Resolving Multiple Formation Damage Mechanism in Carbonate Reservoir Through Systematic Approach Using Combination of Aromatic Solvent and Less Aggressive Acid

There is no well operation that is truly non-damaging. Any invasive operation, even production phase itself, may be damaging to well productivity. An interesting case was found in L-Field which is located in South Sumatra, Indonesia. All four wells are predicted to cease to flow after five-year production and artificial lift have to be installed to prevent steep decline in oil production. Unfortunately, all of wells’ productivity index (PI) decreased post well intervention and therefore, couldn’t achieve target. The PI was continuously decreasing during production phase and aggravated the decline in oil production. Remediation action by systematic approach was applied to solve the problem. Early diagnostic revealed some potential causes through evaluation of both production and well treatment data. Laboratory test such as mineralogy analysis, crude composition and water analysis, solubility and compatibility test have been conducted and clarified the root cause that formation damage occurred in multiple mechanism related to incompatibility of the workover fluid and organic deposition. Then, possible well treatments were listed with pros and cons by considering post water production related to the carbonate reservoir properties. Subsequently, chemical matrix injection was ranked based on less possibility of water breakthrough risk. Diesel fuel and de-emulsifier injection was decided as the first treatment in order to remove formation damage caused by organic deposition. The rate was increased temporary with Water Cut (WC) remained at the same level. The subseqeuent effort was to inject low reaction chelating acid and the result showed temporary improvement and the production did achieve significant gain. Finally, the third attempt indicated promising results with the injection of aromatic solvent followed by chelating acid. The well productivity was increased to more than 20 times of the pre treatment levels. The method can be replicated to other affected wells with similar damage mechanism. High vertical permeability over horizontal permeability becomes a real threat in carbonate strong water driver reservoir in L-field. Thus, matrix acidizing treatment has to be carefully applied to prevent unwanted water production. Non-aggressive and slow reaction acid were chosen to prevent face dissolution reaction that leads to water breakthrough.

Synthesis and research of polyfunctional silylureas used in electric deposition of tin-indium alloy

Polyfunctional silylureas were synthesized by the interaction of 3-aminopropyltriethoxysilane with isocyanates of various structures in an inert aromatic solvent. Commercially available diisocyanates such as isophorone diisocyanate, hexamethylene diisocyanate, 2,4-toluene diisocyanate were used as isocyanates. In this case, freshly distilled toluene was used as a solvent. The structures of the obtained compounds were confirmed by the data of IR and NMR1H spectroscopy. Using the synthesized compounds, formulations of compositions for electrodeposition of a tin-indium alloy on a copper wire were developed. The possibility of using silylureas of various structures as effective surfactants used in the electrodeposition of the tin-indium alloy is shown. The operational characteristics of the obtained wire were investigated, including the wire diameter, coating thickness, tensile strength, electrical resistance, and direct current electrical resistivity.

Photopatterning of PDMS Films: Challenging the Reaction between Benzophenone and Silicone Functional Groups

Direct photopatterning of PDMS (Polydimethylsiloxane) through benzophenone photo-inhibition has received great interest in recent years. Indeed, the simplicity and versatility of this technique allows for easy processing of micro-canals, or local control of PDMS mechanical properties. Surprisingly, however, the chemical reactions between silicone hydride and/or silicone vinyl groups and benzophenone have only been assessed through qualitative methods (e.g., Attenuated total reflection fourier transform infrared). In this communication, the previously proposed reaction pathways are challenged, using nuclear magnetic resonance (NMR) spectroscopy and size exclusion chromatography (SEC) monitoring. A different mechanism depicting the role of benzophenone irradiation on the polyaddition reaction of silicone formulations is proposed, and a simplified procedure involving aromatic solvent is finally disclosed.

