Clay-free drilling fluid filter cake removing system

Abstract

The invention relates to a clay-free drilling fluid filter cake removing system. In the system, cleaning-gelout working solution is prepared by uniformly mixing xylene, petroleum ether, nonylphenol polyoxyethylene ether with the HLB value of 5, nonylphenol polyoxyethylene ether with the HLB value of 13 and 8-10 alcohol polyoxyethylene ether in a weight ratio of 56:25:7:7:5 and mixing clean water,ammonium persulfate, potassium chloride, sodium carbonate, a stratum cleaning agent in a weight ratio of 86:3:2:5:4; corroding-gelout working solution is prepared by mixing the clean water, hydrochloric acid, phosphoric acid, hydrofluoric acid, a corrosion inhibitor SA1-3 and ammonium citrate in a weight ratio of 69.5:15:7.7:5.5:1.8:0.5; and post cleaning working solution is prepared by mixing the clean water, the potassium chloride and the tratum cleaning agent in a weight ratio of 94:2:4. The system has the advantages of obvious improvement on gelout effect, good cleaning effect, high dissolution rate, good anti-swelling effect, strong discharge aiding capability and low corrosion rate.

Description

technical field [0001] The invention relates to a solid-free drilling fluid filter cake removal system used to remove the blockage of the drilling fluid filter cake on the near-wellbore zone during the completion process of a horizontal well that is drilled with solid-free drilling fluid in the target layer and completed with a screen pipe or an open hole . Background technique [0002] During the completion of horizontal wells with screened or open hole completions, conventional methods of eliminating reservoir damage are the use of acids to dissolve acid-soluble weighting materials and / or temporary plugging particles in the drilling fluid filter cake and oxidation The molecular weight of the polymer becomes smaller and loses the bridging and attachment functions, thereby changing the dense and tough filter cake into a loose and broken structure, making the filter cake and solid phase easy to be discharged by the fluid, thereby releasing the impact of the drilling fluid fil...

AI Technical Summary

Problems solved by technology

[0003] ① Poor cleaning effect on crude oil

Crude oil is often mixed into the drilling fluid to improve the lubrication performance. Crude oil has strong adhesion, so the filter cake of drilling fluid will contain a certain amount of crude oil, and crude oil will also adhere to the screen wall, reducing its drainage effect

[0004] ②The gel breaking performance is not very satisfactory and needs to be improved

Some treatment systems need 8-10 hours to break the polymer gel, and some acid solutions use invisible acid, which produces less acid in a short period of time, which affects the dissolution of the solid phase

[0007] ⑤ Some processing procedures are too complicated, which increases the difficulty of construction and the construction period

[0008] ⑥One filter cake removal system is applied to various drilling fluid systems, the main effect is not outstanding, the pertinence is not strong, and it is easy to cause cost waste