The Tulare Steeply Dipping Horizontal Well Project is a multi-year project that is designed to recover oil by steamflooding the Tulare and Amnicola sands in the Cymric and McKittrick fields in the San Joaquin Valley, California utilizing horizontal producers and associated vertical steam injectors. The scope of the project includes ~79 horizontal wells, associated vertical injectors and surface facilities, using a staged-development for a multi-year drilling program. The average horizontal well produces about 100-250 BOPD in comparison to an average vertical well in the reservoir that makes approximately 30 BOPD. Throughout the early phases of the project, the multi-disciplinary team gained insight into improving the design and implementation of the project. Several improvement areas were identified to reduce drilling costs and enhance early oil production, which resulted in improved project economics.

The first stage of development drilled in 1997-98 included eleven horizontal wells. Although these wells demonstrated good productivity and the viability of applying horizontal producers in these fields, the overall economics were poor, partly due to high capital costs and a slow production response. During a low price environment, the team took an initiative to identify areas that would reduce costs and optimize operability for future development of the field with horizontal wells.

Some of the changes affecting costs identified were reducing the casing size in both the build and lateral sections of the wellbore, selecting a directional drilling contractor with extensive experience in the area and eliminating LWD. Operational and start-up changes included cyclic steam stimulation of the horizontal wells before placing them on production, maximizing lift, and the use of fiber-optic temperature surveys to understand heat distribution in and near the lateral. Another change later identified before drilling the next set of horizontal wells were to utilize 3-D well path planning tools to iterate plans in real time with the directional drilling contractor to meet geologic and anti-collision parameters. The eight well drilling program in 2000 resulted in a 30% reduction in both the drilling costs compared with the 1997-98 program. As a result of cyclic steaming, the wells averaged between 150-250 BOPD above forecast for the first six months of production. A third stage of development in early 2002 resulted in a 45% reduction in drilling costs relative to the 1997-98 programs.

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