It holds significant strategic importance for enhancing recovery rate and promoting the sustainable development of oil fields.
Precisely control all aspects of the construction process.
"Continuous" efforts, plus "new tools"! Recently, the downhole operation branch of Daqing Oilfield successfully completed the trial of the first continuous tubing window sidetracking well. This marks an important breakthrough for the branch in the field of continuous tubing sidetracking, and it holds significant strategic importance for enhancing recovery rate and promoting the sustainable development of Daqing Oilfield.
It is known that the coiled tubing sidetracking technology is a cutting-edge petroleum extraction technique, mainly used for the re-development of old wells. This technology relies on coiled tubing instead of conventional drill pipes. With the characteristics of no spacers, high toughness, quick up and down movement, capable of under-pressure operations, sustainable pumping, and small equipment footprint, it can simplify the operation process, reduce drilling costs, and effectively shorten the construction period while avoiding long-term and high-intensity work for the operators. In various well types and complex geological conditions, coiled tubing sidetracking can safely implement underbalanced drilling operations, especially suitable for small wellbore drilling, and is an important technical means for improving the recovery rate of old oil fields and exploring new oil reservoirs.
However, on the first day of the open-hole sidetracking operation, abnormal conditions occurred with the directional tool at the site. In response to this, the downhole operation branch promptly acted and immediately pulled out the faulty tool for a comprehensive "diagnosis". The technical team conducted a detailed analysis of the debris, iron filings, and other impurities inside the tool, combined with information such as the sealing condition, bearing compression marks, pump injection parameters, and construction curves, to accurately identify the "crisis" that affected the stability of the tool and data collection. They then proposed four targeted improvement measures: adjusting the spring size, increasing the yield strength of the material, enhancing the sealing of the core parts, and effectively isolating the mud in the annulus. The improved tool was successfully lowered into the well.
During the construction process, the team employed the dedicated swivel converter MWD adapter for continuous tubing sidetracking, combined with the new tool combination of "small-angle bent screw + PDC bit", to achieve precise control of the tool face within a small range, ensuring the stability of the tool's entry into the well and commencement of drilling. They also summarized the trajectory patterns of dogleg angles, optimized the drilling pressure and pump pressure parameters, effectively avoiding problems such as repeated pulling out of the drill due to mudstone sections falling off.
After a continuous 40-day effort, this well finally achieved the designed depth and successfully verified the feasibility of the continuous tubing open-hole sidetracking horizontal well technology. The successful application of this technology has provided a new technical path for increasing production in old oil fields and implementing the "fewer wells but higher production" model.
Next, the Underground Operations Branch will take this as an opportunity to continue conducting scientific research and technological breakthroughs in window sidetracking, abandoned wells in different wellbore types, etc., optimize the construction techniques for wells that produce sand and rock, and increase the success rate of handling difficult wells. This will help the "special forces" contribute even more to securing the energy supply and safeguarding national energy security.