- Home
- Conferences
- Conference Proceedings
- Conferences
IPTC 2013: International Petroleum Technology Conference
- Conference date: 26 Mar 2013 - 28 Mar 2013
- Location: Beijing, China
- Published: 26 March 2013
121 - 140 of 581 results
-
-
Formation Damage and Treatment of Offshore Water Disposal Wells in Saudi Arabia: Case Studies
Authors K. Mei, H. B. Qahtani, A. S. Al-Kuait and L. A. SukkarIn one Saudi Aramco offshore oil field, the formation fluids are being produced from different platforms and transported to one onshore gas-oil separation plant (GOSP) where the produced water is removed from the hydrocarbon stream. The produced water is injected back to highly permeable formations through disposal wells with no interruption. In this way, the water disposal system is an integral part of the hydrocarbon recovery system. A failure of one of the disposal wells could adversely affect oil production. Saudi Aramco petroleum engineers are placing more and more attention on water disposal wells as a higher volume of produced water from the increasing hydrocarbon production rates has to be disposed of continuously every day. The primary objective of surveillance on the disposal wells is to keep an extra disposal capacity for continuous oil production from the field and to precisely monitor the decline rate of the capacity of each disposal well. A real sweep efficiency and pressure maintenance are not the surveillance scope for water disposal wells in our case. Few technical papers have been published that discuss the problems a water disposal system may have in a matured field and address issues such as surveillance of well performance and water quality, formation damage mechanisms, treatment and so forth. In this paper, the existing water disposal system in a matured offshore oil field is briefly described and discussed with the surveillance of well performance and the quality disposal water, potential problems, and the evolution of the surveillance philosophy. The reasons why most disposal wells experienced severe injection decline are analyzed and discussed in detail. Historic treatments were summarized with actual outputs demonstrating “ineffective” treatments for the issues discussed. After several trial tests, one customized chemical treatment recipe was developed to effectively tackle the issues and actual well data is included showing the effectiveness of those treatments. A new surveillance strategy for better monitoring of well performance and the quality of “waste” fluid is also discussed in this paper. It can be concluded from our work that formation damage exists extensively in wastewater injection wells and that it greatly influences the performance of disposal wells. Any treatment for restoring the injection capacity of water disposal wells impaired by low quality water is expensive. Any successful treatment is rooted into the detailed analysis of the problems. Implementation of a proper surveillance program and appropriate processing of the injection fluid is also vitally important for wastewater management.
-
-
-
Boiler Reliability Study – Abqaiq Plant Experience
Authors S. A. Al-Amoudi, Mohammad H. Al-Hajji and Mohammad S. Al-SuwaianThis paper describes a reliability enhancement study for boilers that was recently conducted at the world’s largest crude oil stabilization plant in Abqaiq, Saudi Arabia. Since its inception in the 1940s, the Abqaiq plant has had to operate a number of water tube boilers to produce high pressure steam that is used to process stabilized oil. In each boiler, there are more than 2,000 tubes and, over the years, several boiler tube failures have occurred. This paper describes a recent study that was conducted to evaluate the history of tubes failure, identify the main factors of the tube failures, and generate recommendations to minimize the number of failures. This paper presents the results of a recent boiler life assessment study that was conducted on one of the boilers at the Abqaiq plant.
