Day 4 Thu, June 14, 2018最新文献

{"title":"Pore-to-Core EOR Upscaling for CO2-Foam for CCUS","authors":"A. U. Rognmo, S. Fredriksen, Z. Alcorn, M. Sharma, T. Føyen, Øyvind Eide, A. Graue, M. Fernø","doi":"10.2118/190869-MS","DOIUrl":"https://doi.org/10.2118/190869-MS","url":null,"abstract":"\u0000 An ongoing CO2-foam upscaling research project aims to advance CO2-foam technology that accelerate and increase oil recovery, with reduced operational costs and carbon footprint during CO2 EOR. Laboratory CO2-foam behavior will be upscaled to pilot scale in two onshore carbonate and sandstone reservoirs in Texas, USA. Important CO2-foam properties such as local foam generation, bubble texture, apparent viscosity and shear-thinning behavior with a nonionic surfactant were evaluated using Pore-to-Core upscaling to develop accurate numerical tools for field pilot prediction of increased sweep efficiency and CO2 utilization. On pore-scale, silicon-wafer micromodels showed in-situ foam generation and stable liquid films over time during static conditions. Intra-pore foam bubbles corroborated apparent foam viscosities measured at core-scale. CO2-foam apparent viscosity was measured at different rates (foam rate scans) and different gas fractions (foam quality scans) at core-scale. The highest mobility reduction (foam apparent viscosity) was observed between 0.60-0.70 gas fraction. The maximum foam apparent viscosity was 44.3 (±0.5) mPas, 600 times higher than that of pure CO2. The maximum apparent viscosity for the baseline (reference case, without surfactant) was 1.7 (±0.6) mPas, measured at identical conditions. CO2-foam showed shear-thinning behavior with approximately 50% reduction in apparent viscosity when the superficial velocity was increased from 1 ft/day to 8 ft/day.","PeriodicalId":178883,"journal":{"name":"Day 4 Thu, June 14, 2018","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128742282","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Open Source Toolkit for Micro-Model Generation Using 3D Printing","authors":"T. Seers, Nayef Alyafei","doi":"10.2118/190852-MS","DOIUrl":"https://doi.org/10.2118/190852-MS","url":null,"abstract":"\u0000 Here, we present an open source toolkit for the generation of micro-fabricated transparent models of porous media (micro-models) from image datasets using optically transparent 3D polymer additive manufacturing (3D printing or sintering). These micro-models serve as both a research and pedagogical tool, facilitating the direct visualization of drainage and imbibition within quasi-2D porous media, generated from a range of image modalities (e.g. thin section micrographs, μCT orthoslices, and conventional digital photography).\u0000 Written in the MATLAB™ language and readily extendible, this open source toolkit is intended to act as enabler for community research for the study of transport in a porous media. In this work, we demonstrate the toolkit's capabilities using X-ray micro-tomographic image data. Orthoslices of scanned rocks (Berea sandstone) are cropped and segmented (binarized), then used to generate watertight 3D meshes of micro-models, which are exported as stereolithography (.stl) files: a native format to most commercially available 3D printers. The generated models are self-contained, with the inlet-outlet ports, synthetic rock matrix and transparent viewing panels printed as a single integrated unit.\u0000 The open source toolkit presented here offers a more accessible and adaptive approach to micromodel fabrication, when compared to conventional etched/molded equivalents, which require highly specialized manufacturing facilities. We suggest that the availability of such a toolset will act as a major enabler for community research in porous media transport phenomena, allowing experimental quasi-2D pore networks to be generated rapidly and cost effectively using readily available additive manufacturing technologies.","PeriodicalId":178883,"journal":{"name":"Day 4 Thu, June 14, 2018","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130762678","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of Variation in Fractures Conductivity and Well Location on Pressure Transient Response from Fractured Reservoirs","authors":"D. Egya, G. Sebastian, P. Corbett","doi":"10.2118/190884-MS","DOIUrl":"https://doi.org/10.2118/190884-MS","url":null,"abstract":"\u0000 Fractures often influence production behaviour in hydrocarbon reservoirs, yet the pressure transients observed in the wells may not show the conventional well-test signatures. In this case, the effect of fractures on production would be misinterperted or even completely missed. Fracture networks are commonly multi-scale and properties including aperture (or conductivity), length, connectivity and distribution vary greatly within a reservoir. The heterogeneous nature of fractured reservoirs make them very difficult to characterise and develop. In addition, the location of a producer within the fracture network also control flow rates and affect the pressure response; however, conventional well-test analysis assumes that the producer is located in symmetrical fracture networks. To improve our understanding of fracture flow behaviour from well-test data, and in order to better characterise the impact of fractures on reservoir performance, we investigate the effect of variations in fracture conductivity and location of the producer in the fracture network on the pressure transient responses.