Rheology and Molecular Structure of HPG Gels

Kramer, Jeffrey F.; Chu, Alice; Prud'homme, Robert Krafft

doi:10.2118/15632-ms

Cited by 20 publications

(3 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For these two purposes two main classes of rheological measurements are useful: steady shear, and dynamic oscillatory shear. Detailed descriptions of both types of measurements and their interpretation have been presented in earlier API reports [1][2][3][4] and SPE papers [5,6]. Steady shear measurements are required to obtain the data needed for fracture simulation (primarily viscosity as a function of shear rate).…”

Section: Rheological Measurementsmentioning

confidence: 99%

Characteristics of Metal-Polymer Interactions in Fracturing Fluid Systems

Kramer¹,

Prud'homme²,

Norman

et al. 1987

SPE Annual Technical Conference and Exhibition

Self Cite

View full text Add to dashboard Cite

A series of model derivatized guar polymer samples were crosslinked with three different metal-ion crosslinkers in order to better understand the complex chemical reactions involved in producing fracturing fluid gels. The gels were studied using steady shear viscosity and dynamic oscillatory measurements. Dynamic oscillatory mea~urements are often more sensitive probes of the structure of crosslinked gels than are steady shear viscosity measurements and, therefore, both viscosity and dynamic oscillatory measurements are needed to fully characterize fracturing fluids. We present examples of fluids with nearly identical viscosities but different moduli--indicating different network structures in the gel. The gels considered represent commonly used fracturing fluids such as titanat~ crosslinked hydroxypropyl guar (HPG), titanate crosslinked carboxymethyl hydroxypropyl guar (CMHPG), and aluminum crosslinked CMHPG. The effect of molar substitution of hydroxypropyl groups (MS level) on HPG crosslinked with two titanate crosslinkers is presented. The effects of MS and degree of substitution of carboxyl groups (DS level) changes for CMHPG gels crosslinked with titanates and aluminum ions are also presented.An explanation of the mechanism involved in titanate crosslinking is offered from evidence gathered from NMR and dynamic light scattering· experiments.

show abstract

Section: Rheological Measurementsmentioning

confidence: 99%

Characteristics of Metal-Polymer Interactions in Fracturing Fluid Systems

Kramer¹,

Prud'homme²,

Norman

et al. 1987

SPE Annual Technical Conference and Exhibition

Self Cite

View full text Add to dashboard Cite

show abstract

“…The performance of a fracturing fluid is governed by the chemical effects from polymer type, crosslinker, breakers, gel stabilizer, and pH control, as well as physical effects from mechanical degradation Conventional guar and guar-based polymers, such as hydroxypropyl guar (HPG) and carboxymethyl hydroxylpropyl guar (CMHPG), have been used in fracturing fluids preparation for many decades. These polysaccharides can be used as simple solutions (liner gel) or as crosslinked gel with boron, zirconium, titanium, aluminum, or chromium crosslinkers (Harris 1993;Harris and Heath 1998;Kramer et al 1986;Kramer et al 1987).…”

Section: Introductionmentioning

confidence: 99%

A Sulfur-Free and Biodegradable Gel Stabilizer for High Temperature Fracturing Applications

Prakash

Songire

2015

Day 2 Tue, September 15, 2015

View full text Add to dashboard Cite

For a successful hydraulic fracturing operation, two of the most important properties required from fracturing fluids are transport proppant into the fractured zone and minimum damage to formation and proppant pack conductivity. As the fluid is pumped downhole, it experiences thermal and shear thinning. Shear recovery and thermal stability are critical in terms of successful fracture creation and proppant placement. These fluid properties can be controlled by proper selection of crosslinker and linkable groups. Thermal stability of fluid at high temperatures can be increased by proper selection of gel stabilizers and it also reduces the amount of gelling agent to be used. Conventional gel stabilizer contains sulfur which could contribute to H 2 S gas when consumed by sulfate reducing bacteria. H 2 S gas is not only corrosive in nature but also harmful to health and thus, although it performs well, several operators seek sulfur-free stabilizers that can perform equivalent to sulfur-based compounds.This paper describes a sulfur-free gel stabilizer developed for enhancing the stability of fracturing fluid, allowing a lower concentration of gelling agent. This gel stabilizer is sulfur-free, nonhazardous, and biodegradable. It also provides better stability for fluids compared to conventional sulfur containing gel stabilizers.Further showcased is the improvement in stability of crosslinked fracturing fluid using the sulfur-free stabilizer under high temperature (HT) conditions of 280 to 320°F. Rheological tests performed using a Chandler high-pressure/high-temperature (HP/HT) viscometer with and without stabilizer are discussed. Results shows a significant change in terms of fluid stability in the presence of this new stabilizer as it provides better stability compared to conventional sulfur containing stabilizer. Also, shear sensitivity tests performed under multiple high shear rate cycles between 100-935-1700 s -1 showed excellent shear recovery after every high shear cycle by completely rehealing in less than 30 seconds.

show abstract

“…Typically, the gels are crosslinked with boron-based reagents for low temperatures (Harris 2003;Harris and Heath 1998;Kesavan and Prud'homme 1992), or multivalent titanium or zirconium transition metals (Clark and Barkat 1989;Prud'homme and Uhl 1984;Kramer et al 1986;Kramer et al 1987) for higher temperatures. These technologies have been successfully employed for many years in thousands of wells; however, as deeper, hotter reservoirs are fractured, the utility of these gels is being challenged.…”

Section: Introductionmentioning

confidence: 99%

A Crosslinkable Synthetic Polymer System for High-Temperature Hydraulic Fracturing Applications

Holtsclaw

Funkhouser

2009

All Days

View full text Add to dashboard Cite

A new hydraulic fracturing fluid has been developed that is capable of reaching fluid-service temperatures up to 450°F (232°C). This fracturing-fluid technology uses a synthetic polymer that is crosslinkable with metal ions to generate high viscosity. The synthetic polymeric fracturing gel overcomes the thermal limitations of traditional guar and derivatized guarbased fracturing fluids. Several advancements have been made in the development of this technology to maximize the efficiency of crosslinking and to give an effective breaking profile, resulting in excellent gel cleanup in the proppant pack. Research efforts have yielded a fracturing fluid with good fluid stability at high temperatures to create better proppant transport and placement in these most-demanding environments.An integral part of this fluid is a crosslinking system that can be "tuned" for crosslinking from 100 to 280°F (38 to 138°C). The crosslinking system allows the treatment schedule to be tailored to the targeted well to help minimize friction pressure. An efficient and effective oxidative-breaker package has been developed to give a controlled rheological break for the synthetic fluid, and provides good retained conductivity data. The new, high-temperature fracturing technology provides a new tool to stimulate hotter, deeper hydrocarbon resources to help maximize hydrocarbon recovery. This fracturing-fluid system has been successfully applied in south Texas at temperatures approaching 450°F (232°C).Rheological data that demonstrates fluid stability, crosslinking performance, and controlled fluid breaks are presented. Dynamic fluid-loss and regained conductivity data are also presented to illustrate fluid cleanup in proppant packs.

show abstract

Rheology and Molecular Structure of HPG Gels

Cited by 20 publications

References 1 publication

Characteristics of Metal-Polymer Interactions in Fracturing Fluid Systems

Characteristics of Metal-Polymer Interactions in Fracturing Fluid Systems

A Sulfur-Free and Biodegradable Gel Stabilizer for High Temperature Fracturing Applications

A Crosslinkable Synthetic Polymer System for High-Temperature Hydraulic Fracturing Applications

Contact Info

Product

Resources

About