-
-
-
Harnessing Intelligent Field Capabilities for Early Understanding of Reservoir Behavior and Proactive Decisions
Authors Amer H. Abuhassoun and Sultan S. ShamraniWith recent advancements in field instrumentation technologies and the expansion of Saudi Aramco’s state-of-the-art intelligent field infrastructure, a wealth of valuable knowledge is being derived from integrating intelligent field capabilities with best-in-class reservoir management practices. Intelligent field applications have already leveraged real-time reservoir surveillance data to enable timely responses and fast interventions for events observed from real-time data. As richer and more granular datasets are collected from the field, deeper insights and understanding of the reservoirs are gained at fractions of the needed time where intelligent field capabilities are not present. The abundance and timely processing of intelligent field data enables more tactical adjustments in reservoir management strategy. This type of real-time reservoir management has already shown great value in reservoir performance optimization. This paper discusses several cases in which an intelligent field enabled early detection of anomalies and shortened the timecycle for an analysis, decision and action. The first case discusses the early detection of localized pressure support anomalies due to poor rock quality. This timely detection, facilitated by intelligent field infrastructure, enabled quick decision making and actions to overcome the anomaly. The second case shows how real-time monitoring of reservoir pressure propagation has helped to detect over-injection in two injectors with malfunctioned meters. This has allowed timely action to ensure uniform pressure propagation and repair of faulty equipment. The third case shows that the utilization of real-time data has assisted in detecting a casing leak in a short time, which helped in making a corrective action to restore the well’s capacity. In all three cases, had an intelligent field not been there, the time-cycle from detection to analysis, and to decision and action, would have been substantially longer, resulting in higher operational costs and an impact on reservoir performance.
-
-
-
Influence of Micro-Computed Tomography Image Resolution on the Predictions of Petrophysical Properties
Micro-CT scanning is a non-destructive technique that can provide three-dimensional images of rock pore space at a resolution of a few microns. . However, these greyscale images cannot be directly input into simulators to predict flow properties; they require image processing to segment the solid and void space in the rock. Dynamic and static single phase properties can then be computed using the images directly or on extracted equivalent network models. In this paper, we study the effect of imaging resolution (five different voxel sizes ranging from 6-20 μm) of Clashach and Doddington sandstone on predicted single phase properties (porosity and absolute permeability) and network properties. Experimental data is used to validate the predictions. The results suggest that the computed porosity was largely independent of resolution and in good agreement with the measured value, while image resolutions of a few microns are sufficient to determine the permeability of a high-permeability rock such as Doddington but may not be sufficient for lower permeability samples. The topologically representative networks are sensitive to resolution, adding additional smaller pores and throats as the resolution is increased. This latter reason was confirmed by a network extraction analysis that indicated the average throat radius was 6 m, similar to the highest resolution used and insufficient to image all important features of the pore space properly.
-
-
-
Calculations of Equivalent Circulating Density in Underbalanced Drilling Operation
More LessUnderbalanced drilling using gasified fluids is one of the most widely used methods to drill depleted, low pressure and highly fractured formations. For ensuring a safe and successful underbalanced drilling operation, accurate prediction of the equivalent circulating density (ECD) is very important. Nevertheless, estimating ECD of gasified fluids is not easy due to the complexity of the two-phase fluid flow inside the wellbore. In this study, there are two major focuses considered; i) validation of the accuracy of Beggs & Brill (1973) model on the prediction of pressure losses of gasified fluids in underbalanced drilling operation, and modification of Beggs & Brill (1973) model for pressure loss estimation inside the wellbore, and ii) to propose an ECD calculation procedure for gasified fluids by using modified Beggs & Brill (1973) model. To validate the accuracy of Beggs & Brill (1973) model, experiments were carried out using Middle East Technical University (METU) Cuttings Transport Facility to obtain the pressure losses of gasified fluids in an annulus and their corresponding flow patterns. Air-water mixtures were used with various in-situ air and water flow velocities of 0-120 ft/s and 0-10 ft/s, respectively, at wellbore inclinations of 90°, 75°, 60°, 45° and 12.5° without inner pipe rotation. Pressures were recorded at several points along the annular test section, and pressure distribution along the test section was measured. Meanwhile, flow patterns were determined by the help of a high speed digital camera. Results showed that although Beggs & Brill (1973) model can estimate pressure losses in low gas and liquid flow rates and low slip ratio between two phases for horizontal and near horizontal annular sections with a reasonable accuracy, this model cannot accurately calculate pressure losses at inclined and vertical annular sections. With some modifications, improved Beggs & Brill (1973) model (by applying suggested procedure) can be used to predict ECD and annular pressure losses of gasified fluids inside the annulus accurately. This information can be directly applied for underbalanced drilling operations when gasified fluids are used.
