Pits versus Tanks: Risks and Mitigation Options for On-Site Storage of Wastewater from Shale Gas and Tight Oil Development

2015 ◽  
Author(s):  
Yusuke Kuwayama ◽  
Skyler Shea Roeshot ◽  
Alan Krupnick ◽  
Nathan D. Richardson
Keyword(s):  
Shale Gas ◽  
Tight Oil ◽  
Mitigation Options ◽  
Oil Development

Risks and mitigation options for on-site storage of wastewater from shale gas and tight oil development

Energy Policy ◽  
2017 ◽  
Vol 101 ◽  
pp. 582-593 ◽  
Author(s):  
Yusuke Kuwayama ◽  
Skyler Roeshot ◽  
Alan Krupnick ◽  
Nathan Richardson ◽  
Jan Mares
Keyword(s):  
Shale Gas ◽  
Tight Oil ◽  
Mitigation Options ◽  
Oil Development

Experimental Investigation on Enhanced-Oil-Recovery Mechanisms of Using Supercritical Carbon Dioxide as Prefracturing Energized Fluid in Tight Oil Reservoir

SPE Journal ◽  
2021 ◽  
pp. 1-16
Author(s):  
Lei Li ◽  
Zheng Chen ◽  
Yu-Liang Su ◽  
Li-Yao Fan ◽  
Mei-Rong Tang ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Water Resources ◽  
Supercritical Carbon Dioxide ◽  
Hydraulic Fracturing ◽  
Clay Minerals ◽  
Oil Production ◽  
Tight Oil ◽  
Injection Mode ◽  
Oil Development ◽  
Live Oil

Summary Fracturing is the necessary means of tight oil development, and the most common fracturing fluid is slickwater. However, the Loess Plateau of the Ordos Basin in China is seriously short of water resources. Therefore, the tight oil development in this area by hydraulic fracturing is extremely costly and environmentally unfriendly. In this paper, a new method using supercritical carbon dioxide (CO2) (ScCO2) as the prefracturing energized fluid is applied in hydraulic fracturing. This method can give full play to the dual advantages of ScCO2 characteristics and mixed-water fracturing technology while saving water resources at the same time. On the other hand, this method can reduce reservoir damage, change rock microstructure, and significantly increase oil production, which is a development method with broad application potential. In this work, the main mechanism, the system-energy enhancement, and flowback efficiency of ScCO2 as the prefracturing energized fluid were investigated. First, the microscopic mechanism of ScCO2 was studied, and the effects of ScCO2 on pores and rock minerals were analyzed by nuclear-magnetic-resonance (NMR) test, X-ray-diffraction (XRD) analysis, and scanning-electron-microscope (SEM) experiments. Second, the high-pressurechamber-reaction experiment was conducted to study the interaction mechanism between ScCO2 and live oil under formation conditions, and quantitively describe the change of high-pressure physical properties of live oil after ScCO2 injection. Then, the numerical-simulation method was applied to analyze the distribution and existence state of ScCO2, as well as the changes of live-oil density, viscosity, and composition in different stages during the full-cycle fracturing process. Finally, four injection modes of ScCO2-injection core-laboratory experiments were designed to compare the performance of ScCO2 and slickwater in terms of energy enhancement and flowback efficiency, then optimize the optimal CO2-injection mode and the optimal injection amount of CO2slug. The results show that ScCO2 can dissolve calcite and clay minerals (illite and chlorite) to generate pores with sizes in the range of 0.1 to 10 µm, which is the main reason for the porosity and permeability increases. Besides, the generated secondary clay minerals and dispersion of previously cemented rock particles will block the pores. ScCO2 injection increases the saturation pressure, expansion coefficient, volume coefficient, density, and compressibility of crude oil, which are the main mechanisms of energy increase and oil-production enhancement. After analyzing the four different injection-mode tests, the optimal one is to first inject CO2 and then inject slickwater. The CO2 slug has the optimal value, which is 0.5 pore volume (PV) in this paper. In this paper, the main mechanisms of using ScCO2 as the prefracturing energized fluid are illuminated. Experimental studies have proved the pressure increase, production enhancement, and flowback potential of CO2 prefracturing. The application of this method is of great significance to the protection of water resources and the improvement of the fracturing effect.

