevitable. Perforating both the gas-rich layer and water-rich layer for commingled production is not desirable, as it can trigger water invasion from the water-rich layer into the gas-rich layer. The gas-rich layer might also be interfered with by water from the neighboring unperforated water-rich layer, where the water might break the barrier (eg weak joint surface, cement in fractures) between the two layers and migrate into the gas-rich layer. Additionally, the gas-rich layer could possibly be interfered with by water that accumulates at the bottom of the wellbore due to gravitational differentiation during shut-in operations.

An Analytical Model Coupled with Orthogonal Experimental Design Is Used to Analyze the Main Controlling Factors of Multi-Layer Commingled Gas Reservoirs

The majority of China’s multi-layer low permeability tight gas reservoirs are currently being extracted through the method of multi-layer co-production. However, due to the significant disparity in physical properties and varying degrees of pressure depletion among the production layers, elucidating the primary factors influencing the productivity contribution of each gas layer remains challenging. A multi-factor analytical model is proposed for commingled gas wells with multiple layers. An unstable model is established for the production of commingled layers, and the problem of flow distribution is addressed using the Duhamel convolution principle. The Laplace transform is subsequently employed to derive the solution in the Laplace domain, which can be inverted utilizing the Stehfest inversion algorithm to obtain a real-time domain solution. The influence of reservoir factors on the stratification contribution rate has been comprehensively analyzed, encompassing permeability, porosity, initial pressure, drainage radius, and layer thickness. The orthogonal test design was employed to conduct range analysis and variance analysis separately, yielding the primary and secondary order as well as influence weight of the five factors. The findings demonstrate that, within this gas reservoir, the discharge radius, thickness, and porosity are identified as the primary factors influencing gas well productivity. Furthermore, seven horizontal flow charts illustrating the double-layer gas reservoir and five horizontal flow charts depicting single-factor variations in the double-layer gas reservoir were constructed. These charts provide a clear visualization of the impact of each reservoir factor on stratification’s contribution rate. In contrast to previous studies, this novel approach presents a comprehensive optimization framework that ranks the influence weights of individual factors and identifies the most significant factors impacting multi-layer gas reservoirs. The presented method also serves as a foundation for the subsequent selection of multi-layer gas reservoirs, formulation of gas well stimulation measures, and efficient development.

Study on Monitoring Reservoir Gas Density by Pulsed Neutron Logging

In mature multilayer gas reservoirs, it is a common problem to evaluate whether a potential reservoir is still productive after casing. Monitoring of unproduced or developing gas formations can guide production action plans. Intervention in unperforated zones with high gas density can increase gas production, whereas intervention in zones with low gas density is uneconomical. An RPM instrument stratum model was established by using the Monte Carlo method in this study. The model was used to simulate the response characteristics of pulsed neutron logging in a sandstone reservoir with 100% gas saturation to different reservoir gas densities, formation porosity, and shale content. The data obtained from the simulation were interpolated to construct a capture gamma ratio plate and a nonbounce gamma ratio plate. Using the constructed chart, the gas density of the reservoir can be quantitatively calculated, and then, the recovery value of the potential gas layer can be evaluated.

Experiment on development of multilayer unconsolidated sandstone gas reservoir with edge water invasion in Qaidam Basin, China

The Quaternary unconsolidated sandstone gas reservoir in the Qaidam Basin is characterized by multiple layers, strong heterogeneity, and active edge water. Based on these characteristics, a physical simulation experiment method for production from multi-layer edge-water gas reservoirs was proposed. In this method, the experimental models were established by using natural cores in series and parallel connection to show the geological characteristics of multi-layer gas reservoirs, and according to the results of the indoor simulation of the whole depletion production process, an experimental study on four layers of commingled production in one well was conducted under three scenarios of gas reservoirs: without the water invasion, with the water invasion without flow, and with the water invasion with flow. In this study, by visually monitoring the water invasion process of a constant-pressure edge water body along layers with different permeability and quantitatively analyzing the influence of gas well production allocation on the water invasion path and advancing speed of the water invasion front, the influence of non-uniform edge water invasion on gas reservoir productivity, recovery factors, and residual gas occurrence characteristics was clarified, and the mechanism of non-uniform edge water invasion along high permeability layers and the formation of water-sealed gas were revealed. The findings of this study can provide a basis for reasonable water control for this type of gas field.

