In this paper, we present for the first time, a classification system for naturally-occurring gas hydrate deposits existing in the permafrost and marine environment. This classification is relatively simple but highlights the salient features of a gas hydrate deposit which are important for their exploration and production such as location, porosity system, gas origin and migration path. We then show how this classification can be used to describe eight well-studied gas hydrate deposits in permafrost and marine environment. Potential implications of this classification are also discussed.
Multilateral drilling technology offers a highly effective method of enhanced oil recovery in fields characterized by complicated geological structure. This paper describes the analysis of sidetracks in an open hole by annular ledge formation with the use of a downhole motor in multilateral wells in Vostochno-Messoyakhskoye field.
Since May 2018, more than 130 sidetracks have been drilled in Vostochno-Messoyakhskoye field with the use of bottomhole assembly (BHA) with a downhole motor in open hole by annular ledge formation. The fundamental difference between this method and conventional sidetracking with a downhole motor is that during sidetracking the entire drill string constantly rotates, rather than just bit rotation produced by downhole motor operation. In the process of technology introduction a comparison was made on how different downhole and geological conditions influence the time and performance results.
The technology introduction resulted in the sidetracking time reduction from 9 hours to just 3 to 4 hours.
A number of additional advantages of sidetracking with annular ledge formation were confirmed in the process of operations:
The constant rotation of the drill string enables smooth weight transfer to the bit smooth, without failures. This contributes to effective and uniform ledge formation. Such sidetracking can be carried out at an extended length of open hole when it is difficult to ensure a free movement of the BHA which is necessary of conventional sidetracking. Constant rotation mitigates the risk of differential sticking. More favorable conditions are created for BHA movement in an interval of the holes diversion and subsequently for liner running in. It is possible to sidetrack with the use of a stiff BHA including a complete set of logging tools. In case of conventional sidetracking, it is preferable to use a short and flexible BHA.
The constant rotation of the drill string enables smooth weight transfer to the bit smooth, without failures. This contributes to effective and uniform ledge formation.
Such sidetracking can be carried out at an extended length of open hole when it is difficult to ensure a free movement of the BHA which is necessary of conventional sidetracking.
Constant rotation mitigates the risk of differential sticking.
More favorable conditions are created for BHA movement in an interval of the holes diversion and subsequently for liner running in.
It is possible to sidetrack with the use of a stiff BHA including a complete set of logging tools. In case of conventional sidetracking, it is preferable to use a short and flexible BHA.
The experience gained in Vostochno-Messoyakhskoye field can be extrapolate to other fields where multilateral wells are drilled with annular ledge formation.
Gas hydrates reservoirs are a type of unconventional reservoir that is an extremely abundant and ubiquitous source of energy. They are also relatively cleaner than most other hydrocarbon sources which makes them an even more attractive source of energy. The potential of this source of energy has, however, not been utilized since very little production has ever taken place from these reservoirs due to their complexity. This research provides an understanding of gas hydrates thermodynamics and reservoir properties in order to assist in properly modelling the hydrate flow in porous media. The research also provides a road map to the current production methods that have been used in pilot tests in order to produce from gas hydrates reservoirs. The production methods explained include depressurization, thermal stimulation, inhibitor injection, combined methods, carbon dioxide injection, and mining. The mechanism of each method is fully explained, and the advantages and disadvantages of each method are also explained. Several case studies worldwide are also discussed to show how each production method has been used to produce from the gas hydrate reservoirs. The results from the case studies are also used to reach conclusions on how each method can be improved upon. To the author’s knowledge, no publication has provided a complete overview on gas hydrates and their production mechanism which makes this research a crucial step in providing an overview on many aspects of gas hydrates reservoirs and their production mechanisms and potential. Understanding the mechanisms to produce from gas hydrate reservoirs is a crucial step in the hydrocarbon industry to allow us to tap into this vast source of energy in the near future.