-
-
-
Performance of Re-Fracturing in Multiple Thin Layers of Low Permeability Oilfields
Authors Liu He and Wang WenjunFor the low permeability formation of Daqing oilfield, we have to stimulate the multiple thin layers in one stage during a separated layer fracturing job because there are many of layers in one well. Based on the logging data analysis, the hard fracturing layers identified method has been built for the multiple thin layers re-fracturing in low permeability layers in Daqing. According to the calculating result of the broken pressure difference within multiple layers, we can recognize the layer which is not been stimulated in the first time multiple layers limited entry fracturing job. We can optimize the fracturing parameters design in the re-fracturing treatment. Based on the research of interference disciplinarian between fractures, we can get the boundary of the least interval without the interference. So we can analysis which layer is not been stimulated enough because of fractures interference in the first time fracturing. Researching the relationship of perforation holes erosion with fracturing treatment parameters can help us to estimate the first time fracturing and optimize the re-fracturing treatment parameters designing. By using above method, we have got a satisfactory re-fracturing result in 27 wells. After fracturing, the oil production is increased 6.8t/d and the water ratio is decreased 4.2%. The oil production is even higher 1.2t/d than the first time fracturing. That shows the new layers have been stimulated.
-
-
-
Classification and Evaluation of Ultra-Low Permeability Reservoirs in the Changqing Oilfield
Authors Xinquan Ran, Anqi Li, Jiyong Zhao and Shuheng LiWith the rapid development of the world economy, the exploration and development of unconventional oil and gas resources have become a new hot spot. As an important subset of unconventional reservoirs, ultra-low permeability (ULP) reservoirs have been greatly concerned. Studies suggest that the ultra-low permeability reservoir belongs to the typical tight reservoir. The current low-permeability reservoir classification criteria available in the literature cannot meet the actual needs of ultralow permeability reservoir development. Through researches, reservoir characterization parameters of effective porosity, mainstream throat radius, movable fluid saturation and starting pressure gradient are screened out to build quaternary classification coefficient. A new standard of classification and evaluation of ultra-low permeability reservoirs is established, and ultra-low permeability reservoirs are divided into three categories. Thus it provides a theoretical basis for speeding up the effective development of ultra-low permeability reservoirs. Keywords: unconventional oil and gas; tight oil; ultra-low permeability reservoir; characterization parameter; classification and evaluation Since the beginning of the 21st century, the world economy has entered a new cycle of development. The demand for oil and gas resources in the countries soared. Facing the huge demand for energy, productivity construction and production rate are relatively insufficient throughout the world. Unconventional oil and gas resources are beginning to receive more attention. Ultra-low permeability reservoirs, as important unconventional oil and gas reservoirs, have huge potential for exploration and development, but the current classification of reservoir evaluation criteria cannot meet the needs of ultra-low permeability reservoir exploration and development. In order to effectively guide the exploration and development practice of ultra-low permeability reservoirs, it is of great significance to launch researches on ultra-low permeability reservoir characterization parameter system, and to establish a new classification and evaluation criteria.
-
-
-
Employing First Principles Model-Based Soft Sensors for Superior Process Control and Optimization
Authors Shuyee D. Lee and Aidhah J. ZahraniThis paper describes the development and implementation of soft sensors at the world’s largest crude oil stabilization plant (Abqaiq) for superior process control and optimization. The soft sensor uses a rigorous steady-state model combined with dynamic synchronization to compute real-time stream properties (i.e., hydrogen sulfide amount (H2S), Reid vapor pressure (RVP), and true vapor pressure (TVP)) so corrective action can be taken immediately. Crude oil is characterized by 19 pure light components and 17 heavy pseudo-components. A non-Random Two-Liquid (NRTL) model is used for predicting thermodynamic properties of the liquid phase while an ideal gas model is used for the vapor phase. Unlike traditional data driven methods, the soft sensor adopts the first-principles modeling approach so current operating conditions can be correctly reflected in the online model based on sound engineering principles. Fault detection, sensor validation, and calibration with laboratory data are also performed online to ensure reliable and accurate predicted H2S, RVP and TVP values.
