A Cost-Effective Stimulation Workflow Unlocks New Perspectives for Matrix Acidizing in Openhole Horizontal Tight Carbonate – A Case Study from West Kuwait

2021 ◽  
Author(s):  
Salem Al-Sabea ◽  
Milan Patra ◽  
Abdullah Abu-Eida ◽  
Nasser Al-Azmi ◽  
Mohammad AlEidi ◽  
...  

Abstract The Mishrif formation in west Kuwait is a tight carbonate reservoir having low oil mobility. It is fractured and heterogeneous with wide variation in porosity ranging from 10 to 25%, matrix permeability of about 0.1 to 10 md, and 20°API oil. Production tests and geomechanical study results have revealed that productivity is mostly from the high-permeability matrix and critically stressed fracture networks. Recently, the Mishrif development has been dominated by horizontal wells to maximize reservoir contact and enhance productivity. However, a challenge in such openhole completion is the stimulation strategy requiring effective diversion technology due to the uneven acid distribution along the lateral section. To address those challenges, a novel engineered workflow has been implemented relying on distributed temperature sensing (DTS) to assess the fluid coverage across the openhole section. Results enable identifying high- and low-intake zones, segmenting the uncased section into intervals requiring different levels of stimulation, and making informed decisions regarding diversion requirements. The intervention was conducted in two stages. Coiled tubing (CT) was the selected fluid conveyance method on the first stage given its capacity for more controlled fluid placement, and high-rate bullheading stimulation was selected for the second stage. During the treatment, multiple challenges were faced, mainly driven by a high-permeability streak identified by the DTS near the heel of the lateral. The CT stimulation procedures were modified on the spot, and measures were taken to minimize the impact on the thief zone, which included a combination of diversion techniques, such as high-pressure jetting, dual injection, and pumping of a near-wellbore nonreactive diverter, which is composed of a customized blend of multimodal particles and degradable fibers to minimize fluid leakoff into the high-intake zone. Likewise, real-time downhole telemetry was crucial throughout the CT stimulation because it allowed the highest injection rate possible below the preset pressure limits, continuous monitoring of downhole dynamics along the intervention, and optimal actuation of the high-pressure jetting tool. Upon completion of the CT stimulation, a second DTS log was carried out to evaluate the fluid coverage and effectiveness of the diversion strategy, enabling further adjustment of the bullhead stimulation program. This stimulation workflow implemented in west Kuwait represents a cost-effective alternative to stimulate openhole tight carbonates. This study brings new perspectives for treating complex reservoirs in the region, and shares lessons learned for future interventions.

2021 ◽  
Author(s):  
Mojtaba Moradi ◽  
Michael R Konopczynski

Abstract Matrix acidizing is a common but complex stimulation treatment that could significantly improve production/injection rate, particularly in carbonate reservoirs. However, the desired improvement in all zones of the well by such operation may not be achieved due to existing and/or developing reservoir heterogeneity. This paper describes how a new flow control device (FCD) previously used to control water injection in long horizontal wells can also be used to improve the conformance of acid stimulation in carbonate reservoirs. Acid stimulation of a carbonate reservoir is a positive feedback process. Acid preferentially takes the least resistant path, an area with higher permeability or low skin. Once acid reacts with the formation, the injectivity in that zone increases, resulting in further preferential injection in the stimulated zone. Over-treating a high permeability zone results in poor distribution of acid to low permeability zones. Mechanical, chemical or foam diversions have been used to improve stimulation conformance along the wellbore, however, they may fail in carbonate reservoirs with natural fractures where fracture injectivity dominates the stimulation process. A new FCD has been developed to autonomously control flow and provide mechanical diversion during matrix stimulation. Once a predefined upper limit flowrate is reached at a zone, the valve autonomously closes. This eliminates the impact of thief zone on acid injection conformance and maintains a prescribed acid distribution. Like other FCDs, this device is installed in several compartments in the wells. The device has two operating conditions, one, as a passive outflow control valve, and two, as a barrier when the flow rate through the valve exceeds a designed limit, analogous to an electrical circuit breaker. Once a zone has been sufficiently stimulated by the acid and the injection rate in that zone exceeds the device trip point, the device in that zone closes and restricts further stimulation. Acid can then flow to and stimulate other zones This process can be repeated later in well life to re-stimulate zones. This performance enables the operators to minimise the impacts of high permeability zones on the acid conformance and to autonomously react to a dynamic change in reservoirs properties, specifically the growth of wormholes. The device can be installed as part of lower completions in both injection and production wells. It can be retrofitted in existing completions or be used in a retrievable completion. This technology allows repeat stimulation of carbonate reservoirs, providing mechanical diversion without the need for coiled tubing or other complex intervention. This paper will briefly present an overview of the device performance, flow loop testing and some results from numerical modelling. The paper also discusses the completion design workflow in carbonates reservoirs.