Engineering Poster E7: A new approach for production forecasting from individual layers in multi-layer commingled tight gas reservoirs

Poster E7 Estimating future production in multi-layer tight gas reservoirs is necessary, but problematic. Initial production looks promising but soon decreases to levels that are much lower than first anticipated. Boundary-dominated flow to which common production data analysis can be applied to, takes up to 8 years to establish, yet future production estimations must be made at the time of drilling. Common industry software does not fully assess individual layer contribution because large uncertainties exist in layer-specific contributions to total production. Many engineers tend to use analysis methods designed for single-layer wells, which leaves future production estimations with large errors, and this can have potentially long ranging consequences for a company. This paper presents a new way of estimating future production in multi-layer tight gas reservoirs by incorporating the uncertainty that can be found in individual layer contributions. Our approach utilises single tank material balance and matches total well production data by changing layer-specific properties. A workflow has been created for the programming language Python that includes a Bayesian element to honour the uncertainty in individual layer effective permeability and individual layer gas in place. Applying this workflow to many wells in a specified area allows probability distribution functions for layer effective permeability and layer gas in place to be generated. This will result in attaining more realistic production forecasts in the form of P10, P50 and P90 for multi-layer tight gas reservoirs, and allowing the engineer to make better-informed early assessments of the future production of wells. To access the poster click the link on the right. To read the full paper click here

Uncertainty Assessment for Field Development Study Using Monte Carlo Simulation on Salap Field Multilayer Gas Reservoir

Uncertainty assessment for Field Development Study is often only carried out in a Deterministic Method by only creating scenario sensitivity based on theoretical assumptions without add subsurface risk factors. In the uncertainty assessment model, when a model is made with a variable that only has one value for each sensitivity is called the Deterministic Method. Meanwhile, when a model is made with a variable that has value in the form of a probability distribution, the method is called the Probabilistic Method. In the Probabilistic Method, the probability distribution is influenced by the risk factors, while in the Deterministic Method, these factors have no effect because the input value is only based on theoretical assumption. Uncertainty assessment for the Salap Field Development Study was carried out using the Probabilistic Method Monte Carlo Simulation. The results of the study provide the number of proven reservoirs, volume in place, volume of resources, number of development wells, plateau production period and field life that already accommodates subsurface risk factors and uncertainty in geological-reservoir data. The paper also compares the assessment result between the Probabilistic Method with the Deterministic Method to see how risk factors influenece the study results.

Production Behavior Evaluation on Inclined Well in Commingled Carbonate Gas Reservoir With Multiple Heterogeneous Layers Without Crossflow

Abstract To estimate production behaviors of inclined well in multilayer heterogeneous carbonate gas reservoir, two semi-analytical models for different formation distribution patterns are proposed, which are named as model I and model II. For model I, the inner region of each layer is fractured-vuggy porous medium, while the outer region only contains matrix. For model II, the inner and outer regions are consisted of matrix and fractured-vuggy porous mediums, respectively. To solve the model, Laplace transformation, Fourier transformation and inversion, Duhamel convolution, and Stehfest numerical inverse are applied. The validities of these models are verified through the comparisons with the published datum, which include well bottom-hole pressure (BHP) and gas production rate of individual layer for vertical and inclined wells in multilayer homogenous gas reservoir. Furthermore, by matching the well BHP data collected from a field case, the applicability of model is validated. The influences of prevailing factors, such as the radius ratio between inner and outer regions, horizontal–vertical permeability ratio, and inclination angle, on production behaviors are analyzed. The results show that influenced by the diverse formation distribution patterns, the variation of radius ratio between inner and outer regions has opposite effect on the well BHP for models I and II. Formation anisotropy and inclination angle have minimal effects on the well BHP of model I, but have significant impacts on model II. To keep the well BHP with a relatively high value, for model I and model II, the penetrate inclination angles should be greater than 50 deg and 55 deg, respectively.

Temperature Response Characteristics of the Production Profile for Multilayered Gas Wells Based on Distributed Temperature Sensing Monitoring

Abstract The distributed temperature sensing (DTS) is used to overcome the defects of traditional production profile testing technology and realize the real-time and accurate temperature monitoring of complex underground reservoirs. However, the temperature response characteristics of the production profile for multilayered gas wells have not been studied clearly, which leads to technical problems of the production profile interpretation of such gas wells monitored by DTS. Therefore, considering the influence of the fluid heat convection, viscous dissipation, and heat conduction which are the involved mechanisms in this process, a model coupling pressure and temperature fields of a multilayered gas reservoir are established in the current study. Subsequently, the formation temperature variation for transient testing of a multilayered gas reservoir is solved by programming, and the effect of model parameters (e.g., gas production, permeability, and rock heat capacity ratio) on the temperature response characteristics of the production profile is analyzed. Finally, the accuracy and reliability of temperature response prediction are verified by fitting the actual DTS temperature test data of an offshore-multilayered gas well. The results of this study provide ideas regarding quantitative interpretation and analysis of DTS monitoring data for the production profile of multilayered gas wells.

