Performing Reservoir Reviews
Reservoir reviews are performed for a variety of purposes; e.g.
- identifying upside potential for an acquisition
- screening properties for optimization potential
- determining reserves (i.e. without economics)
- determining the applicability of horizontal wells
Many people refer to this as “Bread and Butter Reservoir Engineering”. This process normally consists of a review of geology, production performance, and past engineering analysis. To be effective requires a very broad range of experience. Most EOR property optimization hinges on identifying unswept areas, which is controlled by reservoir continuity. This requires geological knowledge. To quickly identify anomalous performance, which suggests optimisation opportunities, requires an exposure to a large number of properties throughout Western Canada. Finally, a good knowledge of technical reservoir engineering is required to know whether past work has covered all possibilities and to identify what the next steps should be.
Determining the Time Commitment
In many cases it is not known exactly how big a time commitment is required for a reservoir. Under these circumstances ARE typically splits a potential project into two parts. The first part is normally a screening process that lasts from a few days to a few weeks. At the end of this time period, interim results are presented. The client may then decide whether or not to continue.
In a very large number of cases adequate information is obtained from screening studies to make an informed decision. ARE believes this is the most cost effective way of approaching many studies.
Interpreting Pressure Transient Analysis
Better interpretations of pressure transient buildup tests are made with a strong background in general reservoir engineering. This is a matter of pattern recognition. Well test analysis frequently does not give a unique solution. Thus, the final interpretation relies on an overall knowledge of the reservoir. As an example, ARE analyzed a number of tests from a foothills gas reservoir as part of an economic evaluation. Improvements were made to the existing AOF and buildup conclusions by amalgamating results from many tests, structural geology, and core data. The new perspective was more consistent, and changed the client’s perception of the reservoir. Development drilling priorities were changed based on this study.
Preparation of Economic Evaluations
ARE generally does not do economic evaluations any more. The principal prefers working on technical studies. However, in the past, ARE has done corporate reserve reports. This experience is very helpful in preparing technical reports. Evaluation reports prepared by ARE concentrated on:
- Detailed Write-ups
- Reserves Continuity Tables
- Reconciliation Of Change In Value
- Year Round Preparation Using A Reserves Database
- An Optimized Program Of Work
- Complete Coverage of Corporate Revenue
- Proven Quality Reports (References)
- Preparation By Experienced Engineers
- Potential To Utilize Technical Experience Gained
The details of these features consume a considerable amount of space and are documented in an example report, which is supplied upon request.