\u0000 Naturally fractured reservoirs (NFR) with well-connected fracture networks are traditionally simulated using the Dual-Porosity (DP) model. However, several studies have shown that the classic DP response (V-shape) corresponding to the DP model is an exceptional behaviour applicable only to certain reservoir geology and does not apply to all NFR. To overcome the limitations of the characteristic flow behaviour inherent to this model, we employ Discrete Fracture Matrix (DFM) modelling technique and an unstructured-grid reservoir simulator to generate synthetic pressure transients in all fracture networks that we analysed. Our rigorous and systematic geoengineering workflow enables us to correlate the pressure transients to the known geological features of the simulated reservoir model.\u0000 We observed that depending on the location of the producer in the fracture network and the properties of the fractures that the producer intercepts, the synthetic pressure transients vary significantly. We therefore use these insights to quantify the impact of variation in fracture conductivity and producer location on fracture flow behaviour and systematically present interpretations to these behaviours. Our findings enable us to interpret some unconventional features of intersecting fractures with variable conductivity. We observed that the behaviour of two intersecting fractures where the well asymmetrically intercepts a finite-conductivity fracture can be similar to that of a well intercepting a fracture in a connected fracture network with uniform fracture conductivity. Furthermore, a well intercepting a finite-conductivity fracture in NFR with both finite- and infinite-conductivity fractures would yield a dual-porosity response that may otherwise be absent if the fracture network is assumed to have uniform conductivity.","PeriodicalId":178883,"journal":{"name":"Day 4 Thu, June 14, 2018","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131210281","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An Experimental Investigation of Immiscible CO2 Flooding Efficiency in Sandstone Reservoirs: Influence of Permeability Heterogeneity","authors":"Duraid Al-Bayati, A. Saeedi, M. Myers, C. White, Q. Xie","doi":"10.2118/190876-MS","DOIUrl":"https://doi.org/10.2118/190876-MS","url":null,"abstract":"\u0000 This paper presents the results of an experimental study on the effects of various CO2-injection modes on immiscible flooding performance in heterogeneous sandstone porous media.\u0000 Core flooding experiments were conducted for n-Decane – synthetic brine – CO2 systems at 9.6 MPa backpressure and 343 K to attain immiscible flooding condition (Minimum miscibility pressure (MMP) of CO2 in n-Decane is 12.4 MPa). For this purpose, two sets of heterogeneous sandstone core samples were assembled with heterogeneity in either parallel (layered samples) or perpendicular (composite samples) to the flow. The results obtained for both composite and layered core samples indicated that heterogeneity tremendously influences the outcome of the CO2 enhanced oil recovery (CO2–EOR). Oil recovery decreases dramatically with increase in the heterogeneity level or permeability ratio (PR). For instance, a recovery of 76.04% in a homogenous sample decreases to 72.15%, 65.97% and 54.71% when in layered samples the PR increases to 2.5, 5, and 12.5, respectively. In addition, the crossflow in layered core sample is found to have a noticeable effect on the ultimate oil recovery (increasing oil recovery up to 5%). It is also worth noting that for the composite samples when we arranged the plugs by putting the low permeability segments closer to the sample outlets the recovery factor increased (e.g. the recovery of 68.32% for Low-High-Low arrangement versus 64.37% for High-Low-High configuration). However, regardless of the segment arrangements, the recoveries in composite cores are less than that obtained from the homogeneous core sample (76.04%)).\u0000 Reservoir heterogeneity plays a critical role in determining the successes of the EOR processes, but its effect has rarely been comprehensively quantified in the laboratory. The limited experimental studies conducted to date seem to suffer from a number of deficiency mainly associated with sample preparation and experimental setup. In the present work, in addition to investigating a number of factors rarely studied experimentally before (e.g. effect of crossflow), attempts have been made to overcome the deficiencies of previous studies. Thus the results of this study can be insightful in overcoming the current challenges in capturing the importance of geological uncertainties in the current and future EOR projects.","PeriodicalId":178883,"journal":{"name":"Day 4 Thu, June 14, 2018","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126319981","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"CSS: Strategies to Recovery Optimization","authors":"E. Trigos, Eduardo Lozano, A. M. Jimenez","doi":"10.2118/190791-MS","DOIUrl":"https://doi.org/10.2118/190791-MS","url":null,"abstract":"\u0000 This paper was written with the main propose to share the experience of more than ten years of cyclic steam stimulation (CSS) in a heavy oil field with a big amount of challenges such as low injectivity, sanding, steam channeling, low steam efficiency, among others.\u0000 For each item identified with a high impact on the CSS production and efficiency, a methodology to analyses and optimization was developed. the first step is identifying the item, recollect the information and quantify the impact; after that, the information is analyzed by the reservoir team, some solution is suggested and evaluated by numerical simulation and other tools; then, the best solution found is apply like a pilot on the field and according to the results it is implemented in a full field scale or replanting until to get the hope results. Finally, corrective actions are taken to avoid similar troubles in the future development of the field. Lesson learners are divulged to the members of the organization.