A Method to Increase the Leaching Progress of Salt Caverns with the Use of the Hydro-Jet Technique

For the storage of hydrocarbons, hydrogen, or other products, underground caverns left over from the exploitation of salt deposits, or made specifically for this purpose, are successfully used. This article analyses the effectiveness of currently used well-leaching technologies in terms of the possibility of increasing the speed of obtaining industrial brine, better control of the shape of the created cavern, and, as a result, a shorter production time. An innovative solution was proposed, which consisted of creating appropriate niches in the walls of the leach well using the high-pressure hydrojet technique, just before the start of the sump leaching. A series of numerical simulations of the technologies were performed for various combinations of niche locations along the well, determining the successive phases of the formation of the cavern space at individual stages and the brine concentration increments for the two assumed technology scenarios. As a result of the modified technology, the possibility of creating a sump with a volume greater than 17%, compared to the classical method carried out at the same time, was indicated. The resulting sump also had a better shape to partially eliminate the reduction in leaching efficiency due to the accumulation of insoluble matter at the bottom. In addition, the brine obtained according to the modified technology had a 15% higher concentration than in the classical method.

The effect of wet-salting preservation method on the physicochemical and microbial quality of Dasyatis sp.

Microbial Dasyatis sp. (stingray fish) was a popular fish in Indonesia. Commonly, this fish is processed into smoked fish and perishable products. Therefore, it needs a preservation method through the handling process. Wet salting was considered as an efficient and inexpensive preservation method. This study aimed to determine the effect of brine concentration on the physicochemical and microbial quality of Dasyatis sp. The research used a Completely Randomized Design with factor of brine concentration (i.e. 10%, 20% and 30%). The statistical analysis consists of variance analysis (ANOVA) and followed by LSD or DMRT test (α=5%). The fish sample was soaked in brine solution at different concentrations for one hour. Total crude protein, physicochemical (total volatile basic nitrogen/TVB-N, tri-methyl amine/TMA, and pH), and (total plate count/TPC) were analyzed. The results showed that the brine concentration effect of physicochemical and microbiological of Dasyatis sp (p<0.05). The best treatment was obtained at the application of 10% brine concentration, which had physicochemical parameters as follows: 6.92 pH, 6.110 mgN/100g TVB-N, 5.520 mgN/100g TMA, 16.78 % protein, and 0.537x105 CFU/ml TPC.

Geochemical features of Eurasian evaporites in the context of the chemical evolution of seawater in Phanerozoic

Studies of evaporites provide new data to characterize the seawater chemistry in the Early Paleozoic and Middle Mesozoic. In particular, we studied the fluid inclusions in halite from Ordovician (China) and Cretaceous (Laos) evaporites. The corresponding sections on the plot of Ca/SO4 oscillations curve in the Phanerozoic seawater are updated. The calcium content in seawater concentrated to halite precipitation stage was 45.6 mol %, 485 million years ago and 24.3 mol % 112.2–93.5 million years ago. By analyzing the previously published and new factual material, it is established that in Permian evaporites the sulfur isotopic composition is inversely correlated with the sulfate ion content in evaporite basin brines. Thus, the evolution of seawater chemistry in Permian is confirmed by the evolution of the isotopic composition of dissolved seawater sulfate. According to the generalization of 38 Phanerozoic marine evaporite formations, it was found that the peculiarities of the clay minerals associations correlate with the change of the seawater chemical type. Clay minerals associations precipitated from the SO4-rich seawater are characterized by a larger set of minerals, among which smectite and mixed-layered minerals often occur; Mg-rich clay minerals (corensite, paligorskite, sepiolite, talc) also occur. Instead, in the associations of evaporite clay minerals formed from the Ca-rich seawater are represented by the smaller amount of minerals, and Mg-rich minerals are extremely rare. The increased content of magnesium in seawater of SO4-rich type is the main factor in the formation of Mg-rich silicates in evaporites. The composition of clay minerals associations depends on the evaporate basin brine concentration; with its increase, unstable minerals are transformed, which theoretically leads to a decrease in the number of minerals in the associations. However, it was found that evaporite deposits of higher stages of brine concentration often still contain unstable clay minerals – products of incomplete transformation of a significant amount of pyroclastic material from coeval volcanic activity. The main factor determining the composition of clay minerals associations of Phanerozoic evaporites was the seawater (and basin brines) chemical type. Geochemical studies of scattered organic matter and fluid inclusions with hydrocarbon phase in evaporites of the Upper Pechora Basin (overlying oil and gas deposits) indicate the presence of allochthonous bitumoids and allow to use this method to predict oil and gas potential of other areas. Analysis of the results of oil and gas exploration in a number of areas of the Transcarpathian Trough indicates the presence of fluid-saturated reservoirs and the prospects for the discovery of new accumulations of hydrocarbons. Geochemical studies proved the effectiveness of gas-flow survey method for oil and gas exploration, assessing the prospects for fluid saturation of seismic structures.

