Ph.D. Theses

Development and application of new methods for formation stimulation and bottom hole zone treatment by the example of Kazakhstan field

Abitova Aygul Zholdashovna

2525.01 - Development and exploitation of oil and gas fields

Design solutions, pilot testing and industrial introduction of various stimulation methods to formation and bottom hole-zone have been successfully realized for many years of field development in Kazakhstan. For all that current oil recovery ratio for specified fields is relatively low.

In connection with this development of new effective stimulation methods to formation and bottom hole-zone remains very actual task.

New oil recovery method was developed using water-alternated-gas injection (WAG) in this dissertation. Different versions of WAG were investigated in laboratory conditions. It is found that, the increment of water flood displacement efficiency was: WAG with methane – 9,4%; WAG with nitrogen – 7,0%; WAG with methane plus SAR (surface active reagent) – 12,0%; WAG with nitrogen plus SAR – 9,0%; during polymer water flooding– 2,4%. Laboratory research results permit to recommend usage of injected water and gas volume ratio in the range of 0,2-0,5 dependence on actual development conditions.

Developed technologies for nitrogen-enriched air and hydrogen disulfide- enriched water production during treatment of hydrocarbon gas can be widely used as working substance in maintenance of reservoir pressure in developed oil-gas fields.

Flow diverting technology (FDT) was developed for formation stimulation based on viscosity control of thickened water fringe. Residual oil displacement efficiency was investigated after water flooding with different modifications of thickened water fringe in laboratory conditions. It is shown that, maximal incremental oil production is reached 45% in viscosity fringe higher than the viscosity of the water used for flooding.

A new method for selective bottom hole-zone treatment was developed by sealing of lower perforated interval with sand column and creating of clay plug on sand column for its sealing using wire-line technique container.

WAG technology was designed based on geological model in experimental area, in “Kalamkas” field Ю-1С horizon. However it was recom- 24 mended to realize WAG technology by co-injection of gas and water into formation, with a treated SAR in a foam system form. The WAG technology realization dynamics of main aspects, including production of oil, liquid and gas was obtained based on experimental area of hydrodynamic model and its adaptation to actual production history on the «Eclipse-100» software of Schlumberger. Herewith cumulative incremental oil production was amounted 2699 thousand tons for 5 years. Experimental-industrial adoption of the WAG technology was started in the field according to recommended project.

Pilot tests proposed by FD technology were carried out in “Uzen” field using POLY-T-101 polyacrylamide, Alcoflood, FP-307 in 2013. Measures were carried out in 73 wells. FD technology effectiveness analysis shown that, it reduces water cut and increase flow rate of the reacting production wells. 171 of 311 surrounding wells responded to injection. General cumulative incremental oil production from implementation of the measures amounted 103,33 thousand tons in 2013.