\u0000 For the case of low injectivity, this was identifying in the first stage of development of the field; we carried on lab cores to found the presence of swelling shales like the main causes. Inhibitors clays were test on lab and implemented in the first cycles; for the next steps of development we acquired steam generators with a high-pressure setting too. On the other hand, steam channeling was identified in wells with more of five cycles of stimulation; others wells with potential channeling was identified too, and a methodology to inject this kind of wells was development with the help of simulation tools and successfully implemented in field. The injection of other fluids with the steam like nitrogen, foam or gels improved the low steam efficiency; the development methodology is included in the paper.\u0000 This papers include a lot of experiences in the improving of cyclic steam stimulation, test lab, numerical simulation and other tools are combined with the field experience obtaining an improve in the oil production. Real data field, CSS information and developed methodologies are included in the paper. For this reason, this paper is useful to future implementation of CSS process and in other fields with similar features.","PeriodicalId":178883,"journal":{"name":"Day 4 Thu, June 14, 2018","volume":"2013 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127317007","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Real-Time Downhole Measurements During Coiled Tubing Campaign Brings Wells Back to Life","authors":"A. Keong, Christoffer Sorensen, Y. Andaloussi","doi":"10.2118/190874-MS","DOIUrl":"https://doi.org/10.2118/190874-MS","url":null,"abstract":"\u0000 Coiled tubing (CT) was used on a field on the Norwegian continental shelf to intervene in four separate wells. The campaign objectives were to restore injectivity to two injector wells, prepare a well for plugging and abandonment (P&A), and bring a newly drilled well onto production. The use of CT was a prerequisite because previous wireline interventions had failed to reach target depths due to ingress of fill into the wellbore.\u0000 Three main challenges were faced during that campaign: demanding cleanout conditions, precision required on downhole weights, and critical perforations. The demanding cleanout conditions were due to the large completions and sensitive formations, which required accurate control of slighty underbalance conditions. The precise measurement of downhole weight and torque was required to effectively manage milling operations and accurately cut a hanger. Finally, the perforations required a depth accuracy within 0.5 m of the target depth, accuracy that was beyond the limits of what surface depth measurements can provide. Real-time downhole measurements quickly appeared as the common denominator to address all those challenges at once.\u0000 To address the demanding cleanout conditions, real-time measurements of downhole pressures allowed controlling the pumping conditions at depth, whilst still allowing high pumping rates. This enabled handling high pumping rates, so the cleanouts could be performed effectively. To obtain precise downhole weights during milling and cutting operations, the exact downhole weight on the bottomhole assembly (BHA) and torque was monitored, which, in turn, opened possibilities for adjusting and optimizing the mill and motor use during the operations. For critical perforations, a selective activation firing head was used along with the full array of pressure, temperature, and depth control modules, which allowed multiple guns to be positioned precisely on depth and separately fired in a single run.\u0000 The application of real-time downhole measurements resulted in objectives being met. Increased injectivity was achieved, while rig days were saved with the P&A preparations.","PeriodicalId":178883,"journal":{"name":"Day 4 Thu, June 14, 2018","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126411235","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Novel Evaluation of Foam and Immiscible Gas Flooding in Glass-Silicon-Glass Micromodels","authors":"Florian Hauhs, H. Födisch, R. Hincapie, L. Ganzer","doi":"10.2118/190815-MS","DOIUrl":"https://doi.org/10.2118/190815-MS","url":null,"abstract":"\u0000 We present a systematic workflow to facilitate the visualization of different fluids behavior/performance. Fluids study in this work are brine, gas and specially foam, during flooding experiments in glass-silicon-glass micromodels. These allow for the detailed evaluation and comparison of the individual flooding experiments. This workflow can then be used as part of screening processes to evaluate the fluid-fluid interaction in a porous medium.\u0000 The experimental setup consists of a cabinet-dryer with a camera mounted on top. Micromodels are placed inside the cabinet and PTFE Teflon® tubings are used as connection lines. Fluids are injected using a syringe pump. Pressure is measured via a differential pressure transducer. This setup allows to visualize the entire pore space every 10 seconds. To achieve more comparable results, a black oil is used as the displaced fluid. Brine flooding is used as a benchmark to which results can be compared to. Foam was generated before injection with a mixture of a commercial surfactant and 3 g/l NaCl brine.