2021 ◽  
Author(s):  
Irma Kusumawati ◽  
Birger Heigre ◽  
Hunter Whitfield ◽  
Samuel Bremner ◽  
Andrea Sbordone ◽  
...  

Abstract This paper describes the utilization of a riserless light well intervention (RLWI) vessel with well control system and flexible downlines to execute a re-stimulation campaign on subsea injection wells located in the Norwegian Continental shelf in the summer of 2019 and 2020. A riserless light well intervention (RLWI) vessel with well control system and flexible downlines was used in combination with a stimulation vessel. The objective of each campaign was to increase injectivity in the wells with high-rate acid treatments. The lessons learned from the 2019 campaign were applied to the 2020 campaign, resulting in reduced health and safety exposure, and improved operational efficiency. Analysis of the treatments and their impact on injection and field pressure support was conducted to assess the effects of these improvements and provide insights for how the treatments can be applied to vessel stimulation in general. In each campaign, the RLWI vessel was connected to the subsea asset, and a dedicated stimulation vessel provided stimulation fluids via a high-pressure flexible hose connected between the two vessels. Both campaigns saw high treatment pump rates of up to 60 bbl/min with low-pH crosslinked gel fluids, 28% hydrochloric acid, and diverters in the form of ball sealers and rock salt. Hose deployment methodologies between the two vessels differed in the two campaigns. The 2019 campaign employed a conventional transfer utilizing the marine crane on the RLWI vessel to lift and lower the hose into a preexisting hanger. Learnings from this operation led to the development and use of a winch pull-in method in which the hose connection was accomplished with a hot stab connector on the RLWI vessel, eliminating human intervention and the use of the crane. The 2019 and 2020 campaigns successfully stimulated five and six subsea injection wells, respectively, and realized post-stimulation improvement in injection rates of 135%. One year of field monitoring from the first campaign shows pressure support benefits with improvements in production throughout the connecting area of the field. The winch pull-in method of hose deployment between the vessels achieved time improvements of 8 hours per stimulation treatment. In addition, the added flexibility of not needing to be within crane reach gave the operation extended working weather limits. The overall result was a significant improvement in operating efficiency between the 2019 and 2020 campaigns. The operations showed how high-rate stimulation can be achieved on subsea assets with the use of an RLWI and stimulation vessels. Detailed analysis of the operational efficiency of each campaign was performed, and the improvements from one campaign to the next documented. The winch pull-in method is a new way of high-pressure hose transfer that can be applied to future stimulation vessel operations to improve operational safety and efficiency.


2014 ◽  
Vol 1019 ◽  
pp. 143-151
Author(s):  
Carl J. Reinhardt ◽  
Morris Murray ◽  
Isaac Bohlken

High Quality Cost Effective Die Castings rely to a large extent on successful, effective and practical die design. A review is carried out of some runner and gate designs which resulted in successful high quality castings. Some High Pressure and Gravity cast casting are evaluated. Simulation results for evaluating the impact on the flow during filling due to Runner Geometries, Gate Geometries and positions as well as venting, overflows or risers are discussed. Thermal intervention through the use of internal thermal channels are also evaluated through the use of simulation results. The paper centres on a discussion of analysis of simulation results, predicting defects which impact on some aspects of surface finish and porosity. A case study is presented showing the value of following and taking heed of lessons learnt from simulation results, to carry out die designs with reduced reliance on simulation. Index Terms: South African Foundries, High Pressure Die Casting, Computerised Fluid Dynamics Simulation, Die Design, Defect Reduction.


2019 ◽  
Author(s):  
Mohamed Mofti ◽  
Leopoldo Sierra ◽  
Alaeldin Saad Frag Alboueshi ◽  
Milan Patra ◽  
Sulaiman Ali ◽  
...  

