Rock mechanics and stimulation aspects of horizontal wells

详细信息    查看全文

• 作者：Soliman ; M.Y. ; Boonen ; Paul
• 关键词：horizontal well ; fracturing ; rock mechanics ; wellbore stability
• 刊名：Journal of Petroleum Science and Engineering
• 出版年：2000
• 出版时间：March, 2000
• 年：2000
• 卷：25
• 期：3-4
• 页码：187-204
• 全文大小：1.08 M

文摘

In certain reservoir conditions, horizontal wells can offer significant production improvement over vertical wells; however, fracturing is often required to maximize the return on investment for these wells. Since its introduction in the late 1980s, the practice of fracturing horizontal wells has become a viable completion option. This is especially true in the case of tight gas formations. This paper reviews best practices in the fracturing of horizontal wells and includes a discussion on the rock mechanics, operational strategies, and the reservoir engineering aspects of fracturing horizontal wells. The rock mechanics discussion reviews the theoretical and experimental work and creation of: (1) transverse and longitudinal fractures, (2) multiple fractures, and (3) fracture reorientation among others factors that are associated with creation of a fractured horizontal well. Stability of the horizontal well as it relates to stimulation is also discussed. The reservoir engineering portion discusses the production performance and testing aspects of a fractured horizontal well. Emphasis is given to fracturing tight gas formations since this area is the one in which this technique is considered to be the most effective. The performance of a longitudinal fracture is examined and compared to a fractured vertical well and to the more popular transverse-fractured horizontal well. Because performance of a longitudinal fracture is similar to that of a fracture in a vertical well, the existing solutions for fractured vertical wells may be applied to longitudinal fractures. This approximation is valid for moderate to high dimensionless fracture conductivity. In the case of transverse fractures, the outer fractures outperform the inner fractures. However, for most cases, more than two fractures are necessary to efficiently produce the reservoir. Operational aspects of fracturing horizontal wells for both transverse and longitudinal fractures are discussed, and advantages and disadvantages of each type are outlined. Examples and case histories are given. The paper also presents guidelines for stimulation of a horizontal well and includes both propped-and acidized fracturing as well as matrix acidizing.