\u0000 The observed behaviour for the three different flooding were in line with the reported in the literature. First, gas flooding depicted the lowest final recovery with 22% of the OIIP produced, with viscous fingering clearly visible. The weak performance of gas was also displayed in the recorded differential pressures. No effect on pressure due to gas injection was observed during the flooding. Second, the brine flood performed better than the gas flood, where 36% of the OIIP was ultimately recovered. Due to the more favorable mobility ratio of brine and oil this improvement was to be expected. Third, foam flooding achieved the best oil recovery with 58% of the OIIP produced. Pore blocking and the thus increased areal sweep efficiency is the reason for this improvement. Differential pressure behavior for foam and brine flood was similar: A steep pressure decrease after entering the model until breakthrough was observed, although foam had a higher initial differential pressure than brine before entering the model. The high initial pressure difference to the brine flood, is assumed to be due to the compressibility of the individual foam bubbles present in the tubing.\u0000 The workflow presented in this paper, could lead to a fast and economical addition to EOR screening processes. Due to only small volumes of fluids being required to get qualitative and quantitative results. This, in turn could provide relevant insight for foam and immiscible process understanding and modelling.","PeriodicalId":178883,"journal":{"name":"Day 4 Thu, June 14, 2018","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123041793","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Viscous Oil Recovery by Polymer Injection; Impact of In-Situ Polymer Rheology on Water Front Stabilization","authors":"B. Vik, A. Kedir, Vegard Kippe, K. Sandengen, T. Skauge, Jonas S. Solbakken, Dingwei Zhu","doi":"10.2118/190866-MS","DOIUrl":"https://doi.org/10.2118/190866-MS","url":null,"abstract":"\u0000 Polymer injection for viscous oil displacement has proven effective and gained interest in the recent years. The two general types of EOR polymers available for field applications, synthetic and biological, display different rheological properties during flow in porous media. In this paper, the impact of rheology on viscous oil displacement efficiency and front stability is investigated in laboratory flow experiments monitored by X-ray.\u0000 Displacement experiments of crude oil (~500cP) were performed on large Bentheimer rock slab samples (30×30cm) by secondary injection of viscous solutions with different rheological properties.\u0000 Specifically, stabilization of the aqueous front by Newtonian (glycerol and shear degraded HPAM) relative to shear thinning (Xanthan) and shear thickening (HPAM) fluids was investigated.\u0000 An X-ray scanner monitored the displacement processes, providing 2D information about fluid saturations and distributions. The experiments followed near identical procedures and conditions in terms of rock properties, fluxes, pressure gradients, oil viscosity and wettability.\u0000 Secondary mode injections of HPAM, shear-degraded HPAM, xanthan and glycerol solutions showed significant differences in displacement stability and recovery efficiency. It should be noted that concentrations of the chemicals were adjusted to yield comparable viscosity at a typical average flood velocity and shear rate.\u0000 The viscoelastic HPAM injection provided the most stable and efficient displacement of the viscous crude oil. However, when the viscoelastic shear-thickening properties were reduced by pre-shearing the polymer, the displacement was more unstable and comparable to the behavior of the Newtonian glycerol solution.\u0000 Contrary to the synthetic HPAM, xanthan exhibits shear thinning behavior in porous media. Displacement by xanthan solution showed pronounced viscous fingering with a correspondingly early water breakthrough.\u0000 These findings show that at adverse mobility ratio, rheological properties in terms of flux dependent viscosity lead to significant differences in stabilization of displacement fronts. Different effective viscosities should arise from the flux contrasts in an unstable front.\u0000 The observed favorable \"viscoelastic effect\", i.e. highest efficiency for the viscoelastic HPAM solution, is not linked to reduction in the local Sor. We rather propose that it stems from increased effective fluid viscosity, i.e. shear thickening, in the high flux paths.\u0000 This study demonstrates that rheological properties, i.e. shear thinning, shear thickening and Newtonian behavior largely impact front stability at adverse mobility ratio in laboratory scale experiments. Shear thickening fluids were shown to stabilize fronts more effectively than the other fluids. X-ray visualization provides an understanding of oil recovery at these conditions revealing information not obtained by pressure or production data.","PeriodicalId":178883,"journal":{"name":"Day 4 Thu, June 14, 2018","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116146592","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of Additional Objective Functions on Uncertainty Reduction and History Matching","authors":"Forlan Almeida, Helena Nandi Formentin, C. Maschio, A. Davolio, D. Schiozer","doi":"10.2118/190804-MS","DOIUrl":"https://doi.org/10.2118/190804-MS","url":null,"abstract":"\u0000 This paper proposes new objective functions to assimilate dynamic data