-
-
-
SMS Skyscrapers
Authors Jamal Khan and Gary AmidenauThis paper offers methodology, guidelines and tools to assist Oil/ Gas plants and other industrial facilities to develop organize and improve local safety programs (SMS) that comply with corporate elements of safety management as in the 11 elements of the “Saudi Aramco Safety Management System”. The development is done through a consistent method and format for writing the system elements and its processes. For simplicity, the model is represented by a Skyscraper building “SMS Skyscraper”. All model processes include definition of crucial characteristics which are: Purpose, Applicability, Description, Flowcharts, Responsibilities, Training, Performance Indicators, Supporting Tools, Documentation and References. Once the model is used, it helps achieve and sustain quality in defining HSE processes. The quality of processes drive quality in execution of safety activities. This in turn paves the path for proper identification Hazards and evaluation Risk every addition to improving the accountability culture. The overall objective is to help organizations develop customized “Safety Management Systems” that capture the knowledge and “know-how” in addition to providing tools that foster world class execution. In time, and with the right leadership, this will transform organizational and community safety culture and consequently reduce incidents ON and OFF the Job. The “SMS Skyscraper” model has been used to develop 100 Safety Management Processes for Khursaniyah Gas Plant Safety Management System (KGP SMS) in the period between February 2009 to March 2010 and is now available on Saudi Aramco intranet portal at http://KGP/SMS. The model has helped Khursaniyah Gas Plant achieve level of ownership of our local SMS in addition to placing the department on the leading edge of safety management in Saudi Aramco. It also helped young individuals in the organization substantially grow their knowledge in safety management. The model has been reviewed and acknowledged by a handful of safety professionals. It has also been recognized by the Upstream business line in Saudi Aramco as the “go-by” model for development of safety processes. Many other departments in Saudi Aramco are now moving towards the Skyscraper model for comprehensive development of local SMS processes.
-
-
-
Assessment of Corrosion and Mechanical Properties Degradation of Pipeline Steel After Long Term Service in High Sour Gas-Field Environments
Authors Cheng Zhang, Qingsheng Zhang, Weiguo Chen, Dexu Liu, Tiongxiong Ou, Xuesong Huang, Can Chen and Changfeng ChenIn this work, the corrosion behavior and mechanical degradation of two types of pipe steel, Inconoy 825 and L360, after two years of high sour environments service in Puguang gas-field were studied. Results demonstrated that a fearful elemental sulfur layer deposited on the inner wall of pipeline, pitting corrosion and hydrogen-induced cracking was observed in L360 pipe. In comparison, no pitting corrosion and hydrogen-induced cracking was found in Inconoy 825 steel pipe due to its excellent resistance to corrosion. Furthermore, mechanical properties (yield strength, impact strength, elongation, hardness, fracture toughness) and stress corrosion cracking were investigated. Results showed that the yield strength decreased obviously and the percentage of elongation increased in Inconoy 825 steel but little change in L360. The analysis a change of the mentioned mechanical characteristics together with the results of the diffusion and tapping of hydrogen of them indicated that the properties degradation of Inconoy 825 pipeline steel after long term service was associated with essential role of hydrogen in these processes. The consequences of sudden failures and severe corrosion of metallic material in the high sour gas-field, which associated with their exposure to H2S/CO2 containing gas, led to the preparation of evaluation tests of pipeline. However, passing evaluation tests cannot guarantee the safety in actual work condition unless the field experience had been at least two years. As the first attempt to exploit high sour gas-field in China, it is anticipated that this work of Puguang provides valuable data and an essential insight into the corrosion and degradation of pipeline steel services in high-sour environmental.
