## Waterflood and Field Study Workshop

### Course overview

This course is designed to cover the fundamentals involved in evaluating the waterflood potential for a reservoir. Concurrent with the discussion of fundamentals, data for an example reservoir is presented to the class. The field study is analyzed to determine the waterflood potential as the course progresses and additional knowledge is acquired by the student. By the end of the evaluation process each participant understands the interplay and integration of reservoir parameters involved for a proper study.

A structure map, well files, production and pressure histories, fluid analysis, well tests and rock properties are given out at the beginning of the class along with course notes. All of these data are commonly available at the field level. Each task requires retrieval of information from the data set to study, draw conclusions and include into the evaluation puzzle. The instructor of the course explains in detail during these work periods.

Tasks cover a variety of interests from, reserves estimates, reservoir extent and continuity, future oil and water producing rates to develop a picture of the subsurface. On the other hand, project implementation often requires surface facility additions such as water injection and pump pressure requirements, affects of plugging which are included in the task list.

Discussions by the lecturer develop the fundamentals which must form the basis for the analysis, along with example problems to show the utility of the concept. Each participant will then apply these ideas to fulfill assigned tasks in the reservoir analysis example.

Go/No Go decision points are included along the way as knowledge is gained through the analysis. Reserves potential and oil and water rates are forecasted but of equal importance proposed well locations, new drills and workovers, expected additional processing facilities, water injection rates and pressures are forecast to complete the plan.

All calculations can be completed with a calculator even though a spreadsheet helps.

The waterflooding course can be divided into either a 3 or 5 day short course. The three day course discusses the fundamentals of reservoir and performance analysis while the 5 day course includes a case history study of an actual reservoir evaluation using data generally located in well files and production records

### Reservoir workshop

The workshop applies commonly available oil field data to describe and forecast future performance from an actual oil field example.

The analysis process is designed around twenty some odd tasks which must be completed in order to analyze reservoir behavior and in the end recommend methods for increasing recovery.

Each task covers a different aspect of the total reservoir evaluation process. A discussion of each principle is developed and discussed before an analysis of a particular task is attempted by the participant.

#### Available information & field data

- Log surveys adn completion logs
- Maps - structure, isopach maps and cross sections
- Oil, gas and water production records
- Pressure records and production test data
- Static bottom hole pressures
- Productivity index and open flow potential test data

- Rock properties
- Log analyses
- Special core analysis

- Reservoir fluid properties

### The course is designed for

Reservoir engineers and professionals who work in collaboration with reservoir engineers, including well engineers, facilities engineers, process engineers, petrophysicists and geoscientists.

### Course outline

**Task 1** – Study structure map and well histories to analyze reservoir performance**Task 2** – Study well production histories to analyze reservoir performance

**Task 3** – Plot BHP’s provided to determine well connectivity

**Task 4** – Estimate initial pressure (Y0) and reservoir pressure at (Y8)

**Task 5** – Calculate original oil (OOIP) and gas in place (OGIP)

**Task 6** – Apply exponential decline principles to determine primary reserves

**Task 7** – Study the structure map and production records to determine if you think a secondary gas cap was formed

**Task 8** - Apply the results of a material balance study to determine OOIP and drive indices for the AA reservoir.

**Task 9** – Calculate maximum recoverable with the difference in saturations equation

**Task 10** - Apply API equations to calculate reserves for water drive & solution gas cases

**Task 11** – Estimate displacement efficiency if a water flood were to be installed. We will look at this again after the Stiles calculation

**Task 12** - Calculate primary and secondary reserves

**Task 13** – What has been the effect of water influx on performance?

**Task 14** - Do you believe a water flood is feasible?

**Task 15** – Calculate reasonable producing life

**Task 16** – Apply material balance equation to calculate reservoir voidage.

**Task 17** – Calculate water injection requirements.

**Task 18** – Estimate production response to water injection. Klins and Clark.

**Task 19** – Couple the core analysis record with the Stiles calculations to predict future performance.

**Task 20** – Calculate hydraulic fracture pressure.

**Task 21** - Apply Darcy equation to calculate water injection rate.

**Task 22** – Estimate the effect of formation damage on the water injection rate.

**Task 23** – Formulate a development plan.

#### Reservoir rocks and framework

- Log profiles and depositional environments
- Rock material
- Correlating sand members, reservoir heterogeneity, structure maps, cross sections
- Problems - questions and correlation problem

#### Reservoir volumes and rock properties

- Porosity and permeability
- Isopach maps & reservoir volumes
- Fluid distribution and capillary pressure
- Shapes of the capillary pressure curve
- Porosity – permeability relations – “j” function
- Mobility ratio and fractional flow equation
- Problems & questions

#### Reservoir fluids

- Reservoir fluids
- Separation systems
- Questions

#### Water influx

- Water encroachment models
- The Fetkovich method of analysis
- Applying material balance to determine water influx effects

#### Displacement concepts

- Frontal advance and Buckley Leverett
- The Stiles method
- Questions

#### Oil reservoirs

- Saturated and undersaturated reservoirs
- Reservoir depletion mechanisms
- Recovery factors and API recovery equations
- Material balance equation – calculating Original Oil In Place
- Material balance equation – calculating water influx
- Material balance equation – calculating drive indices
- Problems & questions

#### Inflow performance

- Above the bubble point – PI, Vogel, Fetkovich methods
- Effect of formation damage – Camacho and Raghavan
- Below the bubble point – Fetkovich
- Future performance predictions – Fetkovich and Klins and Clark5
- Problems

#### Monitoring two phase flow production

- WOR and GOR plots
- Basic performance analysis
- Construction of relative permeability curves from performance data
- Estimating future performance with multiple plots
- Well diagnostic plots
- Problems

#### Waterflooding process

- Water flooding vs. Gas injection
- Sweep efficiency
- Observing flood progression through maps
- Design considerations - sources of injection water, surface facilities
- Injection and producing well design and operation
- Data collection and analyses
- Water flood surveillance

Location | Start Date | End Date | Cost | Trainer | Book |

Atyrau | 22 Oct 2018 | 26 Oct 2018 | £2,950 | Professor Emeritus Steven Poston | |

Bahrain | 10 Dec 2018 | 14 Dec 2018 | £2,950 | Professor Emeritus Steven Poston |

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