A lot of attention is paid today at OAO TATNEFT to combined treatment of bottom-hole zone of productive strata and to water shutoff works. Especially important is the development of multi-purpose, energy and resource-saving technologies.
The leading specialists of OAO TATNEFT and TatNIPIneft have developed a comprehensive technology of directional acid treatment with preliminary restriction of water production.
This technology allows increasing the productivity of oil wells while reducing the share of produced formation water and minimizing the risk of wells water encroachment. In general, the oil recovery factor of the porous-fractured reservoirs is improved through increasing the sweep efficiency at the account of physical and chemical stimulation of the bed. The directive document regulates several technological options for the methodology implementation.
The Company also elaborates technological developments with application of local recipes of "self-regulating" acid compositions. A joint scientific development of the specialists of KSTU (Kazan State Technological University) and TatNIPIneft in the field of visco-plastic cation-active surfactants has found practical application.
A technology of the bottom-hole zone treatment with application of a polymer-acid composition converting into visco-plastic fluid after the reaction of acid with rock has been developed and tested.
The mechanism of physical and chemical processes is built by analogy with the well-known abroad VDA technology. However, the home-grown technology and principal reagents are much more economical and accessible. Experimental tests of the new method were carried out in the wells of NGDU Elkhovneft and NGDU Yamashneft, and positive results were received in terms of the oil production growth.
Developing this trend the experts of KSTU and TatNIPIneft have developed new selective acidizing technologies based on cation-active surfactants that increase the efficiency of flooded wells treatment in carbonate reservoirs (analogous to a foreign OilSEEKER technology). This method contemplates injection of selective blocking materials and acid compositions in a cyclic mode. The purpose of this treatment is to reduce the flow of water with the general increase of the well productivity in oil. All necessary permission documentation has been drawn up and experimental injections have been carried out with positive results.