Oilfield In China Research Articles

Reservoir formation conditions and key technologies for exploration and development in Qingcheng large oilfield

The Qingcheng oilfield, the largest shale oil field in China, was discovered in 2019 in source rock of Chang 7 Member of Mesozoic Yanchang Formation, Changqing Oilfield in Ordos Basin, with newly increased proven geological reserves of 358 million tons, predicted geological reserves of 693 million tons, and a total of 1.051 billion tons of shale oil resources. This achieves a historic breakthrough in exploration of shale oil in Chang 7 Member. In recent years, focusing on key issues, such as whether there develop sweet spots in source rock, whether commercial oil production capacity can be formed, and whether scale-effective development can be achieved, studies about geological conditions for shale oil accumulation have been continuously carried out, key supporting technologies have been developed, and a series of theoretical innovations and technological breakthroughs have been achieved in oil exploration in source rocks. The results indicate that shale oil accumulation in Chang 7 Member is controlled by following factors. Firstly, lacustrine black shale, dark mudstone and other high-quality source rocks lay a material foundation for shale oil formation. Secondly, sandy deposits intercalated within black shale and dark mudstones are exploration sweet spots, and sandbody combination types are controlled by morphology of bottom of the lacustrine basin. Thirdly, reservoir properties are good due to development of micro-nano pore throats. Finally, reservoirs with high oil saturation and high gas-oil ratio are formed due to high-intensity oil charging in source rock. Effective matching of multiple factors is a key for shale oil accumulation in Chang 7 Member in Ordos Basin. Through innovation of key supporting technologies, exploration and development technologies for shale oil are developed, and substantial breakthrough on exploration and development of shale oil is realized. The first application of logging-seismic combination technology in loess plateau improves significantly quality of 3D seismic data, which effectively guides prediction of sandy sweet spots. Three-quality well logging technology is used for further evaluation of geological and engineering sweet spots of shale oil. With volumetric fracturing technology based on precise segmentation of long horizontal wells, initial daily oil production of individual well is increased from previously 10 tons to more than 18 tons. The exploration breakthrough in source rocks in Chang 7 Member in Qingcheng oilfield provides an important resource base for the second accelerated development of Changqing Oilfield. It is predicated that oil production from shale in Chang 7 Member in Qingcheng oilfield will reach three million tons in 2022 and five million tons in 2025.

Systematic Investigation of Integrating Small Wind Turbines into Power Supply for Hydrocarbon Production

In this paper, the technical and economic feasibility of integrating SWTs (Small Wind Turbines) into remote oil production sites are investigated. Compared to large turbines in onshore and offshore wind farms, SWTs are more suitable for individual power generations. A comprehensive approach based on wind energy assessment, wind power prediction, and economic analysis is then recommended, to evaluate how, where, and when small wind production recovery is achievable in oilfields. Firstly, wind resource in oilfields is critically assessed based on recorded meteorological data. Then, the wind power potential is numerically tested using specified wind turbines with density-corrected power curves. Later, estimations of annual costs and energy-saving are carried out before and after the installation of SWT via the LCOE (Levelized Cost of Electricity) and the EROI (Energy Return on Investment). The proposed methodology was tested against the Daqing oilfield, which is the largest onshore oilfield in China. The results suggested that over 80% of the original annual costs in oil production could be saved through the integrations between wind energy and oil production.

