Resman (Norway)

Abstract OMV Austria E&P GmbH operates 26 oil fields in Lower Austria. The majority was developed in the 1950s and 1960s and shows an extended decline period. The challenge of operating brown fields is seen to maintain a reasonable oil production over time in a cost effective manner - this can be tackled by a major chemical enhanced oil recovery field redevelopment project. The scope of the polymer field rollout is to create and efficiently operate horizontal polymer injection patterns in two horizons in Lower Austria. OMV follows the strategy to pilot new reservoir and production technologies before their application in field rollouts. Due to the large project investment volume it is crucial to derive information and lessons learned from existing pilot patterns to optimize conceptual decisions on artificial lift, completion, sand control and injection strategy and to reduce technical risk. In the past 10 years several vertical pilot patterns were created to analyze the efficacy of polymer injection in the Tortonian Horizon. Significant operational experience in water treatment, polymer injection and polymer back production, but also in tracer testing was established. Since already the vertical polymer patterns showed not only operational success, but also significant incremental oil production, the idea of horizontal flooding patterns was born. To confirm and understand the impact of polymer injection also in horizontal wells, a first horizontal pilot pattern was drilled; additional pilot wells are currently following. For a future field redevelopment the technology selection should be de facto based on either standard or pilot-proven technologies. This paper describes measures undertaken in the discipline of production technology to prepare for one of the largest field redevelopment projects in the history of OMV Austria. These measures include the application of several pilot projects in the field of artificial lift, completion design and sand control, production and injection allocation. Therewith production technology serves the needs for active reservoir management and thus, follows a holistic field development approach.

Abstract The scope of this paper is to share a field experience with permanent inflow tracer deployment and monitoring of an intelligent multi-lateral well, completed with Smart-Liner (Limited Entry Liner). It will describe what ADNOC Offshore has learnt through inflow tracing clean up surveillance from several restarts and steady state production through inflow modelling interpretation techniques. This passive method of permanent monitoring technology utilizes chemistry and materials expertise to design tracers that release signature responses when they come into contact with either in-situ oil or formation water. The chemical tracer technology enables wireless monitoring capabilities for up to five years. Unique chemical tracers are embedded in porous polymer matrix inside tracer carriers along select locations in the lower completion to correlate where the oil and water is flowing in a production well. Interpreting tracer signals can provide zonal rate information by inducing transients to create tracer signals that are transported by flow to surface and captured in sample bottles for analysis. The measured signals are matched with models through history matching to yield zonal rate estimates. ADNOC Offshore has installed inflow tracers in an intelligent multi-lateral well to monitor laterals’ contributions, to verify new completion technology, and to estimate the flow profile from individual sections of Smart-Liner, run for the first time in the field. The interpretation results have been able to characterize inflow performance without any intervention in the well. Several restart and steady state surveys are planned to understand some key characteristics of the well completion and reveal how the well has changed since it was put on production. This technology will help allocate commingled production to the three laterals. The use of inflow tracers will provide multiple inflow surveys that will reduce operational risk, well site personnel, costs and will improve reservoir management practices. Permanent inflow tracing is expected to change the way production monitoring can be performed, especially in advanced wells where PLTs or Fiber Optic technology cannot access multi-laterals.

Abstract With the development of well drilling and completion technologies multistage hydraulic fracturing in horizontal wells has proven to be the most effective method of production stimulation at the Priobskoye field with hard-to-recover oil reserves. At that, evaluation of the efficiency of the multistage hydraulic fracturing and of the inflow from each formation fracture currently remains a complex and vital problem for horizontal wells. Several monitoring methods were practiced at the Priobskoye field in order to select the optimum one from the viewpoint of easy application and the accuracy of the information obtained concerning the productivity of each hydraulic fracture. The following conventional and contemporary methods of multi-fractured well monitoring have been considered for practising at the field in Western Siberia: conventional production logging tools using coil tubing and distributed temperature survey monitoring technology (DTS) using fiber optic cable, marked proppant and intelligent inflow tracers.

Abstract Understanding the actual inflow distribution across the reservoir interval is valuable for optimizing reservoir management decisions. It is common to have varying levels of uncertainty in the petrophysical prediction of the inflow distribution. The inflow distribution assessment drives many aspects of the field development plan. A technique is presented for acquiring quantitative measurements of the inflow rate of various reservoirs or layers of a reservoir at various times in the life of the well using interventionless technology. Chemical tracers are embedded in sand screens that are positioned adjacent to reservoir layers at different depths of a well such that fluid exposure causes release of a unique chemical compounds into the oil produced from each layer. Analysis of the transient behavior of each of the chemical compounds from samples of the produced oil provides a quantitative assessment of the rate of inflow occurring from the adjacent reservoir section. The chemical tracer based measurements of inflow are compared to the petrophysical predictions of inflow distribution. The petrophysical rock and fluid properties are determined using tools such as LWD and core analysis. It is common for these sources to contain uncertainty in their assessments of the inflow potential. The chemical tracer technique provides an assessment of the actual inflow distribution that can be compared to the petrophysical prediction. This additional input is very valuable in reducing the uncertainty in the overall reservoir performance assessment. Case histories from two wells in frac-packed wells are presented. Both wells had substantial uncertainties in the petrophysical assessments of the inflow performance of layers in the reservoir. The results from the chemical tracer technique provided insight that led to high value decisions. In Case History #1, the chemical tracer showed a layer to be contributing non-commercial rates. The petrophysical based prediction of inflow indicated this zone was of lower quality than the other zones but it was decided to complete the zone as there was possibility of producing economic rates. Significant savings will be realized in future wells by not completing the non-commercial layer. In Case History #2, the overall productivity of the well was substantially below predictions of the petrophysical data. The chemical tracer inflow profile showed all zones producing similarly. The assessment of similar inflow in each layer implied the kh prediction from LWD to be overly optimistic. This insight changed the production profile forecast for future wells. This insight also prevented the need to perform an expensive PLT log in the well to determine if the entire interval was flowing. Measuring the actual inflow distribution across the reservoir interval in deep, frac packed wells is usually so impractical or prohibitively expensive that it is never performed. The technique presented of using chemical tracers embedded in the completion components provides an on-demand, low cost and minimal risk means of assessing the actual inflow distribution. The inflow distribution information is combined with other data sources to reduce the uncertainty of reservoir management decisions.

