The pdf file of this paper is in Russian. To purchase the paper in English, order SPE-166923-MS.
The problem of computer simulation of mechanical behavior of drill strings in hyper deep vertical, inclined and horizontal bore-holes is stated with the aim of forecasting the possible initiation of emergency situations during carrying out drilling operations. The question of stability and post-critical non-linear deforming and dynamics of the drill strings are considered. It is shown that all of them are singularly perturbed from the mathematical point of view and because of this, they are poorly amenable to theoretical (computational) analysis. The algorithms allowing surmounting these difficulties are proposed.
The software for study of these phenomena is elaborated.
In the stages of design of an elongated curvilinear bore-hole with complicated 3D geometry and technological regimes of their drivage, the elaborated software permits one to construct its trajectory securing the smallest values of resistance forces and to choose the least energy-consuming and safe regimes of drilling. It ensures also the possibility to determine the requirements for the necessary accuracy of the bore-hole drivage and for the acceptable geometrical distortions and imperfections.
In the stage of the bore-hole drivage, the created software permits to calculate forces and moments of resistance forces with allowance made for the real geometry of the bore-hole and admitted distortion of its axial line. It is possible to prognosticate possible emergency situations and design the measures for their exclusion.
At the stage of the emergency situation liquidation, this software allows to simulate the mechanical behavior of the system and its responses to the methods used for elimination of the failure consequences.
The pdf file of this paper is in Russian. To purchase the paper in English, order SPE-166855-MS.
Advanced drilling technologies were used on two offshore multiwell platforms in the Lunskoye and Piltun-Astokhskoye fields, in the Sea of Okhotsk to deliver wells that required complex drilling to manage well-to-well collision risk, and to perform underreaming operations, extended-reach drilling (ERD), sidetracking, geosteering, and acquisition of thorough logging-while-drilling (LWD) data.
The project benefited from the successful implementation of a new concept that combined various groups of technical experts within the operating and service companies to address project challenges through proper well planning, 24/7 monitoring, and intervention, when needed, during the execution phase, as well as post-well analysis fed into the planning of subsequent wells.
The effectiveness of the collaborative drilling technical team was proven by the overall results since implementing the new concept. Four wells were drilled "shoe to shoe?? 25 days ahead of approved for expenditure (AFE) time for the drilling phase. More than 70 proactive interventions to prevent nonproductive time (NPT) were made and delivered to the drilling teams during trial runs; of these, 60% were considered significant and resulted in the implementation of a drilling and engineering operations planning service on subsequent wells. It was the first time in the Lunskoye field that a well had been delivered 8.9 days ahead of AFE for 53.6 days for the drilling phase. The success established good synergy among the client geoscientists and drilling personnel in town, platform teams, including the drilling supervisor (DSV) and offshore drilling engineer (ODE), and service companies providing mud logging services, drilling fluids, directional drilling and LWD services, and bits and underreamers.
Thanks to the successful results obtained from the collaborative drilling technical team concept, it has been accepted for use in this major offshore project as it brings continuous improvement to drilling operations through a cyclic process of planning-execution-evaluation.
This paper describes some of the major issues around drilling world class ERD well in the Baltic Sea by a team of industry professionals from Lukoil, Schlumberger and Eurasia Drilling Company (BKE). The ultimate goal of the well construction organization was to deliver quality well under budget and within schedule with zero environmental impact.
A challenging well was successfully drilled to explore Cambrian production zone in D-41 structure. Key contributing factors to this success were:
- solid preliminary analysis,
- understanding of well bore stability by real time geomechanical modeling,
- comprehensive directional analysis,
- revised casing design,
- application of latest drilling technologies,
- creation of multi-discipline team with common goals.
Since the launch of RADARSAT-1 in 1995 and RADARSAT-2 2007, these SAR sensors have played a pivotal role as a key source of information for the production of ice charts and the provision of near-real time data to support shipping. The RADARSAT-2, wide-swath ScanSAR modes coupled with dual polarized imaging capability are ideally suited for ice mapping applications. The space segment is augmented with a ground segment that has been designed to meet the needs of rapid data processing and delivery of ice information. The wide swath-width combined with high-latitude areas-of-interest provides multiple imaging opportunities per day. Ice-type discrimination, for example first-year versus multi-year ice, can be achieved by using HH polarized data, and HV polarized data can be effectively used for ice-water discrimination. To meet the needs of end-users who require ice products in near-real time, MDA has developed automated ice-water discrimination algorithms and techniques to estimate ice pressure. RADARSAT-2 data are routinely used to support ice-breaking operations, commercial shipping, seismic exploration, and offshore oil drilling. A key requirement to support these activities is to provide the data in an interpretable and interoperable format that best suits end-user needs.
