In general, the objective of horizontal drilling is to maximize reservoir contact within the target interval to achieve the planned well performance in a thin layer or when drilling within a thin oil deposit, when the distance between the reservoir top and the oil-water contact (OWC) is short and there is a risk or borehole exit into the overlying formation or water-bearing zone.

In horizontal drilling, there always exist risks associated with geological uncertainties. If the structural dip is different from expected, lateral thickness or reservoir property variations exist; if subseismic faults are present, the horizontal well, drilled as per plan, may not achieve sufficient reservoir contact. As a result, the well may underperform.

Well placement (or geosteering) is used in horizontal wells to accomplish geological objectives. The well placement process is an interactive approach to well construction, combining technology and people to deliver optimally placed wellbores in a given geological setting to maximize production or injection performance. In Akshabulak field, southern Kazakhstan, multilayer bed boundary detection technology was applied for geosteering in two horizontal wells.

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