| Popis: |
Horizontal and multilateral wells are being drilled as a cost-effective approach to increasing production and adding reservoir value. The data acquisition strategy makes extensive use of formation pressure measurements that are critical to the understanding of the economic potential of a reservoir. Conventional formation testing techniques have proven inadequate for determining producibility and formation pressures in horizontal and highly deviated wells due to high costs and extreme operational risks. In this paper, a low-risk solution is described for obtaining early history formation pressures in these challenging borehole conditions using a very small sized formation tester combined with robust new operational planning, practices, and techniques. The Compact Repeat Formation Tester (MFT), of diameter approximately 2.4 inches, was deployed in memory mode and conveyed to test depth. Extensive operational planning and pre-job modelling was completed to allow for optimum data acquisition while minimizing total operation time. Well conditions prohibited the formation tester from providing real-time surface communication, the formation tester was programmed to accommodate as wide of range of test scenarios as possible. All tool data were stored in onboard memory for retrieval after the formation tester returned to surface. Twenty two pressure stations were attempted in two wells to a depth of 2250m under borehole conditions where information is usually not attainable. The data obtained from the stations was of good quality and the pressure results were subsequently confirmed by production. Several examples are presented to demonstrate this new technique was successful in obtaining pressure data of highest quality and confidence allowing reservoir insights that would otherwise have been unavailable. The ability to take pressures at multiple stations throughout the reservoirs has produced a detailed understanding of critical economic information. Additionally further developments allow very near time transmission of drawdown pressures back to surface to allow for instant analysis. |
