The Impact of Overbalanced Drilling From Exploration/Appraisal Wells to Field Development Plan

2021 ◽  
Vol 62 (6) ◽  
pp. 694-710
Author(s):  
Mohammadhossein Mohammadlou ◽  
◽  
Matthew Guy Reppert ◽  
Roxane Del Negro ◽  
George Jones ◽  
...  
Keyword(s):  
Development Plan ◽  
Core Material ◽  
Reservoir Quality ◽  
Field Development ◽  
The Core ◽  
Well Design ◽  
Well Data ◽  
The Impact ◽  
Initial Exploration

During well planning, drillers and petrophysicists have different principle objectives. The petrophysicist’s aim is to acquire critical well data, but this can lead to increased operational risk. The driller is focused on optimizing the well design, which can result in compromised data quality. In extreme cases, the impact of well design on petrophysical data can lead to erroneous post-well results that impact the entire value-chain assessment and decision making toward field development. This paper presents a case study from an Upper Jurassic reservoir in the Norwegian Sea where well design significantly impacted reservoir characterization. Three wells (exploration, appraisal, and geopilot) are compared to demonstrate the impact of overbalanced drilling on both log and core data. Implications for reservoir quality assessment and volume estimates are discussed. Extensive data collection was initially carried out in both exploration and appraisal wells, including full sets of logging while drilling (LWD), wireline logging, fluid sampling, and extensive coring. Both wells were drilled with considerable overbalanced mud weights due to the risk of overpressured reservoirs in the region. The log data were subsequently corrected for significant mud-filtration and fines invasion, with calibration to core measurements guiding the interpretation. A thorough investigation of core material raised suspicion that there could also be significant adverse effects on core properties resulting from overbalanced drilling. The implications were so significant for the reservoir volume that a strategic decision was made to drill a geopilot well close to the initial exploration well prior to field development drilling. The well was drilled 6 years after the initial exploration phase with considerably lower overbalance. Extensive well data, including one core, were acquired. The recovered core was crucial in order to compare the reservoir properties for comparable facies between all three wells. The results from the core demonstrate distinctly different rock quality characteristics, especially at the high end of the reservoir quality spectrum. Results of the core study confirmed the initial hypothesis that overbalanced drilling had significantly impacted the properties of the core and well logs. This study shows how well design adversely affected petrophysical measurements and how errors in these data compromised geological and reservoir models, leading to a suboptimal field development plan that eroded significant value. This example provides a case study that can be used to improve well designs so that petrophysicists and drillers can both be part of the same value creation result.

THE IMPACT OF OVERBALANCED DRILLING FROM EXPLORATION/APPRAISAL WELLS TO FIELD DEVELOPMENT PLAN

2021 ◽  
Author(s):  
Mohammadhossein Mohammadlou ◽  
◽  
Matthew Guy Reppert ◽  
Roxane Del Negro ◽  
George Jones ◽  
...  
Keyword(s):  
Value Creation ◽  
Reservoir Quality ◽  
Field Development ◽  
The Core ◽  
Reservoir Models ◽  
Well Design ◽  
Well Data ◽  
The Impact ◽  
Initial Exploration

During well planning, drillers and petrophysicists have different principle objectives. The petrophysicist’s aim is to acquire critical well data, but this can lead to increased operational risk. The driller is focused on optimizing the well design, which can result in compromised data quality. In extreme cases, the impact of well design on petrophysical data can lead to erroneous post-well results that impact the entire value-chain assessment and decision making toward field development. In this paper, we present a case study from a syn-rift, Upper Jurassic reservoir in the Norwegian Sea where well design significantly impacted reservoir characterization. Three wells (exploration, appraisal, and geopilot) are compared in order to demonstrate the impact of overbalanced drilling on well data from both logs and core. Implications for reservoir quality assessment, volume estimates, and the errors introduced into both a static geomodel and dynamic reservoir simulation are discussed. This case study highlights the importance of optimizing well design for petrophysical data collection and demonstrates the potential for value creation. Extensive data collection was initially carried out in both exploration and appraisal wells, including full sets of logging while drilling (LWD), wireline logging, fluid sampling, and extensive coring. Both wells were drilled with considerable overbalanced mud weights due to the risk of overpressured reservoirs in the region. The log data was subsequently corrected for significant mud-filtration invasion, with calibration to core measurements guiding the interpretation. Geological and reservoir models were built based on results from the two wells, and development wells were planned accordingly. A thorough investigation of core material raised suspicion that there could also be a significant adverse effect of core properties resulting from overbalanced drilling. The implications were so significant for the reservoir volume that a strategic decision was made to drill a geopilot well close to the initial exploration well, prior to field development drilling. The well was drilled six years after the initial exploration phase with considerably lower overbalance. Extensive well data, including one core, were acquired. The recovered core was crucial in order to compare the reservoir properties for comparable facies between all three wells. The results from the core demonstrate distinctly different rock quality characteristics, especially at the high end of the reservoir quality spectrum. Results of the core study confirmed the initial hypothesis that overbalanced drilling had significantly impacted the properties of the core as well as the well logs. The study concluded that the updated reservoir model properties would significantly increase the in-place volumes compared to the pre-geopilot estimate. This study shows how well design adversely affected petrophysical measurements and how errors in these data compromised geological and reservoir models, leading to a suboptimal field development plan that eroded significant value. This example provides a case study that can be used to improve the well design so that petrophysicists and drillers can both be part of the same value creation result. Future work will include further laboratory investigations on the effects of high overbalanced drilling on core and possible “root causes” for compromised core integrity.

