Practice of downhole sampling in multiphase flows. Part 2: Testing of methods of minimal influence on the flow structure inside the tubing

Aim. The paper presents the results of testing new approaches to the sampling of downhole samples of reservoir oil in a stratified oil-water stream.  

Materials and methods. The influence of two factors of success in capturing reservoir oil was evaluated:

• The position of the inlet channel (top / bottom) relative to the piston of the sample chamber of the downhole sampler. For this purpose, autonomous and cable samplers were used, which were lowered into the well in various configurations.
• The position of the inlet valve relative to the lower forming tubing. To do this, two geophysical centralizers were lowered in combination with samplers.

Results. It is shown that the piston intake chamber can act as an effective trap for oil extraction in a watered stream, even in the case of a narrow winding inlet channel; for samplers with the position of the inlet channel from the bottom of the receiving chamber, no positive effect of geophysical centralizers was revealed; the use of geophysical centralizers in combination with samplers with the position of the inlet channel on top of the sample chamber can lead to the capture of a certain amount of oil sufficient for subsequent laboratory preparation and sample studies.

Conclusion. It is recommended to take the results of the work into account when planning sampling with a possible risk of well flooding.

1. Lobanov A.A., Kuporosov D.N., Yuzhaninov A.V., Fuks A.B. Theory of downhole sampling in multiphase flows. Part 1: Basic terms and concepts of multiphase flows // PRONEFT. Professionally about oil, 2024, v. 1. P. 6–20.

2. Lobanov A.A., Fedorovskiy S.A., Promzelev I.O., Tikhomirov Ye.V., Zvonkov M.A., Kovalenko V.A., Kuporosov D.N., Bastrakov A.A., Nartymov V.S., Harisov A.U., Struchkov I.A., Pleshanov N.N., Makarov S.E., Frolov A.S. End-to-End Quality Control of Downhole Samples from the Sampling Point to the Laboratory Unit: This is Possible and Necessary // SPE Russian Petroleum Technology Conference. 12–15 October, Moscow, Russ. OnePetro, 2021.

3. Lobanov A.A. Safarov I.F., Zvonkov M.A., Antoshkin M.V., Frolov A.S., Piskarev M.A., Harisov A. U., Koloda A.V. How technology obsolescence goes unnoticed: the history of development and new information about the work of downhole samplers // Russian industry energy conference. 3–5 october 2023, p. 16.

4. Lobanov A.A., Fedorovskiy S.A., Promzelev I.O., Tikhomirov Ye.V., Zvonkov M.A., Kovalenko V.A., Kuporosov D.N., Bastrakov A.A., Nartymov V.S., Harisov A.U., Struchkov I.A., Pleshanov N.N., Makarov S.E., Frolov A.S. End-to-End Quality Control of Downhole Samples from the Sampling Point to the Laboratory Unit: This is Possible and Necessary // SPE Russian Petroleum Technology Conference. 12–15 October, Moscow, Russ. OnePetro, 2021.