Controls on Associations of Clay Minerals in Phanerozoic Evaporite Formations: An Overview

Information on the associations of clay minerals in Upper Proterozoic and Phanerozoic marine evaporite formations suggests that cyclic changes in the (SO4-rich and Ca-rich) chemical type of seawater during the Phanerozoic could affect the composition of associations of authigenic clay minerals in marine evaporite deposits. The vast majority of evaporite clay minerals are authigenic. The most common are illite, chlorite, smectite and disordered mixed-layer illite-smectite and chlorite-smectite; all the clay minerals are included regardless of their quantity. Corrensite, sepiolite, palygorskite and talc are very unevenly distributed in the Phanerozoic. Other clay minerals (perhaps with the exception of kaolinite) are very rare. Evaporites precipitated during periods of SO4-rich seawater type are characterized by both a greater number and a greater variety of clay minerals—smectite and mixed-layer minerals, as well as Mg-corrensite, palygorskite, sepiolite, and talc, are more common in associations. The composition of clay mineral association in marine evaporites clearly depends on the chemical type of seawater and upon the brine concentration in the evaporite basin. Along with increasing salinity, aggradational transformations of clay minerals lead to the ordering of their structure and, ideally, to a decrease in the number of minerals. In fact, evaporite deposits of higher stages of brine concentration often still contain unstable clay minerals. This is due to the intense simultaneous volcanic activity that brought a significant amount of pyroclastic material into the evaporite basin; intermediate products of its transformation (in the form of swelling minerals) often remained in the deposits of the potassium salt precipitation stage.

Theoretical and experimental investigation of effect of salinity and asphaltene on IFT of brine and live oil samples

Several factors influence the IFT of oil and formation water. These factors are rooted in the complex composition of oil, presence of different salts in water, water salinity, temperature, and pressure of reservoir. In the first part of this paper, effect of salinity on IFT between brine and an Iranian live oil sample has been studied experimentally. It is observed that IFT increases almost linearly with brine concentration. Also, linear increasing behavior of IFT with respect to pressure is obviously seen. Then, using thermodynamic properties such as surface excess concentration, chemical potential, chemical activity, and activity coefficient, results were analyzed and observed effect of salinity and pressure were justified thermodynamically. In the second part, the effect of asphaltene on IFT reduction has been studied. In previous works, the investigators extracted resin and asphaltene and then examined their effects on IFT in the absence of other fractions of oil phase. We believe that all fractions play a role in this phenomenon so, in this paper, the effect of natural surfactants of oil phase on IFT has been investigated in presence of all fractions of oil. Hence, SARA test was performed on all samples. Then, IFT between oil samples and brine were measured using captive drop instrument at 25 °C and 3000 psia. Results showed that neither asphaltene content nor asphaltene/resin ratio is a good indicator for effect of asphaltene on IFT, whereas colloidal instability index could be a useful tool to predict asphaltene effect on IFT.