Online Cleaning of Carbonate Deposits. The Potential and Limitations of a Novel Cleaning Method

The formation of calcium carbonate scale within produced brine as it passes through topside heaters is a very common flow assurance challenge. Normally this scale risk is predicted and chemically controlled via scale inhibitors deployed upstream of the point of brine supersaturation. In some operations chemical application is not fully effective due to under treating of the chemical or carbonate from the reservoir (fines) builds up within the heaters. In cases of reduced fluid throughput cleaning of the inorganic scale is required. The most common method of cleaning is to take the heater offline and batch clean with acids (mineral or organic) to remove the deposits. This paper outlines an investigation into the performance of conventional batch cleaning vs a more novel application method of online cleaning the heater while operating with application of organic acid into the produced fluid upstream of the heaters. The online cleaning process was evaluated via laboratory tests where packed column of field scale were flushed with organic acid within the produced water, and for comparison mineral acid, to understand the potential for online cleaning vs batch cleaning and what factors influenced the effectiveness of these application methods. Factors evaluated included flow rate/contact time, acid strength and acid type. During these online cleaning tests, the effluent of each column was evaluated for pH and finally weight loss at the end of the tests. The online cleaning results were compared to conventional batch cleaning assessment of the same scale samples via static bottle tests The observations from the tests show that online cleaning using both organic and mineral acids result in the development of preferential flow paths within the scale packed columns that reduces the effectiveness of the cleaning chemicals. Improvements to the cleaning program were investigated such as the scale thickness when cleaning is first started to improve cleaning performance and fluid flow rate, increased acid concentration and liquid to solid ratio changes. Field application data from the initial cleaning programs and improvements to the cleaning programs will be shared as part of this publication The factors that need to be assessed to determine if this method is suitable for a specific process system and likelihood of effective scale removal are presented. This method does present the possibility for some production systems that cleaning of carbonate scale can be carried out without the need to take the heater offline for chemical batch or mechanical cleaning.

Topologies Generated by Two Ideals and the Corresponding j -Approximations Spaces with Applications

Ideal is a fundamental concept in topological spaces and plays an important role in the study of topological problems. This motivated us to use two ideals to generate different topologies to take the advantage of the two ideals at the same time. Two ideals represent two opinions instead of one opinion which is very useful for using the insights of two groups of experts to study the problem and elicit decisions based on their common vision. Topology is a rich source for constructs that is helpful to enrich the original model of approximations spaces. Rough set theory has inbuilt topological concepts. Hence, the main purpose of this paper is to point out that the concept of rough sets has a purely topological aspects nature. To do so, new approximations spaces are introduced and defined based on the topologies generated by two ideals. The results in this paper show that the topological concepts can be a powerful method to study rough set models. The basic properties of these approximations are studied and compared to the previous ones and shown to be more general. The importance of the current paper is not only introducing a new kind of rough set based on bi-ideals, increasing the accuracy measure, and reducing the boundary region of the sets which is the main aim of rough set but also introducing a chemical application to explain the concepts.

Viscous Crude Oil Production Facilitated by Flow Improver Technology: A Holistic Chemical Approach with Successful Field Application

This paper describes the approach taken to evaluate and successfully treat flow assurance challenges associated to high viscosity produced fluids in an oil producing field, offshore Gulf of Mexico. The first section of the paper outlines primary evaluation criteria: discussing base line modeling of crude oil characteristics at various points of the production system, laboratory analyses, detailed explanation of the chemistries considered for reducing the viscosity, and the strategy to remediate multiple flow assurance challenges with subsequent performance testing. The second section presents field trial data from the application of the selected flow improver and its longer-term performance. Initial evaluation of high viscosity was required due to deposition of asphaltene, high levels of emulsion, increased pressure and resultant decrease in production All of these production issues caused increased spending on fluids treatment in a field that is mature and becoming more marginal to produce. Initial analysis of the produced fluid did not result in an immediate, clear approach to address the concern, without considering the multiple factors that can contribute to flow assurance challenges. Organic deposition, such as waxes and asphaltenes, were found to increase fluid viscosity and worsen highly stabilized emulsions. Crude oil/water emulsions also cause increased viscosity and needed to be addressed as part of any holistic solution. Each issue was studied and experimented on its own and in combination to ensure there was no reductive effect in a final chemical application that needed to treat them all. Successful field application of the selected flow improver technology exceeded the performance at laboratory scale achieving over 30% reduction in total fluid viscosity over long-term field deployment with associated benefits to the offshore operator which will be elaborated further in this paper. As an outcome of this field trial, this paper also presents a proposed generic approach in devising chemical solutions for treatment of high viscosity fluids.

