Development of reservoirs with high oil viscosity is usually challenging because of requirement to apply comlex technologies for economical efficient oil recovery. East Messoyakhskoye oil field is a complex project both from geological caracteristics (viscous oil with viscosity 111 cP, highly heterogeneous reservoir with permeability 50-2500 mD, presence of gas cap and aquifer) and due to its remote location (arctic climatic conditions, no transport and industrial facilities). Main reserves are located in reservoir PK, senomanian formation. At the field development plan stage calculations showed requirement of flooding for reservoir pressure maintenance, but waterflooding expected to be risky due to fingering and it was obvious that for efficient reservoir development enhanced oil recovery methods should be considered. This paper presents choosen enhanced oil recovery strategy, the way passed in polymer flooding implementation and current results.

This paper describes succesfull experience of implement hydraulic fracturing at unconsolidated low-temperature formation in Yamal region in Russia. Experience of hydraulic fracturing as known as well stimulation method for deep-water deposits of West-Siberian oil an gas basin. Hydraulic fracturing at terrestrial deposits, which is Vostochno-Messoyakhskoye field, are not used in general practice. There are few reasons for that: shallow depth (about 800m), incompetent rock, gas-cap and oil-water contact have to limit fracture height, low formation temperature (16°C) doesn't available to use traditional oxidezing breakers and resin-coated proppants. But the other hand high viscosity of oil (111CP) promotes to using hydraulic fracturing for increasing coverage ratio at exploration of high-stratified formation. All these points are signing that classic hydraulic fracturing techniqes are not applicable for this facility. The basic development technology is the drilling of horizontal wells with a length of 1000m, equipped uncased liners with filters (both premium and perforated pipes). However, as the first results of drilling and development of wells of full-scale development showed the extraction of reserves located in a highly divided reservoir is a laborious process and requires the attraction of new technologies of drilling, completion and production stimulation. There was developed pilot project of implement hydraulic fracturing technology to directional wells for subsequent replication to horizontal wells using specialized completion systems. This article describes the implemented program of pilot work on directional wells and a set of accompanying surveys, also provides conclusions and plans for further replication to horizontal wells with the transition to multi-stage fracturing technology.

No abstract

No abstract

Field development planning requires a proper understanding of layer permeability in order to predict production rates. Experience with horizontal production wells in the Pokurskaya formation of the Messoyakhskoye field showed systematically lower flow rates from the B sands versus the C layers even though their petrophysical properties appear similar. It was proposed that differing permeability anisotropy between the layers might be the cause and an upcoming well in the field offered the ability to test this hypothesis. A logging program that included Vertical Interference Tests (VIT) with a Wireline Formation Tester tool (WFT) and advanced petrophysical logs, 3D resistivity, NMR and dielectric scanner was run to estimate the the kv/kh ratio pointwise with VIT and extrapolate these measurements through the entire section. VIT tests were done at several depths with a dual-packer for the fluid withdrawing and a pressure probe for pressure monitoring. Estimated anisotropy coefficient varies mainly from 0.02 to 0.07 but with both higher and significantly lower values at some depths, which indicate extremely limited connectivity in some intervals. In general, the kv/kh ratio is significantly lower in the upper interval of the PK1-3 formation versus its lower interval. The triaxial induction logging shown the anisotropy of the reservoir electrical properties (Rv> Rh), caused by thin interbedding of the sandy fraction rocks with the interlayers of clays and siltstones, which are several times lower than the resolution of standard logging methods. Similarly, interlayering of thin sand and silty rock types, which have different absolute permeabilities, causes anisotropy of the formation permeability. It is possible to estimate the permeability of the macroanisotropic formation along and across the bedding knowing the water-retaining capacity as well as the laminated sand fraction coefficient. The VIT and the logging results are consistent enough. The VIT test results are the reference measurements while the 3D induction logging results are used for interpolation and extrapolation of these direct measurements through the entire interval and in wells without VIT tests including horizontal wells. The subsequent analysis showed a significant anisotropy of permeability in the Pokurskaya formation, which varies along the interval of the formation and, probably, laterally. This must be taken into account when calculating the flow rates of the well. The complex of studies makes it possible to perform an express estimation of the permeability anisotropy in the pilot wells in order to select the optimal interval for horizontal wells landing.