Wax: A benign hydrogen-storage material that rapidly releases H2-rich gases through microwave-assisted catalytic decomposition

Hydrogen is often described as the fuel of the future, especially for application in hydrogen powered fuel-cell vehicles (HFCV’s). However, its widespread implementation in this role has been thwarted by the lack of a lightweight, safe, on-board hydrogen storage material. Here we show that benign, readily-available hydrocarbon wax is capable of rapidly releasing large amounts of hydrogen through microwave-assisted catalytic decomposition. This discovery offers a new material and system for safe and efficient hydrogen storage and could facilitate its application in a HFCV. Importantly, hydrogen storage materials made of wax can be manufactured through completely sustainable processes utilizing biomass or other renewable feedstocks

Review of the Applications of Decision Tree Analysis in Petroleum Engineering with a Rigorous Analysis

As oil prices are fluctuating, decision makers are challenged to make the best decisions for field\u27s developments. Decision Tree Analysis (DTA) can help decision makers to make the best decisions. DTA focuses on managerial decisions, such as whether to do workover or not, whether the additional information will be valuable or not. The aim of this work is to review the applications of DTA in petroleum engineering and provide a clear methodology on how to apply DTA for any petroleum engineering application. The combination of Expected Monetary Value (EMV) and DTA is one of the most common methods used in the decision-making process. If EMV is positive, the decision is considered to be feasible. However, that doesn\u27t mean the decision will be successful at all times. It simply means that if a similar decision is made for a larger number of cases, the decision will be successful. DTA will account for the uncertainty in the probability. A good number of papers about the applications of DTA in petroleum engineering were read and summarized into three categories. Also, a clear methodology on how to apply the DTA for any petroleum engineering application was established. After reading and summarizing a good number of papers and case histories about the applications of DTA in petroleum engineering, it was concluded that the applications can be classified into three main categories; applications of DTA and EMV for the whole oil and gas prospect projects, applications of DTA and EMV for a specific operation or development, applications of DTA, EMV, Monte Carlo simulations, and other methods to assess the value of information. These applications were summarized into tables. In addition, a clear methodology accomplished by a flowchart that explains how to successfully apply the EMV and DTA for any petroleum engineering application was provided. The method consists of three main steps: 1) how many scenarios need to be considered and what are they 2) collection of the required data 3) use the visual tool (DTA) or programming to find EMV. Each of the previous steps has its own challenges, thus these challenges were addressed and the solutions to overcome the challenges were provided. Finally, practical guidelines have were developed that when used with the accompanying flow chart will serve as a quick reference to apply the DTA for any petroleum engineering application. As the petroleum engineering applications becoming more complicated nowadays, accomplished by the oil prices fluctuations, the decision-making processes becoming more difficult. The DTA is a very important tool for the decision makers to make the best decision. This paper provides a clear methodology on how to successfully apply the DTA which can serve as a reference for any future DTA applications in petroleum engineering

Applications of Artificial Neural Networks in the Petroleum Industry: A Review

Oil/gas exploration, drilling, production, and reservoir management are challenging these days since most oil and gas conventional sources are already discovered and have been producing for many years. That is why petroleum engineers are trying to use advanced tools such as artificial neural networks (ANNs) to help to make the decision to reduce non-productive time and cost. A good number of papers about the applications of ANNs in the petroleum literature were reviewed and summarized in tables. The applications were classified into four groups; applications of ANNs in explorations, drilling, production, and reservoir engineering. A good number of applications in the literature of petroleum engineering were tabulated. Also, a formalized methodology to apply the ANNs for any petroleum application was presented and accomplished by a flowchart that can serve as a practical reference to apply the ANNs for any petroleum application. The method was broken down into steps that can be followed easily. The availability of huge data sets in the petroleum industry gives the opportunity to use these data to make better decisions and predict future outcomes. This paper will provide a review of applications of ANNs in petroleum engineering as well as a clear methodology on how to apply the ANNs for any petroleum application

Economic Evaluation and Uncertainty Assessment of Lost Circulation Treatments and Materials in the Hartha Formation, Southern Iraq

