Temporary plugging agent for horizontal well staged fracturing of controllable rubber breaking and preparation method thereof

Abstract

The invention relates to a temporary plugging agent for the horizontal well staged fracturing of controllable rubber breaking and a preparation method thereof. The temporary plugging agent consists of diol, an inorganic oxidation strengthening agent, borate, sodium bicarbonate, a controlled-release microcapsule rubber-breaking agent and water, wherein the weight ratio of the components is (10-14): (5-8): (1-1.5): 3: (2-3): 100; the diol is white powder or particles, the molecular weight is 70-100 thousands; the inorganic oxidation strengthening agent is magnesium oxide or aluminum oxide; and the controlled-release microcapsule rubber-breaking agent is covered citric acid or solid nitric acid which is obtained by the boiling granulating technology. The temporary plugging agent performs a crosslinking reaction under 70-90 DEG C of well temperature to form a rubber plug which can bear more than 30MPa of differential pressure, thus the fracturing construction can be performed smoothly; and after fracturing, the capsule dressings of the controlled-release microcapsule rubber-breaking agent are damaged and the viscosity of the rubber-breaking solution is less than 10mPa.s, thus the temporary plugging agent is hydrated and degraded and then is discharged out of the ground through flowback and the harm to the formation is lower.

Description

technical field [0001] The invention relates to a temporary plugging agent for staged fracturing of a horizontal well with controllable gel breaking and a preparation method thereof. Background technique [0002] In the process of oilfield exploitation, the benefits of horizontal wells are far greater than the cost of drilling and completion, and they are more important than vertical wells in the production of heavy oil layers and thick oil layers. The process of horizontal well stimulation involves the use of staged perforation fracturing technology, that is, after the first stage of fracturing is completed, chemical or mechanical methods are used to separate the fractured section from the section to be fractured, so that the target layer be effectively reformed. [0003] In order to increase the number of effective stimulation stages of horizontal wells, major oil companies have begun to compete with each other to research and develop temporary plugging agents for staged ...

AI Technical Summary

Problems solved by technology

Among them, polymers and plugging pellets are the most widely used. Among them, the polymer temporary plugging agent has a good plugging effect due to its firm chemical cross-linked network structure, but there is a phenomenon of slow or even difficult gel breaking. If it is not thorough, it will cause a certain degree of damage to the formation; the plugging ball has the characteristics of high plugging strength and small deformation, but the disadvantage is that it is easy to fall off and the plugging effect is poor. Difficult to dissolve