Real-time wellbore positioning of horizontal wells for improved reservoir deliverability has revolutionized the oil and gas industry. Recent advances in real-time geosteering now enable, with even greater precision, successful targeting of the most desirable layer within a reservoir. These advances have the capability to open more drainage volume for recovery of hydrocarbons. Successful geosteering occurred in a Gulf of Thailand field after overcoming numerous challenges; specifically, fast rate of penetration, gaps in azimuthal resistivity data, etc. This success was achieved through multidisciplinary collaboration between team members and use of advanced LWD sensors to monitor the drilling program. For the scope of these wells; pre-well modeling, real-time geosteering, LWD sensors (azimuthal deep-reading propagation resistivity sensor along with standard triple combo sensors including a 16-bin density image) and real-time visualization services were utilized.Well placement in a thin bed reservoir can be complicated by structural features such as point bar sand variations and sub-seismic faults. These features are typically difficult to resolve using conventional resistivity sensors. The deep azimuthal reading and directional data from the azimuthal propagation resistivity tool allowed for determination of the distance-to-bed boundaries including gas, oil, and water contacts with improved accuracy and directional attributes. Combined with pre-well modeling and real-time updates, the various input options enabled more realistic visualization models to facilitate well placement.The workflow considers how horizontal wells can be drilled to optimize complex thin sand (10 to 20 feet thick) reservoir contacts in a process that places the well near the top boundary in a water-drive oil reservoir.Drilling operations and results from numerous Thailand wells are presented to illustrate the application. The paper examines the azimuthal resistivity tool used in this case study, and describes the modeling and visualization software used to update the real-time model with data obtained while drilling. Changes in the real-time decision-making process as a result of the data are summarized.This paper discusses the teamwork and deployment of real-time geosteering operations, pre-well modeling and real-time drilling updates used in the pro-active geosteering process, as well as new generation LWD technology, used to successfully improve reservoir deliverability.
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