Injectivity and Propagation of Sulfonated Acrylamide-Based Copolymers in Low Permeability Carbonate Reservoir Cores in Harsh Salinity and Temperature Conditions : Challenges and Learnings from a Middle East Onshore Case Study

2021 ◽  
Author(s):  
Nicolas Gaillard ◽  
Matthieu Olivaud ◽  
Alain Zaitoun ◽  
Mahmoud Ould-Metidji ◽  
Guillaume Dupuis ◽  
...  
Keyword(s):  
Middle East ◽  
Polymer Solutions ◽  
Carbonate Reservoir ◽  
Core Material ◽  
Low Permeability ◽  
The Core ◽  
Reservoir Conditions ◽  
Carbonate Cores ◽  
The Impact ◽  
Mobility Reduction

Abstract Polymer flooding is one of the most mature EOR technology applied successfully in a broad range of reservoir conditions. The last developments made in polymer chemistries allowed pushing the boundaries of applicability towards higher temperature and salinity carbonate reservoirs. Specifically designed sulfonated acrylamide-based copolymers (SPAM) have been proven to be stable for more than one year at 120°C and are the best candidates to comply with Middle East carbonate reservoir conditions. Numerous studies have shown good injectivity and propagation properties of SPAM in carbonate cores with permeabilities ranging from 70 to 150 mD in presence of oil. This study aims at providing new insights on the propagation of SPAM in carbonate reservoir cores having permeabilities ranging between 10 and 40 mD. Polymer screening was performed in the conditions of ADNOC onshore carbonate reservoir using a 260 g/L TDS synthetic formation brine together with oil and core material from the reservoir. All the experiments were performed at residual oil saturation (Sor). The experimental approach aimed at reproducing the transport of the polymer entering the reservoir from the sand face up to a certain depth. Three reservoir coreflood experiments were performed in series at increasing temperatures and decreasing rates to mimic the progression of the polymer in the reservoir with a radial velocity profile. A polymer solution at 2000 ppm was injected in the first core at 100 mL/h and 40°C. Effluents were collected and injected in the second core at 20 mL/h and 70°C. Effluents were collected again and injected in the third core at 4 mL/h and 120°C. A further innovative approach using reservoir minicores (6 mm length disks) was also implemented to screen the impact of different parameters such as Sor, molecular weight and prefiltration step on the injectivity of the polymer solutions. According to minicores data, shearing of the polymer should help to ensure good propagation and avoid pressure build-up at the core inlet. This result was confirmed through an injection in a larger core at Sor and at 120°C. When comparing the injection of sheared and unsheared polymer at the same concentration, core inlet impairment was suppressed with the sheared polymer and the same range of mobility reduction (Rm) was achieved in the internal section of the core although viscosity was lower for the sheared polymer. Such result indicates that shearing is an efficient way to improve injectivity while maximizing the mobility reduction by suppressing the loss of product by filtration/retention at the core inlet. This paper gives new insights concerning SPAM rheology in low permeability carbonate cores. Additionally, it provides an innovative and easier approach for screening polymer solutions to anticipate their propagation in more advanced coreflooding experiments.

