Tieguan Wang

The Compatibility of SBS-Modified Asphalt

Abstract Compatibilities of six kinds of base asphalts with styrene-butadiene-styrene (SBS) were evaluated by difference of isolation softening points and intrinsic viscosities of six SBS-modified asphalts. By comparing four-component distribution of six kinds of base asphalts with compatibility evaluation results of SBS modified asphalt, ratio of saturates to aromatics was selected as the main reference. Three base asphalts were mixed with saturates-rich refined oil and aromatics-rich extract oil by furfural according to a reasonable ratio of saturates to aromatics, and compatibility of the three kinds of mixed asphalt with SBS was evaluated. Results show that an isolation experiment combined with intrinsic viscosity can be used to evaluate compatibility of SBS-modified asphalt effectively. colloidal instability index (CI) (saturates + asphaltenes)/(aromatics + resins), content of light components (saturates + aromatics) and ratio of saturates to aromatics all have an influence on compatibility of SBS-modified asphalt, but none is a sufficient condition for determining compatibility of SBS-modified asphalt. Reasonable distribution of four components is a key factor for achieving optimum compatibility. It is proposed that components distribution of a base asphalt that has optimal good compatibility with SBS is CI of about 0.3, content of light components more than 55 wt%, and ratio of saturates to aromatics between 0.42 and 0.55.

Ternary diagram of fluorenes, dibenzothiophenes and dibenzofurans: Indicating depositional environment of crude oil source rocks

Fluorene (FL), dibenzothiophene (DBT) and dibenzofuran (DBF) and their alkylated homologues are important polycyclic aromatic compounds in crude oils and source rock extracts. They share the similar chemical structure and may have genetic relationships. The parent compounds (unsubstituted), methyl-, dimethyl- and ethyl-substituted isomers are identified by comparison with retention indices reported in literatures and correlation with co-injection of internal standards in gas chromatography-mass spectrometry (GC-MS) analysis. Therefore, their relative concentrations can be determined. Based on the large data sets, this paper preliminarily establishes a ternary diagram to interpret the depositional environment/lithology for oils and related source rocks. Five typical depositional environments/lithologies are distinguished on this ternary diagram. Data points from typical marine carbonate, fluvial/deltaic/fresh lacustrine shale and swamp fall into the DBTs, FLs and DBFs end-members, respectively. Oils from marine shale have subequal contents of FLs and DBFs and lie between the zones of fluvial/deltaic/fresh lacustrine shale and swamp, but have a little higher abundance of DBTs. The oils from brackish/saline lacustrine have intermediate contents of DBTs with a wide variety and some degree overlap with that of marine shale. On the basis of the ternary diagrams, two petroleum systems in the cratonic region of the Tarim basis are defined. The majority of discovered oils were derived from the Middle-Upper Ordovician carbonate source rocks. Whereas, some oils from wells TD2, T904, LK1 and TZ62 originated from the Cambrian and Lower Ordovician source rocks. Therefore, the ternary diagram of FLs, DBTs and DBFs is a useful method to interpret depositional environment/lithology for oils and related source rocks and to definite petroleum systems as well.

Preparation of an SBS Latex–Modified Bitumen Emulsion and Performance Assessment

Abstract For resolving the contradiction of the stability between styrene-butadiene-styrene (SBS)-modified bitumen emulsion and the concentration of SBS, a method of preparing SBS latex is provided in this article. Results showed that SBS latex had good stability properties and performance. The effect of emulsifier concentration on the storage stability showed that the maximum stability of SBS latex–modified bitumen emulsion (SBS-LMBE) was obtained at emulsifier weight concentration 1.0% and addition of SBS latex to bitumen emulsion enhanced the difficulty of emulsification. The effects of SBS latex on bitumen properties showed the penetration decreased, whereas the softening point and ductility at 5°C increased, which means that SBS latex plays a role in improving the properties of bitumen. Compared to the base bitumen, saturate and aromatic of evaporation residue of SBS-LMBE decreased. However, resin and asphaltene increased. Analysis of the relationship between the components and properties of bitumen showed that the components change caused by SBS latex was beneficial to the properties of bitumen. The colloidal index (CI) showed that SBS latex also made the colloidal system more stable.

Simulation experiment of immature oil genetic mechanism in lake facies of semi-salt water

The Immature calcareous shale in the south slope of Dongying sag, Jiyang depression, plays a significant role in immature oil genesis, and is sampled to make simulation experiment. The geochemical characters of the products of soluble organic matter and kerogen are researched respectively. The yields of the two components and their relations are made out. The contribution ratio between soluble organic matter and kerogen undergoing earty degradation in lake facies of semi-salt water is figured out for the first time, so the research into the genetic mechanism of immature oil is developed.