-
-
-
Integrating an LNG Plant with an Unconventional Gas Supply
Authors Chris Langley and Adriaan SpaanderArrow Energy is a JV company based in Brisbane, Australia, that is owned 50/50 by the Shell group and PetroChina (a subsidiary of CNPC). Arrow is planning to develop its tenement holdings of Coal Seam Gas (CSG) in the Surat and Bowen Basins of central Queensland. The CSG will be produced at very low pressures from shallow wells, gathered and compressed into two 500 km trunk-lines for delivery to a two train LNG plant, with each train sized at 4.0 mtpa capacity. The LNG plant will be located on Curtis Island, opposite Gladstone harbour, in Queensland. CSG is classed as “unconventional” gas; this is the first time that Shell or PetroChina have designed an LNG plant with an unconventional gas feed. The paper discusses the unique aspects of integrating an LNG plant with this unconventional gas feed.
-
-
-
Production Optimization with Hydraulic Fracturing: Application of Fluid Technology to Control Fracture Height Growth in Deep Hard-Rock Formation
Authors Mohammad Al-Dhamen, Areiyando Makmun and Ahmed HilalHydraulic fracturing is frequently used to create the reservoir-wellbore connectivity required to produce the hydrocarbon from tight formations. Many factors can be considered as risks to the success of operations. One arises in reservoirs with a water-bearing zone in close proximity to the net pay. Many times, the risk of fracture growth into the water zone limits the stimulation options and eliminates the option of a hydraulic fracturing treatment, thereby constraining the well’s future production. The challenges increase when the reservoirs are deep, hot, and exhibit a high Young’s modulus. Under these conditions, it greatly increases the risk of an early screenout, and the introduction of fracturing fluid into the formation before a high-conductivity proppant pack is fully placed will damage the formation and hinder production. In Saudi Arabia, a well in a relatively new field encompassed all three challenging characteristics. The target reservoir section was between two water-bearing zones, had high bottomhole temperature, and high Young’s modulus. Traditional polymer-based crosslinked fluids would address the challenges from the perspective of proppant placement. However, these thick crosslinked fluids would also risk in uncontrolled fracture growth into the water zones. A polymer-free, high-temperature viscoelastic surfactant (VES) fracturing fluid was used to balance the risks of incomplete proppant placement, formation damage, and fracture growth that would result in water production. The VES fluid selected for treatment of Well SH-3 has a low viscosity compared to that of a traditional crosslinked fluid; it therefore generates less net pressure and thus lowers the risk of the fracture growing into the water zones. It also has excellent capacity to carry and suspend proppant. To increase its efficiency, the VES fluid was further enhanced by using a degradable fluid-loss additive. Pumped on a conservative schedule, the hydraulic fracturing treatment placed 61,500 lbm of proppant into the thin reservoir section between two water-bearing zones without any operational issues. The Minifrac analysis, stress profile calculation, and fracture geometry characterization, as well as no water production, has confirmed the controlled fracture height growth. Furthermore, pre- and post-stimulation analyses validated the improved productivity, giving a successful stimulation option for the development of this field.
-
-
-
Mitigating Challenges in Resolving 7” Liner Leak- Case Study
Authors Husain Al Muailu, Konstantinos Zorbalas, Karam Al Yateem and Javier GarciaAn evaluation process was conducted in assessing various solutions towards remedial action to a 7” liner with an identified leak in a water injector well. The leak to the 7” liner was identified through pressure testing of the well. A comprehensive investigation and analysis was performed to identify the liner condition, exact leak location and the extent of the leak. It was accomplished by analyzing all previous activities performed during the life of the well and through running special pressure testing as well as logging the well with ultrasonic and physical logs. The problem identification and proposed solutions were focused on curing the leak and bringing the well back on injection with the least operational risk and highest possibility of success. Corrosion and cement bond logs were ran and showed a better picture in regards to the extent of the corroded section and the quality of cement behind it. A caliber log was also run in the open hole which showed a washed out area near the 7” liner shoe. Several solutions that could repair the 7” liner leak were assessed including: i) cement squeeze in the leak zone, ii) setting an off bottom 4.5” liner and iii) using a 5.5” expandable liner. The evaluation process included each solution’s impact on the future injectivity of the well, the effectiveness of each option, operational challenges and associated risks. Moreover, nodal analysis was performed to evaluate possible reduction of the injection rate associated with each solution. The final decision to repair the leak was to run an expandable liner and it was based on its advantages and deployment challenges. Lessons learned from this operation included the methods used to identify and assess the damage of the casing leak. Proper preparation and cleanout of the corroded section and the operation procedures performed to expand the liner are summarized in this paper.
