Artificial Intelligence Strategy Minimizes Lost Circulation Non-Productive Time in Brazilian Deep Water Pre-Salt

Author(s):  
R. A. Leite Cristofaro ◽  
G. A. Longhin ◽  
A. A. Waldmann ◽  
C. H. M. de Sá ◽  
R. B. Vadinal ◽  
...  
2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Abdulmalek Ahmed ◽  
Salaheldin Elkatatny ◽  
Abdulwahab Ali ◽  
Mahmoud Abughaban ◽  
Abdulazeez Abdulraheem

Drilling a high-pressure, high-temperature (HPHT) well involves many difficulties and challenges. One of the greatest difficulties is the loss of circulation. Almost 40% of the drilling cost is attributed to the drilling fluid, so the loss of the fluid considerably increases the total drilling cost. There are several approaches to avoid loss of return; one of these approaches is preventing the occurrence of the losses by identifying the lost circulation zones. Most of these approaches are difficult to apply due to some constraints in the field. The purpose of this work is to apply three artificial intelligence (AI) techniques, namely, functional networks (FN), artificial neural networks (ANN), and fuzzy logic (FL), to identify the lost circulation zones. Real-time surface drilling parameters of three wells were obtained using real-time drilling sensors. Well A was utilized for training and testing the three developed AI models, whereas Well B and Well C were utilized to validate them. High accuracy was achieved by the three AI models based on the root mean square error (RMSE), confusion matrix, and correlation coefficient (R). All the AI models identified the lost circulation zones in Well A with high accuracy where the R is more than 0.98 and RMSE is less than 0.09. ANN is the most accurate model with R=0.99 and RMSE=0.05. An ANN was able to predict the lost circulation zones in the unseen Well B and Well C with R=0.946 and RMSE=0.165 and R=0.952 and RMSE=0.155, respectively.


2021 ◽  
Vol 4 (1) ◽  
pp. 132-144
Author(s):  
A.N. Dmitrievsky ◽  
◽  
N.A. Eremin ◽  
A.D. Chernikov ◽  
L.I. Zinatullina ◽  
...  

The article discusses the use of automated systems for preventing emergency situa-tions in the process of well construction using artificial intelligence methods to increase the productive time of well construction by reducing the loss of working time to eliminate compli-cations. Key words: problems and complications during drilling, emissions, gas and oil water showings, stuck, artificial neural networks, digitalization, drilling, well, field, oil and gas blockchain, artificial intelligence, machine learning methods, geological and technological research, neural network model, oil and gas construction wells, identification and forecasting of complications, prevention of emergency situations.


2012 ◽  
Vol 52 (1) ◽  
pp. 253
Author(s):  
Melvin Devadass

The Tambun Field in Indonesia was initially developed in the 1990s to exploit oil reserves from the Baturaja Formation (BRF). Since the initial drilling program, reservoir pressure in the field has steadily declined from more than 2,600 psia to less than 1,970 psia resulting in severe circulation losses and an increase in non-productive time (NPT) during drilling and completion programs. The use of hollow glass microspheres, commonly known as glass bubbles—a low density additive (LDA)—in ultra-low density drilling fluids (< 0.9 g/cc) is a novel approach in addressing this issue. A seven-well managed pressure drilling and completion exercise was undertaken by P.T. Pertamina EP Jawa region in the first half of 2010 under challenging drilling conditions in this low-pressure, high-permeability carbonate reservoir. The glass bubble mud system was selected because it would reduce or eliminate lost circulation and stuck pipe problems, reduce formation damage, eliminate the need for post drilling stimulation and give early analysis of reservoir behaviour and production rates. This paper describes the front-end engineering design, project management, risk mitigation, detailed engineering and design, operational results and lessons learnt from this project.


2021 ◽  
Author(s):  
Ali Khalid ◽  
Qasim Ashraf ◽  
Khurram Luqman ◽  
Ayoub Hadj-Moussa ◽  
Agha Ghulam Nabi ◽  
...  

