At present, low-permeability formations become increasingly important in global hydrocarbon production. Simultaneous development of several reservoir zones with single well pattern - along with hydraulic fracturing became the most common for the today's upstream. At the same time, less attention has been paid so long-term monitoring of such comingled pay zone development with hydraulic fractures. Traditional monitoring methods offer minor benefits in such conditions. Based on theoretical considerations and numerical modeling of velocity, pressure, and temperature fields in tight formations tapped by hydrofracs (Eclipse 300), the authors proposed a new production monitoring technology. This technology is based on comprehensive production logging and well testing methods and involves the following innovations: It was found that in case of hydraulically fractured pay-zone the fracture will affect spinner logging showing homogeneous flow (injection) profile even in heterogeneous formation. Analysis of transient temperature survey in the assumption of linear geometry of temperature field is proposed as an alternative method.The authors assessed existing capabilities of long-term monitoring of downhole pressure and flow rates under conditions of comingled fractured tight reservoirs development, with individual zone real-time estimation of formation pressure, permeability, and skin factor. To avoid uncertainties of these parameters, the authors justified, in addition to this monitoring technology, the alternating well off take and shutdown cycles.A new methodology for estimation of permeability and skin-factor of individual layers (including the hydrofrac-related ones) based on well monitoring data using permanent downhole monitoring systems.The authors justify a comprehensive approach to tight reservoir development monitoring with hydraulic fractures, based on continuous acquisition, storage, and analysis of long-term, multifaceted survey which is critical for numerical modeling information support.

This study considers the potential use of well-testing for investigating cross-flows in production wells. Using a numerical model, the authors detected pressure behavior patterns which may become informative characteristics for diagnosing a cross-flow. To increase diagnostic reliability, the optimization of measurement technologies and interpretation methods to manage pressure behavior pattern characteristics are substantiated. These testing techniques make it possible to distinguish behind-the-casing fluid movement where background interference is present. One of the most interesting areas of application of the results obtained in this study is monitoring unsteady fracture creation in injection wells. Such fractures occur when the injection pressure exceeds reservoir fracturing pressure, and they break down shale layers between formations. When pressure is reduced, the fractures close up, and cross-flow stops. That is why the derivative behavior during the injection cycle significantly differs from that of the static state. Numerous examples illustrate that well testing is considerably more successful when combined with downhole logging. Introduction The conventional purpose of well testing is to investigate filtration characteristics, energy properties, formation geometry, and perfection of well penetration. 1,2,3,4,5,6,7, etc. Until now, the influence of interlayer behind-the-casing cross flows on well testing results has been considered an obstacle to reliable determination of formation parameters. Cross flow investigation, however, is an important independent task. The primary obstacle for its solution is that cross flow effect is difficult to identify against a background of numerous disturbances 8,9,10,11,12. To evaluate the informative value of well testing for this task, the authors used numerical modeling. Two types of cross-flows were considered: a cross-flow through permeable cement stone, and through a hydraulic fracture. The model included the following parameters: filtration characteristics, degree of perfection of formation penetration, behind-the-casing flow intensity, shape and size of the cross-flow channel, characteristics of well operation regimes, etc. Analysis of the modeling results enabled us to identify the unique features of well pressure behavior related to fluid and gas movement behind-the-casing. Cross-flow diagnostics based on these characteristics, however, is not always unequivocal. Similar well testing results may relate to other causes as well. The main idea of the work presented here is as follows: In order to increase the reliability of well testing interpretation, well research must be conducted in such a way that the primary effect under study (behind-the-casing flow in this instance) is manifested as distinctly as possible against the background of other influencing factors. Existing injection wells are among the most promising objects for implementing such an approach. It is well known that water-injection wells are frequently fractured due to the high bottom hole pressure and consequently have a negative skin effect. These fractures heal upon well shutdown. An induced fracture may connect adjacent formations, which is the primary cause of cross-flow initiation. The cross-flow intensity will depend on pressure. Filtration parameters detected by well testing in such unsteady systems will depend on the mode of well operation. This is primarily related to changes in effective thickness participating in operation. When integrated research involves start-up, flow rate change, and shutdown cycles, then interpretation of well testing results must change appropriately from one cycle to the other. This effect, along with a specific configuration of pressure derivative curve, is an additional cross-flow diagnostic feature.

Paper presents production logging (PL) problems in tight comingled reservoirs. Quantitative evaluation is possible when PL is done with JET pump or ESP & T-tool or naturally flowing wells.Authors have made series of numerical simulations to determine temperature distribution in producers and optimize production logging and interpretation procedure.Simulation illustrates traditional temperature interpretation technique with comparing well temperature logging curve with geothermal gradient is useless in case of tight reservoirs due to high influence of previous production and unstable flow. New way can handle that problem.New way of temperature interpretation to individual evaluation of tight comingled reservoirs can be used even in difficult for traditional temperature logging cases: horizontal wells, inflow control valves (ICV) presence in the wellbore, etc.Author's method is based on mathematical simulation and on production logging case studies. In high rate producers temperature logging were compared with spinner and results were the same.Technology implementation on comingled wells of Western Siberia oil fields gives each formation rate and pressure. That results in production and injection optimization to increase sweep efficiency and recovery.

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This paper describes experience gained through the field pilot exploitation of completion systems designed for simultaneousseparate exploitation (SSE) of multihorizon wells in conditions of South License Area (SLA) of Priobskoye oil field. Possibility of particular formation parameters monitoring and control is the main benefit of such systems. Overview of completion systems for SSE, ways and technologies used for control of multihorizon wells, experience of such systems application and opportunity for future application are also discussed in this work. Two main points are considered: Simultaneous Separate Production (ОРД -Russian abbreviation) for production monitoring and control of multihorizon wells and Simultaneous Separate Injection (ОРЗ -Russian abbreviation) completion system for water injection control in multihorizon injection wells. A special attention was paid to the long term monitoring of each penetrated formation on different flow regimes. The monitoring was conducted with downhole gauges (flow rate, temperature and humidity). Opportunity of such monitoring is one of the most important SSE advantages. Described technologies are part of the field intellectualization project. Purpose of this project is identification of the most effective system which enables control and surveillance of multihorizon wells. As a result, the unified system for the exploitation parameters control and monitoring, based on the observation wells network will be created.