Foam enhancer for micro-foam drilling fluid as well as preparation method and application thereof

Abstract

The invention provides a foam enhancer for a micro-foam drilling fluid. The foam enhancer comprises a compound with a structure shown in formula I, the foam enhancer provided by the invention is relatively low in relative molecular mass; the compound has good surface activity and relatively low steric hindrance; the synergistic effect of the compound with a surfactant in the drilling fluid can berealized; the arrangement density and the wall thickness of micro-bubbles of the surfactant are increased, the air core sealing performance in the micro-bubbles is improved, the stability and the compression resistance of the micro-bubbles under the conditions of high temperature and high pressure are enhanced, air is prevented from escaping from the micro-bubbles under the condition of high pressure at the bottom of a well, and the leakage-proof performance of the micro-foam drilling fluid is improved. The invention further provides a preparation method and application of the micro-foam drilling fluid foam enhancer.

Description

technical field [0001] The invention relates to the technical field of microfoam drilling fluid, in particular to a foam enhancer for microfoam drilling fluid and its preparation method and application. Background technique [0002] At present, during the drilling process of low-pressure and leaky formations such as gas storages in domestic oil fields, due to the low formation pressure coefficient, foam drilling fluid is often used to reduce the density of drilling fluid and reduce the loss of drilling fluid. However, in conventional foam drilling fluids, due to the relatively large foam particle size, it is easy to affect the water supply efficiency of the mud pump, and it requires supporting gas injection equipment such as a compressor, and the drilling cost is relatively high. In response to these problems, some oilfields in China have successively carried out research on recyclable microbubble drilling fluids used under near-equilibrium conditions. It can effectively pr...

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Problems solved by technology

Therefore, microbubbles must maintain a certain degree of compression resistance under high pressure conditions at the bottom of the well to prevent the foam wall from breaking, thereby affecting the leak-proof performance of microbubble drilling fluids

The microfoam drilling fluid system in the prior art all uses xanthan gum, LV-CMC and HV-PAC mixture and other substances with thickening effect to improve the stability of the microbubbles. Although it has a certain effect, the microbubble drilling fluid There are insufficient stability and compression resistance under high temperature and high pressure. Under the high pressure condition at the bottom of the well, the foam wall may rupture, causing air to diffuse out from the microbubbles, resulting in an increase in the density of the microbubble drilling fluid and a decrease in the leak-proof performance. Drilling Fluid Construction Safety

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