It is recognized that there is no single solution to lost circulation, and most treatment and trial-and-error. However, the screening guide presents a high-level \u27go to\u27 document with coherent guidelines, which engineers can utilize in making decisions regarding lost circulation treatments in major oil fields. The aim of this work is to describe how mud engineers can use the decision tree analysis (DTA) to evaluate and select the best treatments path for mitigating mud losses. Lost circulation events of Southern Iraq oil fields were statistically analyzed to determine treatment effectiveness. Also, the cost of each treatment, as well as the NPT that is associated with the treatment, is considered in this study. Data from over 1000 wells were gathered from various sources and reports; the treatments were classified by scenario -partial, severe, and complete losses - as well as cost, efficiency, and formation types. This paper is developed based on probabilities, expected monetary value (EMV), and decision tree analysis (DTA) to recommend the best-lost circulation treatments path for each type of losses. Traditionally, lost circulation in Southern Iraq area has been treated in a multitude of ways without consistent methodology. This analysis identifies and ranks the most effective treatments to create a best method/product recommendation and a flowchart suggesting additional measures in treating losses to optimize success and reduce overall cost and NPT. This paper presents the best treatment for each scenario - partial loss, severe losses and complete losses - both for product selection and engineering. This paper utilizes probability and economics in the decision-making process. This is the first study that considers a detailed probability and cost to treat the lost circulation problem. Thousands of treatment scenarios for each type of losses are conducted, and the EMVs for all scenarios are calculated. For each type of losses, the lowest EMV treatment strategy- that is practically applicable in the field and makes sense-is selected to be used to treat each type of losses to minimize NPT and cost. If the losses didn\u27t stop after utilizing the proposed treatment strategies, it is recommended to use liner hanger to isolate the losses zone and then continue drilling. One challenge in drilling wells in Southern Iraq oil fields is the inconsistency of approaches to the lost circulation problem. Therefore, the result of this data analysis provides a path forward for Southern Iraq area lost circulation events and suggests probable methods that can be used in similar formations globally. Additionally, the methodology can be adapted to studying other types of formations and drilling challenges have the same geological properties in any major oil field

Mud Losses Estimation using Partial Least Squares Algorithm

Lost circulation is a very expensive drilling problem and very common in highly permeable formations, fractured formations or depleted reservoirs. Estimates of annual cost worldwide for lost circulation are over a billion for lost time and materials, and remediation costs. The drilling industry has a large toolbox from which to customize lost circulation responses. However, putting a value on the effectiveness of these lost circulation mitigation methods is harder to quantify. The Rumaila field, Iraq, is one of the world\u27s largest oilfields with overlying formations that are notorious for lost circulation issues as the formations are depleted, highly permeable and fractured. Because of the significance of the Rumaila field and the common lost circulation problems faced in drilling any well in the area, it is an ideal candidate for a statistical study to model anticipated mud losses and compare the model with actual mud losses. The resulting model should be able to predict average mud losses, along with other drilling parameters affecting lost circulation, and compare the different lost circulation methods used to mitigate known losses. This study provides a larger data set and different models, using a machine learning algorithm than previous studies in the Rumaila field. Data of key drilling parameters for more than 500 wells are gathered from daily drilling reports, technical reports, final wells reports, and drilling programs. Sensitivity analysis identified the most critical parameters and provides insight into the impact of those parameters on mitigating lost circulation. The models of mud loss, equivalent circulating density (ECD) and drilling rate (ROP) are then tested with new data and compared with previous regression models developed for the area. Using the same techniques, modeling of any formation can be used to analyze the current situation and develop techniques for mitigating lost circulation by controlling drilling fluid properties, the rate of penetration, response to lost circulation events, and other field parameters

An Assessment of the Impact of Rheological Properties on Rate of Penetration using Data Mining Techniques

The rate of penetration (ROP) plays a major role in reducing drilling costs, making it an important area of investigation. There are various controllable and uncontrollable factors that affect the ROP, and the variation in these variables affecting the ROP made it a very pivotal drilling parameter that has a significant effect on non-productive time. In this work, sensitivity and statistical analysis were carried out using data from over 1000 wells in Basra oil fields, Iraq. The scope of this work is to determine the effect of rheological properties on ROP, to provide a method for estimating the recommended range for drilling fluid properties based on data mining techniques. In this work, huge real field data from over 1000 wells drilled in Basra oil fields, Iraq were gathered and analyzed to better understand the characteristics of a drilling fluid that enhance ROP and quantify the impact of each drilling fluid rheological properties on ROP. The data used in this study were collected from mud logging data, daily drilling reports (DDR), and geological information. Statistical and sensitivity analyses were performed in order to identify the relationship between ROP and drilling fluid rheological properties. The correlation coefficient (CC) was utilized to understand the effect of solid content (SC), yield point (Yp), and plastic viscosity (PV) on ROP. The results showed that SC is the most influential rheological property on ROP, then PV and finally Yp. In addition, this work demonstrates how bit hydraulics can be improved by means of modifying the rheological properties rather than adjusting the flow rate or nozzle size. Large-scale collection and interpretation of field data or in other words data mining can be considered as a strong tool in understanding the impact of different parameters on the ROP in order to estimate the recommended range of rheological properties, which will result in improving the ROP

