Horizontal wells have a long history in Russia in many different producing basins. This paper relies on published sources to give the reader both general and detailed information about the applications, well types and performance which could be gleaned from published articles in Russian journals and books. A period of 60 years is covered, from 1947 to 2007, during which about 3000 horizontal wells have been drilled in Russia. The current rate of drilling is about 300 wells per annum. The paper looks at horizontal wells in four regions of Russia: Volga-Urals, Timan-Pechora, western Siberia and the Far East.
In the early days spectacular improvements in production were reported, in the range 10 to 20, compared with production from vertical wells. Lower improvement factors have been reported more recently in Tatarstan, in the range 1.3–1.6 in limestone formations and 1.5–3.5 in sandstone formations but in one case in western Siberia a factor 10+ improvement was seen. In heavy oil fields the rate improvement factors reported are 5–10. Underbalanced drilling has been tried successfully using oil-nitrogen mixture as drilling fluid. The improvement over horizontal wells drilled with conventional overbalance is 4 times.
It is proposed that an industry-wide data base be sponsored by the Ministry of Natural Resources so that operators could pool their data, establish a set of best practices and cooperate to optimize the performance of wells with horizontal well bores.
Techniques such as:
logging on coiled tubing,
well testing with packers and downhole shutin,
completions with downhole monitoring and control (smart well completions),
are used in Russia only by a small number of operators. Their benefit is in enabling the operator to check that the well is flowing over its full horizontal length and that the mechanical skin is close to zero. If not then drilling and completion practices need to be improved.