Gazprom Neft begins exploratory drilling at the Ayashsky block in the Sea of Okhotsk
Gazpromneft Sakhalin (a subsidiary of Gazprom Neft) has begun drilling the first exploratory well at the Ayashsky licence block, located on the continental shelf of the Sea of Okhotsk. The programme of works to be completed during the 2017 ice-free season envisages well drilling, core sampling, the completion of extended geophysical investigations, and testing at target intervals. Detailed analysis of existing experience in implementing works on the continental shelf of the Sea of Okhotsk were analysed in detail in developing the basis for the drilling programme, as was experience in Arctic fields being developed by Gazprom Neft as operator.
A semisubmersible drilling rig (the “HAKURYU-5”)
Leading Russian and international companies have been engaged in implementing the project, and extensive preliminary activities essential to project completion successfully undertaken. Drilling and well testing in 2017 will be performed by a semisubmersible drilling rig (the “HAKURYU-5”), delivered to the field in mid-June, its equipment having undergone extensive modernisation and further adaptations in line with the climatic conditions of the Sea of Okhotsk in 2016.
Cutting-edge technologies will be utilised in constructing the well, with drilling fluids (drilling mud) used in drilling from the very beginning — i.e., “rathole” drilling, allowing the use of an innovative system for riser-free sludge disposal, in order to improve wellbore stability. A rotary steerable system will provide automatic support in hole straightening, reducing drilling time as well as volumes of drilling sludge, and minimising run-in-hole operations. In order to ensure “zero emissions” all waste drilling mud, sludge and cuttings will be shipped onshore for recycling. Innovative downhole testing technologies create scope to speed-up investigations into promising strata and take high-precision measurements in the safest and most effective way possible.
The results obtained will allow a subsequent field investigation programme to be developed and preparations made for test drilling during the 2018 ice-free season.
The Ayashsky block, located next to the developed fields of the Sakhalin-1 and Sakhalin-2 projects in this already proven oil- and gas-bearing region, forms part of the Sakhalin-3 project. Gazprom Neft Sakhalin has now completed analysis of geological and geophysical information allowing a decision to be made on selecting the most promising structures for geological prospecting works. Recoverable reserves at this latest Gazprom Neft asset are estimated at more than 100 million tonnes of oil equivalent (mtoe). Some 2,150 square metres of 3D seismic works have previously been completed at the Ayashsky block, although no exploratory drilling undertaken.
Gazpromneft Sakhalin is a subsidiary of Gazprom Neft. Established in 2002, the company is primarily engaged in exploration and development of oil and gas fields. Today the company holds licences for the development of the Dolginskoye oil field and the North-West block of the Pechora Sea, the Kheisovsky block in the Barents Sea, and the Severo-Vrangelevsky block, covering the East-Siberian and Chukhchi Seas.