Methods of removing and preventing the scale deposition in the wells of White Hare field, Vietsovpetro JV

UDK: 622.276.72

DOI: 10.24887/0028-2448-2020-8-82-86

Key words: reservoir water composition, scaling conditions, scaling treatments, bottomhole treatment, acid solution, inhibitor, downhole equipment, bottomhole area

Authors: D.I. Varlamov (Research and Engineering Institute, Vietsovpetro JV, the Socialist Republic Vietnam, Vung Tau), E.N. Grishenko (Research and Engineering Institute, Vietsovpetro JV, the Socialist Republic Vietnam, Vung Tau), S.S. Zakharov (Research and Engineering Institute, Vietsovpetro JV, the Socialist Republic Vietnam, Vung Tau)

White Hare field has been developed since 2016 at Block 09-1 of Vietnam. Main producing zones are classic deposits of the Upper Oligocene and Lower Miocene. The wells are operated by the compressed gaslift method with multi-packer assembly for dual production from the Upper Oligocene and Lower Miocene. The complicating factor, driven by increased watering over time, is the formation of non-organic scale deposits at the inner surface of the downhole equipment. Scaling negatively effects the well operation. Resistance to a fluid flow increases and results in deterioration of lifting, power consumption increases and fluid rate decreases.
The article covers the results of reservoir water lab tests and highlights the dependencies of scaling intensity on reservoir and well P-T (pressure-and-temperature) conditions. Compatibility assessment for reservoir and injecting water has been performed. The main method of scaling control is the scaling treatment. The article describes the results of applying scaling treatment with acid compositions. Frequent treatments have been observed, as well as their negative impact on the downhole equipment and increased oil underrates. It is considered the Scale Squeeze technology application, which consists of pumping the inhibitor in the bottomhole area following its adsorption at the rock surface and inhibiting the associated water. The paper describes the pilot tests results of inhibitor bottom-hole batching technology, and pinpoints the factors that influence the technology efficiency. The article identifies the strategic pathway for scaling control efficiency in wells of White Hare field for 2020–2021.