A Behind-the-Scenes Account of Tackling Blockages in Tarim Oilfield's Kuche Mountain-Front Gas Wells

Fact: Out of the 25 production wells at Tarim Oilfield's Dina-2 gas field, 21 wells have developed "asthma."

　　Due to: inaccurate understanding of blockage phenomena and the underlying mechanisms, as well as inadequate matching of unblocking technologies, the results have been less than ideal.

　　Bonus: Understanding the issue requires looking beyond surface symptoms to address its root causes, creating a "1134" anti-blockage system that tackles both the symptoms and the underlying issues.

　　Result: 28 wells were successfully unblocked—every single intervention hit the mark, and all treated wells experienced increased production.

　　As of April 10, the Keshen 805 well, which had been "running out of breath" due to a blocked wellbore, saw its daily natural gas production surge from 49,200 cubic meters before shutdown to 163,500 cubic meters after continuous tubing intervention combined with acid-based wellbore cleanup operations.

　　At the end of 2017, during the peak period for winter supply assurance, 21 out of Dinna-2 Gas Field's 25 producing wells experienced varying degrees of foreign-object blockages. Meanwhile, the situation at Keshen-2 Gas Field was equally severe: out of a total of 27 wells, 15—representing 56% of the total—were experiencing abnormal wellbore blockages.

　　Due to foreign objects blocking the wellbore, gas wells have developed "asthma"—they're struggling to "breathe," resulting in a significant drop in production. Some wells have even been forced to shut down frequently due to excessive sand production, while the blocked wellbores are also stifling the path toward efficient development of the Kuche Mountain Front Gas Field complex.

　　Unblocking a gas well is like diagnosing an illness in traditional Chinese medicine—key is accurately identifying the "pulse" of the wellbore blockage, pinpointing the root cause, and prescribing the right "remedy." Treating this gas well's "chronic condition," however, has proven to be anything but straightforward, with challenges unfolding in unexpected twists and turns.

　　Before 2015, researchers analyzed samples taken from the wellhead and concluded that the foreign material in the wellbore was sand production. Based on this finding, they implemented a countermeasure involving "tubing perforation combined with an increased production pressure differential," which delivered immediate results—but unfortunately, it didn’t provide a permanent solution and often led to a "rebound" effect, causing blockages to recur.

　　From 2015 to 2018, during single-well overhauls or coiled tubing operations, samples of downhole blockages were collected, revealing the composition of the deposits. This led to a refined understanding of wellbore blockage types, now recognized as a combined "sand + scale" blockage pattern. Building on this new insight into the nature of the deposits, technicians developed a customized remediation fluid system—primarily designed to dissolve scale, with secondary capabilities for sand removal. This innovative solution not only effectively reduces tubing corrosion but also slashes single-well blockage treatment costs by an impressive 300,000 to 400,000 yuan.

　　After 2018, researchers conducted 500 analytical tests and precisely determined that wellhead samples were primarily composed of sand, while tubing samples contained a mix of sand deposits and scale. In contrast, full-wellbore samples revealed scale as the dominant component of the blockage. Based on these findings, they developed a comprehensive "1134" integrated wellbore cleanup technology: - For single wells with partial blockages and existing fluid-pressurized channels, the approach focuses on "acid-based cleanup." - For severely blocked wells lacking fluid-pressurized channels, the strategy relies on "continuous-tubing + acid-based cleanup." - And for wells with severe blockages where continuous tubing cannot effectively clear the obstruction, the solution is "continuous-tubing-based pinpoint acid dissolution for cleanup."

　　The "1134" solution for addressing supply bottlenecks builds upon the foundation of "targeted therapy," while placing greater emphasis on "syndrome differentiation and individualized treatment"—a holistic approach that tackles both symptoms and root causes. This strategy not only provided an urgent fix to meet the surge in gas demand during winter 2018 but has also emerged as a long-term, sustainable solution for high-quality development in the Kuche mountainous region.

　　The Keshen 2-2-8 well was shut in for more than six months, becoming the first test well to undergo "targeted therapy," after which it resumed producing 340,000 cubic meters of gas per day. Since 2018, a total of 28 wells in the Kuqa Mountain Front area have undergone unblocking measures, resulting in an average daily gas increase of 3.91 million cubic meters and an oil increase of 246 tons per well. Collectively, these efforts have led to a cumulative gas production boost of 1.23 billion cubic meters and an additional 82,500 tons of oil, while also preventing major overhaul operations on 10 wells.