Time-Lapse Seismic for Reservoir Management: Case Studies From Offshore Niger Delta, Nigeria

2016 ◽  
Vol 19 (03) ◽  
pp. 391-402
Author(s):  
Sunday Amoyedo ◽  
Emmanuel Ekut ◽  
Rasaki Salami ◽  
Liliana Goncalves-Ferreira ◽  
Pascal Desegaulx
Keyword(s):  
Case Studies ◽  
Niger Delta ◽  
Reservoir Management ◽  
Time Lapse ◽  
Seismic Survey ◽  
Elastic Model ◽  
Field Development ◽  
4D Seismic ◽  
The Impact

Summary This paper presents case studies focused on the interpretation and integration of seismic reservoir monitoring from several fields in conventional offshore and deepwater Niger Delta. The fields are characterized by different geological settings and development-maturity stages. We show different applications varying from qualitative to quantitative use of time-lapse (4D) seismic information. In the first case study, which is in shallow water, the field has specific reservoir-development challenges, simple geology, and is in phased development. On this field, 4D seismic, which was acquired several years ago, is characterized by poor seismic repeatability. Nevertheless, we show that because of improvements from seismic reprocessing, 4D seismic makes qualitative contributions to the ongoing field development. In the second case study, the field is characterized by complex geological settings. The 4D seismic is affected by overburden with strong lateral variations in velocity and steeply dipping structure (up to 40°). Prestack-depth-imaging (PSDM) 4D seismic is used in a more-qualitative manner to monitor gas injection, validate the geologic/reservoir models, optimize infill injector placement, and consequently, enhance field-development economics. The third case study presents a deep offshore field characterized by a complex depositional system for some reservoirs. In this example, good 4D-seismic repeatability (sum of source- and receiver-placement differences between surveys, dS+dR) is achieved, leading to an increased quantitative use of 4D monitoring for the assessment of sand/sand communication, mapping of oil/water (OWC) front, pressure evolution, and dynamic calibration of petro-elastic model (PEM), and also as a seismic-based production-logging tool. In addition, 4D seismic is used to update seismic interpretation, provide a better understanding of internal architecture of the reservoirs units, and, thereby, yield a more-robust reservoir model. The 4D seismic in this field is a key tool for field-development optimization and reservoir management. The last case study illustrates the need for seismic-feasibility studies to detect 4D responses related to production. In addition to assessing the impact of the field environment on the 4D- seismic signal, these studies also help in choosing the optimum seismic-survey type, design, and acquisition parameters. These studies would possibly lead to the adoption of new technologies such as broad-band streamer or nodes acquisition in the near future.

The Impact of Fault Sealing and Transmissibility on Field Development. Case Study: Eureka Field Experience, Onshore Niger Delta

2020 ◽  
Author(s):  
Okiemute Amuboh ◽  
Suleiman Ahmed ◽  
Dolapo Enya ◽  
Gbolade Ibikunle ◽  
Imonite Imorame ◽  
...  
Keyword(s):  
Niger Delta ◽  
Field Experience ◽  
Field Development ◽  
The Impact

scholarly journals Spinnability and characteristics of polyoxymethylene-based core–sheath bicomponent fibers

2019 ◽  
Vol 14 ◽  
pp. 155892501985944
Author(s):  
Jitlada Boonlertsamut ◽  
Supaphorn Thumsorn ◽  
Toshikazu Umemura ◽  
Hiroyuki Hamada ◽  
Atsushi Sakuma
Keyword(s):  
Lactic Acid ◽  
Structural Characteristics ◽  
Core Material ◽  
Poly Lactic Acid ◽  
Bicomponent Fibers ◽  
Fiber Properties ◽  
The Core ◽  
The Impact ◽  
Fiber Processing ◽  
Selection Of

In this work, the spinning abilities of polyoxymethylene-based core–sheath bicomponent fibers were investigated. Bicomponent fibers were prepared using polyoxymethylene as the core material and poly(lactic acid) blended with polyoxymethylene or pure polyoxymethylene as sheath materials, and their characteristics were investigated and compared. Fiber properties such as elongation are important because they directly relate to the spinning performance during fiber processing. This work reports the impact of the composition designation of the core–sheath bicomponent fibers on the controllable stability of poly(lactic acid) in polyoxymethylene–poly(lactic acid) blends in the fibers, as well as the influence of the core–sheath material on the structure, fiber diameter and distribution, thermal stability, and mechanical properties of the core–sheath bicomponent fibers. It was found that the selection of core and sheath materials affected the structural characteristics of the fibers. The polyoxymethylene core–polyoxymethylene sheath (FV) fiber showed dimensional stability. However, the polyoxymethylene core–poly(lactic acid)/polyoxymethylene sheath (FT30) fiber provided the optimum limit of poly(lactic acid) content for controlling the stable properties of the core–sheath bicomponent fibers.

