How Geomechanical Data Integration helped constrain the Placement of the first Horizontal Well in a new Tight Gas Field

摘要

In 2009 Petroleum Development Oman LLC (PDO) started an ambitious tight and deep gas exploration programme exploring for previously untapped reservoirs. The exploration strategy is focusing on both conventional tight gas plays as well as deep unconventional gas resources. These resources are typically in previously undrilled formations at great depths, with high temperatures and unknown pressure regimes, and uncertain fluid fill and composition. The unique geological properties of this type of reservoir require different strategies and technology deployment in order to make them viable and sustainable. With unique Geomechanical, reservoir, and geological properties, some of the large gas-bearing prospects within the Fahud Basin in the Sultanate of Oman require innovative drilling and completion practices. A revised drilling and completion workflow, with specific technology deployment and operational flexibility, has been developed in order to account for such reservoir complexity. This workflow includes the incorporation of rock strength acquisition and stress state of the reservoir prior to completion, in order to identify targets for hydraulic fracturing and quantify hydraulic fracturing performance versus reservoir deliverability. The unparalled challenges encountered whilst exploring for these resources required resolving to new technologies from outside the region and adapting them to local conditions (Briner et al, 2012). This paper demonstrates how the understanding of the Geomechanical stress regime obtained through the integration of data from multiple Petroleum Engineering disciplines helped to determine the location & orientation for the first horizontal well in a new Tight Gas discovery. In addition the paper will summarize the results of a Geomechanical analysis that aided the planning of appropriate hydraulic system to maintain borehole integrity in the Build-Up and Horizontal sections of the well through the highly stressed overburden and reservoir sections.