Flow mechanism of production decline during natural depletion after hydraulic fracturing of horizontal wells in tight oil reservoirs

2021 ◽  
pp. 1-18
Author(s):  
Yi Yang ◽  
Wei Xiong ◽  
Guangzhi Liao ◽  
Shusheng Gao ◽  
Rui Shen ◽  
...  
Keyword(s):  
Hydraulic Fracturing ◽  
Horizontal Wells ◽  
Oil Reservoirs ◽  
Tight Oil ◽  
Flow Mechanism ◽  
Tight Oil Reservoirs

scholarly journals Supplementary energy development boundaries of staged fracturing horizontal wells in tight oil reservoirs

2020 ◽  
Vol 38 (6) ◽  
pp. 2217-2230
Author(s):  
Lijun Lin ◽  
Wei Lin ◽  
Shengchun Xiong ◽  
Zhengming Yang
Keyword(s):  
Horizontal Well ◽  
Evaluation Model ◽  
Horizontal Wells ◽  
Simulation Method ◽  
Energy Development ◽  
Oil Reservoirs ◽  
Water Flooding ◽  
Tight Oil ◽  
Reservoir Development ◽  
Tight Oil Reservoirs

Staged fracturing horizontal well technology is an important means of improving tight reservoir development efficiency. Taking a typical tight oil block in the Oilfield A as the studied area, the vertical well–horizontal well joint arrangement pattern is adopted in this study. The energy supplementary development effects of multiple permeability scales, different arrangement spacing, and different media (H2O, CO2) are discussed through the numerical simulation method. Combined with the principles of petroleum technology economics, the economic evaluation model for staged fracturing horizontal wells in tight oil reservoir development is proposed, thereby determining the technical boundary and economic boundary of supplementary energy development with different media. Studies indicate that the technical boundary and economic boundary of water-flooding development in the Oilfield A are 0.4 and 0.8 mD, respectively, and the technical boundary and economic boundary of CO2-flooding development are 0.1 and 0.4 mD, respectively. This study provides theoretical support for field operation of Oilfield A and guidance for selection of development mode for tight oil reservoirs.

scholarly journals Performance Optimization of CO2 Huff-n-Puff for Multifractured Horizontal Wells in Tight Oil Reservoirs

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Mingqiang Hao ◽  
Songlin Liao ◽  
Guangming Yu ◽  
Xinhui Lei ◽  
Yong Tang
Keyword(s):  
Crude Oil ◽  
Horizontal Wells ◽  
Production Performance ◽  
Oil Reservoirs ◽  
Co2 Injection ◽  
Tight Oil ◽  
Production Parameters ◽  
Sensitivity Factors ◽  
Tight Oil Reservoirs ◽  
The Impact

In this paper, the sensitivity factors of CO2 huff-n-puff for multifractured horizontal wells (MFHWs) in tight oil reservoirs were investigated through an experimental test and numerical simulation. The pressure-volume-temperature (PVT) experiment and the slim tube experiment are used to understand the interaction mechanism between CO2 and crude oil, and the minimum miscibility pressure (MMP) of the CO2-crude oil system is 17 MPa. The single-well model was firstly established to analyze the sensitivity factors on production performance of MFHWs by using CO2 huff-n-puff. The controlling factors of CO2 huff-n-puff for MFHWs in tight oil reservoirs were divided into three categories (i.e., reservoir parameters, well parameters, and injection-production parameters), and the impact of individual parameter on well performance was discussed in detail. The range of reservoir parameters suitable for CO2 huff-n-puff of MFHWs is obtained. The reservoir permeability is from 0.1 mD to 1 mD, the reservoir thickness changes from 10 m to 30 m, and the reservoir porosity is from 7% to 12%. Based on the reservoir parameters of the target reservoir, the reasonable well and fracture parameters are obtained. The sensitivity intensity was followed by the horizontal well length, fracture conductivity, fracture spacing, and fracture half-length. CO2 injection-production parameters are further optimized, and the sensitivity intensity was followed by the single-cycle cumulative CO2 injection rate, the soaking time, the injection rates, and the production rates. It provides a reference for parameter optimization of CO2 huff-n-puff for MFHWs in tight oil reservoirs.

Prediction of Refracturing Timing of Horizontal Wells in Tight Oil Reservoirs Based on an Integrated Learning Algorithm

Energies ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6524
Author(s):  
Xianmin Zhang ◽  
Jiawei Ren ◽  
Qihong Feng ◽  
Xianjun Wang ◽  
Wei Wang
Keyword(s):  
Support Vector Machine ◽  
Learning Algorithm ◽  
Prediction Method ◽  
Horizontal Wells ◽  
Songliao Basin ◽  
Oil Reservoirs ◽  
Support Vector ◽  
Tight Oil ◽  
Integrated Learning ◽  
Tight Oil Reservoirs

Refracturing technology can effectively improve the EUR of horizontal wells in tight reservoirs, and the determination of refracturing time is the key to ensuring the effects of refracturing measures. In view of different types of tight oil reservoirs in the Songliao Basin, a library of 1896 sets of learning samples, with 11 geological and engineering parameters and corresponding refracturing times as characteristic variables, was constructed by combining numerical simulation with field statistics. After a performance comparison and analysis of an artificial neural network, support vector machine and XGBoost algorithm, the support vector machine and XGBoost algorithm were chosen as the base model and fused by the stacking method of integrated learning. Then, a prediction method of refracturing timing of tight oil horizontal wells was established on the basis of an ensemble learning algorithm. Through the prediction and analysis of the refracturing timing corresponding to 257 groups of test data, the prediction results were in good agreement with the real value, and the correlation coefficient R2 was 0.945. The established prediction method can quickly and accurately predict the refracturing time, and effectively guide refracturing practices in the tight oil test area of the Songliao basin.

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