The influence of different types of core materials on the impact behaviour of sandwich composites

2018 ◽  
pp. 78-83
Author(s):  
Cihan Kaboglu
Keyword(s):  
Sandwich Structures ◽  
Core Material ◽  
Sandwich Composite ◽  
Balsa Wood ◽  
Impact Behaviour ◽  
The Core ◽  
Glass Fibre Reinforced Polymer ◽  
Glass Fibre Reinforced ◽  
The Impact ◽  
Core Materials

Sandwich structures are popular in applications in which the weight of the component affects the efficiency, especially in the aviation and aerospace industries. This study aims to understand the impact behaviour of sandwich structures with different core materials. Sandwich structures are manufactured with glass fibre reinforced polymer skins and balsa wood, polyethylene terephthalate (PET) and polyvinyl chloride (PVC) core through resin infusion under flexible tools. Three different core materials were tested and compared using the damaged area of the back face of the sample. The effect of the core materials on the mechanical behaviour of the structures is crucial. The results showed that the microstructure of the core materials plays an important role, because althoughthe density of balsa wood is greater than the density of PET and PVC, the structures having PVC and PET as core materials undergo less damage than those having balsa wood as a core material. Keywords: Sandwich composite, impact behaviour, core materials.

100% Great Songs, reverse positioning of Delta FM Radio, Indonesia

2013 ◽  
Vol 3 (6) ◽  
pp. 1-11
Author(s):  
Amalia E. Maulana ◽  
Pandu Jati Kuncoro ◽  
Lexi Z. Hikmah
Keyword(s):  
Learning Outcomes ◽  
Market Segmentation ◽  
Emerging Market ◽  
Subject Area ◽  
Content Type ◽  
The Core ◽  
Fm Radio ◽  
The Difference ◽  
The Impact

Subject area Reverse positioning, market segmentation, customer-centric organization. Study level/applicability Postgraduate program; Master in strategic marketing and Master in business administration. Case overview Declining radio listenership is triggered by lack of attention of the radio managers to the desires of radio listeners. Delta FM radio, as part of Masima Media Group, is a radio that realized the need for revitalization. They changed their target audience and positioning to regain its former glory. Delta FM radio get back to the core benefit with the tagline: “100% Great Songs”. Shifting from highlighting the emotional benefits to functional benefits and to cut a variety of benefits is called “reverse positioning”. Expected learning outcomes The objective of this case study is to give deeper comprehension a new concept called reverse positioning or reverse branding. It is an example of the dynamic of hyper competition in media market in practice, in the emerging market such as Indonesia. It provides clear picture of the difference between listener oriented vs advertiser oriented company and the impact of the imbalance portion between them. Supplementary materials Teaching notes are available for educators only. Please contact your library to gain login details or email [email protected] to request teaching notes.

Field Optimization Via Data Approach: A Case Study of Data Mining for Tight Gas Flowback Evaluations

2021 ◽  
Author(s):  
Yuan Liu ◽  
Bin Li ◽  
Hongjie Zhang ◽  
Fan Yang ◽  
Guan Wang ◽  
...  
Keyword(s):  
Data Mining ◽  
Production Performance ◽  
Reservoir Quality ◽  
Tight Gas ◽  
Well Performance ◽  
Gas Field ◽  
Field Development ◽  
Field Level ◽  
Depth Analysis ◽  
The Impact

Abstract The economics of tight gas fields highly depend on the consistency between expected production and the actual well performance. A mismatch between the reservoir quality and the well production often leads to a review of the individual well. However, such mismatch may vary from case to case, and it is hard to perform a field-level analysis based on individual well reviews. We introduce a new method based on data mining to assist the field-level diagnosis. LX gas field is located the in eastern Ordos basin. Compared to the main gas field in the center of the basin, LX field is less predictable in well performance. This predictability issue hinders field development in LX field because the field economics are substantially jeopardized by the inconsistency between the reservoir quality and the production performance. The traditional workflow to understand this issue at the field level is to review the details of a large number of individual wells in the area. This is typically an intense task, and too much detail from multiple disciplines may hide the true pattern of the field behavior. To resolve this issue, we applied data mining in our field development diagnosis workflow. Our new workflow in LX area started with the existing field datasheet, including logging summaries, completion treatment reports, and flowback testing datasheets. With the data extracted from these different sources, we visualized the consolidated information in various plots and graphs based on regression analysis, which revealed the relation between flowback ratio and the production, the flowback rate consistency from the different service suppliers, and the impact of water productions. The data mining approach helped to generate new understandings in LX gas field. With the in-depth analysis of the flowback data together with reservoir properties and operation parameters, the key problems in the field were identified for further development optimization, and the field economics can be significantly improved. The diagnosis method can be easily adapted and applied to any field with similar problems, and data mining can be useful for almost all large-scale field development optimizations.

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