Scale deposits are a common problem in oil and gas wells and can have detrimental effects on well production. Depending on the severity, scaling can stop production entirely as scale forms anywhere in the well production system, including the formation, perforations, casing or tubular, and in or on the artificial lift equipment. There are several chemical and mechanical methods for removing scale deposits. However, to prevent scale deposition, the only solution is chemical inhibitors injected into the formation. The typical production system includes artificially lifted, stimulated wells (propped hydraulic fractures) placed in reservoirs where pressure maintenance is achieved by water flooding. The artificial lifting is typically accomplished through use of electric submersible pumps (ESPs). In reservoirs where produced fluids exhibit scaling tendencies, ESP run life is significantly shortened by scale formation on the pump elements restricting rotation. By treating the formation with chemical inhibitors, the life of the ESP can be extended. In this paper we provide approaches for improving a compatibility of a novel hydraulic fracturing fluid (used in Russia) and scale inhibitor. A 3-year campaign to combine scale inhibition with the hydraulic propped fracture effectively increased the average run life of ESPs in the Mayskoe and Snezhnoe oil fields.

The most efficient way of production enhancement is the hydraulic fracturing which has proven efficient in majority of the fields in Western Siberia and over the world. Despite wide stimulation experience in the Siberian region there are still some unresolved issues. One is the proppant flowback, a root cause of well equipment damage and also reduction in conductivity of the fracture itself. One of the ways to prevent the problem is the usage of resin-coated proppant (RCP). However there is a disadvantage of this method - agglomeration of polymeric material reduces fracture conductivity in the near-wellbore area. Since 2013 a pilot campaign with the usage of rod-shaped proppant has started in a region. This unique product has two main advantages over a classical spherical proppant: enhanced conductivity of a proppant pack and inherited proppant flow back prevention. Due to the rod-shaped form of the particles, pack has improved stability. Comparison of conductivity tests for different proppants shows that rod-shaped proppant outperforms conventional ones typically used in the region. This also leads to better fluid and polymer recovery and results in increased effective fracture length, hence in substantial production enhancement. There are 9 oil fields near Langepas a city in Khanty-Mansiysk district. These oil fields are at the latest stage of development: decreasing production rates and recovery of the most part of resources. Drilling has shifted to edge zones of the reservoirs and wells start-up is challenging due to low production rates (small net pays and low values of permeability and porosity). At the moment rod-shaped proppant has been successfully implemented in 4 wells on Jurassic and Achimov formation and the first positive results have been obtained - no proppant flow-backs detected and wells productivity enhanced by 20%. Detailed results of the first project with rod-shaped proppant application in Western Siberia (Russia), including a comprehensive analysis of well production performance, are covered in this paper.

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Accelerated multi-stage hydraulic fracturing at the Samotlor Field significantly contributes to the reduction of time and financial costs for well construction and well interventions. High friction pressure loss is one of the main causes of complications, extra process operations, and, as a result, extra time and financial costs for multi-stage hydraulic fracturing with selective packers and burst port collars. A comprehensive analysis of MS frac data and testing of new approaches to mini-frac confirmed a potential significant reduction in MS frac costs at the Samotlor Field. The work consisted of three stages. The first stage included the following: Compared the data from wellhead and downhole gaugesAnalyzed in-situ temperature profileAnalyzed the results of Step Down Tests (SDT)Identified patterns of pressure changes in the bottomhole and near-wellbore zonesAnalyzed the causes of high working pressures at collar activation stages. The second stage covered a mini-frac pilot against a modified approach: Cancelled Step Down TestsIncreased planned fluid ratesCancelled a mini-frac with proppantDetermined methods for optimizing the main hydraulic fracturing. The third stage confirmed the efficiency of new approaches to multi-stage hydraulic fracturing with a selective packer and burst port collars at the Samotlor field. The paper analyzes the data on wells with the following types of completions: 34 wells with cemented liners14 wells with non-cemented liners with swellable packers. 330 hydraulic fracturing stages were analyzed. The sensitivities of friction changes in the bottomhole zone and the frac collar zone to various factors were evaluated: Number and types of injection jobsFluid flow rateEffect of hydraulic fracturing fluid and abrasive effects of proppant. The design features of internal-flush sleeves with burst port collars were studied and factors affecting fluid flow restrictions in the near-wellbore formation zone were determined. Based on the analysis, recommendations were made to optimize injection jobs during a pilot and the main hydraulic fracturing. Pilot jobs were carried out in 40 wells, which included 150 stages without traditionally performed test injections (a step-down test with a decrease in flow rate and a calibration test on crosslinked fluid with proppant). The tested methods allowed to accelerate the hydraulic fracturing process, reduce the volume of injected fluid, speed up the decision-making process related to field jobs, which led to accelerated operations and reduced cost of multi-stage hydraulic fracturing at the Samotlor Field. The novelty of the work lies in the development and justification of an individual approach to a set of test studies and the types of changes in hydraulic fracturing programs depending on subsurface and engineering factors, working pressure profile, and estimated friction losses. As mentioned earlier, the proposed approach will significantly reduce the time and financial costs of multi-stage hydraulic fracturing at the Samotlor Field. The approaches can be adjusted and rolled-out to other fields in case of applying burst port collars and selective packers.