An Efficient Downhole Oil/Water-Separation System with Sucker-Rod Pump

Summary At present, many oil fields in China have entered the high-water-cut production period, and the water cut of oil wells has continued to rise. Therefore, how to reduce the water cut of the produced liquid, reduce the amount of surface water treatment, shorten the ineffective water circulation, and reduce the comprehensive production cost have become the key problems restricting the sustainable economic exploitation of a high-water-cut oil field. To this end, the development model of circular displacement and the oil-recovery technology of a downhole oil/water-separation system with sucker-rod pump (DOWS-SRP) are proposed. The technology system consists of downhole oil/water-separation devices, an injection/production pump-string system, a sealing system, and downhole data-test system, mainly applied to separating the oil and water in the well through the separation device. The separated water is then directly injected into the formation and the separated concentrated liquid is lifted to the ground so the water injection and oil recovery are completed simultaneously in the same wellbore. The field-test data show that after the implementation of injection/production technology in the same well, the surface liquid-production volume decreased by 90%, the water-cut decreased by 27%, and the water/oil ratio decreased by 93%. In addition, the liquid volume of lifting, gathering, and treatment was greatly reduced, as well as the surface infrastructure investment, to achieve the purposes of cost saving, energy saving, and consumption reduction. At the same time, the downhole reinjection replaces surface water injection, transforming ineffective surface water circulation into effective internal displacement power in the reservoir and improving the yield and recovery rate. The successful application of the quaternary-oil-recovery block has made it possible to redevelop a large number of abandoned oil reservoirs, providing a potential basis for quaternary oil production. In addition, the preliminary energy-saving effect and economic-benefit analysis are performed. The data show that the energy-saving effect of this technology is obvious and good economic benefit is obtained.

Experimental study the flow behaviors and mechanisms of nitrogen and foam assisted nitrogen gas flooding in 2-D visualized fractured-vuggy model

Fractured-vuggy carbonate reservoir played a significant role in unconventional reservoirs, but it was difficult to be developed due to its complex reservoir types. Therefore, it was crucial to find a suitable development program to enhance oil recovery. In this work, a two-dimensional visual physical model of fractured-vuggy reservoir was designed and fabricated according to actual geological data and injection-production characteristics of a representative fractured-vuggy carbonate reservoir, Tahe Oilfield in China. Nitrogen flooding experiment, nitrogen flooding under the high gas energy experiment, nitrogen flooding under strong bottom water energy experiment and foam assisted nitrogen gas flooding experiment were carried out respectively by using two-dimensional visual model. The flow behaviors and the main mechanisms for enhanced oil recovery were revealed by analyzing the oil displacement performance in the visual physical model. Experiment results showed that the gas cap energy and the bottom water energy played a synergistic effect in the nitrogen flooding. The stronger the bottom water energy was, the larger the gas spread area was, and the increase of oil recovery would be very high. If the gas injection rate was too strong, the dominant gas flow channel would be formed prematurely, and the oil recovery was little increase. In addition, foam could effectively control the gas mobility, delay the formation of gas channeling. Meanwhile, the oil recovery of foam assisted nitrogen gas flooding was higher 12% than that of nitrogen flooding. Therefore, the mechanism for improving the degree of development was obtained mainly through gravity differentiation to form the secondary gas top and realize the development of the remaining oil.

Study on an emulsion-type blockage removal agent for heavy oil recovery enhanced by polymer

In polymer flooding process, the poor solubility of polymer and the wrap of incompletely dissolved polymer particles with heavy oil lead to the generation of complicated blockage, which seriously affects the normal production of wells. Therefore, how to fabricate an effective blockage removal agent is particularly important. Based on the blockage from Bohai Offshore Oilfield in China, a blockage removal agent composed of (0.5wt% potassium persulfate+kerosene (the ratio of kerosene: blockage is 3:5)+0.3wt% OP-10, the oil-water ratio is 1:9) was developed. The removal effect and mechanism were characterized by weight loss method and core test. Moreover, the emulsification property of the removal agent was also evaluated by microscopic appearance. The results showed that the blockage removal agent can be formulated as an O/W emulsion and had good stability for more than 72h. Core test showed that the permeability had a significant improvement after injection of removal agent. The emulsion-type removal agent can demulsify after contact with the blockage, then the oil-soluble detergent as internal phase in emulsion can be released which contributes to the wash off of heavy oil. Accompanied with the polymer degradation by the oxidant, this agent realized the effective dissolution and removal of blockage.