Development Prospect of Unconventional Oil and Gas Resources

2013 ◽  
Vol 421 ◽  
pp. 917-921
Author(s):  
De Xun Liu ◽  
Shu Heng Tang ◽  
Hong Yan Wang ◽  
Qun Zhao
Keyword(s):  
Shale Gas ◽  
Global Economy ◽  
Large Scale ◽  
Oil And Gas ◽  
Small Scale ◽  
Tight Oil ◽  
Environmental Capacity ◽  
Unconventional Oil ◽  
Oil And Gas Resources ◽  
Unconventional Oil And Gas

Affected by the constant development of global economy and the imbalance in distribution of conventional oil and gas, oil and gas resources can no longer meet the demand in many countries. Development of unconventional oil and gas has begun to take shape. Shale gas and tight oil become the focus of global attention. Unconventional oil and gas resources are relatively abundant in China. Preliminary results have been achieved in the development of shale gas. Tight oil has been developed in small scale, and the main technologies are maturing gradually. Yet we face many challenges. Low in work degree, resources remain uncertain. Environmental capacity is limited, and large scale batch jobs will confront with difficulties.

Modeling of Matrix/Fracture Transfer with Nonuniform-Block Distributions in Low-Permeability Fractured Reservoirs

SPE Journal ◽  
2019 ◽  
Vol 24 (06) ◽  
pp. 2653-2670 ◽  
Author(s):  
Didier–Yu Ding
Keyword(s):  
Shale Gas ◽  
Shape Factor ◽  
Oil Reservoirs ◽  
Dual Porosity ◽  
Tight Oil ◽  
Fracture Networks ◽  
Matrix Block ◽  
Matrix Fracture ◽  
Discrete Fracture ◽  
The Matrix

Summary Unconventional shale–gas and tight oil reservoirs are commonly naturally fractured, and developing these kinds of reservoirs requires stimulation by means of hydraulic fracturing to create conductive fluid–flow paths through open–fracture networks for practical exploitation. The presence of the multiscale–fracture network, including hydraulic fractures, stimulated and nonstimulated natural fractures, and microfractures, increases the complexity of the reservoir simulation. The matrix–block sizes are not uniform and can vary in a very wide range, from several tens of centimeters to meters. In such a reservoir, the matrix provides most of the pore volume for storage but makes only a small contribution to the global flow; the fracture supplies the flow, but with negligible contributions to reservoir porosity. The hydrocarbon is mainly produced from matrix/fracture interaction. So, it is essential to accurately model the matrix/fracture transfers with a reservoir simulator. For the fluid–flow simulation in shale–gas and tight oil reservoirs, dual–porosity models are widely used. In a commonly used dual–porosity–reservoir simulator, fractures are homogenized from a discrete–fracture network, and a shape factor based on the homogenized–matrix–block size is applied to model the matrix/fracture transfer. Even for the embedded discrete–fracture model (EDFM), the matrix/fracture interaction is also commonly modeled using the dual–porosity concept with a constant shape factor (or matrix/fracture transmissibility). However, in real cases, the discrete–fracture networks are very complex and nonuniformly distributed. It is difficult to determine an equivalent shape factor to compute matrix/fracture transfer in a multiple–block system. So, a dual–porosity approach might not be accurate for the simulation of shale-gas and tight oil reservoirs because of the presence of complex multiscale–fracture networks. In this paper, we study the multiple–interacting–continua (MINC) method for flow modeling in fractured reservoirs. MINC is commonly considered as an improvement of the dual–porosity model. However, a standard MINC approach, using transmissibilities derived from the MINC proximity function, cannot always correctly handle the matrix/fracture transfers when the matrix–block sizes are not uniformly distributed. To overcome this insufficiency, some new approaches for the MINC subdivision and the transmissibility computations are presented in this paper. Several examples are presented to show that using the new approaches significantly improves the dual–porosity model and the standard MINC method for nonuniform–block–size distributions.

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