A new approach for production forecasting from individual layers in multi-layer commingled tight gas reservoirs

Estimating future production in multi-layer tight gas reservoirs is necessary, but problematic. Initial production looks promising but soon decreases to levels that are much lower than first anticipated. Boundary-dominated flow to which common production data analysis can be applied to, takes up to 8 years to establish, yet future production estimations must be made at the time of drilling. Common industry software does not fully assess individual layer contribution because large uncertainties exist in layer-specific contributions to total production. Many engineers tend to use analysis methods designed for single-layer wells, which leaves future production estimations with large errors, and this can have potentially long ranging consequences for a company. This paper presents a new way of estimating future production in multi-layer tight gas reservoirs by incorporating the uncertainty that can be found in individual layer contributions. Our approach utilises single tank material balance and matches total well production data by changing layer-specific properties. A workflow has been created for the programming language Python that includes a Bayesian element to honour the uncertainty in individual layer effective permeability and individual layer gas in place. Applying this workflow to many wells in a specified area allows probability distribution functions for layer effective permeability and layer gas in place to be generated. This will result in attaining more realistic production forecasts in the form of P10, P50 and P90 for multi-layer tight gas reservoirs, and allowing the engineer to make better-informed early assessments of the future production of wells.

Production Performance Analysis for Deviated Wells in Carbonate Gas Reservoirs With Multiple Heterogeneous layers

Deviated wells are used to improve the performance of carbonate reservoirs with multiple heterogeneous layers and penetrate the “sweet spot” of each layer, which is full of fractures and vugs. It is difficult to consider in-layer and inter-layer heterogeneities simultaneously, and predict the production performance for these wells accurately. Therefore, a semi-analytical model to analyze the production performance of deviated wells in a multilayer heterogeneous stress-sensitive carbonate gas reservoir is proposed. For each layer, the inner region is a fractured-vuggy porous medium, while the outer region is merely a tight formation with matrix and formation properties, and penetrated inclination angles may be distinct. Pseudo-time/pressure factors are introduced to consider fracture stress sensitivity. Through the application of Laplace transformation, Fourier transform and inverse, Duhamel convolution, and Stehfest numerical inversion, the presented model is solved. The validity of this model is verified through comparison with single-layer composite formation with different porous mediums and vertical well in a multilayer carbonate gas reservoir. Moreover, by matching bottom-hole pressure data collected from a slanted well in the Anyue gas field, the applicability of this model is validated. A synthetic case, which has two composite formations, the first (upper) layer is more permeable than the second (lower) layer, is used to study the variations of inner region radius, fracture/matrix permeability, and inclination angles on production behaviors. The results show the properties of the first layer determine well bottom-hole pressure, whereas the rise of permeability, inner region radius and penetrated angle for the second layer can improve the gas recovery of this layer. In practice, to maintain well bottom-hole pressure with a relatively high level and enhance gas recovery of the tight layer, the inclination angle should be larger than 60° for each layer, and be increased to as large as possible. The findings of this study can help for a better understanding of the production behaviors of deviated wells in multilayer heterogenous reservoirs and could provide some guidance for the design of well trajectory.

Dynamic production characteristics and effect analysis of combined gas production well of coalbed methane and tight gas

For gas reservoirs with poor physical properties, the implementation of a single well with multi-layer combined production is an effective means to achieve efficient development. However, because of the differences in the geological conditions of the vast majority of multi-layer gas reservoirs, the dynamic characteristics of the gas wells will be complex under the multi-layer combined mining mode, and the inevitable interlayer interference in the production process will affect the development effect. In this paper, the coal seam and the dense layer are opened for production at the same time. The two kinds of different types of production are not only restricted by the heterogeneity of each layer, but also the special development mode of the coal seam. Through analyzing and summarizing the productivity equation of two kinds of production layers and the characteristics of the change of production pressure, the coupling calculation is carried out by the iterative programming of node analysis method in the wellbore, which can dynamically predict the dynamic gas production. In comparison with the dynamic gas production dynamics of combined production and the overlay production of each production layer, it is found that the amount of accumulated gas production of multiple production layers in the forecast period is only 2.56% lower than that of the single production of the multi-production layer, but the investment cost of the single well multi-layer production is far lower than that of the single production, and the stable production time of the combined production is longer, indicating that the stable production time is longer.