Identification method of water-flooded layer based on analytic hierarchy process——Taking the Keshang Formation reservoir in the J188 well area as an example

Most oil fields in China have entered the high water cut stage, the identification of water flooded layers is a very important task. At present, the identification of water-flooded layers usually adopts the combination of qualitative method and quantitative method to carry out the work. However, the qualitative method is difficult to be characterized by quantitative numerical values, so the work efficiency is very low; the quantitative method needs to be taken in the actual operation. The oil-water relative permeability of the reservoir, the viscosity of the oil and water, and the original oil saturation, the calculation accuracy of these parameters are inevitably large errors. This paper explores a semi-quantitative method to overcome the insufficiency of qualitative methods, the simplification of quantitative parameters, and the error of water-flooded layer identification. The analytic hierarchy process was used to identify the water-flooded layer in the Keshang Formation reservoir in the 188 well area. The water production rate, oil saturation, production index and relative permeability index were integrated into a comprehensive water-flooded layer identification index. The results show that the total water-flooded layer identification coincidence rate reaches 70%. The method of water flooded layer identification based on analytic hierarchy process is feasible.

A novel exopolysaccharide-producing and long-chain n-alkane degrading bacterium Bacillus licheniformis strain DM-1 with potential application for in-situ enhanced oil recovery

A novel Bacillus licheniformis strain (DM-1) was isolated from a mature reservoir in Dagang oilfield of China. DM-1 showed unique properties to utilize petroleum hydrocarbons and agroindustrial by-product (molasses) for exopolysaccharide (EPS) production under oil recovery conditions. The DM-1 EPS was proven to be a proteoglycan with a molecular weight of 568 kDa. The EPS showed shear thinning properties and had high viscosities at dilute concentrations (<1%, w/v), high salinities, and elevated temperatures. Strain DM-1 could degrade long-chain n-alkanes up to C36. Viscosity reduction test have shown that the viscosity of the crude oil was reduced by 40% compared with that before DM-1 treatment. Sand pack flooding test results under simulated reservoir conditions have shown that the enhanced oil recovery efficiency was 19.2% after 7 days of in-situ bioaugmentation with B. licheniformis DM-1. The obtained results indicate that strain DM-1 is a promising candidate for in situ microbial enhanced oil recovery (MEOR).

Zhaonella formicivorans gen. nov., sp. nov., an anaerobic formate-utilizing bacterium isolated from Shengli oilfield, and proposal of four novel families and Moorellales ord. nov. in the phylum Firmicutes

A novel obligately anaerobic, thermophilic and formate-utilizing bacterium K32T was isolated from Shengli oilfield of China. Cells were straight rods (0.4-0.8 µm × 2.5-8.0 µm), Gram-stain-positive, non-spore-forming and slightly motile. Optimum growth occurred with pH of 7 and 0.5 g l-1 NaCl under temperature of 55-60 °C. Nitrate could be reduced into nitrite, syntrophic formate oxidation to methane and carbon dioxide occurred when co-culturing strain K32T and Methanothermobacter thermautotrophicus ΔH. The main cellular fatty acids were iso-C15 : 0 (24.0 %), anteiso-C15 : 0 (21.7 %), C16 : 0 (12.7 %) and C14 : 0 (10.8 %), and the main polar lipid was phosphatidylglycerol. The G+C content of the genomic DNA was 46.3 mol%. The 16S rRNA gene sequence of K32T shared ≤90.4 % of sequence similarity to closest type strains of Desulfitibacter alkalitolerans, Calderihabitans maritimus and members of the genus Moorella. Based on the phenotypic, biochemical and genotypic characterization, Zhaonella formicivorans gen. nov., sp. nov. is proposed with K32T (=CCAM 584T =DSM 107278T=CGMCC1.5297T) as the type strain, which is the first representative of Zhaonellaceae fam. nov. In addition, the order Thermoanaerobacterales and family Peptococcaceae were reclassified, and three novel families in the novel order of Moorellales ord. nov. were also proposed.

Microbial community composition and diversity in production water of a high-temperature offshore oil reservoir assessed by DNA- and RNA-based analyses