The pdf file of this paper is in Russian. To purchase the paper in English, order SPE-166845-MS.
The Kharyaga oil field is located beyond the polar circle in northeastern Europe, and since 1999, has needed first-class thermal insulation for its ESP-lifted wells to produce. In these Arctic conditions, the permafrost typically reaches thickness of up to 300 meters. And with the wax appearance temperature (WAT) or pour point as high as 50°C and 30°C for some geological objects, managing wells in order to minimize wax scraping operations is a real challenge. Especially during shut-in periods, as the produced fluids cool down the risk of wax totally plugging the tubing is significant.
To combat that risk, the production or injection annuli are systematically filled with gelled diesel. Permanent real-time temperature monitoring by fiber optic sensors has been deployed in the production annulus of six wells so far, to measure temperature distribution along the wellbore across the permafrost layer, down to the reservoir. And thermal modeling, using the Enthalpy Balance thermal model, shows a good match with the temperatures thus measured. It also confirms the fine thermal quality, as per expectations, of the gel deployed.
For the purposes of further development of the Kharyaga field, which includes wells with liquid expected rates less than 1,000 bpd, well modeling flags up the necessity for additional thermal insulation. Using 3½?? instead of 4½?? tubing is a first solution: trials on two wells have shown a gain of up to 12°C. The benefit and design of field proven double-wall tubing was also assessed for the many additional development producers planned. One set of vacuum-insulated tubing (double-wall tubing with vacuum inside) is already on the spot ready for a field trial on a future work-over in the Kharyaga environment.
Total E&P Russia has operated "Objects 2 & 3C, 3N" reservoirs since October 1999. Production is exported via the pipeline to the Primorsk terminal located ~2500 km from Kharyaga on the Baltic Sea coast. Kharyaga reservoir rocks are highly heterogeneous, fractured and karstified carbonates. The behavior of the main object is driven by secondary permeability network (karst, fractures) which makes prediction of reservoir properties and field behavior extremely complex.
The pdf file of this paper is in Russian. To purchase the paper in English, order SPE-166857-MS.
Maintaining a high level of production volume means the maximum use of the opportunities of each well. The application of a number of ways to intensify well productivity, such as hydraulic fracturing, acid treatment, heat treatment, etc. is not always possible due to a number of geological and technological reasons. In addition, each of these methods has a negative component effect on the reservoir properties. The effectiveness of these methods, the impact on the bottom zone (producing zone) is often limited by the lack of reliable hydrodynamic connection between wells producing formation, which may be caused by deterioration of reservoir properties over time, the lack rock permeability, reservoir heterogeneity, insufficient length of perforations, etc. .
Description of the proposed perfodrill design and operation.
The new technology is designed to increase the perforation production flow rates and increase injection capacity of injection wells (by increasing filtration area producing zone), reduce water cut (by reducing the drawdown), as well as improving the turnaround time for well operation (by increasing the hydraulic perfection of producing zone) .
The technology involves the removal of the casing of the first stage of research and development project (hereinafter - drilling through the casing with change bit without lifting oriented capture and anchors for drilling in rock shown in Figure 2. The extension of the main trunk, injecting insulating special gelling agent, the creation of cement plug, drilling out its auxiliary barrel, drilling super long channels according to the predicted trajectory in one run [2, 3, 6].
According to expert assessment current level of world oil production of 4,2 - 4,5 billion tons per year will be held till the end of fortieth years of XXI century /1/. The forecast for the Russian Federation for 2013 - oil production will be 581 million tons.
Oil pollution belongs to the massive and the most dangerous expressions of anthropogenic influence on nature systems. Losses of oil products during extraction, transportation and refining reach 3-5% from total volume.
Soil and water contamination with oil products significantly worsens ecological situation in the regions and leads to damaging of soils structure; growth of acidity; reducing of soil fertility (cause of humus loss process) and homeostasis; changings in structure of soil biocoenosis of microorganisms with accumulation of phytopathogenic microorganisms; degradations and depressions of vegetation and damaging of biocoenosis structure in general.
