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Fattahpour, Vahidoddin (RGL Reservoir Management Inc.) | Roostaei, Morteza (RGL Reservoir Management Inc.) | Hosseini, Seyed Abolhassan (University of Alberta) | Soroush, Mohammad (University of Alberta) | Berner, Kelly (RGL Reservoir Management Inc.) | Mahmoudi, Mahdi (RGL Reservoir Management Inc.) | Al-hadhrami, Ahmed (Occidental Petroleum Oman) | Ghalambor, Ali (Oil Center Research International)
Summary Most of the test protocols developed to evaluate sand-screen designs were based on scaled-screen test coupons. There have been discussions regarding the reliability of such tests on scaled test coupons. This paper presents the results of tests on wire-wrapped screen (WWS) and slotted liner (SL) test coupons for typical onshore Canada McMurray formation sand. A unique sand control evaluation apparatus has been designed and built to accommodate all common stand-alone screens that are 3.5 in. in diameter and 12 in. This setup provides the capability to have a radial measurement of pressure across the sandpack and screen for three-phase flow. Certain challenges during testing such as establishing uniform radial flow and measuring the differential pressure are outlined. Produced sand is also measured during the test. The main outputs of the test are to assess the sand control performance and the mode of sanding in different flow directions, flow rates, and flow regimes. It was possible to establish uniform radial flow in both high-and low-permeability sandpacks. However, the establishment of radial flow in sandpacks with very high permeability was challenging. The pressure measurement at different points in the radial direction around the screen indicated a uniform radial flow. Results of the tests on a representative particle size distribution (PSD) from the McMurray Formation on the WWS and SL test coupons with commonly used specifications in the industry (aperture sizes of 0.012, 0.014, and 0.016 in. We also included aperture sizes smaller and larger than the common practice. Similar to previous tests, narrower apertures are proven to be less resistant to plugging than wider slots for both WWS and SL. Accumulation of fines close to the screen causes significant pore plugging when conservative aperture sizes were used for both WWS and SL. In contrast, using the test coupon with a larger aperture size than the industry practice resulted in excessive sanding. The experiments under linear flow seem more conservative because their results show more produced sand and smaller retained permeability in comparison to the testing under radial flow. It also provides insight into the fluid flow, fines migration, clogging, and bridging in the vicinity of sand screens. Introduction Sand production is one of the important phenomena in oil recovery from weakly consolidated and unconsolidated sandstone oil reservoirs. Because of operational and financial constraints such as workover and well cleaning costs, operators tolerate a limited amount of sand production in oil wells.
Fattahpour, Vahidoddin (RGL Reservoir Management Inc.) | Roostaei, Morteza (RGL Reservoir Management Inc.) | Soroush, Mohammad (RGL Reservoir Management Inc., University of Alberta) | Hosseini, Seyed Abolhassan (RGL Reservoir Management Inc., University of Alberta) | Berner, Kelly (RGL Reservoir Management Inc.) | Mahmoudi, Mahdi (RGL Reservoir Management Inc.) | Al-hadhrami, Ahmed (Occidental Petroleum Oman) | Ghalambor, Ali (Oil Center Research International)
Standalone screens (SAS) have been widely employed as the main sand control solution in thermal projects in Western Canada. Most of the test protocols developed to evaluate screen designs were based on the scaled screen coupons. There have been discussions regarding the reliability of such tests on scaled coupons. This paper presents the results of the tests on full-scale wire-wrapped screen (WWS) and slotted liner coupons for typical McMurray Formation sands.
A large-scale sand control evaluation apparatus has been designed and built to accommodate all common SAS with 3 1/2″ in diameter and 12″ in height. The set-up provides the capability to have the radial measurement of the pressure across the sand pack and liner, for three-phase flow. We outline certain challenges in conducting full-scale testing such as establishing uniform radial flow and measuring the differential pressure. Produced sand is also measured during the test. The main outputs of the test are to assess the sand control performance and the mode of sanding in different flow direction, flow rates and flow regimes.