for history matching, and evaluates their influence on the uncertainty conditioning. Representative events are observed and evaluated separately for the available dynamic data. The proposed objective functions evaluate two specific events: (1) the production transition behavior between the historical and forecasting period, and (2) the water breakthrough time. To assess production transition behavior, the deviation between the latest available historical data is compared with the forecast value, at a specific moment, under forecasting conditions. To assess water breakthrough, the irruption time error is measured in addition to the water-rate objective function. The new objective functions are normalized using the Normalized Quadratic Deviation with Sign, for comparison with conventional objective functions (i.e. NQDS-oil production rate). These additional objective functions are included in a probabilistic and multi-objective history matching and applied to the UNISIM-I-M benchmark for validation. Two history-matching procedures evaluate the impact of the additional objective functions, based on the same parameterization, boundary conditions and number of iterations. The first procedure (Procedure A) includes objective functions traditionally used such as fluid rates and bottom-hole pressure, computed using all the historical data points. The second procedure (Procedure B) considers the same as for A as well as the two additional objective functions. The advantages of including the additional objective functions was the supplementary data used to constrain the uncertainties, improving attribute updates. Consequently, Procedure B generated better-matched models considering the historical period and more consistent forecasts for both field and well behavior when compared to available reference data. The addition of the breakthrough deviation improved the quality of the match for water rates because breakthrough deviation is sensitive to reservoir attributes different to those objective functions related to water rate. The production transition error assisted the identification of scenarios that under or overestimated well capacity. Production transition error also improved the transition of the models from the historical to the forecasting period, reducing fluctuations due to the changes in boundary conditions. Despite the increased number of objective functions to be matched, the improved reliability for forecasting is an incentive for further study. Other representative events, such as oil rate before and after the start of water production could be separated and evaluated, for example. The improved reliability for forecasting supports the inclusion of the proposed objective functions in history-matching procedures.","PeriodicalId":178883,"journal":{"name":"Day 4 Thu, June 14, 2018","volume":"568 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116529583","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pressure Detrending for Harmonic Pulse Test Data Preprocessing","authors":"D. Viberti, E. S. Borello, F. Verga","doi":"10.2118/190879-MS","DOIUrl":"https://doi.org/10.2118/190879-MS","url":null,"abstract":"\u0000 Harmonic Pulse testing was developed as a form of well testing that can be applied during ongoing production or injection operations. A pulsed signal is superimposed to the background pressure trend thus no interruption of well and reservoir production is required before and during the test. The pulsed pressure and rate signal analysis is performed in the frequency domain; to this end, the pressure and the rate signals need to be decomposed into harmonic components. The derivative of the harmonic components in the frequency domain can then be analyzed similarly to a conventional well test. In practice the interpretability of the derivative of the harmonic components can be significantly improved if the pressure trend to which the pressure pulses are superimposed is removed, i.e. a detrending of the pressure data is performed prior to well test interpretation.\u0000 In the present paper, the results obtained after applying different detrending methodologies to pressure data recorded during pulse tests in different reservoir conditions are presented and discussed.\u0000 Analyses on synthetic test data proved that polynomial detrending is effective in removing the pressure trend induced by field depletion and constant well interference but cannot deal with transient effect related to preexisting rate history or ongoing production changes. Conversely, some of the detrending algorithms based on a heuristic approach are very effective to remove both. Moreover, detrended data can be further regularized by excluding anomalous cycles from the analysis, i.e. cycles that do not respect the designed test periodicity, such as in the case of well interference and/or temporary interruption of the pressure pulses during the execution of the test.\u0000 The adoption of an effective detrending strategy can considerably improve the quality of the pressure data obtained from harmonic pulse tests and thus the test interpretability. Therefore, it offers the possibility of overcoming the limitation of applicability due to the difficulty of imposing a regularly pulsing rate for the whole test duration (typically lasting several days). This makes harmonic pulse tests very attractive for well performance monitoring, as in gas storage fields.","PeriodicalId":178883,"journal":{"name":"Day 4 Thu, June 14, 2018","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117121813","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}