Over the past few years, there has been a vision in Shell that Optimal Value Testing (OVT) would some day replace conventional drill stem tests for in-situ measurement of dynamic reservoir properties such as permeability and drainage volume. This vision is that OVT would be safer, less costly, and friendlier to the environment, but the key impediment to OVT was that the quality of the results might be inadequate for the difficult development decisions that we face.

Definitions of OVT may vary, but in Shell we define it as the testing method that yields fit-for-purpose results with the lowest cost and HSE impact. In more pragmatic terms, it is any pressure transient test in which live hydrocarbons are not produced directly to surface. Currently we have three types of well tests in our OVT toolbox – wireline formation testers, the closed system test with cleanup and repeat surges, and injectivity testing. We have recent examples of closed system tests and wireline formation tests that show we can get comparable data quality to a conventional DST. Injection testing, aimed at determining drainage volume, is less mature and we have yet to execute an injection test. However, there has been considerable design work that makes us believe, given the recent experience with closed chamber systems, that that technology can also be successful.

This paper describes the strengths, weaknesses, and opportunities of each OVT type. We present several examples of design, execution, and analysis of these tests. The technology is immature, and there are more issues to resolve than with a conventional drill stem testing. However, by drawing on our increasing breadth of experience, future value of information decisions we take about doing in-situ dynamic measurements will more often include the cheaper, safer, and more environmentally friendly OVT.

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