We were able to establish uniform radial flow in both high and low permeability sand packs. However, the establishment of the radial flow in sand packs with very high permeability was extremely challenging. The pressure measurement in different points in radial direction around the liner indicated a uniform radial flow. Results of the tests on a representative PSD from McMurray Formation on the WWS and slotted liner coupons with commonly used specs in the industry have shown similar sanding and flow performances. We also included aperture sizes smaller and larger than the common practice. Similar to the previous large-scale tests, narrower apertures are proven to be less resistant to plugging than wider slots for both WWS and slotted liner. Accumulation of the fines close to screen causes significant pore plugging, when conservative aperture sizes were used for both WWS and slotted liner. On the other hand, using the coupon with larger aperture size than the industry practice, resulted in excessive sanding. The experiments under linear flow seems more conservative as their results show higher produced sand and lower retained permeability, in comparison to the full scaled testing under radial flow.
This work discusses the significance, procedure, challenges and early results of full-scale physical modeling of SAS in thermal operation. It also provides an insight into the fluid flow, fines migration, clogging and bridging in the vicinity of sand screens.
Montero, J. D. (University of Alberta) | Chissonde, S.. (University of Alberta) | Kotb, O.. (University of Alberta) | Wang, C.. (University of Alberta) | Roostaei, M.. (University of Alberta) | Nouri, A.. (University of Alberta) | Mahmoudi, M.. (RGL Reservoir Management Inc.) | Fattahpour, V.. (RGL Reservoir Management Inc.)
Abstract This paper presents a critical review of current evaluation techniques for the selection and design of sand control devices (SCD) for Steam Assisted Gravity Drainage (SAGD) wells. With the industry moving towards exploiting more difficult reservoirs, there is a need to review the current testing methods and assess their adequacy for sand control evaluation for different operational and geological conditions. In addition to a critical review of existing sand control testing approaches for SAGD, the paper also discusses the testing parameters in previous studies to evaluate their representativeness of the field conditions in terms of interstitial seepage and viscous forces, and flow geometry. Moreover, the paper reviews the analysis and results of sand control testing in the literature and assesses the sand control design criteria in terms of the level of acceptable sand production and plugging. Furthermore, the review evaluates the suitability of the sample size, sand preparation techniques, representation of the SCD in the testing, and experimental procedures. The review shows variations in the existing sand control testing in SAGD, in terms of not only approach, sand control representation, and sample size, but also regarding operational test conditions, such as flow rates and pressures. Ideally, large-scale pre-packed tests that include the effects of temperature and radial flow geometry would more closely emulate the actual conditions of SAGD wells than most existing tests allow. High temperatures may affect sanding and plugging through changes in wettability, permeabilities, and mineral alterations. Further, the varying velocity profile in radial flow towards the SCD influences the fines migration pattern differently from the linear-flow conditions in the existing Sand Retention Tests (SRT). However, large-scale radial-flow tests are constrained by cost and complexity. Most SRT experiments have employed high flow rates, exceeding the equivalent field rates. Utilizing realistic rates for the tests and appropriately capturing the actual fluids ratios, water cuts and steam breakthrough scenarios can improve the quality of testing data. Accordingly, existing SRT experiments can be designed to incorporate, if not all, but some of the relevant physics in SAGD by employing representative viscosities, flow rates, fluid properties and ratios, stress conditions and obtain suitable live and post-mortem measurements. This critical review compiles various aspects of current sand retention tests and evaluates their applicability to SAGD well conditions. It serves as a starting point for future research by providing an overview of existing testing methods, highlighting the strengths and opportunities for improvements.
Roostaei, Morteza (RGL Reservoir Management Inc.) | Cespedes, Edgar Alberto (Ecopetrol) | Uzcátegui, Alberto A. (RGL Reservoir Management Inc.) | Soroush, Mohammad (RGL Reservoir Management Inc. and University of Alberta) | Hosseini, Seyed Abolhassan (RGL Reservoir Management Inc. and University of Alberta) | Izadi, Hossein (University of Alberta) | Schroeder, Brad (RGL Reservoir Management Inc.) | Mahmoudi, Mahdi (RGL Reservoir Management Inc.) | Gomez, Dionis M. (Ecopetrol) | Mora, Edgar (Ecopetrol) | Alpire, Javier (Ecopetrol) | Torres, Joselvis (Ecopetrol) | Fattahpour, Vahidoddin (RGL Reservoir Management Inc.)