-
-
-
Raising Upstream Digital Professionals' Competency and Productivity Using Performance-Based Training
Authors Kenneth K. Lau and Nashid AbdulkhaaliqSaudi Aramco has established the Upstream Professional Development Center (UPDC) to train its geoscientists and engineers to independently and proficiently conduct a wide range of exploration and production operations and its systems analysts in providing a collaborative environment for executing these operations. Its purpose is not to replace academic institutions but rather to complement them by introducing activity and performance-based training (PBT) programs. The objective is not only to improve the organization‘s overall performance level but to raise the standards of its entire workforce as well. This paper describes how UPDC‘s Upstream Computing job family designs, develops and delivers its courses for recently hired Upstream digital professionals (computer scientists and software engineers). It outlines how to effectively train them to acquire a fundamental understanding of a wide range of oil and gas exploration and production (Upstream) operations and to use this knowledge to support, maintain and develop an equally wide range of software applications used for facilitating everyday Upstream operations. Saudi Aramco‘s systems analysts are loaned by their line organizations to UPDC to design and implement these courses based on their work experiences and best practices. To teach and/or re-enforce technical concepts, and for employees to gain appreciation of these practices, over 50% of class time is devoted to activities, assessments, reviews and discussions. For the advancement of mid-career digital professionals, performance-based curriculums (identified by Saudi Aramco as ―career professional curriculums‖) are also being developed. An overview on how these curriculums are designed based on job outcome requirements will be outlined. UPDC instructors use advanced audiovisual, animation and simulation technologies for effective course delivery and promoting in-class activity participation.
-
-
-
Achieving Brazilian Extended Reach Drilling Records on Polvo Project with Ultra-High Torque Connection
Authors Nathan Biddle, Luciana Osório, Hector Arevalo, Marcelo Velho, Vincent Flores and Scott GrangerThe Polvo project is a platform based drilling rig located ~95km off the Brazilian coast in the Campos Basin. The field consists of two distinct reservoirs, a carbonate reservoir to the southwest, and a sandstone reservoir to the east. The Polvo project began drilling in March 2007 and has since drilled a total of 32 wellbores. The wells range in difficulty from “short reach” to “very extended reach” wellbores. The deviation is from 3-7º DLS at angles of 30-92º. Wellbores are 3-dimensionally designed in order to improve total reservoir exposure. Extended reach, deep and high deviation wells require the use of a drill string that has both higher torsional yield strength drill pipe body and greater torque capacity tool joints than are afforded by standard API connections. VAM Express double shoulder connection has been designed in order to address the drilling challenges linked to the development of such complex wells. This proprietary high torque connection incorporates four major design features allowing pushing further the drilling envelope limits: quick rig make-up, high torque performance, user friendly and durability. After beginning the project and platform placement, it was discovered that sandstone reservoir targets further to the east had higher productivity than expected. After drilling 12 wells and numerous lessons learned, the furthest extended reach well in the history of Brazil was attempted and successfully completed. The Pol-O wellbore was drilled to a total measured depth of 6,489 m (2,429 m TVD) and a vertical section step out of 5,615 m. This wellbore was and continues to hold the record for furthest reach wellbore in the history of Brazil. In addition to obtaining this extended reach record, Polvo also attained the record of fastest 24 hours drilling in an 8 ½” hole with 1,610 m in 24 hours. To obtain this drilling record, it was not only critical to have high on bottom ROP, but also to optimize connection time. The high torque connection helped to achieve this fast connection time and also prevented any drillstring failure. Having drilled over 100,000m of total hole in highly deviated wellbores using the same drillstring, there has not been any twist-offs or back-offs on the Polvo project. By being able to drill these further reach wellbores successfully and more economically, the Polvo Platform has proved up further reserves that can be produced without requiring installation of another platform or subsea tiebacks. The rig is not limited by connection strength and plans are in place to improve the top-drive to deliver more torque, while staying with the same double shoulder connection size.
