Going Beyond Exploration

Slide 11

• The development department has a platform built, installed, and start to produce oil at Alpha
• The initial production rates (barrels/day) are about what they predicted
• Now the field is turned over to the Production Department
• In production, geoscientists are needed to answer questions such as:
  • How should we …………
  • Can we ……….
  • What about ……..
  • Is there ………….
  • Can we build …….

Slide 12

• A very useful tool for production people is a reservoir simulation
• A detailed geologic model of the reservoir is built – rock type/lithology, porosity, permeability, etc.
• Then fluids are placed within each cell of the geologic model along with fluid properties
• The reservoir simulator models how the fluids move through time
• Until recently, the first simulation would be run after about 5 years of production time
• The simulation would be calibrated by doing a history match - comparing the simulated production (red curve) with the actual production data (blue boxes)
• If a reasonably good history match is obtained, the model is taken to be fairly accurate
• Then we can simulate future production – 10, 20, 30 years into the future
  • We can do some 'what if' scenarios – e.g., if we placed 3 additional producers at these locations and 5 injectors at these locations, how much additional oil would we produce?
  • If the cost of these 8 wells is less than the value of the additional oil, we might do it
  • Obviously if the cost of the 8 additional wells would not be recovered, we would not do it – look for other 'profitable' scenarios
  • We can also look for portions of the reservoir that are not swept of oil (in the simulations) and target these locations with additional wells – if profitable

Slide 13

• So geoscientists can have great value to an energy company
• They can:
  • Do work that leads to added HC reserves – making new discoveries, getting more from producing zones, or finding additional zones to produce
• They can get more reserves at lower costs
  • Investing in ……
  • Drilling in ………..
  • Correctly assessing ………
  • Avoiding …….
• For example, say that:
  • I am on a team of 4 working production at the Alpha field
  • The initial plan was to drill 10 wells
  • Average cost for a well is $75 million
  • Through our team effort, we determine that we can get the same amount of oil with only 8 wells drilled in more optimum locations
  • The team of 4 saved the company $150 million (cost of 2 wells)
  • That would be enough to pay each person for 50+ years – they have certainly earned their keep!

Slide 14

• Let's go forward 5 years after the start of production (drawing fluids out of the reservoir)
• Our main objective is to maximize production while minimizing the costs
• We would build a computer model of the subsurface – with rocks and fluids
• We would simulate how each well would produce fluids over the 5 years of production
• We use the actual well production to calibrate the model (simulation)
• If we get the model to match actual production, we build confidence that the model is close to reality
• Then we can model production into the future
• With the model, we can test ideas such as "what if we add to producers at locations A, B and C and an injector at location Z?"

Slide 15

• The subsurface (geologic model) is an integration of all geologic, geophysical, petrophysical and interpreted or conceptual information about the reservoir into a single 3D numerical description of that reservoir

Slide 16

• Each cell in the model is assigned rock and fluid properties:
  • Rock type (lithology)
  • Porosity
  • Permeability
  • Fluid Saturation
  • Water properties
  • Oil properties
  • Gas properties
  • Etc.
• Cell size can vary depending on the field size, computing resources, etc.
• But they are typically about 50 to 100 m in X and Y and about 1 m in depth (Z)

Slide 17

• The first task is to get a history match – a model (simulation) that matches the history of field production
• If this is done, then we start to model future production
• We can see the impact of using EOR – enhanced oil recovery methods
• Or of doing infill drilling
• The main question is will the cost of EOR and/or infill drilling going to result in enough extra production that the extra costs are more than recovered by the extra oil or gas to sell

Slide 18

In summary …..