Economic Analysis of Lost Circulation Events to Optimize the Drilling Process in Basra Oil Fields, Iraq

Lost circulation is a unique challenge unlike other factors contributing to non-productive time (NPT). Due to the variability in the nature and type of lost circulation prone formations; there is no universal solution to this challenge. This publication presents a new approach to guide the decision-making process of which and when to apply a certain treatment as compared to another. If implemented correctly, a significant reduction in NPT related to lost circulation can be expected. Also, the cost of each treatment, as well as the NPT that is associated with the treatment, were examined in this study. Lost circulation events for three formations which are the Dammam, Hartha, and Shuaiba were gathered from over 1000 wells drilled in Basra oil fields, Iraq using various sources and reports; the treatments were classified by scenario -partial, severe, and complete losses - as well as cost, efficiency, and formation types. This paper is developed based on probabilities, expected monetary value (EMV), and decision tree analysis (DTA) to recommend the best-lost circulation strategy for each type of losses. This paper utilizes probability and economics in the decision-making process. This is the first study that considers a detailed probability and cost to treat the lost circulation problem. Thousands of treatment scenarios for each type of losses are conducted, and the EMVs for all scenarios are calculated. For each type of losses, the lowest EMV treatment strategy- that is practically applicable in the field and makes sense- is selected to be used to treat each type of losses to minimize NPT and cost. If the losses didn\u27t stop after utilizing the proposed treatment strategies, it is recommended to use liner hanger to isolate the losses zone and then continue drilling. A change in well design is also suggested to help to minimize NPT and cost. In addition, a formalized methodology for responding to losses in the Dammam, Hartha, and Shuaiba formations is established and provided as means of assisting drilling personnel to work through the lost circulation problem in a systematic way. One challenge in drilling wells in Basra oil fields is the inconsistency of approaches to the lost circulation problem. Therefore, the result of this data analysis provides a path forward for the Basra area lost circulation events and suggests probable methods that can be used in similar formations globally. Additionally, the methodology can be adapted to studying other types of formations and drilling challenges have the same geological properties in any major oil field

Investigation of the Relationship between Rate of Penetration and Mud Weight based on the Hardness of the Rock

The rate of penetration (ROP) plays a major role in drilling optimization, making it an important area of investigation. In this work, sensitivity and statistical analysis were carried out using data from over 100 wells in the Rumaila field, Iraq. The goal is to assess the effect of mud weight (MW) on ROP, to provide a method for estimating the recommended range for operational mud weight based on the hardness of the rock. Drilling intervals from data collected from drilling reports from over 100 wells in the Rumaila field, Iraq, were categorized as weak, medium, hard, and very hard, based on UCS, depth, and lithology. Statistical and sensitivity analysis was conducted, developing correlation coefficients (CC) to represent relationships between rock hardness, ROP, and MW from field data. This methodology combines data from mud logging, daily drilling reports, and geological information to investigate the relationship between ROP and MW for different rock types and strengths. It is well known that MW can dramatically impact ROP, and well documented in literature and laboratory studies. Several early studies focused directly on MW, clearly demonstrating the effect of MW on bit conditions, and therefore ROP. However, these studies do not include consideration of the hardness or lithology of the rock. There is also a strong discrepancy between results from different studies. Different literature concludes the relationship between MW and ROP is inverse, and in some it is direct. For this study, field data have been gathered (more than 100 wells) to further investigate the relationship between MW and ROP, and how it varies with rock hardness. Field data have been categorized based on the hardness of the rock. The results showed that MW has an inverse relationship with ROP for the weak formation with a CC of -0.57. Thus, MW should be maintained as minimum as possible when drilling through the weak formation. On the other hand, MW has a direct relationship with ROP for medium, hard, and very hard formations with CC of 0.31, 0.4, and 0.42 respectively. Hence, MW has to be maintained as high as possible to maximize ROP for medium, hard, and very hard formations. Large-scale collection and interpretation of field data were collected to demonstrate the effects of MW on ROP with varying rock hardness and lithology. While field data of this scale is inherent of interest, this analysis also investigates relationships previously unexplored and extends understanding of how MW effects ROP