The Belgrade-based company WIG has developed an automatized system for the preparation of saline solutions for an efficient filling of oil wells following the exploitation, thereby solving one of the extremely complex problems of storing contaminated layer water in oil and gas exploitation.
The solutions available in Serbia so far have usually been based on manual labor and laboratory analyses, whereas the implementation of the automatized facility for the preparation of the saline solution designed by the Belgrade-based company enables a ten time more efficient process of preparation, as well as the control and the management of the entire process, compared to the processes available so far, both in quantities and in reducing the time needed to carry them out.
The system was made in response to the needs of the leading producer of oil and gas in Serbia and has had a strong economic and environmental effect.
Since December 2017, the facility has been operating at full capacity, and since this is an original technological solution, modern technological equipment and the adequate monitoring provide a foundation for the implementation of the process in a larger number of oil wells in Serbia and abroad.
During the life cycle, that is, the exploitation of an oil field, water appears in oil wells in various amounts and of different composition. This so-called layer water contains various polluting maters, paraffin and other heavier hydrocarbons, raw oil and others, and the impurities in the layer water that is injected in the well are not desirable for multiple reasons. Among other things, the matters act as polluters to the sediments of the geological layer, which is why layer water needs to be filtered and prepared before being introduced to the well.
There are several thousand oil wells in Serbia and there’s a great need for them to be closed properly following the exploitation, so as not to collapse. The problem used to be solved by manually preparing the saline solution (layer water), so that it could be put back into active oil wells. This method, however, limits the amount of the saline solution that can be prepared in a given amount of time, which slows down the process of raw oil exploitation.
The company which exploits raw oil from oil and gas wells in Serbia and which meets the problem of contaminated layer water stated the problem and requested, through a public contest, a suitable, rational and economically cost-effective solution. The problem needed to be solved from two angles: by solving the environmental problem (1) and by finding a way to return the self-filtered layer water back to the well or the prepared saline solution more quickly (2).
The automatization of the system for the preparation of the saline solution and the control of the process parameters, designed by WIG, achieves significant environmental, economic and safety effects, thanks to the company’s engineers, headed by Marija Borak Pirec, technology engineer, who had researched all the situations occurring in oil wells.
In order to prepare a suitable solution, it is necessary to know what the composition of the ground is, which is determined through the analysis of the pumped-out layer water. In this process, before the layer water is let into the oil well, geological exploration of the ground is performed in order to determine which layer water/saline solution combination is suitable for the area. In the Republic of Serbia, an analysis of ground minerals showed that the best results are produced through the implementation of saline solutions including the NaCl, KCl, CaCl2 and CaBr2 salts. In addition to producing solutions in a certain density range, the dissolution of these salts produces solutions with an adequate concentration of cations, which are important for the stabilization of minerals inside the oil wells.
In order for oil wells left after the exploitation to be filled with environmentally acceptable layer water, a facility is installed next to them – mobile units for the dosing of the saline solution, in which saline solutions are mixed with water on the spot and then used to fill the oil wells.
The facility of the Belgrade-based company WIG consists of 6-7 large cisterns, measuring devices and pumps and is slightly smaller than one half of a soccer field. The formulas are defined at the control and supervision system which manages the process of mixing and monitoring all the process parameters at any moment. Per need, the facility can be dismounted and moved to another oil well.
As the process of preparation of saline solutions for oil wells is dictated by the quantity ratio in the production of raw oil, the rate of acceleration of the processing of layer water is in direct correlation with an increase in the extraction of raw oil, and, with it, important economic effects as well. As such oil wells generally used to be filled manually, the process was considerably slower, as the mixture needed to be sampled, which could take up to two weeks, whereas the implementation of the automatized system for the preparation of the saline solution considerably accelerates the process. The process of making the solution complementary to the geological soil is carried out in advance, and data show that the processing of layer water of around 30,000 m3 per oil well using the automatized facility enhances the procedures of making the saline solution, making them nearly 10 times faster, better and more efficient than manual mixing. For the said amount, savings per well are estimated at up to EUR 1,000,000 a year.
In 2017, WIG commissioned the facility in phases as per the investor’s needs, and the facility has been operating at full capacity since December 2017.
The realization of this project has solved one of the extremely complex problems of storing contaminated layer water in exploitation of oil and gas (based on the 2008 data, around 1,495,000 m3 of layer water was produced along the process of production of oil and gas), which produces considerable positive environmental and safety effects. By using the automatized facility and controlling process parameters (analyses of density, temperature, pressure, flow), the control of the process is enhanced, the manual labor is reduced, and the analysis of the entire process becomes simpler.
In Serbia, there are several thousand oil wells and there’s a great need to seal them properly following the exploitation, so that they would not collapse. Layer water, which rises to the surface after the drilling, gets contaminated, as it gathers ecologically harmful hydrocarbons in contact with the oil, which makes the sealing of oil wells with this water (as used to be the practice) an environmental problem on its own, as it leads to further pollution. Also, the fields treated this way become ecologically dead. By implementing the saline solution under controlled conditions, layer water compatible with the geological composition of the ground is returned to the oil well, and the automatized system considerably accelerates the entire process compared to the manual process.
The collection of layer water as a byproduct of drilling is the responsibility of the producer. It can be used as industrial waste.
In order for an adequate solution, such as the Serbian market needed, to be found, WIG used relevant scientific methods and pertinent engineering skills and knowledge. Thanks to mastering the knowledge and experience in designing and developing modern products of this kind, the company’s development center can expect new contracts with clients and new connections with producers of individual components.
The facility is entirely a result of local know-how and can be implemented in other markets as well.
The automatized system for preparation of saline solutions of the Belgrade-based company WIG provides an original solution to the very complex problems in an important and propulsive industry – raw oil exploitation and Serbia and beyond.
Although the facility was built for a concrete investor in the local market, it is not meant solely for this investor, and other countries are also interested in the technological solution of WIG’s engineers (Serbian know-how).
WIG already has experience in similar projects they’ve researched and developed at their center. The company is trusted and has a great reputation among customers worldwide when it comes to systems and installations meant for the processing industry, the oil industry above all, within which it innovates its production program in line with global tendencies.
According to WIG’s findings, the principle at the basis of the development of the automatized facility for industrial preparation of saline solutions might be implemented in other industries as well – for the removal of snow and ice from the roads, the softening of water, cooling (steel and other metals), in the chemical industry etc.
If WIG’s automatized system for preparation of saline solutions is your investment of the year favorite, you can vote for it on the official website of the Aurea award