-
-
-
Hydraulic Fracturing Candidate-Well Selection by Interval Type-2 Fuzzy Set and System
Authors Mansoor Zoveidavianpoor, Ariffin Samsuri and Seyed Reza ShadizadehSelecting a target formation(s) among a vast numbers of zones/sub-layers within huge numbers of hydrocarbon producing wells in a reservoir, is considered a difficult task, particularly if the selection goes through a group of parameters having different attributes and features; such as geological aspect, reservoir and fluid characteristics, etc. The trend of candidate-well selection (CWS) process for Hydraulic Fracturing (HF) had recognized to be complex, nonlinear, un-equilibrium, and adherent with uncertainty. Interval Type-2 Fuzzy Logic and Systems (IT2-FLSs) are very useful in circumstances where it is difficult to determine an exact membership function (MF) for a Fuzzy Set (FS); hence they are very effective for dealing with uncertainties. Classical FLS which called T1-FLS is not capable of fully capturing the linguistic and numerical uncertainties in the terms used and the inconsistency of the expert's decision-making. Therefore, the need arises to use a method that could handle uncertainties. The procedure of applying this novel study in the area of HF CWS, will have illustrated through a case study in a carbonate reservoir. The utilization of a modern and right problem-solving tool such as T2-FSS should be considered a great concern to the petroleum industry. Although sizeable clarity has been achieved in this area, no conceptualization such as dealing with uncertainty, has yet answered by the previous studies. New requirements force the previous methods to advance and novel techniques expected to meet the requirements and remove the existing weakness. In highlighting this need, the question has been answered about why IT2-FLSs should be used in this study. Also, its advantages over T1-FLS will be illustrated. This paper critically assesses the importance of the proposed methodology to develop a reliable model of HF CWS. This investigation is the first research which applied such a cutting-edge approach and tries to fill the gap between recent developments in uncertainty management through utilization of IT2-FLSs in HF candidate-well selection.
-
-
-
A Case Study: Innovative Open Hole Well Completion Provides Superior Results in Tight Gas Formation in Jilin District, China
Authors Wang Feng, Changyu Liu, Yingan Zhang, Yong Wang, Hai Liu and Ka Tong KuDrilling of horizontal wells has increased steadily over the last few years in China on land. As technology has developed, operators have seen the economic and production benefits of drilling horizontally 1, 2. In the Changling gas field, the Deng Louku formations are primarily low porosity (average 5.2%) and low permeability (average 0.17md) tight sand. Typically, wells in this area are drilled vertically and completed with cemented casing. Proppant fracturing was necessary to produce the well economically due to the low permeability nature of the formation. However the production results from the conventional vertical fracturing completions were not very promising and most of the wells experienced rapid production decline once they were put on production. Thus it became crucial to find an engineering solution to effectively unlock the reserves and obtain sustained long term productivity. Multistage fracturing of the DP2 horionatal well is a milestone for the operator due to: 1) the deepest, and most stages in a single horizontal well in a tight sand formation in China was completed and fractured; 2) the biggest fracturing job for a single well in terms of proppant and fracture fluid volume was successfully pumped continuously by first time application of the precise continuous mixer (PCM) in China; 3) an innovative multistage fracturing design workflow was developed to optimize the horizontal well completion design including several disciplines: geology, reservoir modeling and fracturing. This workflow was set as the standard design process for multistage fracturing design in the field. The DP2 horizontal well was completed in ten stages in the 837 m openhole section and the ten fracturing stages were pumped continuously in 3 days. The PCM was used to improve the fracturing operation efficiency. A total of 1425 tons of 30/50 proppant was successfully placed into the formation using 4870 m3 fracturing fluid. The well produced 320,000 m3/day initially and was stabilized at 180,000 m3/day with 20 MPa wellhead pressure, which is 5 times higher than the average offset well. The application of real time hydraulic fracturing monitor technology helpped to verify that the optimized fracture half-length was achieved, and to adjust the fracturing schedule in real time for the second stage.