Today, when most reservoirs have low productivity, the question of whether hydraulic fracturing can be applied to the oil rims becomes very important. During hydraulic fracturing at Novoportovskoe field, the operator was faced with a complex geological model of the reservoir characterized by an absence of strong barriers and minor contrasts in stress between interlayers associated with high risks of breakthrough into the gas zone. An outstanding example of oil rim stimulation and application of new technology was a project in Novoportovskoe field where 30-and 27-stage multistage fracturing operations (MSF) were successfully performed with a shifting ports completion operated by coiled tubing. Currently, oil and gas companies are increasingly demanding technical and technological aspects of the MSF, where the determining factors are the efficiency of operations, the number of stages, the length of the horizontal part of the well, the possibility of refracturing, and ability to open / close sleeves after operation for water and gas shut-off. The experience gained shows the possibilities of modern technologies, where the use of coiled tubing enables meeting the high requirements and also expanding the boundaries of the application. The 30-stage boundary was successfully overcome and allowed to increase the formation coverage by means of more fracturing stages. At the same time, the completion method made it possible to perform MSF without pulling the coiled tubing out of hole and to use all the capabilities and benefits of CT in the case of a screenout (SO). The teamwork between the customer and several of the contractor's product lines enabled successful completion of the integrated project under the difficult geological and climatic conditions of the Novoportovskoe field, which is located beyond the Arctic Circle. An optimized concept of MSF with the use of re-closable full-pass hydraulic fracturing sleeves, operated by a single-trip coiled tubing-conveyed shifting tool was developed and implemented.
With the current increase in demand on hydrocarbons, production from unconventional reservoirs has become extremely high. One of the most abundant, yet still not mass produced from, unconventional reservoirs is gas hydrates. This research investigates the applicability of steam injection in increasing gas recovery from gas hydrate reservoirs, and its impact on water production from gas hydrate reservoirs. The reservoir model was built based on data collected from previous models found in the literature. After specifying all parameters for the reservoir, and the hydrate layer, a systematic study was performed in order to assess the use of steam flooding as the primary hydrate production mechanism. The production methods studied include depressurization as the base case, and then steam injection. The conditions for the steam flooding were kept the same during all runs in order to be able to compare them. Results indicated that the use of the thermal stimulation alone without inhibitor managed to increase recovery, however, the problem of hydrate reformation occurred which caused a cessation of production. Also, water production increased significantly when using steam injection compared to depressurization, mainly due to the rapid hydrate dissociation during steam injection, and also due to the increased volume of water resulting from the injected steam. To the authors’ knowledge, no extensive study has been performed on using steam injection as the primary hydrate production mechanism, and assessing its impact on increasing water production form gas hydrate reservoirs. This research can help in improving real field gas hydrate projects by making the overall project much more economic by increasing hydrocarbon recovery.
Arctic is widely considering as the last world biggest storehouse of natural resources. But its unique nature should always remain the main concern for all the energy projects development in this area. To achieve this development of the Arctic should go along with innovative technologies development. The ambition of this paper is to provide assessment of main Arctic projects on international energy markets development.
Russia always plays an important role on iternational energy markets as one of the major oil and gas producers and exporters since the country entered international enrgy market in the middle of the last century. And this role will remain stable at least till the year 2040 according to current forecasts. BP estimates, that Russia will cover around 5% of the global energy demand by the year 2040. Though, Russia has around 17,4% of world gas reserves (OPEC's estimates its even more - around 24,6% due to the different methodology) and only around 6% in world oil reserves, Russia contributes 17,3% to world gas production and 12,2% to world oil production in 2018, according to BP's Statistical Review of World Energy. Developing of enormous gas and oil reserves was extraordinary challenging for the country due to harsh climate conditions, lack of infrastructure, unsufficient financing and need to develop not only fields but the whole remote areas of the country. Though the country was widely ctitised for its dominancy on the European gas market, in this paper it will be outline that developing of the European gas market was of mutual interest of Russia and European Union and both counterpart became beneficiary of it. This paper focuses on challengies with developing enormous gas reserves as Russia has several mega giant gas fields and its experience can be usefull in developing other mega projects around the world.