The pressure drop funnel method was used to evaluate the discharge range of each layer

The east side of yulin gas field belongs to the multi-layer gas reservoir, and the dominant vertical layer is not prominent. At present, there is a lack of productivity evaluation method for single well of multi-layer system, and the scope of discharge and control factors of small layer of gas well are not clear. Based on the well pattern data, geological and test data of the eastern yulin gas field, and referring to the development experience of similar blocks at home and abroad, the production evaluation of gas Wells and control reserves evaluation of multi-layer gas reservoirs were completed, the reserve production characteristics, discharge range and control factors of multi-layer gas reservoirs were clarified, and the well spacing of well pattern was optimized.

Gas drainage radius evaluation and well pattern optimization of multilayer gas reservoirs

In the development process of shenmu gas field, there are “few wells and low production of reserves; Many wells, high development investment and easy cross-well interference”, it is particularly important to optimize the well spacing of development well pattern. In view of this problem, on the basis of deepening geological understanding, it is necessary to clarify the gas drainage radius of each well, and combine various methods to demonstrate and optimize the well spacing of gas field well pattern.

Pressure transient behavior of layered commingled reservoir with vertical inhomogeneous closed boundary

The multilayered deposition is the main feature of the tidal flat reservoir in the western Sichuan Basin. The boundary distance among layers of the tidal flat reservoir is different. To understand the influence of vertical inhomogeneous closed boundary (VICB) on pressure transient behavior, an extended n-layer VICB reservoir model is presented.Firstly, the VICB is discretized into n boundary segments representing the characteristics of the individual layer, and the reservoir is divided into n horizontal layers accordingly. The pressure transient model of the n-layer VICB reservoir is established by the seepage equations and boundary conditions of the individual layer. Secondly, solving Bessel equations consisting of 2n boundary conditions by the Cramer's rule to obtain the bottom-hole pressure solution in Laplace space. The wellbore storage and skin effect are taken into account by Duhamel's principle in the Laplace domain. Lastly, the bottom-hole pressure solution in the real-time domain is obtained by the Stehfest numerical inversion algorithm. The comparison result with the bottom-hole pressure of the two-layer reservoir proves the reliability of the n-layer VICB reservoir model.In the n-layer VICB reservoir model, a new VICB radial flow regime is identified which easily mistaken as the outer radial flow of the composite reservoir model. The result of sensitivity analysis shows that the pressure transient behavior of the n-layer VICB reservoir has the “equivalent compound zone effect” and “equivalent boundary radii effect”. There is a quantitative relation between the distribution of VICB and the characteristics value of pressure derivative during the VICB radial flow regime stage.The “equivalent compound zone effect”, “equivalent boundary radii effect” and the quantitative relation provide a simple and fast analytical method for identifying the vertical distribution and distance range of VICB. Finally, a field case from the western Sichuan Basin multilayered gas reservoir is discussed in detail to validate the capabilities of our model.

Secondary formation damage of low-pressure layer during commingled production in multilayered tight gas reservoirs

This paper experimentally investigates fluid back-flow behavior and formation damage during commingled production in multilayered tight gas reservoirs. The development of fluid back-flow in commingled tight gas reservoirs was simulated using a newly designed experimental platform. The results indicate that when there is a pressure difference between different layers during commingled production from tight gas reservoir, water produced from the high-pressure layer will invade the low-pressure layer along with gas back-flow and will accumulate in the near-wellbore area. This will lead to an increase in water saturation and a decline in permeability in the low-pressure layer and result in a significant reduction in ultimate recovery. The outcomes of these experiments demonstrate that as well as the formation damage caused by the working fluid during drilling and fracturing, “Secondary Formation Damage” also occurs during commingled production in multilayered tight gas reservoirs. This secondary formation damage mainly occurs in the near-wellbore area of low-pressure layers and is more severe with greater proximity to the wellbore. Through further experimentation to assess the factors influencing secondary formation damage, it is shown that the degree of secondary formation damage increases with decreasing original formation pressure, original water saturation, and permeability in the lower-pressure layer.

Prediction of Water Production in Multi-layer Gas Reservoirs by Production Logging-based Multi-phase Flow Simulation

Prediction of Water Production in Multi-layer Gas Reservoirs by Production Logging-based Multi-phase Flow Simulation