This Paper describes the challenges and successful application of Inflow Control Devices ("ICDs") combined with sand control screens for horizontal wells. The ICDs were installed to reduce water and gas coning at the Shoba field. Shoba was the first field in Kazakhstan to use ICD technology and the first field in the Pre-Caspian basin where shallow horizontal wells were drilled.

The Shoba field is located within the Zharkamys West 1 block in western Kazakhstan. The Triassic-age sandstone reservoir consists of sweet 34° API oil. The field was initially developed with seven (7) vertical wells. However, high vertical permeability, in combination with high gas and water mobility, resulted in excessive gas and water breakthrough that marginalized the field's economics. An alternate development plan utilizing ICDs and horizontal well technologies was necessary to enhance field commerciality. This project presented numerous challenges. Since the field is relatively small and wells of this type had not been drilled in the region, there was little opportunity for a "learning curve", no margin for excessive cost over-runs, or well failures. Some of the issues overcome that will be presented:

  • ICD design and selection considerations

  • Wellbore instability for shallow horizontal wells

  • Isolation of a sizable gas cap above the productive oil zone

  • Plugging of the sand control screens during their placement

  • Premature gas or water coning

Shoba's first two horizontal wells were drilled and completed on time and under budget, with early results confirming a reduction of water and gas coning. A significant increase in production rates has also been realized. Given the project's initial success, additional horizontal well development drilling continues.

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