Strong-inhibition anti-caving polyamine drilling fluid for slim-hole drilling of gas wells and horizontal wells and preparation method thereof

Abstract

The invention provides a strong-inhibition anti-caving polyamine drilling fluid used for slim-hole drilling of gas wells and horizontal wells and capable of preventing the collapse of mudstone, and apreparation method thereof. The drilling fluid comprises the following raw materials by mass: 0.3 to 0.4% of organic amine mainly used as a powerful mudstone inhibitor and an auxiliary alkalinity regulating agent, 3 to 5% of a soluble salt used as an inhibitor and a liquid phase weighting agent, 0.2 to 0.4% of a tackifier, 1.5 to 2.5% of a filtrate reducer, 4.0 to 6.0% of a plugging agent, 0.05 to0.1% of a n alkalinity controlling agent, 1.5 to 2.5% of a lubricant and a weighting agent, with the balance being water. The drilling fluid provided by the invention is applicable to casing window sidetrack drilling of slim-hole horizontal wells in the Sulige gas field in Changqing, especially to construction of long open-hole sections, i.e., inclined shaft sections and horizontal sections, containing mudstone well sections prone to sloughing. The drilling fluid has powerful anti-caving performance, conducts good anti-caving effect on mudstone well sections prone to hydration and sloughing,allows borehole walls to be stable and regular, reduces the incidence rate of accidents in the pit, improves production time efficiency and produces good economic benefits.

Description

technical field [0001] The invention relates to a drilling fluid formula and preparation method in drilling operations in oil and gas fields, which is suitable for the drilling of slim borehole horizontal wells in Changqing gas field, especially for the drilling of complex mudstone formations in long open hole sections with deviated well sections and horizontal sections. Drilling fluid formulation and preparation method. Background technique [0002] At present, in the Sulige block of Changqing gas field, due to the increasingly high environmental protection requirements, using the old wellbore at the old well site to carry out casing window drilling and sidetracking slim hole horizontal well construction can not only use the old well site, but also reduce the pressure of land acquisition. Reducing the amount of drilling fluid, reducing the discharge of waste drilling cuttings, reducing the cost of waste drilling fluid treatment, and at the same time, it is also an effective...

AI Technical Summary

Problems solved by technology

[0004] In order to overcome the existing problems of easy sidetracking caused by well filling, greatly prolonging the drilling cycle, increasing drilling costs, and causing certain losses and unnecessary waste, the present invention provides a gas well horizontal well slimhole polyamine strong inhibition prevention Drilling fluid formula and preparation method. The present invention is suitable for safe drilling operations in long horizontal sections with complex formations containing shale, ensuring safe drilling, improving production timeliness, and reducing drilling costs. The present invention selects two kinds of mud shale organic and inorganic shale with different emphasis on functions. Inhibitor, at least one polymer viscosifier, at least one polymer fluid loss reducer as the main additive, plugging agent, one alkalinity control agent, one lubricant, and more than one weighting agent are formulated into drilling fluid