This course is designed for engineers concerned with detailed design and analysis of hydraulic pressure treatments. A good understanding and familiarity with fracturing fundamentals, materials selection (fluids/proppant), and applications is required. The emphasis is placed on analyzing fracturing pressure data during pumping and the subsequent pressure decline, and the use of this data to recognize common problems. Many real-field situations will be examined in the practical sessions (which comprise over half the course). The “workshop” format of this course uses examples of actual problem wells from many different environments. The examples are viewed using Stimplan™/E-Stimplan™ and 3-D fracture modeling. The course includes actual solved case histories ranging from Australian tight gas wells, to Gulf of Mexico frac packs, to North Sea tip screenout (TSO) treatments. The practical applications during the week are built on complete and detailed real-field problems. This format allows the participants to gain a deeper understanding of the field in a short time. Participants are also encouraged to bring data sets from their own fractured (or fracture candidate) wells for use in the practical sessions.

When the term DFIT was coined, it was an acronym for “Diagnostic Fracture Injection Test”. That is now somewhat misleading, as a common DFIT today consists of pumping a small volume of fluid (nearly always water) into the formation at low (but above frac) rates. Given this procedure, the test does not measure any fracture properties (i.e., height, efficiency, etc.). Rather, DFIT should be an acronym for “Diagnostic Formation Injection Test”. The goal of the test is to measure formation parameters of closure pressure, reservoir pressure, formation permeability, and the existence of stress-sensitive permeability (i.e., natural fracture permeability).

This 2-Day seminar will concentrate on the design and analysis of the DFIT injection in a workshop fashion, where every discussion is built around actual case histories. Participants are also invited to bring sharable examples. Data examples include log sections identifying the target, any general formation information (such as expected porosity and permeability), and digital injection/decline data. Well location and post-frac production would not be included in participant examples.

The course emphasizes the multi-disciplinary nature of Acid Fracturing, covering the differences between propped fracturing and acid fracturing integrated with acid chemistry, etched conductivity, acid reaction kinetics, wormholing fluid loss, acidizing materials, and treatment execution quality control. The concepts taught in the course are reinforced by designing treatments for several case histories using both spreadsheets and the fully gridded acid fracturing software included in StimPlan.

Prerequisite – The attendees of this school should have attended NSI’s 5-day Propped Hydraulic Fracture School or an equivalent school. This Acid Fracturing School assumes that the attendee is well-versed in the principles of rock stresses, fracture geometry modeling, evaluating fracture performance, and treatment scheduling of hydraulic fracturing.

Basics of Fracturing

A brief review of the fundamentals of fracturing will be presented. The contrast between tensile rock failure and shear rock failure will be discussed. A short summary of properties that influence geometry, pressure response, gravel placement, and final proppant concentrations will be included. There will be a detailed discussion of defined terms that are used in both hard rock and soft rock fracturing; these terms have specific meaning in the context of fracpack environments and are different within the hard rock fracturing community. This will also include the issues with sand control hardware and descriptors of events during installation.

Design Workflow

A workflow will be presented that should aid the participant in being able to generate a design and procedure for executing fracpack completions. This includes the data that should be collected during the well construction process, modeling data that can be generated from those measurements and some laboratory data that is required. The discussion will include proppant and fluid selection, selection and placement of hardware in the borehole, and sensitivity studies on various parameters.

Designing Frac Packs

Class problems are used to reinforce the workflow, assure understanding of specific topics, and generate procedural elements to address known and probable issues.

Planning & Execution

After covering a high-level summary of the entire installation scenario, participants will begin to formulate process stages and procedural elements to make the measurements necessary to calibrate the model, redesign the schedule, and monitor the installation. Discussion around measurement parameters that are meaningful and indicators of successful installation will be included.

Evaluating Execution

How to utilize the data collected to identify possible issues will be discussed. Real-life examples of installation execution will be scrutinized by the participants. These reviews will be used to help incorporate appropriate procedural elements to be able to address topics that are of concern.

Score Card Development

When managing complex processes, it is important to understand what to measure, when to measure, how to use the data, and formulate KPIs to provide a meaningful indication of progress, success, and timely feedback to adjust current operations to improve the processes involved. The participants will walk through a review of the planning, design, execution, and evaluation process, putting key indicators that the progress is addressing the appropriate goals and normalized in a score card.

This course is to make attendees aware of the importance of geomechanics in every facet of field development, from exploration to abandonment. Sound theoretical bases will first be established, with regular reference to pertinent applications. Practical exercises will be solved in order to illustrate and clarify the concepts. Key course components include:

• Historical developments of Rock Mechanics
• Importance of Rock Mechanics in the petroleum industry
• Engineering rock classification and index properties
• 2D and 3D stress and strain analyses
• Friction and discontinuities
• Stereographic projections
• Elasticity
• Static and dynamic rock properties
• Failure criteria
• Laboratory testing
• In-situ stresses and their determination

This course is to make attendees aware of the major differences between a “vertical” and a “far-reaching” borehole; i.e. two-dimensional vs. three-dimensional analyses. The various potential instabilities will be discussed in detail. Rigorous theoretical equations will be derived from fundamental concepts and illustrated via practical examples. Perforation instabilities will also be covered.

NSI Technologies can provide any of its existing courses to a client’s team of in-house engineers. Course content can also be tailored to include particular topics of concentration and client-specific case studies. In-house courses usually last one week, but courses from one day to two weeks in duration can be provided. NSI can also design a complete training syllabus comprising a series of training courses, starting with introductory level through to advanced level. These can be customized for clients to enhance their in-house team’s technical expertise over a period of 6 to 18 months.