Low Extrusion Pressure Polymer Gel for Water Shutoff in Narrow Aperture Fractures in Tight and Shale Gas and Oil Reservoirs

2012 ◽  
Author(s):  
Kush Gakhar ◽  
Robert H. Lane
Keyword(s):  
Shale Gas ◽  
Oil Reservoirs ◽  
Extrusion Pressure ◽  
Polymer Gel ◽  
Water Shutoff

scholarly journals Method for Visualizing Fractures Induced by Laboratory-Based Hydraulic Fracturing and Its Application to Shale Samples

Energies ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1976 ◽  
Author(s):  
Youqing Chen ◽  
Makoto Naoi ◽  
Yuto Tomonaga ◽  
Takashi Akai ◽  
Hiroyuki Tanaka ◽  
...  
Keyword(s):  
Hydraulic Fracturing ◽  
Ultraviolet Light ◽  
Shale Gas ◽  
Laboratory Method ◽  
Oil Reservoirs ◽  
Thermosetting Resin ◽  
Fluorescent Substance ◽  
New Approach ◽  
Induced Fractures ◽  
Observation Method

A better understanding of the process of stimulation by hydraulic fracturing in shale gas and oil reservoirs is necessary for improving resource productivity. However, direct observation of hydraulically stimulated regions including induced fractures has been difficult. In the present study, we develop a new approach for directly visualizing regions of shale specimens impregnated by fluid during hydraulic fracturing. The proposed laboratory method uses a thermosetting resin mixed with a fluorescent substance as a fracturing fluid. After fracturing, the resin is fixed within the specimens by heating, and the cut sections are then observed under ultraviolet light. Based on brightness, we can then distinguish induced fractures and their surrounding regions impregnated by the fluid from other regions not reached by the fluid. Polarization microscope observation clearly reveals the detailed structures of tortuous or branched fractures on the micron scale and interactions between fractures and constituent minerals. The proposed experimental and observation method is useful for understanding the process of stimulation by hydraulic fracturing and its relationship with microscopic rock characteristics, which is important for fracturing design optimization in shale gas and oil resource development.

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.

Seismo-electric Conversion in Sandstones and Shales using 2 Different Experimental Approaches, Modelling and Theory

2020 ◽  
Author(s):  
Paul Glover ◽  
Rong Peng ◽  
Piroska Lorinczi ◽  
Bangrang Di
Keyword(s):  
Zeta Potential ◽  
Numerical Modelling ◽  
Clay Minerals ◽  
Shale Gas ◽  
Streaming Potential ◽  
Oil Reservoirs ◽  
Low Permeability ◽  
Experimental Measurements ◽  
Frequency Range ◽  
Potential Coefficient

<p>The development of seismo-electric (SE) exploration techniques relies significantly upon being able to understand and quantify the strength of frequency-dependent SE conversion. However, there have been very few SE measurements or modelling carried out. In this paper we present two experimental methods for making such measurements, and examine how the strength of SE conversion depends on frequency, porosity, permeability, and why it is unusual in shales. The first is based on an electromagnetic shaker and can be used in the 1 Hz to 2 kHz frequency range. The second is a piezo-electric water-bath apparatus which can be used in the 1kHz to 500 kHz frequency range.</p><p>The first apparatus has been tested on samples of Berea sandstone. Both the in-phase and in-quadrature components of the streaming potential coefficient have been measured with an uncertainty of better than ±4%. The experimental measurements show the critical frequency at which the quadrature component is maximal, and the frequency of this component is shown to agree very well with both permeability and grain size. The experimental measurements have been modelled using several different methods.</p><p>The second apparatus was used to measure SE coupling as a function of porosity and permeability, interpreting the results using a micro-capillary model and current theory. We found a general agreement between the theoretical curves and the test data, indicating that SE conversion is enhanced by increases in porosity over a range of different frequencies. However, SE conversion has a complex relationship with rock permeability, which changes with frequency, and which is more sensitive to changes in the petrophysical properties of low-permeability samples. This observation suggests that seismic conversion may have advantages in characterizing low permeability reservoirs such as tight gas and tight oil reservoirs as well as shale gas reservoirs.</p><p>We have also carried out SE measurements on Sichuan Basin shales (permeability 1.47 – 107 nD), together with some comparative measurements on sandstones (0.2 – 60 mD). Experimental results show that SE conversion in shales is comparable to that exhibited by sandstones, and is approximately independent of frequency in the seismic frequency range (<1 kHz). Anisotropy which arises from bedding in the shales results in anisotropy in the streaming potential coefficient. Numerical modelling has been used to examine the effects of varying zeta potential, porosity, tortuosity, dimensionless number and permeability. It was found that SE conversion is highly sensitive to changes in porosity, tortuosity and zeta potential in shales. Numerical modelling suggests that the cause of the SE conversion in shales is enhanced zeta potentials caused by clay minerals, which are highly frequency dependent. This is supported by a comparison of our experimental data with numerical modelling as a function of clay mineral composition from XRD measurements. Consequently, the sensitivity of SE coupling to the clay minerals suggests that SE exploration may have potential for the characterization of clay minerals in shale gas and shale oil reservoirs.</p>

scholarly journals Performance Evaluation of Polymer Gel Composite Resin Coated Sand Water Shutoff System

2021 ◽  
Vol 859 (1) ◽  
pp. 012016
Author(s):  
Kai Wang ◽  
Mingzhong Li ◽  
Taifei Bi ◽  
Xuesheng Wang ◽  
Chunsheng Pu ◽  
...  
Keyword(s):  
Performance Evaluation ◽  
Composite Resin ◽  
Polymer Gel ◽  
Water Shutoff ◽  
Coated Sand

Water Shutoff in the North Sea: Testing a New Polymer Gel System in the Heather Field, UKCS Block 2/5

1996 ◽  
Vol 11 (02) ◽  
pp. 108-112 ◽  
Author(s):  
D.D. Whitney ◽  
D.W. Montgomery ◽  
R.D. Hutchins
Keyword(s):  
North Sea ◽  
Polymer Gel ◽  
The North ◽  
Water Shutoff ◽  
The North Sea ◽  
Gel System
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