Hydraulic fracturing is usually needed to realize the economic development of shale gas reservoir due to its tight matrix [1], [2], [3].Gas wells often experience well …

ABSTRACT:. To investigate the impact of surface roughness on proppant crushing and its effect on fracture conductivity in Shale Gas Formations, laboratory conductivity experiments were performed on standard core columns drilled along hydraulic fractures. The morphology of proppants within the fractures was observed using …

Compared to hydraulic fracturing, SC-CO 2 displays unique physical properties. Its low viscosity facilitates the creation of complex fractures in shale reservoirs [23], [24].Additionally, CO 2 has better adsorption in shale than CH 4, which effectively lowers the fracture initiation stress, forms intricate fracture networks, and enhances …

Unconventional natural gas resources, including shale gas and coalbed methane (CBM), are becoming increasingly important worldwide. In 2016, 56% and 9% of the unconventional gas production in the world were shale gas and CBM, respectively (Cedigaz, 2017).For shale gas, about 16.76 trillion cubic feet (Tcf) or about 475 billion …

Summary. Heterogeneously distributed micromineral aggregates (MMAs) are common in shale reservoirs. The interfaces between these MMAs and the surrounding minerals significantly affect fracture propagation behaviors during shale oil exploitation. In this paper, the concept of interfacial transition zone (ITZ) between the MMAs (e.g., …

fractures during hydraulic sand fracturing; (2) when the conning pressure increases, the number of shale specimens before and after rupture is the largest, but the total number …

Summary. This paper presents a discussion of fractured-horizontal-well performance in millidarcy permeability (conventional) and micro- to nanodarcy permeability (unconventional) reservoirs. It provides interpretations of the reasons to fracture horizontal wells in both types of formations. The objective of the paper is to highlight the special …

Abstract. Slick-water, which be used as the main fracturing fluid in shale gas fracturing, has poor sand-carrying capacity and severe fluid loss capacity. So, the sand …

Using x-ray microtomography at the ALS, researchers identified and characterized the microscale factors affecting fluid flow through shale fractures propped open with sand or ceramic spheres. A better understanding of propped fractures can lead to safer and more efficient recovery of hard-to-reach oil and gas resources. Read more »

The Marcellus shale play is the largest shale gas reservoir and gas producer in the United States. The annual gas production in the Marcellus shale gas play …

Marine Paleozoic shale gas resources in the Sichuan Basin are abundant [1], [2], where reservoirs are mainly stimulated by using bridge-plug staged fracturing of horizontal wells [3], [4], in the form of casing injection.Marine Paleozoic strata experienced multi-stage and strong orogenic movements, leading to large and complex in-situ stress.

Abstract. The results of hydraulic fracture modeling in a hydrocarbon reservoir consisting of laminated sand and shale sequences are presented. Work previously published by other authors addresses hydraulic fracture growth characteristics in layered intervals, but little published information is available for growth in thin-bedded …

Ozkan, E., Raghavan, R.: Modeling of fluid transfer from shale matrix to fracture network. Paper SPE 134830 presented at the SPE Annual Technical Conference and Exhibition, Florence, Italy, 19–22 Sepetember 2010. doi: 10.2118/134830-MS

When shale plates are used, the critical flow rate that prevents the proppant flowback was found to be 5.5 × 10 –4 –1.6 × 10 –3 m/s for the 30/50 mesh sands (around 55–340 m 3 /d for a typical horizontal well), and the retained permeability decreased from 23.33 to 22.86% due to an increase of closure stress from 21 to 30 MPa. Results ...

The mass ratio of water, fine sand and No. 52.5 cement was 1.5:1:2. The specimen is a standard square with an edge of 300 mm. After 28 days of curing, the uniaxial compressive strength and Young's modulus of the specimen were 58 MPa and 16 GPa, respectively. ... Investigating the Propagation of Multiple Hydraulic Fractures in Shale …

There is a growing interest in efficiently extracting hydrocarbon from the deep shale reserves. The stress in the underground formation can be defined by three principal stress vectors: σ V (Vertical stress), σ H (Maximum horizontal stress), and σ h (Minimum horizontal stress). Hubbert and Willis discovered that when the hydraulic …

Shale gas wells have been fractured with slurries carrying low proppant concentration during early stages (0.25–1.0 lb of proppant per gallon of fluid, or ppga).The proppant concentration during the "tail-in" stage is higher, usually from about 2 to 3.5 ppga (Palisch et al., 2008).Small size proppants such as 100 mesh and 40/70 mesh are …

Laboratory experiments were conducted to investigate the effect of proppant concentration on fracture conductivity for Eagle Ford Shale samples. The test samples were obtained from outcrops at Antonio Creek, Terrell County, Texas. ... Terrell County, Texas. A 100-mesh sand was utilized, as it is representative of the industry practice in …

Oil shale differs from conventional oil and gas reservoirs as the kerogen of oil shale should first be dry distilled before it can be decomposed to produce the oil and gas contained within it [6].Oil shale development modes can be classified into ground dry distillation and underground in-situ conversion technology [7].Owing to increased …

Shale rock fragments can even be reworked and redeposited and mixed with sands into a shaly sand with true shale fragments dispersed into the matrix. Furthermore, clay minerals such as diagenetic illite or illitization of smectite, can form interior clay particles in the pore system of the clastic rocks.

However, due to the impact of the mechanical properties of bedding planes, the propagation of hydraulic fractures in shale-sand reservoirs can be quite complex (Gu et al., 2008). Therefore ...

Extend your reach—and your oil and gas production—in tight sand and shales. Whether you need to stimulate production from a few vertical wells or a full field of horizontal multistage wells, maximize your oil and gas production potential with efficient, high-conductivity fractures that extend deep into the reservoir—but avoid detrimental frac …

Meanwhile, the TPAs within the segment are primarily distributed near the perforation cluster apertures which initiated complex fractures. Key words: shale; temporary plugging and diversion fracturing; multi-cluster sand jetting perforation; distribution of tem- porary plugging agent; fracture propagation law Introduction Shale …

The experimental study showed up to 88% reduction in fracture conductivity after water flow under 4000 psi closure stress. The conductivity loss was due to severe proppant embedment as the shale fracture face was softened after its exposure to water. Direct measurement of embedment depths indicated that for fractures that were …

Sensitivity analyses investigate the impact of quartz sand degree of crushing, compressive strength, particle size, particle combination ratio, and closure pressure on fracture conductivity, demonstrating the reliability of quartz sand as a substitute for ceramic proppant in deep shale applications.

Water-based fracturing fluid has recently garnered increasing attention as an alternative oilfield working fluid for propagating reservoir fractures and transporting …

Since shale has extremely low permeability (10 −10 –10 −4 mD), hydraulic fracturing is the primary stimulation technique to exploit such reservoirs, and the performance of shale oil wells is heavily dependent on the scale of the fracture network (stimulation reservoir volume) and the effectiveness of the fractures [2], [3].

Vertical orthogonal CT slices (XZ100, YZ100) (Fig. 14 b) demonstrate that the fracture mode of shale is related to the loading conditions of the shale itself. The mode of the fractures in the three shale samples are diverse with few conjugate and simple shear fractures. Clay-rich shale (S1,S2) and siliceous shale (S3) depict fractures that are ...

The limited-entry technology was a key technology in the multistage fracturing of shale oil and gas horizontal wells to help distribute fracture fluid among multiple …

Coupled fluid flow/geomechanics. In our current work, we have assumed minimal temperature variation during deep shale development, thereby neglecting its influence on stress and focusing solely on ...