Microbial activity is ubiquitous and important in petroleum reservoir systems; however, current knowledge regarding the diversity and functions of microbial communities that are active in offshore petroleum reservoirs remains very limited. In the present work, high-throughput sequencing analysis of the 16S rRNA gene (DNA) and transcripts (RNA) was applied to respectively characterize the genomic and active microbial communities from two production wells in a high-temperature offshore oilfield in China. The results showed that the microbial community compositions in the two wells (X1 and X2) were very different. At the genus level, the dominant members in both genomic and active communities of sample X1 were Bosea, Acinetobacter, Sphingomonas, Candidatus Methanofastidiosum and Methanocalculus. Both genomic and active communities in sample X2 were mainly represented by Pseudomonas, Acinetobacter, Methanothermobacter, Methanosaeta, Candidatus Nitrosopumilus, Candidatus Methanomethylicus, Thermococcus, Candidatus Methanofastidiosum and Methanocalculus. Moreover, using an RNA-based approach, genera with a very low abundance and even undetected genera (based on a DNA approach) were shown to have increased activity. Besides the abundant active members, the comparison between the DNA- and RNA-based datasets also permitted the identification of genera that were relatively more active in the two production water samples. The existence of these active microorganisms suggested they might have potential functions associated with reservoir issues in the offshore oilfield. This study highlights the importance of assessing microbial diversity through a combination of DNA- and RNA-based analyses, and promotes a comprehensive and deep understanding of microbial compositions and their roles in offshore petroleum reservoirs.

Pseudomonas Saliphila sp. nov., a Bacterium Isolated from Oil-Well Production Water in Qinghai Oilfield of China.

Strain 16W4-4-3T was isolated from the oil-well production water in Qinghai Oilfield, China. Cells were Gram-stain-negative, rod-shaped, catalase- and oxidase-positive, facultatively anaerobic and motile by single polar flagellum. The 16S rRNA gene sequences of strain 16W4-4-3T showed the highest similarities with Pseudomonas profundi M5T (98.8%), P. pelagia CL-AP6T (98.0%), P. salina XCD-X85T (97.7%), and P. sabulinigri J64T (97.5%). The phylogenetic trees based on multilocus sequence analyses with concatenating 16S rRNA, gyrB, rpoD and rpoB genes suggested that this strain should be affiliated to the genus Pseudomonas but remotely related from other species. In addition, whole genome analyses revealed that the digital DNA-DNA hybridization values and average nucleotide identities of strain 16W4-4-3T against its close relatives were all below 28.8% and 86.5%, respectively. Furthermore, the isolate had totally different whole cell protein profile as compared to those of other species. Major fatty acids were summed feature 8 (C18:1ω7c and/or C18:1ω6c), C16:0, summed feature 3 (C16:1ω7c and/or C16:1ω6c) and C17:0cyclo. Major isoprenoid quinone was ubiquinone (Q-9), and major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, and phosphatidylethanolamine. The DNA G + C content was 58.5mol%. Therefore, phenotypic, phylogenetic, genomic, chemotaxonomic, and proteomic traits showed that the isolate represented a novel species of the genus Pseudomonas, the name Pseudomonas saliphila sp. nov. is proposed. Type strain is 16W4-4-3T (= CGMCC 1.13350T = KCTC 72619T).

Investigation on leakage cause of oil pipeline in the west oilfield of China

A crude oil pipeline used in an oilfield in the west oilfield of China leaked many times in a short time. Serious corrosion was found near the leaking position of the failed pipe, the wall thickness of pipeline also decreased near the failure section. To determine the reason for this, the failed pipeline was investigated and analysed by macroscopic analysis, chemical composition tests, metallurgical analysis, mechanical property analysis, scanning electronic microscopy (SEM) analysis, X-ray diffraction (XRD) analysis and corrosion simulation tests. Based on the systematic analysis, it can be concluded that the mechanical properties of the failed pipeline met the related standards. The crude oil conveyed in the pipeline contained a large amount of formation water; because the formation water was acidic (the pH value was 5.0–6.5) and had high salinity, the materials of the pipeline had a very high corrosion rate when exposed to the crude oil, which was confirmed by the corrosion simulation test. At the same time, because the fluid flow changed suddenly in the pipeline lifting location, fouling deposition occurred inside the pipeline, which led to serious localized corrosion caused by the small anode/big cathode corrosion galvanic cell reaction, and the wall thickness decreased quickly in a short time. Finally, the pipeline leaked due to fluid erosion and the high speed impact of solid particles and grit in the crude oil. Improvement suggestions are put forward to the pipeline user at the end of this paper, such as improving the pipeline design, reducing the salinity in the conveying fluid, adding a corrosion inhibitor and replacing the pipeline lifting segment with an anticorrosive coating inside the tube; the crude oil pipeline did not leak again after following these suggestions.

