Executive Summary

This class is designed to provide know-how expertise on hydraulic fracturing technology from vertical to horizontal wells and from conventional to unconventional reservoirs. Case histories of special applications will be covered such as fracturing for sand control, fracturing to bypass damaged zone, fracturing near a water zone, waterless fracturing, and fracturing for geothermal energy and CO2 storage.

References

PDF presentations will be provided. Knowledge is conveyed through practical problem solving. The following are good references:

• Chapter 5 – Rock mechanics in wellbore construction, by Hazim Abass and Justo Neda- as part of the Petroleum well construction book, 1998, edited by M.J. Economides, L.T. Watters, and S. Dunn-Norman
• Chapter 14 – Hydraulic fracturing: experimental modeling, by Hazim Abass and Christopher Lamei, of the Hydraulic fracture modeling book, 2018, edited by Yu- Shu Wu.
• Reservoir Stimulation by Michael Economides and Kenneth Nolte
• Fracturing Horizontal Wells by Mohamed Soliman and Ron
• Modern Fracturing: Enhancing Natural Gas Production, edited by Michael Economides and Tony Martin.
• Unconventional Oil and Gas Resources Exploration and Development, edited by Usman Ahmed and D. Nathan Meehan.

Executive Summary

Hydraulic fracturing was a milestone technology of the oil and gas industry that has been used since its inception in 1948. The fundamentals of this technique have not changed; however, the hardware, materials, and procedures have been augmented, optimized, and improved to maximize efficiency, minimize risk, and reduce HSE impacts. Hydraulic fracturing has been applied to increase production in low permeability (conventional reservoirs) and extremely tight permeability (unconventional reservoirs). It has also also been successful in sand control in high permeability unconsolidated sandstone reservoirs. Recently, its application has been effectively extended to cover gas and CO2 storage and geothermal energy recovery. For each application, a sequence of tasks will be discussed: defining objective, collecting data, modeling treatment design, performing diagnostic tests, real-time analysis, and assessing results. Specific fracturing applications demonstrated by case histories will be discussed and presented after breakout sessions. Finally, the course will include new innovative methods being researched and piloted related to waterless fracturing technologies.

Who Should Attend

Hydraulic fracturing becomes a critical discipline in developing oil and gas reservoirs, this class will benefit completion, production, and reservoir engineers who are involved in planning and designing well completion operations, production enhancement and stimulation, and reservoir management for gas and oil fields.

Course Outcomes

• Provide the knowledge and engineering tools to make a hydraulic fracturing design and making real-time engineering decisions with the service-company engineer. Following the treatment, post fracturing evaluation will be
• Understand that fracturing requires knowledge of geology, drilling, and completion The need to leverage core storage and chemistry and rock mechanics laboratories will be explained.
• Importance of knowing the hardware/software capabilities of a service company & teaming up to achieve objective.
• Document the experience and lessons learned, for a given field, to optimize upcoming treatments in same field.
• How to polish theory with experience- rules of thumb change. I will show you fracturing is science, art, & innovation.
• Generate ideas for you to write technical

Course Outline

Near wellbore phenomena

• Fluid flow through porous media
• Darcy and non-Darcy flow in linear and radial flow systems
• Understanding flow mechanisms through drainage and near wellbore areas
• Skin concept and formation damage assessment and analysis
• The significances of near wellbore phenomenon and its role in stimulating conventional and unconventional reservoirs
• The new near-wellbore stresses due to drilling a
• Dimensionless fracture conductivity: fracture width and length

Required data, modeling, and design

• Identify reservoir layers within, above, and below targets
• Determine physical and mechanical properties for all
• In-situ stress profile – Magnitude and direction, calculations, and measurements
• Select fracturing fluids: type, Leak-off characteristics, rheology, and
• Production increase criterion: Prat’s, Cinco-Ley & Samaniego, McGuire & Sikora, Tannich & Nierode, and Tinsley et. Al. models
• Proppant materials – types, size, conductivity, proppant flowback control, CRCP, proppant settling, micro-proppant, long-term proppant damage.
• Fracturing models and fracture geometry
• Design methods: material balance, unified fracture design, 3-D model
• Design the treatment: injection rate, proppant schedule, stages’ volumes, and procedures.

Field operations: pre-frac testing (DFIT), fracturing execution, and post-frac analysis

• Diagnostic Fracture Injection Test (DFIT)
• Fracturing pressure-time analysis: fracture and reservoir domains, SRT, Square root method, G-function, Nolte-Smith plot, ISIP, net pressure, water hammer phenomenon, surface pressure vs bottomhole pressure, and proppant curves
• Perforation: perforation friction: near-wellbore-tortuosity friction, jet perforation, and perforation erosion
• Determining HHP, actual fracture closure, friction, in-situ stresses, tensile strength, leak off mode and coefficient, and permeability.
• Other diagnostic techniques: microseismic, fiber sensors, and tiltmeter
• Realtime (on the fly) design adjustment: volume of pad, number of perforations taking fluid, modifying proppant schedule, including sand plugs, reperforation, and other potential changes of the predesign.
• Case histories

Hydraulic fracturing of unconventional reservoirs

• Fluid flow through porous media; advection, diffusion, Knudsen effect, molecular diffusion, desorption, Klingenberg effect, non-Darcy flow
• Source vs trap reservoirs
• Well-pad configuration and horizontal wells
• Well completion: Multistage fracturing; sliding sleeves vs plug & perf
• Fracturing design: sweet spot, stages spacing, clusters spacing and stimulated reservoir volume (SRV), critically stressed natural fractures and beddings shearing mechanism.
• Fracturing fluids; slick water and high viscosity friction reducers
• Proppant selection: local sand and light weight proppant
• Complex fracture modeling: Stress shadowing effect, shearing natural fractures, facture hit.

Special objectives/Designs of Hydraulic fracturing

• Fracturing for sand control (FracPack): oriented perforation, selective perforation, effective stress concept, Hollow
• Carbonate reservoir fracturing: acid fracturing, critical in-situ stress and temperature, creeping characteristics, compressive strength of asperities, acid-fracture conductivity. Proppant fracturing in carbonate reservoirs, Proppant, and acid fracturing in carbonate formations.
• Fracturing near a water zone: SettleFrac
• Fracturing for condensate banking
• Fracturing for geothermal energy
• Fracturing for fluid storage- CO2 injection
• Waterless fracturing; energetic fracturing, Pulse fracturing, Cryogenic fracturing, Exothermic chemical pulse fracturing, and laser perforation/fracturing

Discuss and provide Excel Sheets for the problems

• Determining near wellbore stresses given the 3 principal stresses to determine Breakdown, Closure pressure, reopening pressure, Tensile strength, and fracture toughness.
• Calculating production increase due to fracturing using Prat’s, Cinco-Ley & Samaniego, McGuire & Sikora, Tannich & Nierode, and Tinsley Al. models
• Using extended leak-off data during drilling to determine closure pressure (the minimum horizontal stress)
• Derive the total leak-off coefficients from the sub coefficients (spurt loss + wall-building + viscosity-dependent + compressibility-dependent)
• Estimate the maximum horizontal stress from Break-out angle observed from the log.
• Design a fracturing treatment based on material balance
• Optimize fracturing treatment from the unified fracturing design (UFD)
• Determine a fracture geometry using 2-D models (PKN and CGD)
• Plot G-function components (P, dP/dG, and G dP/dG) vs Gtime, then determine closure pressure, fluid efficiency, Pi, Kres, and
• Use step-down testing data to determine perforation and tortuosity