Critical drawdown pressure of sanding onset for offshore depleted and water cut gas reservoirs: Modeling and application

Zhang, Rui; Shi, Xuguo; Zhu, Ruifeng; Zhang, Chong; Fang, Manzong; Bo, Kehao; Jiang, Feng

doi:10.1016/j.jngse.2016.06.057

Cited by 20 publications

(13 citation statements)

References 17 publications

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“…But the later studies found that after a long‐term production of hydrocarbon resources, reservoir pressure will be depleted, in turn, a reduction of in situ stress acting within the reservoir will generate. Therefore, fracture pressure will be changed finally after reservoir depletion . The results showed that fracture pressure will be decreased due to reservoir depletion.…”

Section: Introductionmentioning

confidence: 99%

A novel evaluation on fracture pressure in depleted shale gas reservoir

Zhao

Yuan²,

Feng

et al. 2018

Energy Science & Engineering

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Fracture pressure is the key parameter both for horizontal drilling and hydraulic fracturing in the shale gas reservoir. Reservoir depletion will push for the change of the fracture pressure. Previous studies showed that fracture pressure will be decreased with reservoir depletion, which is not suitable for the anisotropic shale gas reservoir. Aiming at resolving this problem, a novel evaluation was established, which can be used to evaluate the influence on fracture pressure of the reservoir depletion, the anisotropy, and the well inclination. The results showed that the fracture pressure will be increased for the strongly anisotropic reservoir with reservoir depletion, and the fracture pressure has a tiny difference between the various anisotropic reservoirs before reservoir depleted, but a larger difference will appear after reservoir depleted, at the later depletion period, the fracture pressure is higher for the stronger anisotropic one. When the anisotropy and the depletion are both the same, the fracture pressure for the higher deviated well is lower. The method and the results can provide a theoretical basis both for the drilling and hydraulic fracturing in depleted shale gas reservoir.

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Section: Introductionmentioning

confidence: 99%

A novel evaluation on fracture pressure in depleted shale gas reservoir

Zhao

Yuan²,

Feng

et al. 2018

Energy Science & Engineering

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“…The CTD can be defined as the maximum difference between the reservoir pressure and the minimum well bottomhole flowing pressure that the formation can withstand without sand production. Some researchers used analytical models like Mohr Coulomb and modified Lade to predict the CTD; nevertheless, the models have some assumptions such as the formation rock mechanics properties are homogenous and isotropic [10][11][12]. Kanj and Abousleiman [13] used ANNs, feed-forward backpropagation network (BPN), and generalized regression neural network to predict the CTD using data of 31 wells from the Adriatic Sea.…”

Section: Introductionmentioning

confidence: 99%

A robust fuzzy logic-based model for predicting the critical total drawdown in sand production in oil and gas wells

et al. 2021

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Sand management is essential for enhancing the production in oil and gas reservoirs. The critical total drawdown (CTD) is used as a reliable indicator of the onset of sand production; hence, its accurate prediction is very important. There are many published CTD prediction correlations in literature. However, the accuracy of most of these models is questionable. Therefore, further improvement in CTD prediction is needed for more effective and successful sand control. This article presents a robust and accurate fuzzy logic (FL) model for predicting the CTD. Literature on 23 wells of the North Adriatic Sea was used to develop the model. The used data were split into 70% training sets and 30% testing sets. Trend analysis was conducted to verify that the developed model follows the correct physical behavior trends of the input parameters. Some statistical analyses were performed to check the model’s reliability and accuracy as compared to the published correlations. The results demonstrated that the proposed FL model substantially outperforms the current published correlations and shows higher prediction accuracy. These results were verified using the highest correlation coefficient, the lowest average absolute percent relative error (AAPRE), the lowest maximum error (max. AAPRE), the lowest standard deviation (SD), and the lowest root mean square error (RMSE). Results showed that the lowest AAPRE is 8.6%, whereas the highest correlation coefficient is 0.9947. These values of AAPRE (<10%) indicate that the FL model could predicts the CTD more accurately than other published models (>20% AAPRE). Moreover, further analysis indicated the robustness of the FL model, because it follows the trends of all physical parameters affecting the CTD.

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“…In turn, the fracture gradient will be decreased [3,[9][10][11][12][13]. Thus, when using the same drilling fluid density as in the early stage of oilfield development, significant lost circulation and sticking problems will be experienced during the drilling process due to the current lower pore pressure and fracture pressure in depleted reservoirs.…”

Section: Introductionmentioning

confidence: 99%

Moderate Collapse in a Shale Cap of a Nearly Depleted Reservoir

et al. 2017

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Abstract:Reservoir depletion will cause the safe equivalent circulation density (ECD) operating window of drilling fluids to narrow, or even disappear. Previous studies have proposed a set of two specific casings at the top and bottom of the depleted reservoir, respectively, or conducted wellbore strengthening to increase fracture pressure, but these will cause a waste of time and costs, or differential pressure sticking. Aiming at resolving this problem, a novel concept and evaluation method of moderate collapse in the shale cap was developed and case calculations were performed. The results show that the degree of collapse is different for wells drilled in different types of fault regimes, and it can be controlled by optimizing the well trajectory. The collapse pressure within the shale cap was decreased due to reservoir depletion, and when a certain degree of collapse was acceptable, the collapse pressure can be even lower and a safe operating window will appear which can be beneficial to optimizing the casing program and drilling design. The research results provide a theoretical basis and new design idea for successfully and economically drilling into new untapped reservoirs in deeper horizons through depleted zones in the future.

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Critical drawdown pressure of sanding onset for offshore depleted and water cut gas reservoirs: Modeling and application

Cited by 20 publications

References 17 publications

A novel evaluation on fracture pressure in depleted shale gas reservoir

A novel evaluation on fracture pressure in depleted shale gas reservoir

A robust fuzzy logic-based model for predicting the critical total drawdown in sand production in oil and gas wells

Moderate Collapse in a Shale Cap of a Nearly Depleted Reservoir

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