English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

In the recent years, some domestic overflow and blowout events have shown that we can not apply conven- tional methods to successful well killing under some certain conditions, therefore, bullheading as an unconventional well killing can be considered. Bullheading by pumping kill fluid into wellbore makes the wellbore gas compressed so that bot- tomhole pressure exceeds formation pressure and gas leaks off to the formation. In this study, applicable conditions of bullheading have been discussed. Based on gas compressibility law and gas-liquid flow behavoir, bullheading operation is divided into three stages, including gas compression stage, gas seepage stage and gas-liquid seepage stage. The mathe- matical model for each stage is formulated to predict and interpret well killing mechanism. The calculated results showed good agreement with field case data. This paper might serve as an operational guideline during bullheading.

Study on Applicable Conditions and Mathematic Models of Bullheading