2019 ◽  
Author(s):  
Mohamed Mofti ◽  
Leopoldo Sierra ◽  
Alaeldin Saad Frag Alboueshi ◽  
Milan Patra ◽  
Sulaiman Ali ◽  
...  

Author(s):  
Onyemaechi Ngozi Edith ◽  
Malann Yoila David

Aim: This research aim was to investigate the impact of living conditions (Socio demographic characteristics) of pregnant women on their malarial status. Study Design: In order to achieve the objectives of the study, Cross sectional survey was used. This is because only a subsect of the population was used. Descriptive designs was utilised in the Questionnaire aspect of the study. Place and Duration of Study: The Presidential Malarial initiative PMI/USAID - funded Insectary Laboratory at Nasarawa State University, Keffi/six (6) Months. Methodology: Blood samples were collected from the participating pregnant women by pricking their thumb and the blood droplet was examined using a direct thin and thick blood smear preparation stained with giemsa for the presence of the ring form stages of the parasites in the blood of the individuals in the laboratory. Qualitative data were sourced through Questionnaire administration to 589 pregnant women in Antenatal care clinics (ANC) in the area and their malaria status was also determined. Results: Study results showed a high prevalence rate of malaria in pregnancy (70.5%), the greater number of occurrences being in Lugbe (42.3%) than in Gosa (28.2%). Those living in houses built with wood recorded more positive cases of malaria and are at greater risk of infection (odds = 1.866%). Conclusion: This study has shown an increased rate of malaria infection amongst pregnant women living in wood and mud houses. The result also shows high rate of malaria occurrences due to low living conditions amongst pregnant women domiciled in this area of study. Hence, pregnant women should as a routine be placed on malaria prophylaxis and periodically checked as they can be asymptomatic, only exhibiting symptoms when its already late.


Author(s):  
Andreas Fabricius ◽  
James Malloy ◽  
Mark Taylor ◽  
Peter Jackson ◽  
David Moelling

Abstract This paper presents key lessons learned from hundreds of field missions for assessing the condition of HRSGs at sites around the world. These involved field inspections, root cause of failure analyses and performance assessments on HRSGs of nearly every design, fuel type and operating mode. Statistics on degradation and failure risk areas are presented. Analysis techniques used in both preparing for field work and in assessing field examination results are also discussed. Trends in the evolution of the principal damage mechanisms over the years are examined, and predictions of future problem areas are considered with a view to guiding asset management actions. The impact on HRSG integrity of changes in unit designs, such as the move to flexible operation in response to the increasing contribution from renewables, is also assessed, and likely future trends are outlined. The use of qualitative and quantitative risk-based methods is also discussed and compared to the use of condition-based inspection methods as a basis for a fleet wide management strategy. A case study including a large IPP with several generating assets in its portfolio is presented and the most cost-effective method with respect to current corporate strategy is discussed. Recommendations for fleet management strategies are made.


2021 ◽  
Author(s):  
Maad Hasan Qayad Subaihi ◽  
Muhammad Syafruddin ◽  
Avnish Kumar Mathur ◽  
Jaber Abdulmajeed Abdulla ◽  
Nestor Molero ◽  
...  