Chemical Sand Consolidation and Agglomeration Control Sand Production

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 202419, “Performance Review of Chemical Sand Consolidation and Agglomeration for Maximum Potential as Downhole Sand Control: An Operator’s Experience,” by Nur Atiqah Hassan, SPE, Wei Jian Yeap, SPE, and Ratan Singh, Petronas, et al., prepared for the 2020 SPE Asia Pacific Oil and Gas Conference and Exhibition, originally scheduled to be held in Perth, Australia, 20–22 October. The paper has not been peer reviewed. Chemical sand consolidation (SCON) and sand agglomeration have been identified as effective chemical treatments to control sand production downhole. Both treatments involve injection of chemicals into the near-wellbore area of the reservoir with the aim of improving the strength of the formation and thus reducing the tendency for sand production. The complete paper presents lessons learned and best practices from several chemical SCON and sand-agglomeration treatments performed in mature fields in Malaysia. SCON and Sand Agglomeration History and Performance Petronas has deployed approximately 20 SCON and three sand-agglomeration treatments over nine different offshore fields since 2009. Of 20 planned SCON jobs, four were suspended for a variety of reasons such as budget constraints or operational complexity. Of the 16 SCON jobs executed, a success rate of approximately 75% was achieved. The number of sand agglomeration jobs executed is significantly lower; only three were completed, with one failure case. In terms of effective production, SCON has better overall performance than sand agglomeration. The average effective production period for SCON is approximately 2.9 years, while the average effective production period for sand agglomeration is approximately 2.5 years. Criteria for Candidate Selection Completion Type. - In considering the historical success rate of SCON and sand-agglomeration jobs according to completion type, most viable candidates were completed with perforated cased hole, contributing to approximately 87% of all chemical SCON and sand-agglomeration jobs. Despite the challenges caused by chemical placement in openhole completions, all of these jobs have been successful because of stringent planning. Overall, the success rate for chemical SCON and agglomeration under cased-hole completion is approximately 73%. Perforation Interval Length. - For effective chemical placement, the perforation interval length is limited to 20 ft according to internal guidelines, especially for cases using bullheading as the placement method. For perforation interval lengths greater than 120 ft, the failure rate can be as high as 10%. According to historical trends, no failure was encountered for chemical SCON and sand-agglomeration jobs with perforation intervals of less than 40 ft. The historical analysis indicates, therefore, that the benchmark criteria of perforation interval length could be extended to 40 ft from the current 20 ft. Placement Method. - Most chemical treatment jobs executed were completed using bullheading, contributing to approximately 80% of all chemical SCON and sand-agglomeration jobs. No failure cases were recorded for treatments that used coiled tubing because of the controlled chemical placement. Perforation intervals of almost 100 ft using bullheading placement methods have succeeded. One contributing factor for successful treatment in long intervals using bullheading is the use of diversion techniques. Nitrogen is commonly used as part of a diversion method along with chemical application.

A REVIEW ON NON-CHEMICAL WEED MANAGEMENT IN MAIZE (ZEA MAYS L.)

Weed is omnipresent species that compete with major crops for light, nutrients, space, and water for their growth and development and ultimately deteriorate the ideal environment for crops growth. In the present context, herbicide application is the easiest and seemingly economical approach for weed control in south-Asian countries. In contrary, the side effects of herbicide on health and environment impose to adopt for the non-chemical method of weed management. This paper reviewed the menace of herbicide, crop weed association, the critical period of crop-weed competition, and different methods of organic weed control implemented especially for maize. The main objective of this review is to maneuver a weed control strategy for maize other than the chemical application. The findings of different research suggested that a critical period of crop-weed competition in maize lies between 2 to 8 weeks after crop sowing. Many mechanical methods for weed control in maize proved efficient but seemed labour intensive and biological methods provided maximum security against specific weed species. The cultural method in combination with other methods effectively reduced the weed population in the maize field. It was found that, if various components of non-chemical weed management are implemented systematically, we can control the weed population with higher economic return and achieve the goal of organic food production with sustainable solutions. Weed control in the organic system focuses on management techniques designed to prevent weed emergence, give a competitive advantage to the main crop, and act for sustainable solutions. The non-chemical integrated weed management system is recommended to reduce the use of herbicide and for sustainable production. A review of non-chemical weed management in maize could be helpful for researchers to provide useful, sustainable, and environmentally friendly solutions to farmers to solve the problem of weed infestation in the maize crop along with substantial yield improvement.

