Evaluation of Reservoirs, Seals and Pay
Instructor: Prof. John G. Kaldi
Who Should Attend
Exploration and development geologists and reservoir engineers will benefit from the straightforward and intuitive presentation of principles governing hydrocarbon accumulations and their practical applications.
About the Course
This course demonstrates the use of basic petrographic, wireline and capillary pressure data to evaluate reservoir rock quality, pay vs. non-pay, expected fluid saturations, seal capacity (thickness of hydrocarbon column a seal can hold before it leaks), depth of the reservoir fluid contacts, and thickness of the transition zone. It also explains the use of 2-way capillary pressure analyses to approximate recovery efficiency during primary or secondary recovery. This popular course has received extremely favorable reviews when presented previously to the AAPG, IPA and PESA and as an internal training course for several major oil and gas companies.
The course will be a workshop format. Participants will delve into the details of working with data specifically in five exercises:
Introduction to evaluation of reservoirs, seals and pay.
- Basic Principles of Capillary Pressure
Discussion of uses of capillary principles in reservoir evaluation; fundamentals of capillarity: buoyancy vs. capillary pressure; wettability; contact angles; derivation of capillary pressure equations; definition of Free Water Level; description of the mercury injection apparatus.
- Exercise 1
Use of capillary pressure data to determine Sw at various heights above the Free Water Level / subsurface depths.
- Exercise 2
Scenario is that a large structure has been identified by seismic and a well is drilled at the crest. Task is to use given rock properties, structure and capillary pressure data to evaluate reservoir quality of encountered rock types, locate fluid contacts and establish saturations with depth. Also, use these data to determine seal capacity, and assess depths at which each rock type becomes pay.
- Seal Evaluation(3 Case Studies)
Review concepts of top seal, "sealing" faults, "leaking" faults.
- Demonstrate application of integrated petrophysical and geochemical techniques in evaluation of seal potential in Talang Akar Fm., offshore NW Java.
- Details of combining fault analysis, production data and reservoir geochemistry to determine degree of compartmentalisation in Pagerungan Gas Field.
- Description of seal evaluation in dynamic petroleum systems: example from East Java and Northwest Shelf , Australia
- Pore Geometry
Discuss the effects of pore geometry (size, shape, distribution of pores and pore throats) on relative permeability and capillary pressure. Relate these properties to amounts, types and rates of fluids produced. Use drainage and imbibition capillary pressure data to evaluate recovery efficiency of reservoirs on primary depletion as well as to judge the distribution of remaining fluids prior to secondary production.
- Exercise 3
Relate capillary pressure curves to pore geometry. Qualitatively estimate key MICP attributes from rock descriptions; match petrographic images to capillary pressure curves.
- Net Pay Determination
Review conventional methods of determination of net pay in a reservoir and demonstrate some improved techniques using data from core, sidewall core, cuttings, conventional plug measurements (porosity and permeability) in conjunction with capillary pressure data.
- Exercise 4
Use available reservoir data and production constraints to predict recovery efficiency; calculate recoverable reserves and evaluate reservoir management options.
- Exercise 5
Course participants 'risk' their own capital to purchase available data to calculate reserves and evaluate worth of field. Actual data (logs, maps, core, petrography, capillary pressure) from field in offshore NW Java, Indonesia are used to determine net pay.
Four days (optional 5th day where company specific examples are worked, can be included by request).
Course notes are provided. A hand calculator, coloured pencils and a ruler are required.