The volume of global market of cleaning of territories from oil pollution is estimated at 25 billion dollars according to ecological organizations data. Total economic damage for the Russian Federation caused by oil and petrochemicals reaches hundreds of billions of rubles annually.
Known technologies of soil cleanup and water purification from hydrocarbon pollution can be conditionally divided into three groups: mechanical, physiochemical and microbiological. They are applied separately or in combination in each specific case.
1. Mechanical means of pollution elimination (collecting, oil fraction separation, waste removal and recycling). These measures are ineffective in difficult conditions of application. Always require advanced treatment. Not eco-friendly in general.
2. Physiochemical methods (usage of oil adsorbents and chemical decomposition of oil products). Lead to accumulation of waste. Require advanced treatment. Little eco-friendly.
3. Microbiological technologies (application of bio products on the basis of microbes-destructors of oils or activation of native microbiota). Eco-friendly. However microbiological treatment is ineffective at high concentration of impurities. Require the agrochemical actions to secure optimal conditions for microorganisms activity (watering, cultivation, mineral fertilizing).
This work is dedicated to the search and analysis of the microbial communities able to perform quick and effective biodestruction of the aqueous oily wastes. We developed a method for estimation of efficiency of existing preparations and for qualitative evaluation of the degree of carbon compounds degradation. This method will be the basis of the technology of oily decontamination of water and forelands in the arctic conditions. The experiments wede done in the conditions very close to the arctic (on the White Sea Biological Station and in a laboratory setting. We have isolated several microbial communities that are able to perform the destruction oil carbohydrates. On the basis of these communities, we plan to create the preparations highly effective in the arctic conditions.
Utilization of oily wastes in the low temperatures conditions is of great actuality when developing oil fields in the far north. In the moderate climate regions, oil residuals (after the physical and/or physic-chemical purification) are utilized by soil microorganisms or using several commercially available microbial preparations that accelerate the process. The active components of such preparations are usually carbohydrate-oxidizing microorganisms that are able to perform oil conversion into the bacterial biomass of organisms that, in turn, transfer the oily wastes into the safe components. These biopreparations are actively used after the physical and/or physic-chemical remediation. Microbial bioremedation allows effective utilization of residual oily wastes, if using of other methods is economically unadvizable, technically complicated and/or ecologically unsafe. At the same time, the end-product of microbial conversion of oily wastes is the biomass of carbohydrate-oxidizing bacteria which serves as a feed for the other organisms of this geobiocoenosis.
The literature search has shown that nowadays many preparations are developed that are aimed to the control of the oily wastes. These preparations are masses of viable microorganisms-biodestructors and differ one from another by strains used for their creation. These strains are characterized by different physiological and biochemical properties, such as thermotolerance, osmophility, optimal ???, ability to utilize different classes of carbohydrates and n-alkanes in their metabolic processes. These properties of the strains- biodestructors determine the efficiency of their using in different climatic zones in order to control chemically different wastes.
Generally, all existing preparations are intended for the destruction of the oily wastes of not only soil, but also fresh-water basins, areas of seas, factory runoffs and contaminated inner surfaces of process reservoirs and tanks.
The pdf file of this paper is in Russian. To purchase the paper in English, order SPE-166931-MS.
The goal of this article is the development of the research software for precise estimations of seismic resistance of ground facilities. The base of the method proposed is the mathematical modeling of elastic waves propagation originated in the earthquake hypocenter through heterogeneous media. As a source of the perturbation the geophysical focal mechanism model based on the slipping along the fault is used. For the description of dynamic behavior of media the hyperbolic system of equations of elastic media is used with the explicit allocation of contact borders of all heterogeneities. It is solved using the grid-characteristic method on curvilinear structured 3D meshes. One feature of used numerical algorithm is its high scalability per number of cores. The usage of curvilinear meshes allows description of a wide variety of geometries with high precision. Assessments of seismic resistance are based on the analysis of plasticity and rupture criteria (Mises, Tresca, etc.). Mathematical formulation of problem, development of the research software and a set of numerical experiments were done by authors. The results of modeling of propagation of seismic perturbation through geological multilayered medium and assessment of seismic resistivity of ground facility are described in this article. The estimation of software scalability per core was carried out. The wave response from a cluster of gas-filled vertical cracks was obtained in 3D case.