-
-
-
Drilling of Multilateral Wells Aided with Geochemical Analysis, Kuwait
This paper describes the utilization of Real-Time geochemical analysis to support geosteering of a smart multi-lateral well, located in one of the highest flow potential areas in Kuwait. The Burgan reservoir consists of vertically stacked channel sands along with a fault network connected to the aquifer and contains highly viscous reservoir fluid. This drastically enhances the water mobility, and results in severe premature water breakthrough. Hence, leaves zones of by-passed oil. For optimum reservoir characterization, it was essential to integrate all reservoir-related data from macro to micro scale. X-ray Fluorescence elemental data collected from offset cores were used to predict key rock attributes and calibrated with standard petrophysical logs.The scope was constructing predictive models for the following properties: 1) lithological variations which cannot be captured by other LWD tools 2) detailed mineralogy to determine the diagenetic overprint 3) depositional environment of different Burgan sand facies. XRF elemental analysis while drilling was used to improve borehole positioning, and identify faults in correlation with Image logs. Nature of the fractures/faults, contributing to porosity and communicating with the aquifer, was inferred from XRF-obtained elemental markers. The integrated approach has resulted in successful geosteering and placing the well with maximum reservoir contact. Moreover, XRF elemental markers have been utilized for isolation of faulted and lower reservoir quality zones, splitting up of horizontal sections and optimization nozzle sizes of the ICDs and hence an optimized Smart completion design. X-ray fluorescence analysis on cuttings in Real-Time provides lithological information otherwise not available while drilling. It gives proxies contributing to the identification of faults and reservoir intervals in an otherwise homogeneous sequence. It helps designing the completion string, isolating sections of low quality or potentially producing water.
-
-
-
Modeling Production and Well Performance Forecasting of Complex Volcanic Reservoir
Authors Liu He, Zhang Yingan, Zou Honglan and Gao YangThe formations of DaQing gas field are mainly volcanic reservoirs which have the characteristics of low permittivity and complex formation structures. Most of these wells need fracturing remodeling to meet the standards of industrial gas stream, and also, the gas productivity tests as well as the pressure recovery tests conducted on these wells are different from other regular gas reservoirs. Considering the nature of the volcanic reservoir, such as dissolution pores, karsts caves, natural fracture development, we built two mathematical models of dissolution pores development and natural fracture development under both of the Darcy flow conditions and Non-Darcy flow conditions separately to predict the production of triple porosity reservoir after gas reservoir well fractures. By using the Laplace transform and numerical inversion, the equation to calculate production of complex volcanic gas wells is obtained. Based on these researches, law of volcanic reservoir productivity is investigated. The theoretical data are compared with the practical data collected from the field operation. The comparison results reveal how the parameter of the fluid volume, proppant indexes, and conductivity of artificial fracturing induced fractures and length of fractures change affect the productivity. The research work reported in this paper provides theoretical support on the optimization method of fractured wells design of volcanic gas reservoir.
-
-
-
CSEM inversions using the Gauss-Newton method and a model compression scheme
Authors Aria Abubakar, Yun Lin, Maokun Li and Tarek M. HabashyWe present a model compression scheme for improving the efficiency of the regularized Gauss-Newton inversion algorithm for marine controlled-source electromagnetic applications. In this scheme the unknown model parameters (the resistivity distribution) are represented in terms of a basis such as Fourier, cosine, or wavelet. By applying a proper truncation criterion, the model may then be approximated by a reduced number of basis functions, which is usually much less than the number of the model parameters. Furthermore, since the controlled-source electromagnetic measurements have low-resolution, we will show that for inversion it is sufficient to only keep the low-spatial frequency part of the image. This model compression scheme accelerates the computational time as well as reduces the memory usage of the Gauss-Newton method. For demonstration purposes, we show both synthetic and field data inversions. The results show that we are able to significantly reduce the algorithm computational complexity without compromising the quality of the inverted models.
-