Effect of Chemical to Herb Control on Performance of Sesame (Sesamum indicum) under Irrigated Conditions

Weed management greatly influences on weed infestation and yield of sesame under irrigated condition. An experiment was conducted at Bagusala farm, M.S. Swaminathan School of Agriculture, CUTM, Paralakhemundi, Odisha to find out the effectiveness of pre and post emergence herbicides on performance of summer sesame under irrigated conditions. The soil of experimental site was sandy clay loam in texture, slightly acidic in reaction with pH of 6.4. The experiment was laid out in randomize block design with three replications, assigning twelve treatments combinations of chemical application irrigated sesamum cultivation. The yield with hand weeding at 20 and 40 DAS was comparable with Pendimethalin @ 500 g a.i ha-1 3 DAS + Imazethapyr @ 60g a.i ha-1 at 20 DAS, Imazethapyr @ 60g a.i ha-1 at 20 DAS, Oxadiargyl 80wp @ 60g a.i ha-1 3 DAS and Oxadiagyl @ 40 g a.i ha-1 3 DAS + Imazethapyr @ 60 g a.i ha-1 20 DAS and significantly superior over all other treatments. The weed number observed in all chemical weed control treatments was significantly lower than un-weeded control. Application of herbicides was found to be effective in reduction of weed population in summer sesamum under irrigated conditions. The weeds can be effectively controlled through application herbicides in sesame grown under irrigated conditions during summer season.

Effect of foliar application of different elicitors on occurrence of pest and diseases during chia (Salvia hispanica L.) cultivation

Chia is an important medicinal crop with lot of nutritional value in seeds and there is lot of demand to chia seeds grown without any chemical application. In this context, present study was concentrated on foliar application of different elicitors at 25 and 50 days after sowing as effective plant protectants by inducing plant defense response. Both black and white chia plants sprayed with chitosan at 200 ppm were un-affected by any pest and diseases. The plants sprayed with other elicitors like 100 ppm of salicylic acid, methyl jasmonic acid, potassium silicate, 200 ppm of boric acid, humic acid and 5000 ppm of dry yeast and PGPR are less prone to pest and disease attack. Whereas, the maximum pest infestation and disease incidence were noticed in plants sprayed with gibberellic acid (pest - 2.38 and 1.93%; disease - 0.89% in both) and in control (pest - 1.34 and 1.04%; disease - 1.34 and 0.74%) in black and white chia respectively.

New bioassay cage methodology for in vitro studies on Varroa destructor and Apis mellifera

Varroa destructor Anderson and Trueman, is an ectoparasitic mite of honey bees, Apis mellifera L., that has been considered a major cause of colony losses. Synthetic miticides have been developed and registered to manage this ectoparasite, however, resistance to registered pyrethroid and organophosphate Varroacides have already been reported in Canada. To test toxicity of miticides, current contact-based bioassay methods are designed to evaluate mites and bees separately, however, these methods are unlikely to give an accurate depiction of how miticides interact at the colony level. Therefore, the objective of this study was to develop a bioassay cage for testing the toxicity of miticides on honey bees and Varroa mites simultaneously using amitraz as a reference chemical. A 800 mL polypropylene plastic cage holding 100–150 bees was designed and officially named “Apiarium”. A comparison of the effects of three subsequent dilutions of amitraz was conducted on: Varroa mites placed in glass vials, honey bees in glass Mason jars, and Varroa-infested bees in Apiariums. Our results indicated cumulative Varroa mortality was dose-dependent in the Apiarium after 4 h and 24 h assessments. Apiarium and glass vial treatments at 24 h also had high mite mortality and a positive polynomial regression between Varroa mortality and amitraz dose rates. Moreover, chemical application in the Apiarium was less toxic for bees compared to the Mason jar method. Considering these results, the Apiarium bioassay provides a simple, cheap and reliable method for simultaneous chemical screening on V. destructor and A. mellifera. Furthermore, as mites and bees are tested together, the Apiarium simulates a colony-like environment that provides a necessary bridge between laboratory bioassay testing and full field experimentation. The versatility of the Apiarium allows researchers to test a multitude of different honey bee bioassay experiments including miticide screening, delivery methods for chemical products, or development of new mite resistance-testing methodology.