Evaluating of VIT performance
Statistics, Finite Element Analysis (FEA), Computational Fluid Dynamics (CFD)
The utilization of Vacuum Insulated Tubing (VIT) is necessitated by the growing oil and gas development in northern regions of the Earth and application of thermal oil recovery methods. Conceptually, VIT consists of two (external and internal) pipes coaxially fixed at the ends, with the annular space filled with thermal insulation including getters (gas absorbers). After the pipes are assembled, air is evacuated from the annular space to create vacuum. Getters are fully activating within vacuumizing. Prior to commercial utilization at Gazprom, the VIT was tested at the Gazprom VNIIGAZ Institute (Russia) on a dedicated thermophysical testing bench. Tests were designed to measure the Coefficient of thermal conductivity (k-factor) of the VIT Vacuum Shield Thermal Insulation. Results obtained during the tests are as follows: with hot air (84…93°C) passing through the tube, the temperature of its external surface remained within the range of 28…35°C, while k-factor was 0.004…0.008 W/(m*K). Gazprom requirements k-factor with max. 0.012 W/(m*K). When VIT successfully passed bench tests, they were approved for utilization in the commercial development of the Bovanenkovskoye field operated by Gazprom. In order to gauge heat flux and effective k-factor of VIT walls at different gas flow rates and fluid temperatures, the design provides for satellite pipes to be installed within the gas well's cement column. At the moment, wellhead soil temperature observations are carried out regularly at VIT-equipped wells. Some gas wells have been monitored for 3 years now. The results of monitoring of 18 well pads (163 wells) the temperature stabilization of the permafrost soil at which is carried out only through the operation of seasonally active cooling systems (without the use of VIT) show temperature increases in the soil along the wellbore. Wells operated with VIT and cooling systems keep freezing temperatures within the cement column throughout the entire annual cycle. For steam injection technologies, may be used theoretically estimation about how temperature of steam decreases from top to bottom of well depending on VIT k-factor and length of VIT string. Such information needs for VIT well design.
Empirical information about VIT utilization
Buchinskiy, Stanislav (LLC Tyumen petroleum research center) | Kovalenko, Alexander (LLC Tyumen petroleum research center) | Permyakov, Alexander (LLC Tyumen petroleum research center) | Khakimov, Artur (LLC Tyumen petroleum research center) | Savchuk, Danil (LLC Kynsko-Chaselskoe Neftegaz)
The article is devoted to creation problems of the strategy for involving of fields group in development, taking account of geological, logistic, organization factors, and aspects of forming the unite field facilities construction. In the present work the importance of conceptual approaches while planning of involvement in development of quite small fields group that are relatively near to each other is described.
Shturn, Dmitriy (Achimgaz) | Zavyalov, Nikolay (Achimgaz) | Perfilyev, Dmitriy (Achimgaz) | Kamenskiy, Leonid (Wintershall) | Tyurin, Victor (Independent consultant) | Astafyev, Vladimir (Halliburton) | Osipov, Ilya (Halliburton) | Zolnikov, Denis (Oil Energy)
The primary objective of large fracturing treatments (from 150 to 300 tons of proppant) in the Urengoyskoe (Urengoy) field is to increase the drained volume of the producing zone of the target reservoir by increasing the fracture length and placing a larger mass of proppant while maintaining similar fracture widths and heights.
The basic goal of fracturing is to increase production from the target reservoir. In this study, to increase the fracture length and propped fracture length in the target zone, linear gel fluid was used for the main fracture pad stage instead of the traditional cross-linked fluid pad. Because of the high filtration rate of linear fluids and their reduced efficiency, pads of larger volumes were used and were pumped at a higher rate. An additional goal of this strategy was to increase the formation coverage. The fracturing treatment proppant stages were pumped using crosslinked fracturing fluid, which helped to reduce the risk of screenout.
Large fracturing treatments using linear fluid pads increase risk because of the high possibility of screening out and because of undetermined economic efficiency. The initial strategy of the Achimov formation development for the given section of the field planned to complete wells using standard large fracturing treatments on S-type wells with crosslinked fracturing fluid throughout all of the main stages. Because of similar geological conditions across the field, the significant number of previous well stimulation operations performed, and the use of extensive logging by the operating company (including bottomhole pressure and temperature online monitoring during fracturing job, and production logging), it was possible to evaluate and compare the economic efficiency of large fracturing treatments using linear fluid pads and large fracturing treatments using crosslinked pads. The comparison of the results from geophysical studies after the fracturing and the subsequent well productivity analysis have been performed.
The described operations enabled fracturing risks and economic efficiency to be understood, both in the Achimov formations of the Urengoy field and in similar gas reservoirs with low permeability. Well productivity after fracturing with a linear pad increased in comparison with offset wells treated with crosslinked fracturing pad fluid.