Delayed expansion behavior and mechanical properties of water-swelling rubber/OMMT composites

To meet the harsh water plugging conditions for a crack fracture-type rock reservoir of Tahe oilfield in China, which are high temperature, high salinity and above 4000 m underground, a novel delay-expansion water-swelling rubber/OMMT (DWSR) with silty-resistant and lower hydrophilic resin migration behavior was developed. HNBR, semi-HEMA@PU, polyacrylamide (PAM), OMMT and other rubber additives were mechanically blended in an open mill mixer. The semi-HEMA@PU blocked by double bond and isocyanate group was prepared by the reaction of NCO group (50% mole fraction) with hydroxyethyl methacrylate. The semi-HEMA@PU reacted with the amino group from PAM and the unsaturated double bond of HNBR, respectively. A crosslink network constructed among PU, PAM and HNBR matrix made the DWSR/OMMT composite exhibit high salinity resistance and low hydrophilic resin migration features. With an increase of PU content, the crosslinking density of DWSR increases gradually. When the semi-HEMA@PU content was 10 phr, the tensile strength reached a maximum of 13.6 MPa. The influences of OMMT content on swelling behavior were investigated. When the mass content for OMMT was about 1phr, the delayed expansion time was more than 50 h. The presence of OMMT significantly improved the delayed expansion property of DWSR.

Geochemical characteristics and depositional environment of the Shahejie Formation in the Binnan Oilfield, China

Abstract Trace elements in sedimentary rocks are highly sensitive to palaeoaquatic environmental changes in a sedimentary environment, making them an effective means for studying the paleoclimate and paleoenvironment during the deposition of sediments. The trace elements and major elements of mudstone cores sampled in the Binnan Oilfield in China were tested by inductively coupled plasma mass spectrometry (ICP–MS). Strontium (Sr), barium (Ba), vanadium (V), nickel (Ni) and boron (B), which are all sensitive to the sedimentary environment, were selected as discriminant indicators, and the sedimentary environment of the Shahejie Formation in the Binnan Oilfield was studied by combining with sedimentary indicators. The results show that the equivalent B content and the Sr/Ba ratio discriminate the research area for salt water and freshwater sedimentary environments. The V/(V + Ni) ratio is between 0.65 and 0.81, meaning that this area has a highly reductive sedimentary stratum. The trend of the Rb/Sr curve indicates that the paleoclimate of the Shahejie Formation changed from dry to humid and then back to dry.

Electric submersible pump broken shaft fault diagnosis based on principal component analysis

Electric Submersible Pump (ESP) is currently widely employed to help enhance production for nonlinear-flowing well with high production and high water cut well. However, ESP broken shaft is common in the oil industry. The broken shaft leads to production disruptions, resulting in significant economic losses. The objective of this paper is to evaluate Principal Component Analysis (PCA) as an unsupervised machine learning technique to detect the cause of the breakage of the ESP shaft. This method was successfully applied in the Penglai block of Bohai Oilfield in China to detect the ESP shaft fracture in real-time. A two-dimensional plot of scores of Principal Component 1 and Principal Component 2 can be used to identify different clusters of the stable region, unstable region and failure region. By this means, potential ESP shaft fracture will be found when the cluster starts deviating away from the stable region. Moreover, a PCA diagnostic model is built to predict the time at which the ESP shaft fracture occurs and to determine the main decision variable most responsible for ESP broken shaft. This paper demonstrates that the application of the PCA method performs well in monitoring the ESP operation system and predicts the impending breakage of ESP shaft with high accuracy.

