Effective Well Testing Is The Key To Planning Of Major New Developments Particularly In Remote Areas And Offshore Operations

Abstract

Abstract This paper discusses the merits of conducting production and injection tests in the context of frontier areas be they offshore, deep sour gas wells or discoveries in remote, hostile areas. A discussion is included of the data that needs to be collected and how the results affect development planning. To illustrate this, various field development case histories are referenced both in the North Sea and western Canada. Reservoir and production engineering well test design requirements are outlined and the methods for obtaining this data discussed. The case for multirate and extended tests are examined in the context of defining a cost-effective test program. The importance of obtaining adequate fluid samples is also discussed. Finally, an example of the mechanical equipment needed to achieve these requirements is presented for an offshore well test. Introduction As the oil and gas industry explores for future petroleum reserves in increasingly "frontier" areas, the need for adequately designed, conducted and analyzed well testing becomes even more important. Whether it is a sour gas plant in the Foothills or an offshore platform off the East Coast, a proper understanding of the reservoir and fluid properties is essential for cost-effective and efficient development planning. Having spent millions of dollars drilling a delineation well to prove-up the reserve, it is negligent to leave that well without establishing the basic data that will be required for planning the exploitation of the reserve. There are numerous cases where operators have had to re-enter or redrill a well or, worse still, have installed ill-designed facilities and proceeded with an uneconomic development as a result of inadequately planned, insufficiently long, poorly supervised or misinterpreted well tests. At this stage it is important to note that one of the major differences, and perhaps the most important, between conventional and frontier hydrocarbon fields is that large capital investments have to be made for frontier field development based almost completely on exploration and delineation well data. This situation is also applicable albeit on a lesser scale to development of land fields in remote areas, such as western Canadian deep sour gas wells in the Foothills. While the conventional field development can be periodically updated in a staged manner using the latest drilling and production results, most frontier field developments require a commitment to spend the majority of funds long before any production history is available. Logically then, the data obtained from the exploration and delineation wells must be comprehensive and of the best quality possible.