Coiled tubing drilling fluid and method of use thereof

Abstract

The invention discloses a coiled tubing drilling fluid and a using method thereof. The drilling fluid is composed of drilling fluid A and drilling fluid B; drilling fluid A is composed of clay stabilizer, friction reducer and water; drilling fluid B is composed of drag reducer suspension, clay stabilizer and water; clay stabilizer is quaternary ammonium salt, sulfonyl quaternary ammonium salt or benzyl quaternary ammonium salt; friction reducer is swire oil, ethylene glycol, isomerized thirteen Oil-in-water emulsion formed by alcohol polyoxyethylene ether and water; drag reducer suspension is a non-aqueous system formed by thickener, suspending agent, activator and dispersant; when used, first replace drilling fluid A in the wellbore , when running the coiled tubing to the target well section, pump the coiled tubing plugging fluid A or the mixture of drilling plugging fluid A and drilling plugging fluid B in the coiled tubing with a certain displacement; the coiled tubing drilling fluid is not easy to spoil , Strong ability to carry drill cuttings and rubber, can eliminate the "self-locking" phenomenon when the tubing is run in, the time required for drilling the plug is short, no damage to the formation, and good compatibility.

Description

technical field [0001] The invention relates to the technical field of downhole operations in exploration and development of oil and gas fields, in particular to a coiled tubing drilling fluid and a method for using the same. Background technique [0002] With the in-depth exploration and development of unconventional oil and gas resources such as shale oil and gas and tight oil and gas in my country, the drilling technology of long horizontal section horizontal wells and the combined staged fracturing technology of bridge plug-cable perforation have become the mainstream technologies of exploration and development. At the same time, the horizontal section is getting longer and the interval between sections is gradually shrinking. The number of sections and bridge plugs are increasing, which increases the difficulty of drilling plugs after coiled tubing pressure and the downhole complexity. In order to reduce the construction risk of coiled tubing plugging operations, Coordi...

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Problems solved by technology

[0004] However, the current continuous oil drilling plug fluids have the following deficiencies: 1) Most of the thickener components that carry drill cuttings contain xanthan gum, etc. This type of plant gum is easy to rot, and the drilling plug fluid is not easy to store for a long time. 2) When the plugging fluid is made of powdery thickeners such as polyacrylamide, polyvinyl alcohol, carboxymethyl cellulose and other polymers, it takes a long time to completely swell and dissolve. And the preparation concentration is low, and the drilling plug fluid with high thickener concentration is easy to produce "fish eyes", which makes it difficult to prepare by conventional methods; 3) Surfactants are commonly used as anti-friction lubricants to reduce the friction coefficient between coiled tubing and wellbore, However, the use of high content of surfactant is easy to foam, which is not conducive to the preparation of drilling fluid and the safety and environmental protection of the well site after replacement

Although the coiled tubing drilling fluid system solves the problem of suspending and carrying cuttings out of the well through viscosity control, it still has the problem of slow swelling and dissolving of the thickener (10min), and the addition of a fungicide is required for the vegetable gum Maintain the defects such as the viscosity of the drilling plug fluid, and do not solve the frictional resistance between the coiled tubing and the wellbore, which may lead to the obstruction of running in the long horizontal section of the horizontal well during the construction process

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