The Evaluation and Sensitivity of Decline Curve Modelling

The development of prediction tools for production performance and the lifespan of shale gas reservoirs has been a focus for petroleum engineers. Several decline curve models have been developed and compared with data from shale gas production. To accurately forecast the estimated ultimate recovery for shale gas reservoirs, consistent and accurate decline curve modelling is required. In this paper, the current decline curve models are evaluated using the goodness of fit as a measure of accuracy with field data. The evaluation found that there are advantages in using the current DCA models; however, they also have limitations associated with them that have to be addressed. Based on the accuracy assessment conducted on the different models, it appears that the Stretched Exponential Decline Model (SEDM) and Logistic Growth Model (LGM), followed by the Extended Exponential Decline Model (EEDM), the Power Law Exponential Model (PLE), the Doung’s Model, and lastly, the Arps Hyperbolic Decline Model, provide the best fit with production data.

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An integrated workflow to perform reservoir and completion parametric study on a shale gas reservoir

Journal of Petroleum Exploration and Production Technology ◽

10.1007/s13202-019-00829-9 ◽

2020 ◽

Vol 10 (4) ◽

pp. 1497-1510

Author(s):

Mohamed Mahmoud ◽

Ahmed Aleid ◽

Abdulwahab Ali ◽

Muhammad Shahzad Kamal

Keyword(s):

Shale Gas ◽

Gas Production ◽

Production Performance ◽

Analytical Models ◽

Well Performance ◽

Short Term ◽

Gas Reservoirs ◽

Shale Gas Reservoirs ◽

The Impact

AbstractThe main objectives of this paper are to assess the long-term and short-term production based on both reservoir parameters and completion parameters of shale gas reservoirs. The effects of the reservoir parameters (permeability and the initial reservoir pressure) and completion parameters (fracture geometry, stimulated reservoir volume, etc.) on the short-term and long-term production of shale gas reservoirs were investigated. The currently used approach relies mainly on the decline curve analysis or analogs from a similar shale play to forecast the gas production from shale gas reservoirs. Both these approaches are not satisfactory because they are calibrated on short production history and do not assess the impact of uncertainty in reservoir and well data. For the first time, this study integrates initial production analysis, probabilistic evaluation, and sensitivity analysis to develop a robust workflow that will help in designing a sustainable production from shale gas plays. The reservoir and completion parameters were collected from different available resources, and the probability distributions of gathered uncertain data were defined. Then analytical models were used to forecast the production. Two well evaluation results are presented in this paper. Based on the results, completion parameters affected the short-term and long-term production, while the reservoir parameters controlled the long-term production. Long-term well performance was mainly controlled by the fracture half-length and fracture height, whereas other completion and reservoir parameters have an insignificant effect. Stimulation treatment design defines the initial well performance, while well placement decision defines well long-term performance. The findings of this study would help in better understanding the production performance of shale gas reservoirs, maximizing production by selecting effective completion parameters and considering the governing reservoir parameters. Moreover, it would help in accomplishing more effective stimulation treatments and define the potentiality of the basin.

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

Mehran University Research Journal of Engineering and Technology ◽

10.22581/muet1982.2002.19 ◽

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.

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Uncertainty Assessment of Production Performance for Shale-Gas Reservoirs

10.2523/16866-abstract ◽

2013 ◽

Cited By ~ 1

Author(s):

Jiang Xie ◽

Seong H. Lee ◽

Zhiming Wang ◽

Xian-Huan Wen

Keyword(s):

Shale Gas ◽

Uncertainty Assessment ◽

Production Performance ◽

Gas Reservoirs ◽

Shale Gas Reservoirs

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Investigation of the Main Factors During Shale-gas Production Using Grey Relational Analysis

The Open Petroleum Engineering Journal ◽

10.2174/1874834101609160207 ◽

2016 ◽

Vol 9 (1) ◽

pp. 207-215 ◽

Cited By ~ 5

Author(s):

Hongling Zhang ◽

Jing Wang ◽

Haiyong Zhang

Keyword(s):

Shale Gas ◽

Gas Production ◽

Gas Reservoirs ◽

Fracture Conductivity ◽

Matrix Permeability ◽

Shale Gas Reservoirs ◽

Main Factors ◽

Grey Relational ◽

The Impact ◽

Half Length

Shale gas is one of the primary types of unconventional reservoirs to be exploited in search for long-lasting resources. Production from shale gas reservoirs requires horizontal drilling with hydraulic fracturing to achieve the most economic production. However, plenty of parameters (e.g., fracture conductivity, fracture spacing, half-length, matrix permeability, and porosity,etc) have high uncertainty that may cause unexpected high cost. Therefore, to develop an efficient and practical method for quantifying uncertainty and optimizing shale-gas production is highly desirable. This paper focuses on analyzing the main factors during gas production, including petro-physical parameters, hydraulic fracture parameters, and work conditions on shale-gas production performances. Firstly, numerous key parameters of shale-gas production from the fourteen best-known shale gas reservoirs in the United States are selected through the correlation analysis. Secondly, a grey relational grade method is used to quantitatively estimate the potential of developing target shale gas reservoirs as well as the impact ranking of these factors. Analyses on production data of many shale-gas reservoirs indicate that the recovery efficiencies are highly correlated with the major parameters predicted by the new method. Among all main factors, the impact ranking of major factors, from more important to less important, is matrix permeability, fracture conductivity, fracture density of hydraulic fracturing, reservoir pressure, total organic content (TOC), fracture half-length, adsorbed gas, reservoir thickness, reservoir depth, and clay content. This work can provide significant insights into quantifying the evaluation of the development potential of shale gas reservoirs, the influence degree of main factors, and optimization of shale gas production.

