Gazpromneft-Khantos, a subsidiary of Gazprom Neft, has completed 30-stagehydraulic fracturing (fracking*) operations at the Yuzhno-Priobskoye field, Khanty-Mansiysk Autonomous Okrug — the first time such an operation has ever been undertaken in the Russian oil and gas industry, completion of which has been made possible thanks to the application of new technologies, which now promise greater effectiveness in the company’s development of its assets. Hitherto, the most extensive such operation undertaken by Gazprom Neft had been an 18-stage fracking operation through a single horizontal well shaft, achieved in March 2016, again at Gazpromneft-Khantos’ Yuzhno-Priobskoye field.
The 30-stage fracking operation was undertaken in what is a record horizontal well shaft for the Yuzhno-Priobskoye field, running for 1,500 of the well’s total length of more than 4,600 metres. The oil-bearing strata lies at a depth of more than 2,600 metres. Isolation of those stretches in which fracking has already been completed is achieved through the use of a multi-set packer (a device for ensuring the hermetic sealing of separate well sections), running the full length of the flexible lifting pipe. Managing the 30-stage fracking operation required 1,200 tonnes of proppant**. Another feature of the well involved the cementing of the entire length of the horizontal section, allowing greater efficiency in managing fissures, thanks to the isolation achieved through the cement column.
The anticipated operational capacity of the new well is likely to be in excess of 130 tonnes of oil per day, some 20 percent higher than forecast levels following lower-stage fracking operations. The application of non-ball-and-socket technology*** in fracking strata means the company also has the opportunity not just to speed up the launch of the well but also undertake geophysical investigations throughout the entire period of its operation, as well as undertaking investigations in re-fracturing.
Vadim Yakovlev, First Deputy CEO, Gazprom Neft, commented: “Gazprom Neft’s long-term development strategy is inextricably bound with the search for effective production technologies. Improving oil recovery and bringing into development reserves previously considered non-viable are key components of the company’s Technology Strategy, the implementation of which is, already, allowing us to apply advanced techniques in enhancing oil recovery, and which we will, in the future, be able to use throughout our other assets.”
* Hydraulic fracturing (fracking) is a means of intensifying oil production, through the high-pressure injection of a mixture of fluids and a special proppant agent (proppant) into strata. The process of injecting the mixture creates highly conductive channels (“hydraulic fractures”) connecting the well (bore hole) and the strata. These fractures allow oil to flow that would not, under other circumstances, reach the well. Under multi-stage fracking, multiple fracking operations can be undertaken from a single horizontal well, allowing a manifold increase in the catchment area covered from that well.
** Proppant — an artificial agent necessary for maintaining fissures in an open state after completion of fracking operations in a well.
*** The key feature of this new technology, predominantly, lies in isolating the frac ports (the points inside the well from which fracking is expected be undertaken) from previously treated zones. Under more traditional “ball and socket” technology, each new fracking zone is separated from the preceding one by a metal (or composite) ball. The diameter of these balls increases from zone to zone, with the result that the way these wells are constructed makes more than 10 fracking operations impossible. Multi-stage fracking at the Yuzhno-Priobskoye field does not involve using balls as isolators, but, rather, a special instrument with a multi-use compacted “cushion”, which expands to isolate those areas in which fracking has been completed. Once work has been completed this deflates to its normal size and the equipment can be transported to the next area, for downhole fracking (in contrast to the more traditional balls, which have to be destroyed once fracking is completed). In which circumstances, the number of fracking operations is limited only by the extent of the well itself, and by technical and economic considerations. In addition to which, this method allows research to be undertaken from within the well, as well as allowing repeated fracking and the quick commencement of production once all fracking operations have been completed.
