Process for improving bearing capacity of formation

Abstract

The invention discloses a process for improving bearing capacity of a formation. The process for improving the bearing capacity of the formation comprises the following steps of: a, working out respective sizes of formation pores according to formation fracture data obtained by block coring, and preparing different sealing slurry by using gel and sealing particles of corresponding dimensions according to the respective sizes of the formation pores; b, pumping the prepared sealing slurry into a shaft, and closing a blowout preventer after the sealing slurry is full of the shaft; c, continuously pumping the sealing slurry into the shaft to enable the sealing slurry in the shaft to be extruded into the formation; and d, respectively building frameworks at the formation pores by rigid sealing particles in the manner of bridging, filling and compacting flexible sealing particles among the rigid sealing particles to fill pores near the formation of the shaft to the greatest extent so as to enable the casing pressure value of the blowout preventer to be increased continuously, therefore improving the bearing capacity of the formation. According to the process for improving the bearing capacity of the formation, bearing sealing is performed on the formation in advance, through the formation fracture data obtained by the block coring, the sealing is performed on the formation by using the chemical gel which is equivalent to formation porosity and the rigid and flexible sealing particles when drilling is performed, and therefore, the bearing capacity of the formation is artificially improved, the phenomenon that drilling fluid leaks from the formation due to the fact that drilling fluid density rises at the later stage of construction is prevented, and drilling construction can be smoothly performed.

Description

technical field [0001] The invention relates to a technique for improving the pressure-bearing capacity of formations, which belongs to the technical field of drilling construction and can be used for drilling construction in weak pressure-bearing blocks of oil fields. Background technique [0002] In the existing technology, the pressure bearing capacity of the formation in some blocks of the oilfield is weak, and the drilling fluid density exceeds 1.05g / cm 3 Leakage is prone to occur, and the original technology is usually to stop the lost circulation after the occurrence of lost circulation. For example, Chinese Patent No. "201010502689.X" discloses a method of sequential compound method for plugging in well drilling. The publication date is May 02, 2012 The method described is to send two or more kinds of plugging fluids with different components and different properties into the downhole leakage layer in proportion and successively for plugging, including the following ...

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Problems solved by technology

[0003] In order to solve the above problems, "Drilling Fluids and Completion Fluids" published "Technology for Improving Formation Pressure-bearing Capability" in Issue 02, 2009, and "Research on Improving Formation Pressure-bearing Capability" was published in "Drilling and Completion Fluids" Issue 05, 2011. Although these technologies improve the pressure bearing capacity of the formation before lost circulation occurs, there are still the following shortcomings: 1. The opening of formation fractures calculated theoretically is quite different from the actual one. The success rate of leaking is very low; 2. The plugging slurry is prepared only by pure inert plugging agent. After the inert plugging agent enters the fracture, it cannot be cemented well, and the dispersion is strong, and it cannot stay in the formation pores, which improves the pressure of the formation. Capability is limited, the success rate of plugging is low, and leakage is easy to repeat during later construction

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