Due to the relative infancy of chemical tracer surveillance, field applications to date have focused on either pilot wells within a sector of the field or at a well or interval level, providing limited qualitative resolution of production performance. The Siakap North - Petai field is intended to be the first field developed employing full chemical tracer coverage across each producing well. This has been made possible through the co-ordinated efforts between service providers and the operator. A total of 40 oil marking and 40 water marking tracers, will be installed in 8 production wells, with resolution varying from 3 Screen joints per (Oil + Water) tracer up to 1 screen joint per (Oil + Water) tracer, depending upon the lithology and therefore level of feedback deemed necessary to help profile production performance within the well. Siakap North - Petai field will be a deepwater subsea tieback to the existing Kikeh FPSO approximately 15km away. Phase 1 development will comprise 8 production and 5 injection wells. As a result, conventional intervention and surveillance techniques will be cost prohibitive. Each production well will commingle oil from two reservoir intervals with differing lithologies (a mixture of laminated thin-beds and amalgamated thick bedded sections). A means of determining flow contribution along the completed interval will help characterise the complex architecture of the field, aid in reservoir management and identify future infill or workover opportunities. This paper will focus on the system design, quality control and application of the chemical tracer network from conception through to field installation. A follow-up paper focusing on sampling and production based observations will be published at a later date, once sufficient production data has been gathered.

Abstract Optimizing production from a multilateral well requires understanding and characterization of the well and completion performance in the flow path from the reservoir to the separator. Situations when crucial information may be gathered includes transient flow phases such as cleanup and restart after shut-ins. Understanding the inflow from the near-wellbore into each lateral and monitoring the functionality of completion components are important tools in establishing completion effectivness and wellbore performance. This paper describes new applications of chemical tracers in multilateral horizontal wells and utilizes flowbacks in understanding cleanup efficiency, confirming inflow from the toe-section of long horizontal wells and monitoring the functionality of ICV components based on a case study on four multilateral wells in the Alvheim field, Norway. A new generation of chemical tracers were embedded in a polymer matrix and installed in ICD screens on four long horizontal multilateral wells. In total, 27 unique oil tracers were used for 12 months of oil marking period designed for monitoring early production. The oil tracers were released when the tracers were in contact with oil and mobilized to topside sampling point with the produced fluids when the wells were opened for cleanup. The samples were analyzed in a laboratory and the tracer responses were used to study cleanup efficiency and to monitor ICV during sequential cleanup of laterals. The tracers were also used to understand the inflow contribution from the toe section of each lateral. The case study showed that intelligent well tracers provide a direct proof of contribution from the toe-sections of the multilateral wells and enabled monitoring of ICV functionality and synchronization.

Abstract Deepwater developments are very high cost ventures in complex reservoir environments. Acquiring insight into the reservoir inflow distribution and location of water inflow using conventional technology, such as production logging tools, is very problematic in the deepwater environment where wireline intervention into live wells is a major risk and cost. Intelligent chemical tracers are an emerging technology that provides insight into the inflow distribution without intervention operations or major alterations to the completion design. The tracers consist of unique chemical compounds that are combined with unique polymer formulations into a matrix that resembles strips of plastic. The matrix is designed to release the tracer when contacted by the target fluid, either oil or water. The matrix strips are deployed with the initial completion installation at strategic locations in the completion so that fluids entering the completion contact the matrix. At the surface, samples of the produced fluid are acquired and analyzed for the presence and concentration of each unique tracer that has been deployed in the completion. The concentration data is plotted vs time or produced volume. Analysis of these plots can yield answers to very valuable reservoir management questions such as: Are all the intervals producing? What is the relative contribution of each interval? Where is water break-thru occurring? Deepwater completions are frequently completed with sand screens. The typical sand screen design contains spaces where the tracer can be integrated without any changes to the design. If the screen design is not readily compatible with the matrix strips, specially design tracer carrier mandrels can be added to the completion. The passive nature and very low risk of deploying this technology is very attractive in deepwater wells. This paper reviews the fundamentals of intelligent tracer technology, methods of integration into deepwater completions and some field examples previous deployments.