Maturity assessment of severely biodegraded marine oils from the Halahatang Depression in Tarim Basin

Seventeen Ordovician oil samples from Halahatang Depression are investigated for their thermal maturation. On the basis of GC analysis of the alkane fraction as well as GC-MS analysis of the demethylated hopanes, it is assumed that the oils are mixtures of severely biodegraded and nonbiodegraded oils. Therefore, their maturation is assessed on the basis of the distribution and abundance of compounds strongly resistant to biodegradation. The P1 together with the P2 values of C7 light hydrocarbons suggest that the late filled nonbiodegraded oils for Halahatang are super mature. Triterpane and sterane isomerization maturation parameters indicate they barely reached the peak oil generation stage, consistent with the results obtained from the equivalent vitrinite reflectance Rc1 (0.80–0.95%), while the Rc2 (1.28–1.60%) delineate a high maturity of Halahatang oils. However these conventional triterpane and sterane isomerization maturation parameters gave only general information and a comparatively narrow range of maturity. Correlation between the maturation parameters of Pr/nC17 and Ph/nC18, Ts/(Ts + Tm) and C29Ts/(C29Ts + C29H), MPI1 and MPI3, 4-/1-MDBT and 4, 6-/1,4-DMDBT are rather good, confirming the validity to assess and differentiate the maturity of the severely biodegraded oils examined, with the exception of naphthalene maturation parameters(DNR1 and TNR2). According to the maturation classification assembled with selected effective maturity parameters, such as the MPI3 together with the corresponding [P], the thermal maturities of Halahatang oils are moderate, while Ts/(Ts + Tm) together with 4-/1-MDBT demonstrate a moderate-high maturity.

Early hydrocarbon generation of biological lipids in non-marine lacustrine basins——a genetic mechanism of immature oil

Taking both eastern Linqing Depression and North Jiangsu Basin as examples, based on geochemical features of immature oils as well as source inputs of hydrocarbons and macerals, it is revealed that a mixed source input of alga bio-lipids and higher plant waxes is a basic characteristic of source material for immature oils in non-marine brackish-saline lacustrine basins.

Initial organic geochemical investigation on Late Neoproterozoic-Early Cambrian sediments in the Yangtze region, China

Abstract Totally 19 samples of typical Upper Proterozoic-Lower Cambrian sedimentary rocks were collected and analyzed for an organic geochemical investigation. Almost all these rocks have high TOCs, super-maturities and similar biomarker distribution. As an exception, however, the Sinian Nantuo Tillite shows much lower TOCs and little phytane and pristane in comparison with those in other strata, which implies a very faint photosynthetic process, and a restricted euphotic zone and quite limited sunlight within the sedimentary water column during the Sinian glaciation age in the western Yangtze region providing an evidence for palaeo-oceanic environment of the Neoproterozoic Snowball Earth age.

The Catalytic Effect of Organometallic Additives on Low-temperature Oxidation of Light Crude Oil During Air Flooding

To improve the safety of air flooding, static and dynamic oxidation experiments are conducted to research catalytic low-temperature oxidation (CLTO) technology. The results show that the additives can accelerate the oxygen consumption rate significantly. Saturates and aromatics are converted to resins and asphaltenes during low-temperature oxidation (LTO), and the addition of additives can enhance the changing trend. CLTO technology can accelerate the oxygen consumption and delay the gas breakthrough time. This study can provide guidelines to improve the safety and increase the application of air flooding technology.

Oil filling history of the Bashituo Oilfield in the Markit Slope, SW Tarim Basin, China

The Markit Slope is an important area for the petroleum exploration in the Tarim Basin. Elucidation of the oil filling history of discovered oilfields has great significance for recognizing the accumulation processes of the whole region. Using molecular geochemistry, fluid inclusion techniques and basin modeling, we studied the oil filling process of the Bashituo Oilfield that is located in the west of the Markit Slope. The molecular migration indexes, such as the methyldibenzothiophene ratio (4-/1-MDBT), trimethylnaphthalene ratio (TMNr) and pyrrolic nitrogen compounds content, decrease from west to east, indicating that the charging direction and migration pathways are from west to east. Lithological analysis and homogenization temperatures of saline fluid inclusions accompanied with oil fluid inclusions suggest that two charging periods occurred in the Devonian oil reservoir. Combining the burial history and heating history of well BT4, Basinmod ID software modeling shows the two oil filling periods are from 290 Ma to 285 Ma and from 10 Ma to 4 Ma, respectively, and later oil filling dominates. This study may be helpful to understand the accumulation process and provide useful references for oil and gas exploration in the Markit Slope.

Geochemical analysis of mixed oil in the Ordovician reservoir of the Halahatang Depression, Tarim Basin, China

In this study, 12 crude oil samples were collected and analyzed from the Ordovician reservoir in the Halahatang Depression, Tarim Basin, China. Although the density of oil samples varies considerably, based on saturated hydrocarbon gas chromatographic (GC), saturated and aromatic hydrocarbon gas chromatographic-mass spectrometric (GC/MS) and stable carbon isotopic composition analyses, all the samples are interpreted to represent a single oil population with similar characteristics in a source bed or a source kitchen, organic facies and even in oil charge history. The co-existence of a full suite of n-alkanes and acyclic isoprenoids with UCM and 25-norhopanes in the crude oil samples indicates mixing of biodegraded oil with fresher non-biodegraded oil in the Ordovician reservoir. Moreover, according to the conversion diagram of double filling ratios for subsurface mixed crude oils, biodegraded/non-biodegraded oil ratios were determined as in the range from 58/42 to 4/96. Based on oil density and oil mix ratio, the oils can be divided into two groups: Group 1, with specific density >0.88 (g/cm3) and oil mix ratio >1, occurring in the north of the Upper Ordovician Lianglitage and Sangtamu Formation pinchout lines, and Group 2, with specific density <0.88 (g/cm3) and oil mix ratio <1, occurring in the south of the pinchout lines. Obviously, Group 2 oils with low densities and being dominated by non-biodegraded oils are better than Group 1 oils with respect to quality. It is suggested that more attention should be paid to the area in the south of the Upper Ordovician Lianglitage and Sangtamu Formation pinchout lines for further exploration.