Implementation of hydrojet perforation technology with acid fracturing on carbonate formations with horizontal noncemented completion

Background. The article describes the experience of using one of the directions of hydrojet perforation technology with acid fracturing in wells, the design of which is a non-cemented horizontal section in a fractured carbonate object. The technology is considered from the point of view of the method for refracturing into zones which were not previously stimulated (or where stimulation was only in the form of acidizing). A complicating factor is the presence of hydrogen sulfide in borehole products with a content of up to 6 %, which limits the pool of technologies and methods that are applicable to this type of facility.

Materials and methods. In the work, using the example of well, is given the logic of evaluating reservoir stimulation during primary acidizing. The result made it possible to choose a method of stimulation and zones of interest for further work. The most suitable solution was to apply the hydrojet perforation technology with acid fracturing for two formation intervals at once. The isolation of annular space from hydrogen sulfide was performed by packer setting. Also, were used bottom hole pressure and temperature gauge for evaluation quality of the job and prove the result of intervals separation.

Results. The authors show the company’s internal experience, industrial tests, methods and schemes of technology adaptation. The results presented in the article allow us to conclude that the solution applied at the facility, with a high-quality selection of candidates for fracturing, can have an effect in the form of additional production and, thereby, prolong the life of existing wells.

Conclusion. This article shows the successful experience of implementation of the hydrojet perforation technology with fracturing in terms of preparation and execution of jobs, analysis of available information, risks and limitations. A qualitative approach made it possible to successfully complete all planned activities at the well, starting from the running down hole tubing with equipment, two-stages of fracturing and ending with its running out. The authors believe that with the correct assessment of candidate wells, their potential and previously performed work, the solution can be widely used in similar geological and completion conditions.