Summary Designing and selecting the proper sand control mechanism for horizontal wells in unconsolidated heavy-oil reservoirs tend to be underlooked in some cases. Standalone completions pose some sand control challenges, which could jeopardize the oil production or even lead to critical problems. Massive sand production, screen/formation plugging, hot spots, and mechanical integrity failures are some of the well-known issues. This study attempts to optimize the slotted liner design for horizontal wells in a heavy-oil field in Colombia. A careful selection of representative core data was made to study the variation of sand particle-size distribution (PSD) within the development area. Reservoir fluid properties were analyzed. Based on PSD variation and current design criteria in the industry, several seamed slotted-liner configurations were proposed as an alternative completion for testing. Later, a series of large-scale sand retention tests (SRTs) were performed to assess the selected alternatives under typical field production conditions. The effects of aperture size and open-to-flow area were investigated to evaluate flow and sand control performance. This investigation started with a detailed study of the PSD, particle shape variation, and composition of fines in the development area. The PSD then classified into four distinct minor and major sand facies, ranging from medium to very coarse sand with different fines content. Further investigations have shown that current design is only suitable for a limited number of the PSDs, while the overall PSD classes indicate the requirement for wider slot aperture sizes. The results of the SRTs indicated that the flow performance of the screen is mainly controlled by the slot aperture. Choosing the optimized aperture size avoids unacceptable sanding even for the multiphase flow scenarios with gas. Results also indicated that by increasing the aperture size and application of the seamed slots for the studied formation, plugging could be mitigated. A comprehensive sand control design workflow for cold primary heavy-oil production in horizontal wells is presented in this work. The current study is one of the first that investigates and compares conventional straight slotted liners with seamed slotted liners at a larger scale for this field. Moreover, this study helps to better understand the effect of design parameters of seamed slotted liners on sand control, flow performance, and plugging tendency.
Montero Pallares, Jesus David (University of Alberta) | Wang, Chenxi (University of Alberta) | Haftani, Mohammad (University of Alberta) | Pang, Yu (University of Alberta) | Mahmoudi, Mahdi (University of Alberta) | Fattahpour, Vahidoddin (University of Alberta) | Nouri, Alireza (University of Alberta)
Abstract This study presents an evaluation of Wire-Wrapped Screens (WWS) performance for SAGD production wells based on Pre-packed Sand Retention Testing (SRT). The impacts of features such as flow rates, water cut, steam-breakthrough events and fluid properties on flow performance and sand production are analyzed. The aim is to obtain a better understanding of WWS performance under several SAGD operational conditions for typical sand classes in the McMurray Formation in Western Canada. The study employs a large pre-packed SRT to assess the performance of WWS with different aperture sizes and standard wire geometries. The testing plan includes sand samples with two representative particle size distributions (PSD's) and fines contents. Testing procedures were designed to capture typical field flow rates, water cut, and steam-breakthrough scenarios. The amount of sand production and pressure drop across the zone of the screen and adjacent sand were measured and used to assess the screen performance. Furthermore, fines production was measured to evaluate plugging tendencies and flow impairment during production. The experimental results and data analysis show that aperture selection of WWS is dominated by their sand retention ability rather than the flow performance. The relatively high open flow area (OFA) makes WWS less prone to plugging. There is an increase in flow impairment after finalizing the injection scheme (oil+water+gas); however, it is controlled over the acceptable margins even with a narrow aperture. Further, a comparison of initial and final turbidity measurements showed that fines mobilization and production during single-phase brine flow was higher than in two-phase brine-oil flow at the same liquid flow rate. Excessive produced sand was observed for wider slots during the multi-phase (brine, oil, and gas) flow when gas was present, highlighting the impact of the breakthrough of wet steam on sand control performance. Flow impairment and pressure drop evolution were strongly related to the mobilization and accumulation of fines particles in the area close to the screen coupon; it is critical to allow the discharge of fines to maintain a high-retained permeability. Results also signify the importance of adopting adequate flow rates and production scenarios in the testing since variable water cuts and GORs showed to impact both sanding and flow performances. This research incorporates both single-phase and multiphase flow testing to improve design criteria for wire-wrapped screens and provide an insight into their performance in thermal recovery projects. An improved post-mortem analysis includes fines production measurements to correlate these to the retained permeability caused by the pore plugging, which has hardly been evaluated in previous studies.