Cost-effective Techniques for the Independent Producer to Identify Candidate Reservoirs for Horizontal Drilling in Mature Oil and Gas Fields
Saibal Bhattacharya, Paul M. Gerlach, Timothy R. Carr, 2003. "Cost-effective Techniques for the Independent Producer to Identify Candidate Reservoirs for Horizontal Drilling in Mature Oil and Gas Fields", Horizontal Wells: Focus on the Reservoir, Timothy R. Carr, Erik P. Mason, Charles T. Feazel
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Horizontal wells have exploited successfully the remaining oil potential in mature reservoirs around the world. Because a typical horizontal well costs 1.3 to 4 times that of a vertical well, it must produce significantly greater volumes of oil to be considered an economic success. Previous studies have concluded that poor selection of target reservoirs has been the principal cause of failure of horizontal wells. Many mature fields in the Midcontinent of the United States have significant volumes of residual reserves, and vertical wells have proved to be uneconomic for producing these unswept assets. Small independent producers with limited financial and technological resources operate most of these fields. In Kansas, few horizontal infill wells have been drilled, and results have been mixed. Operator concerns for an appropriate economic return and the difficulty in cost-effectively identifying candidate reservoirs have restricted application of horizontal-drilling technology in many mature production areas of the Midcontinent.
Recent declines in cost factors have brought horizontal-drilling technology within the economic reach of small independent producers, but they have been constrained by the lack of low-cost tools and methodology to screen, evaluate, and target horizontal wells to produce incremental reserves in mature areas.
We present several low-cost approaches that can be used to evaluate candidate reservoirs for potential horizontal-well applications. These cost-effective, efficient screening techniques apply at the field scale, lease level, and well level, and enable the small, independent producer to identify candidate reservoirs and predict the performance of horizontal-well applications. Field examples have been used to demonstrate the application of each technique. The demonstrated tools use easily available, standard spreadsheet and mapping packages to analyze production data, map geologic data, integrate and compare geologic and production data, conduct detailed petrophysical analyses, carry out field-and lease-level volumetric analyses, and conduct material-balance calculations. The methodology that the independent operator might follow to identify prospective areas in a production region or field can include any combination of these tools. This paper describes the use of PC-based freeware simulators to history-match well and field production, map residual reserves on a field scale, and predict performance of targeted horizontal infill wells. This process of identifying candidate reservoirs or leases and evaluating their productive potential for horizontal infill drilling will enable independent producers to study the viability of horizontal applications before drilling, and thereby help them select targets appropriately.
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Horizontal Wells: Focus on the Reservoir
This book provides an overview of the new technical approaches required for best use of horizontal and extended-reach technology in different reservoir situations. The volume is a selection from more than 50 papers presented at an AAPG/SPWLA Hedberg Research Symposium, “International Horizontal and Extended Reach Well Symposium: Focus on the Reservoir,” held in The Woodlands, Texas, on October 10 14, 1999. The 16 chapters describe horizontal and extended-reach wells and drilling programs in a variety of geologic settings all over the world.