Day 4 Thu, May 05, 2022最新文献

{"title":"Downhole Pressure Prediction for Deep Water Gas Reservoirs Using Physics-Based and Machine Learning Models","authors":"Jincong He, M. Avent, Mathieu Muller, Lauren Bordessa","doi":"10.4043/31758-ms","DOIUrl":"https://doi.org/10.4043/31758-ms","url":null,"abstract":"\u0000 Pressure measurement from permanent downhole gauges (PDHGs) during extended shut-ins is a key piece of information that is often used for model calibration and reserve estimate in deep-water gas reservoirs. A key challenge in practical operation has been the failure of permanent downhole gauges (PDHGs) within the first few years of operation. To overcome this challenge, innovative modeling solutions have been developed to enable accurate bottom-hole well pressures to be calculated.\u0000 Both the physics-based model and machine learning model are developed to predict PDHG pressure and temperature measurement from the wellhead and other measurements during well shut-in events. These models are calibrated and blind-tested with data collected while the PDHG is still functioning. The key to the physics-based model is our model of the gas temperature profile within the wellbore and cool-down rate on shut-in, which has been inspired and validated by independent OLGA transient well simulations. In addition to physics-based models, machine learning (ML) models have also been developed, which directly perform regression on available data.\u0000 The physics-based model is shown to be able to predict PDHG pressure and temperature accurately by capturing two key physics. Firstly, on well shut-in, a significant gas density gradient develops, as the wellhead (usually on the ocean floor) cools rapidly, while the bottom-hole temperature remains high. This changing temperature profile along the wellbore path has been accurately captured by a data-driven temperature model in the physics-based model. In addition, the decline of temperature along the wellbore has been observed to depend on the well's production history. With higher/longer production of hot gas through the wellbore and additional heating of wellbore surrounds, a slower cool-down rate is observed. A data-driven decline-curve model is devised within the physics-based model and has been shown to successfully capture this dependency.\u0000 Compared to the physics-based model, the machine learning model is much simpler to devised. It also has the flexibility to incorporate new input features other than those that we can physically interpret. Multiple ML models are tested, and the random forest has shown the best performance. The accuracy of the ML model is comparable to that of the physics-based one.\u0000 In this work, novel physics-based models and ML models are presented and compared for estimating PDHG measurement from wellhead measurements. The build-up pressures from PDHG during well shut-ins are the principal input for reservoir surveillance, analysis, and optimization (SA&O) activities, including material balance estimates of gas-in-place and reservoir simulation history matching.","PeriodicalId":391718,"journal":{"name":"Day 4 Thu, May 05, 2022","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128667829","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":"A Standardized Qualification Approach for Subsea All-Electric Drop-in-Place Actuators","authors":"Carsten Mahler, Harald Schuhmacher, Birthe Thiele, Johannes Reiner Pocher","doi":"10.4043/31933-ms","DOIUrl":"https://doi.org/10.4043/31933-ms","url":null,"abstract":"\u0000 Electric actuation technology represents the future of subsea production systems. So far there are no standardized generic requirements documented for electrical actuators. A recent Joint Operator Specification attempted to address this lack of information, but it provided only a few details about how electric actuators could meet subsea industry requirements.\u0000 Recently, there has been a visible increase in the use of electric actuators, especially on less safety-critical valves. Considering the UN sustainability goals, companies will likely implement more all-electric technologies to reduce the CO2 footprint of the upstream sector in the near future. Hence, large suppliers and smaller companies see their chance to establish corresponding products in the marketplace.\u0000 This paper proposes the development of a documented qualification program for subsea all-electric actuators based on a foundation of existing industry standards. To clarify and enhance those standards, comprehensive research was conducted and requirements were derived and documented based on customer specifications as well as engineering and project organization experience.\u0000 The proposed program outlines specifications and documents a wealth of information based on project organization and engineering experience. This comprehensive list of requirements will serve as the basis for a generic comparison and qualification program, which has already been carried out for various drop-in-place actuators and has, so far, led to smooth acceptance of the technology by the operators, wherever it has been implemented.\u0000 This paper will serve as a further step in advancing an all-electric approach for the industry. The methods outlined herein will help operators compare different products on a uniform basis and will give suppliers the opportunity to compete fairly. To this end, the paper presents the above-mentioned approach for obtaining the requirements and identifies the main sources as well as the procedure for developing a generic qualification approach.","PeriodicalId":391718,"journal":{"name":"Day 4 Thu, May 05, 2022","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125414267","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":"Reservoir Souring in Mature Offshore Field Malaysia: Root Cause, Mitigation, and Management of H2S","authors":"A. H. Mithani, E. A. Rosland, M. Jamaludin, W. R. W Ismail, Maxwell Tommie Lajawi, I. H. A Salam","doi":"10.4043/32141-ms","DOIUrl":"https://doi.org/10.4043/32141-ms","url":null,"abstract":"\u0000 The field under study is a mature brownfield with no H2S in the fluid stream (PVT) at the time of development. However, concentrations more than 1000 ppm were recorded recently causing wells to close in (few already closed). Hence, the shut-in wells have to be brought on stream and an assessment of souring potential in the field has to be completed. This paper will share our experience in H2S mapping at reservoir-well-facilities modelling, history matching and prediction of H2S. We will highlight the workflow adopted to find the root causes of souring via sampling and modelling approach since the H2S is measured throughout the field across all the reservoirs, including those undergoing waterflood. Moreover, various options that were studied through simulation will be discussed for mitigation and management of H2S within this field to safeguard the production, and thus recovery of the field.\u0000 A systematic phased approach is adopted to mitigate and manage the unwanted sour gas (H2S). In first phase we performed the analysis on the historical development of H2S throughout the field and developed the concept for possible souring causes. In second phase, we designed and conducted a comprehensive sampling and laboratory analysis program end-to-end to fill the existence knowledge gap. In third phase, we performed 3D dynamic reservoir souring modelling where we history matched the H2S and assessed the future potential via forecasting. Finally, we developed multiple mitigation scenarios ranging from nitrate injection, sulphate reducing unit, limiting the nutrient supply for microbe growth via water mixing etc.\u0000 It was evident that a) increased injection water contributed to souring wells, b) link between souring wells and nutrient availability, c) increased negative fractioning of Sulphur isotope as H2S concentration increases, d) and mesophilic SRBs detected in some souring wells. This evidence suggested that BSR is the predominant cause of souring. It was also seen based on water chemistry that injection water was rich in sulphate while formation water rich in volatile fatty acids. Results indicate that the nitrate injection (up to 200ppm) alone may not be an attractive option to mitigate the H2S within this field. However, the combination of SRU and nitrate injection of 150ppm could be a technically feasible options to mitigate such higher concentration of H2S within allowable facilities limits of H2S.","PeriodicalId":391718,"journal":{"name":"Day 4 Thu, May 05, 2022","volume":"75 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130100093","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}