T-type drilling technology is a new and creative drilling technology which is developed based on the conventional sidetrack drilling technology. T-type drilling technology uses special flexible drilling tools and trajectory control technology to achieve a build-up rate of 5.73°~57.3°/m. All its program, including casing milling, deflecting, and horizontal drilling, can be completed in the same reservoir. And its horizontal hole can extend several hundreds of feets in depth. For its trajectory profile is similar to letter“T", it is called T-type drilling technology.
1.Tapping the potential of remaining oil in old oilfields;
2.Developing low-permeability or thin reservoirs;
3.Developing the reservoir with active bottom water or top water;
4.Uesd in the injected well which can make water injecting accurately;
5.Revive of the casing damage well;
6.Used in the new well for multi-branch completion.
1.Superhigh building-up rate: Not only reduce ineffective footage and drilling costs, but also increase the number of branches in the same oil layer. So we can drill several branches in a single wellbore;
2.The trajectory of T-type branch should be Optimized and controlled. We adopt multiple patented technologies to strictly control the trajectory of T-type branches;
3.Larger hole size and longer stable production cycle: the T-type branch has a hole size between 114mm-152mm, and which is a round hole difficult to close;
4.Selectivity of well completion: according to requirement of the layer and wellbore, we can choose different way of well completion, including: Flexible screen completion; Branch and subsection fracturing; Circulation filling sand control completion, etc;
5.It is easy to implement: For T-type drilling, model 350, 450 workover rigs can be used, and the mud is normal; don’t need special equipment;
6.Short term of operation: One horizontal branch can be completed in 4-7 days, and two branches in 7-11 days ( Taking the well depth of 2000 meters as an example).
In 2009, we developed T-type drilling technology. From then on, We constantly develop and improve technology in the oil-field application. Now, the ninth generation of drilling product has been made and the technology is gradually mature. As of the year 2022, our company has provided 122 T-type drilling services in major domestic oilfields and 212 T-type branches has been drilled. The success rate of the project was 98.0%. The average liquid and oil production of effective wells increased by 3-5 times and 4-6 times respectively.
CNOOC oilfield, well XXX, depth 3150m. In order to improve oil production, tap the potential of Zhujiang formation, which is 1.5m thick vertically, with medium porosity and permeability. We designed two T-type branches , targeting remaining oil from high dip areas. Actually, we drilled two T-type branches with lengths of 102 meters and 98 meters respectively. The measured deviation rate is 16 °/m. The cumulative construction time is 185 hours, with an average drilling speed of 6.5m/h. Open well production, daily liquid production of 165 m3/day, daily oil production of 123 tons/day.
