Measurement of Gel Cleanup in a Propped Fracture With Dynamic Fracture Conductivity Experiments

Marpaung, Fivman; Chen, Feiyan; Pongthunya, Potcharaporn; Zhu, Ding; Hill, A.D.

doi:10.2118/115653-ms

Cited by 17 publications

(15 citation statements)

References 10 publications

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“…Classification of polyelectrolytes in terms of their charge, Koets and Kosmella [36] .... 19 Figure 10 Simplified illustration of the surface and zeta potential for a charged suspension drop dispersed in high (saline water) and low (fresh water) electrolyte concentration aqueous solution [37] .. [28,43] Figure 19 Tertiary structure of proteins [28,43] Quaternary structure of proteins [28,43] Schematic picture for catalytic reaction of enzymes [28,43] Figure 25 Comparing the viscosity reduction obtained by a commercial enzyme and a hightemperature enzyme (Tayal et al) [58] Vitthal [61,62] Figure 38 Schematic of a disassembled 175 mL static fluid loss cell presented by Asadi et al [69] See page 64 (Marpaung et al) [80] . (Barati et al) [7] ... pore volume injected [93] .…”

Section: List Of Figuresmentioning

confidence: 99%

“…Marpaung et al [80] , Chen et al [81] and Zou et al [82] presented a dynamic conductivity cell similar to that of Much and Penny [79] and Penny [78] to compare the results traditionally presented using static conductivity cells with the dynamic results using wet gas to clean up the broken fracturing fluids from the proppant pack. Using the setups presented in Figure 47 and Figure 48 for fluid loss and cleanup of fluid they reported that the measured conductivity using the static conductivity cells is much higher than that measured using the dynamic cells.…”

Section: Figure 46 Flow Effects On Filter Cake Using Different Dynamimentioning

confidence: 99%

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Fracturing fluid cleanup by controlled release of enzymes from polyelectrolyte complex nanoparticles

Ghahfarokhi

Johnson

McCool

et al. 2011

J of Applied Polymer Sci

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Guar-based polymer gels are used in the oil and gas industry to viscosify fluids used in hydraulic fracturing of production wells, in order to reduce leak-off of fluids and pressure, and improve the transport of proppants. After fracturing, the gel and associated filter cake must be degraded to very low viscosities using breakers to recover the hydraulic conductivity of the well. Enzymes are widely used to achieve this but injecting high concentrations of enzyme may result in premature degradation, or failure to gel; denaturation of enzymes at alkaline pH and high temperature conditions can also limit their applicability.In this study, application of polyelectrolyte nanoparticles for entrapping, carrying, releasing and protecting enzymes for fracturing fluids was examined. The objective of this research is to develop nano-sized carriers capable of carrying the enzymes to the filter cake, delaying the release of enzyme and protecting the enzyme against pH and temperature conditions inhospitable to native enzyme.Polyethylenimine-dextran sulfate (PEI-DS) polyelectrolyte complexes (PECs) were used to entrap two enzymes commonly used in the oil industry in order to obtain delayed release and to protect the enzyme from conditions inhospitable to native enzyme. Stability and reproducibility of PEC nanoparticles was assured over time.An activity measurement method was used to measure the entrapment efficiency of enzyme using PEC nanoparticles. This method was confirmed using a concentration measurement method (SDS-PAGE). Entrapment efficiencies of pectinase and a commercial high-temperature enzyme mixture in polyelectrolyte complex nanoparticles were maximized. Degradation, as revealed by reduction in viscoelastic moduli of borate-crosslinked hydroxypropyl guar (HPG) gel by commercial enzyme loaded in polyelectrolyte nanoparticles, was delayed, compared to equivalent systems where the enzyme mixture was not entrapped. This indicates that PEC nanoparticles delay the activity of enzymes by entrapping them. It was also observed that control PEC nanoparticles decreased both viscoelastic moduli, but with a slower rate compared to the PEC nanoparticles loaded with enzyme.Preparation shear and applied shear showed no significant effect on activity of enzyme-loaded PEC nanoparticles mixed with HPG solutions. However, fast addition of chemicals during the iv preparations showed smaller particle size compared to the drop-wise method. PEC nanoparticles (PECNPs) also protected both enzymes from denaturation at elevated temperature and pH.Following preparation, enzyme-loaded PEC nanoparticles were mixed with borate crosslinked HPG and the mixture was injected through a shear loop. Pectinase-loaded nanoparticles mixed with gelled HPG showed no sensitivity to shear applied along the shear loop at 25 °C. However, EL2X-loaded PEC nanoparticles showed sensitivity to shear applied along the shear loop at 40 °C.Filter cake was formed and degraded in a fluid loss cell for borate crosslinked HPG solutions mixed with either enzymes or...