Modeling and Simulation of Asphaltene Inhibition and Remediation Using Aromatic Solvents

Asphaltene precipitation and deposition occur in the reservoir, near-wellbore, inside the tubing, and production facilities during primary, secondary, or tertiary production. As more water-flooded oil fields produce under miscible gas flooding, this problem becomes more common around the world. If asphaltene deposition occurs in the reservoir or wellbore, it can severely affect the economics of the field in terms of production loss, intervention cost, and the requirement for chemical additives, if necessary. In some severe cases, intervention would be impossible and side-track well needs to be drilled. Hence, the best strategy for oil production in asphaltenic reservoirs is to control asphaltene precipitation and deposition through prevention and remediation jobs to minimize the number of well shut-ins, the downtime of the wells, and the associated cost. In this paper, we reviewed the common asphaltene prevention and remediation techniques along with their pros and cons. Since removing asphaltene deposits from the problematic wells is relatively expensive and sometimes requires substantial downtime of the well, we focused on one of the prevention techniques (i.e., continuous solvent injection through capillary injection string), which has become more popular, to control asphaltene precipitation in the wellbore. We obtained the physical properties of an aromatic solvent from literature and then characterized it as a component to be used with PC-SAFT EOS. Subsequently, we used the in-house wellbore model to evaluate the effectiveness of the continuous solvent injection with different injection rates on preventing asphaltene precipitation and deposition along the wellbore.

Selectivity switch by phase switch - The key to a high-yield furfural process

We show the effective conversion of xylose into furfural, with selectivities >90 mol%, in an aqueous-organic three-solvent system, composed of an apolar aromatic solvent, a polar organic solvent and acidic...

RESEARCH OF COMPOSITION OF ANTIWEAR ADDITIVES FOR JET FUELS

In the framework of the state import substitution program for the development of a domestic antiwear additive for jet fuels the physicochemical characteristics of the approved foreign antiwear additives of DNK, HITEC 580 and Unicor J were analyzed at the first stage. The analysis revealed that using solvents during the production of HITEC 580 additives and Unicor J improve their consumer properties (low temperature characteristics). At the second stage of the study the composition of currently used additives HITEC 580 and Unicor J was studied by gas chromatography-mass spectrometry. It was shown, that the same active component is used in their composition - dimers of unsaturated fatty acids C18, namely a mixture of dimers of linolenic, linoleic and oleic acids, among which the dimer formed from linoleic and oleic acids prevails. An analysis of the solvents used in the additive composition showed that in the production of Unicor J additives they use an aromatic solvent containing 92% of monoaromatic compounds, mainly of the C10 series, which is probably the product of gasoline reforming, and HITEC 580 additives use an aliphatic solvent containing mainly n alkanes (41%). From the presented results of the study it follows that when developing a domestic antiwear additive formulation, it is necessary to choose compounds containing 1 or 2 carboxyl groups as the active component, and as the solvent either aromatic or aliphatic, depending on the cost and availability on the domestic market.

Asphaltene Deposition and Removal in Flowlines and Mitigation by Effective Functional Molecules

Summary Efficient removal of deposited asphaltenes on the surface of metallic flowlines by functional molecules is investigated by nonionic and ionic surfactants at low concentrations. Deposition removal by aromatic solvent toluene is measured as a reference. Water is often coproduced with crude oil and may affect deposition of asphaltenes and removal. In this study, we investigate the effect of water in both asphaltene deposition and removal by functional molecules. Two different crudes from different fields that give rise to serious asphaltene deposition are extensively investigated. For these two crudes, we find one ionic and one nonionic surfactant to be effective in deposition removal at 1 wt% concentration in the crude. This concentration is much lower than that of the commonly studied acidic dodecylbenzene sulfonic acid (DBSA) surfactant. Toluene concentration in the crude varies from 40 to 60 wt% for asphaltene deposition removal. Water delays deposition significantly. However, water does not have an appreciable effect on performance of functional molecules on removal of deposited asphaltenes.

A New Approach Using Aromatic-Solvent-Induced Shifts in NMR Spectroscopy to Analyze β-Lactams with Various Substitution Patterns

The chemical shifts of protons depend not only on the properties of the solute molecule but also on the medium in which the solute resides. A series of β-lactams with various substitution patterns were synthesized to study aromatic-solvent-induced shifts (ASISs) in chloroform and benzene by using 1H NMR spectroscopy. The results agreed with those obtained by theoretical density functional theory calculations. The protons of the β-lactam ring are the most affected by the ASIS effect, and they tend to overlap due to the anisotropic effect of benzene.