Abstract Over the past decade, coiled tubing (CT) has been one of the preferred fluid conveyance techniques in tight carbonate oil producers completed with an uncased horizontal section. In the onshore Middle East, conventional CT stimulation practices have delivered inconsistent results in that work environment. This is mainly due to a mix of reservoir heterogeneity, limited CT reach, lower CT pumping rates, uncontrolled fluid placement, and uncertainty of downhole dynamics during the stimulation operations. An intervention workflow recently validated in onshore Middle East to acidize tight carbonate openhole horizontal water injectors was introduced for the first time in an oil producer. The advanced stimulation methodology relies on CT equipped with fiber optics to visualize original fluid coverage across the openhole interval through distributed temperature sensing (DTS). Real-time downhole telemetry is used to control actuation of CT toolstring components and to understand changing downhole conditions. Based on the prestimulation DTS survey, the open hole is segmented into sections requiring different levels of stimulation, fluid placement techniques, and diversion requirements. The candidate carbonate oil producer featured an average permeability of 1.5 md along 8,003 ft of 6-in. uncased horizontal section. Because of the horizontal drain's extended length and the presence of a minimum restriction of 2.365-in in the 3 1/2-in. production tubing, a newly developed CT slim tractor was essential to overcome reach limitations. In addition, a customized drop-ball high-pressure jetting nozzle was coupled to the extended reach assembly to enable high-energy, pinpoint acidizing in the same run. The instrumented CT was initially run until lockup depth, covering only 53% of the horizontal section. The CT slim tractor was then precisely controlled by leveraging real-time downhole force readings, enabling full reach across the open hole. Prestimulation DTS allowed identification of high- and low-intake zones, which enabled informed adjustments of the acidizing schedule, and in particular the level of jetting required in each section. After its actuation via drop-ball, the high-pressure jetting nozzle was operated using downhole pressure readings to ensure optimum jetting conditions and avoid exceeding the fracturing threshold. Upon completion of the stimulation stage, post-stimulation DTS provided an evaluation of the fluid placement effectiveness. After several weeks of production, the oil rate still exceeded the operator's expectations fivefold. This intervention validates the applicability of the advanced matrix stimulation workflow in tight carbonate oil producers completed across a long openhole horizontal interval. It also confirms the value of real-time downhole telemetry for optimal operation of extended reach toolstrings and the understanding of the downhole dynamics throughout stimulation treatments, the combination of which ultimately delivers breakthrough production improvements compared to conventional stimulation approaches, in a sustainable manner.


2021 ◽  
Vol 22 (4) ◽  
pp. 392-406
Author(s):  
Tat'yana Yu. SEREBRYAKOVA

Subject. This article deals with the issues of accounting and write-offs of management costs and disclosure in reporting, their role for top managers, as well as improving the delineation and qualification of the types of costs to be accounted for as managerial, and the impact of the proposed approaches on reporting performance. Objectives. The article aims to justify the need for a clearer definition of management costs and a more logical, cost-effective division of costs into production and management ones. Methods. For the study, I used the systems approach, logical generalization and abstraction. Results. The study shows that not all expenses that organizations account for as the management ones are actual. Many of the costs relate to production activities. Since the methodological guidelines for accounting for material and operational costs have been abolished in connection with the adoption of FSBU 5 – Inventories, they may not be applied any more. Conclusions and Relevance. The subject terminology and a clear concept of management costs need to be defined. IFRS 2 – Inventories gives a more logical notion of management costs in combination with administrative costs. This makes it possible to adapt the accounting according to the Russian standards to the running accounting practice with a minimum recalculation. The presented study results are intended to develop theoretical views on the formation of the actual cost of finished products, the full cost of implementation and interpretation of these indicators for management. The results can be used for scientific and practical activities related to financial and management accounting research.


2003 ◽  
Vol 30 (2) ◽  
pp. 391-405 ◽  
Author(s):  
Aminah Robinson Fayek ◽  
Ahmed Shaheen ◽  
Ayo Oduba

The industrial construction sector in Alberta has recently undergone a period of rapid growth, resulting in a shortage of skilled workers in almost all of the major industrial sector trades. To meet these shortages, a need has arisen to increase the utilization of apprentices on industrial construction projects. In an effort to address this issue, the Construction Owners Association of Alberta has established a goal of developing an industry Best Practice on how to improve the on-the-job portion of apprenticeship training and identify means by which the industry can more effectively use apprentices. The challenge is to increase their usage in a cost-effective manner that also provides apprentices with adequate training opportunities. Before this can be done, the impacts and benefits to the various parties involved in industrial construction must be quantified and assessed. This paper describes the findings of a pilot study that was conducted on a major industrial project to help in quantifying the impact of the use of apprentices in the industrial construction sector and to identify methods of effectively increasing their use while simultaneously enhancing their on-the-job learning experience. The main conclusion of this paper is that apprentices can be effectively incorporated in industrial construction, and they can be both productive and cost-effective, provided they are given adequate instruction and supervision. The lessons learned from the study are discussed to provide insight into conducting future studies. Recommendations for an industry Best Practice on the effective utilization of apprentices are presented.Key words: apprentice, electrician, industrial construction, journeyman, labour force, pipefitter, productivity, training, work sampling.


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