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Section: List Of Figuresmentioning

confidence: 99%

Section: Figure 46 Flow Effects On Filter Cake Using Different Dynamimentioning

confidence: 99%

Fracturing fluid cleanup by controlled release of enzymes from polyelectrolyte complex nanoparticles

Ghahfarokhi

Johnson

McCool

et al. 2011

J of Applied Polymer Sci

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“…Modifications to the API/ISO recommended testing apparatus and operational procedures have been made for specific applications (Marpaung et al, 2008). A modified API conductivity cell is 10 inches long, 3.25 inches wide, and 8 inches in height.…”

Section: Introductionmentioning

confidence: 99%

Laboratory Measurement of Hydraulic Fracture Conductivities in the Barnett Shale

Zhang

Kamenov

Zhu

et al. 2013

Day 2 Tue, February 05, 2013

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Horizontal wells intersecting multistage transverse fractures created by low viscosity fracturing fluid with low proppant loadings are the key to revitalizing production from the Mississippian Barnett shale of the Fort Worth Basin in Texas. However, direct laboratory measurements of both natural and induced fracture conductivities under realistic experimental design conditions are needed for reliable well performance analysis and fracture design optimization.In this work, a series of experiments were conducted to measure the conductivity of unpropped natural fractures, propped natural fractures, unpropped induced fractures and propped induced fractures using a modified API conductivity cell at room temperature. Fractures were induced along the natural bedding planes preserving fracture surface asperities. Natural fracture infill was kept for initial conductivity measurements and then removed for subsequent propped fracture conductivity tests. Proppants of various sizes were manually placed between rough fracture surfaces at realistic concentrations. The two sides of the rough fractures were either aligned or displaced with a 0.1 inch offset. After pressure testing on the system integrity, nitrogen was flown through the proppant pack or unpropped fracture to measure the conductivity.Results from the 88 experiments show that the conductivity of hydraulic fractures in shale can be accurately measured in a laboratory with appropriate experimental procedures and good control on experimental errors. It is proved that unpropped induced fractures can provide a conductive path after removal of free particles and debris due to the brittleness and lamination of shale. Moreover, poorly cemented natural fractures and unpropped displaced fractures can create conductivities up to 0.5 md-ft at formation closure stress, which is one order of magnitude higher than the conductivity provided by cemented natural fractures and unpropped aligned fractures. This study shows that propped fracture conductivity increases with larger proppant size and higher proppant concentration. Longer term fracture conductivity measurements also show that within 20 hours the fracture conductivity could be reduced by as much as 20%.

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“…Attempts have been made to modify existing API fracture conductivity test cell [Marpaung et al, 2008;Zhang et al, 2013],…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation of Propped Fracture Network Conductivity in Naturally Fractured Shale Reservoirs

Wen

Jin

Shah

et al. 2013

SPE Annual Technical Conference and Exhibition

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Microseismic mapping of horizontal well multi-stage fracturing of shale reservoirs has proven that the geometry of fracture is not planar as assumed/observed in conventional reservoirs, but rather a complex connected fracture network. The network is assumed to be constructed by three basic fracture types (Horizontal and vertical fractures parallel to, and vertical fracture perpendicular to flow direction -Type I, Type II, and Type III fractures respectively). A new fracture test cell is designed and constructed for investigating propped fracture network conductivity similar to the API standard fracture conductivity test cell that is presently used by the oil and gas industry.In the experimental investigation, nitrogen gas is selected as fluid for safety reasons and also its physical properties are similar to methane gas. Marble is selected as a substitute for shale in constructing the fracture network in laboratory tests because of its similarity with shale in both permeability and wettability. Shale samples cannot be easily obtained and shale slices are difficult to prepare. A lightweight (1.5 g/cc), small size proppant (40-70 mesh) is selected because of its wide use in shale gas development and ease of transportation in the fracture network. The fracture widths of the three fracture types are assumed to be equal in the same propped fracture network. Twenty-two groups of successful experiments are selected to calibrate equipment, investigate the influence of actual fracture width, number of each fracture type, and closure stress on propped fracture network conductivity by selecting various combinations of fracture patterns, confining pressures, and proppant concentrations. Darcy's law is employed in calculating propped fracture network conductivity by introducing concepts of equivalent fracture width, equivalent proppant concentration, and equivalent fracture conductivity.The experimental results showed that the modified API fracture conductivity test cell was calibrated well against the API standard cell. The deviations were in the range of 4.4% to 8.1%. The value of equivalent propped fracture conductivity measured by the modified API fracture conductivity test cell is acceptable. It was observed that the propped fracture network conductivity (1) decreases with increasing closure stress, and reached a limiting value when closure stress exceeded a critical value and (2) increases with increasing actual fracture width (proppant concentration). Furthermore, increasing number of Type-I and II fractures will increase propped fracture network conductivity, and Type-II fracture is more dominant than Type-I fracture, but Type-III fracture does not affect propped fracture network conductivity as significant as other two fracture types do.

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Measurement of Gel Cleanup in a Propped Fracture With Dynamic Fracture Conductivity Experiments

Cited by 17 publications

References 10 publications

Fracturing fluid cleanup by controlled release of enzymes from polyelectrolyte complex nanoparticles

Fracturing fluid cleanup by controlled release of enzymes from polyelectrolyte complex nanoparticles

Laboratory Measurement of Hydraulic Fracture Conductivities in the Barnett Shale

Experimental Investigation of Propped Fracture Network Conductivity in Naturally Fractured Shale Reservoirs

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