TATNEFT PJSC uses dual completion technology (DCT) to recover oil from horizons with different physical and chemical properties by single well. However, for horizontal wells it is necessary to run a pump to an interval with large curvature (more than 42°) to reduce bottomhole pressure to optimum values. In such conditions, standard pump valves are unable to operate or there is a delay in valve actuation which significantly reduces volumetric efficiency (down to 0,3). Design sizes of known standing and traveling valves used in horizontal wells do not allow their implementation as an auxiliary standing valve in downhole pumping equipment arrangements for wells with 114 mm production string or less. Thus, recovery of potential well flow rate is not ensured. Simple, reliable, and compact standing and traveling valves have been created which provide operation of dual completion arrangement using tubing sucker-rod pump in horizontal wells with hole curvature in 42-90° range and volumetric efficiency no less than 0,65. The following hole inclinations were modeled for comparative trials: 42°, 50°, 60°, 70°, 80°, 90°, 105°. Additionally, the developed valve with ST-TC1 balls was tested to determine critical inclination angle at which valve is unable to operate. The test was based on simulation of the moment plunger reaches upper «dead» point when fluid in tubing rushes downwards and closes standing valve. Closure speed and the amount of returned fluid determine volumetric efficiency. As a result of benchmark and field trials it was found that the minimum volumetric efficiency (even with greater inclination at pump seating of 76-77° after installation versus 44,38° before installation) after installation of new valves is 24% higher than the maximum volumetric efficiency before the installation and the average is 51% higher. Newly designed valve meets requirements and is properly functioning. Moreover, it has been proven that it’s properly functioning in horizontal hole unlike valve of standard design.
References
1. Patent RU 2764943 C1, Sucker-rod pump valve, Inventors: Garifov K.M., Kadyrov A.Kh., Glukhoded A.V., Balboshin V.A., Rakhmanov I.N., Voronin N.A.
2. Mishchenko I.T., Raschety v dobyche nefti (Calculations in oil production), Moscow: Nedra Publ., 1989, 245 p.
