Study of regularities on how drilling cuttings block pores and fractures of oil-bearing formation

Abstract

Regularities on how drilling cuttings block pores and fractures of oil-bearing formation are studied. There are complex physical and chemical processes at well bottomhole occur during entering oil-bearing formation by rotary or rope drilling. That is caused by quality of drilling fluid, intensity of washing, rotation of a drill string, presence of cuttings at bottomhole and a drilling technique. There are hydraulic impulse effects with alternating signs in bottomhole formation zone appear during rope drilling that have a significant impact on quality of work. Underestimation of mentioned factors during entering oil-bearing reservoirs leads to decrease in permeability of oil rocks and well production rate. A clear understanding of physical and chemical processes at bottomhole while entering oil-bearing reservoirs and management of these processes allow to avoid reduce in conductivity of reservoir rocks to a large extent and intensify it in some cases. The main conditions to increase efficiency of oil wells drilling are application of such methods of entering and development of an oil-bearing reservoir that ensure preservation of its natural porosity and permeability or contribute to their increase in bottomhole part of a well. Physical and chemical parameters of oil-bearing formation are the governing factor while choosing its entering and development technology. In recent years, great attention has been paid to issues of entering and development oil reservoirs. Parameters such as geological and physical properties of a reservoir, physical and chemical properties of reservoir oil, rocks and washing liquid, hydrodynamic interaction in an "oil reservoir-well" system are not considered enough in a number of cases during entering and development of a formation. That often leads to incorrect conclusions about a possibility to use actual reserves for needs of national economy. Drilling of oil-bearing formations is a technological process, which create a bore hole in a productive oil-bearing formation for equipment of oil part of a well. Bringing a well on production include technological operations that provide installation of equipment into an oil part of a well and restoration of natural oil permeability of a formation or its artificial increase to achieve maximum production rate of a well.

Keywords

• oil-bearing formation
• drilled cuttings
• blocked layer
• oil rate
• drilling fluid
• colmatant
• drill pipes
• entering
• pressure drop
• drilling
• well
• fractured rocks
• liquid motion
• bottomhole