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Development of A Semi-Analytical Model for Simulation of Gas Production in Shale Gas Reservoirs

Proceedings of the 2nd Unconventional Resources Technology Conference ◽

10.15530/urtec-2014-1922945 ◽

2014 ◽

Cited By ~ 14

Author(s):

Wei Yu ◽

Kamy Sepehrnoori

Keyword(s):

Analytical Model ◽

Shale Gas ◽

Gas Production ◽

Gas Reservoirs ◽

Shale Gas Reservoirs

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Study Evaluates Fracturing Interference for Multiwell Pads in Shale Gas Reservoirs

Journal of Petroleum Technology ◽

10.2118/0821-0067-jpt ◽

2021 ◽

Vol 73 (08) ◽

pp. 67-68

Author(s):

Chris Carpenter

Keyword(s):

Hydraulic Fracturing ◽

Shale Gas ◽

Technical Conference ◽

Gas Production ◽

Gas Reservoirs ◽

Well Drilling ◽

Recovery Potential ◽

Shale Gas Reservoirs ◽

Well Spacing ◽

Southwest Region

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 201694, “Interwell Fracturing Interference Evaluation of Multiwell Pads in Shale Gas Reservoirs: A Case Study in WY Basin,” by Youwei He, SPE, Jianchun Guo, SPE, and Yong Tang, Southwest Petroleum University, et al., prepared for the 2020 SPE Annual Technical Conference and Exhibition, originally scheduled to be held in Denver, Colorado, 5–7 October. The paper has not been peer reviewed. The paper aims to determine the mechanisms of fracturing interference for multiwell pads in shale gas reservoirs and evaluate the effect of interwell fracturing interference on production. Field data of 56 shale gas wells in the WY Basin are applied to calculate the ratio of affected wells to newly fractured wells and understand its influence on gas production. The main controlling factors of fracturing interference are determined, and the interwell fracturing interacting types are presented. Production recovery potential for affected wells is analyzed, and suggestions for mitigating fracturing interference are proposed. Interwell Fracturing Interference Evaluation The WY shale play is in the southwest region of the Sichuan Basin, where shale gas reserves in the Wufeng-Longmaxi formation are estimated to be the highest in China. The reservoir has produced hydrocarbons since 2016. Infill well drilling and massive hydraulic fracturing operations have been applied in the basin. Each well pad usually is composed of six to eight multifractured horizontal wells (MFHWs). Well spacing within one pad, or the distance between adjacent well pads, is so small that fracture interference can occur easily between infill wells and parent wells. Fig. 1 shows the number of wells affected by in-fill well fracturing from 2016 to 2019 in the basin. As the number of newly drilled wells increased between 2017 and 2019, the number of wells affected by hydraulic fracturing has greatly increased. The number of wells experiencing fracturing interaction has reached 65 in the last 4 years at the time of writing.

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Simulation of Fracturing Water Invasion and its Impact on Gas Production in Shale-gas Reservoirs

ECMOR XIV - 14th European Conference on the Mathematics of Oil Recovery ◽

10.3997/2214-4609.20141884 ◽

2014 ◽

Cited By ~ 2

Author(s):

N. Farah ◽

D.Y. Ding ◽

Y.S. Wu ◽

A.M. Khrouf

Keyword(s):

Shale Gas ◽

Gas Production ◽

Gas Reservoirs ◽

Shale Gas Reservoirs

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Variations of Gas Flow Regimes and Petro-Physical Properties During Gas Production Considering Volume Consumed by Adsorbed Gas and Stress Dependence Effect in Shale Gas Reservoirs

10.2118/174996-ms ◽

2015 ◽

Cited By ~ 5

Author(s):

Jing Wang ◽

Haishan Luo ◽

Huiqing Liu ◽

Yuchen Ji ◽

Fei Cao ◽

...

Keyword(s):

Physical Properties ◽

Shale Gas ◽

Gas Flow ◽

Flow Regimes ◽

Gas Production ◽

Stress Dependence ◽

Gas Reservoirs ◽

Adsorbed Gas ◽

Shale Gas Reservoirs

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Productivity Evaluation Study of Shale Gas Reservoirs

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1073-1076.2296 ◽

2014 ◽

Vol 1073-1076 ◽

pp. 2296-2299

Author(s):

Peng Xiang Diwu ◽

Rui Liu ◽

Tong Jing Liu ◽

Bin Jia

Keyword(s):

Pressure Gradient ◽

Shale Gas ◽

Production Capacity ◽

Flow Characteristics ◽

Evaluation Study ◽

Gas Production ◽

Gas Reservoirs ◽

Compression Factor ◽

Shale Gas Reservoirs ◽

Stable Production

The seepage mechanism of unconventional gas is very complex, and has a unique seepage mechanism and dynamic flow characteristics. It is difficult to use conventional gas production capacity to predict recoverable reserves. In this paper, starting from fluid mechanics, based on reservoir characteristics of the shale gas fracturing, a composite model of shale gas reservoirs was established, and stable production time was determined. We analyzed the effects of inside and outside zone permeability, the radius, pressure gradient, desorption influence of the compression factor and reservoir thickness, etc., and the established a shale gas well productivity equation refer to Vogel equation. The results show that: area permeability, penetration outside the area, zone radius, reservoir thickness and desorption compression factor were sensitive to shale gas production capacity; skin factor and the pressure gradient is not sensitive factor; through reliability analysis, the productivity formula which was referred to Vogel equation can determine the production capacity of shale gas wells quickly and accurately.

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