Abstract As oil and gas reserves mature the world over, operators are looking towards advanced methods of increasing the ultimate recovery from their ageing fields. An energy deficient country of Pakistan relies heavily on oil and gas imports. The country was once self sustaining in at least natural gas needs. A major portion of this gas was produced from the Field-X which was discovered in the 1950’s. The primary reservoir in Field-X is the YZ-Limestone reservoir which bears sour gas. Due to extensive production from the YZ-Limestone formation, the reservoir pressure has depleted to a mere 2.0 PPG in equivalent mud weight, and it being a naturally fractured limestone formation presents numerous drilling challenges. The operator has evaluated a potential higher pressured formation in the deeper horizons of sui field but that requires drilling through approximately 650-690 meters of the YZ-Limestone formation. This feat when attempted conventionally is plagued with numerous problems like, total lost circulation, differential sticking, influxes due to the loss of a sufficient hydrostatic head, and stuck pipe following well control events. To mitigate these challenges the operator, need an effective method to drill through this depleted formation without pumping heavy LCM pills, and multiple cement plugs across the massive cavernous thief zones in the YZ-Limestone formation which could have been detrimental to the production of nearby wells. Moreover, such remedies with specialized LCM’s and acid soluble plugs would have resulted in excessive material cost and non-productive time, which in some instances extended to a period of more than a month. To address the aforementioned challenges in drilling the YZ-Limestone formation, a multiphase managed pressure drilling system was suggested to drill the formation with minimal non-productive time and cost. Multiphase hydraulics were performed to assess appropriate pumping parameters for a near-balanced condition across the YZ-Limestone formation. A closed loop MPD equipment system was designed to help maintain near-balanced conditions in pumping and static (non-circulating) periods. The designed equipment system would also ensure that the risk of H2S exposure to the atmosphere was eliminated. The application of a closed loop nitrified mpd system on a recently drilled well proved to be highly successful and reduced the drilling time to just 28 hours by not only eliminating fluid lost circulation but by also delivering an extremely high rate of penetration of 39.2 m/hr. The successful and exemplary application of nitrified MPD has opened up a new horizon for the development of deeper prospects in the Field-X and similar neighboring fields. The paper outlines the design and execution of the closed loop nitrified MPD system.


2021 ◽  
Author(s):  
Angela Gorman ◽  
Sandip Patil ◽  
Kyriacos Agapiou

Abstract Lost circulation (LC), commonly encountered in drilling and cementing operations, can be a costly problem that increases non-productive time, especially in highly permeable formations. When LC occurs during cementing, zonal isolation can be compromised. Risks associated with LC affect most applications, including offshore operations. This paper presents the evaluation of a new tailored spacer system (TSS) designed to effectively mitigate LC and its use in deepwater cementing operations to meet zonal isolation objectives.


1988 ◽  
Vol 62 (01) ◽  
pp. 1-8 ◽  
Author(s):  
Ronald E. Martin

The utility of benthic foraminifera in bathymetric interpretation of clastic depositional environments is well established. In contrast, bathymetric distribution of benthic foraminifera in deep-water carbonate environments has been largely neglected. Approximately 260 species and morphotypes of benthic foraminifera were identified from 12 piston core tops and grab samples collected along two traverses 25 km apart across the northern windward margin of Little Bahama Bank at depths of 275-1,135 m. Certain species and operational taxonomic groups of benthic foraminifera correspond to major near-surface sedimentary facies of the windward margin of Little Bahama Bank and serve as reliable depth indicators. Globocassidulina subglobosa, Cibicides rugosus, and Cibicides wuellerstorfi are all reliable depth indicators, being most abundant at depths &gt;1,000 m, and are found in lower slope periplatform aprons, which are primarily comprised of sediment gravity flows. Reef-dwelling peneroplids and soritids (suborder Miliolina) and rotaliines (suborder Rotaliina) are most abundant at depths &lt;300 m, reflecting downslope bottom transport in proximity to bank-margin reefs. Small miliolines, rosalinids, and discorbids are abundant in periplatform ooze at depths &lt;300 m and are winnowed from the carbonate platform. Increased variation in assemblage diversity below 900 m reflects mixing of shallow- and deep-water species by sediment gravity flows.


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