Machine-Learning-Based Early-Warning System Maintains Stable Production

This article, written by JPT Technology Editor Judy Feder, contains highlights of paper SPE 197365, “A Novel Early Warning System of Oil Production Based on Machine Learning,” by Kang Ma, Hanqiao Jiang, and Junjian Li, China University of Petroleum-Beijing, et al., prepared for the 2019 Abu Dhabi International Petroleum Exhibition and Conference, Abu Dhabi, 11–14 November. The paper has not been peer reviewed. After long-term waterflooding, a number of mature oil fields in China have entered the high-water-cut stage, and abnormal production decline has become the primary problem for stable production. This paper describes an accurate, three-step, machine-learning-based early warning system (EWS) that has been used to monitor production and guide strategy in the Shengli field. Adding artificial samples to the training process improved the system’s prediction accuracy greatly (Fig. 1). Introduction For conventional Chinese oil fields that have entered the high-water-cut stage after decades of waterflooding, stabilizing production has become increasingly difficult. After stimulation treatments throughout the field’s history, abnormal decline rates—that is, exceeding 5%—occurred more frequently. Production declined dramatically in 2004 and has not been maintained since then. To prevent future abnormal production declines, an effective EWS was needed that could release a production alarm to enable engineers to take preventive measures in advance. The complete paper includes a discussion of various early-warning models and their limitations. The paper discusses an EWS based on a neural network method using a previously established data set. Factors that can affect the abnormal decline were selected. The index sets of production composition and injected and produced water obtained from practical statistics were considered as the main assessment indicators. Grey relational analysis was used to evaluate the importance of the different indicators and to eliminate redundant parameters. Machine learning was adopted to build the EWS. Using the degree of deviation from normal as the input data for the prediction model provided the highest accuracy. However, the basic machine-learning model contains many input parameters that cannot be obtained easily. The number of input parameters was optimized on the basis of the variation of accuracy under different input parameter numbers. To improve prediction accuracy, artificial samples were added to the training process. The prediction accuracy of the final optimization model can reach 92%. The result reveals the possibility of the occurrence of anomalous decline in different reservoirs, which can guide oilfield production strategy effectively. The EWS was verified by oilfield production. Fundamentals of Neural-Network Classification Neural networks use existing data to determine the implicit model between input and output data. Classification and prediction are the most common applications. Neural networks are used in the industry to solve classification and regression problems.

2D High-Resolution Crosswell Seismic Traveltime Tomography

This paper presents a method for combining the hybrid eikonal solver and the prior velocity information to obtain high-resolution crosswell imaging. The hybrid eikonal solver in this technique can ensure rapid and reliable forward modeling of traveltime field in an unsmoothed velocity model. We also utilize the sonic well logging curve to properly develop an initial reference velocity model, and use the sonic well logging data as the prior information for the inversion part, which can restrict the problem of non-uniqueness. The results of the numerical experiment of traveltime in multi-layer media showed that the hybrid eikonal solver was more accurate than the finite difference method. The case study of an oil field in eastern China demonstrated that our method can derive a high-resolution reconstruction of the subsurface structure by inverting the primary traveltime datasets. These results suggest that even though the eikonal equation is a high frequency approximation to the wavefield, the hybrid eikonal solver can provide an accurate traveltime field in the forward modelling step of seismic crosswell tomography, which is critical to ensure high-resolution invert imaging in a highly heterogeneous environment.

Case study: Seismic resolution and reservoir characterization of thin sands using multiattribute analysis and bandwidth extension in the Daqing field, China

The Daqing field, located in the Songliao Basin in northeastern China, is the largest oil field in China. Most production in the Daqing field comes from seismically thin sand bodies with thicknesses between 1 and 15 m. Thus, it is not usually possible to resolve Daqing reservoirs using only conventional seismic data. We have evaluated the effectiveness of seismic multiattribute analysis of bandwidth extended data in resolving and making inferences about these thin layers. Multiattribute analysis uses statistical methods or neural networks to find relationships between well data and seismic attributes to predict some physical property of the earth. This multiattribute analysis was applied separately to conventional seismic data and seismic data that were spectrally broadened using sparse-layer inversion because this inversion method usually increases the vertical resolution of the seismic. Porosity volumes were generated using target porosity logs and conventional seismic attributes, and isofrequency volumes were obtained by spectral decomposition. The resulting resolution, statistical significance, and accuracy in the determination of layer properties were higher for the predictions made using the spectrally broadened volume.

Solirhodobacter olei gen. nov., sp. nov., a nonphotosynthetic bacterium isolated from oil-contaminated soil.

A nonphotosynthetic, Gram-stain-negative, rod-shaped and motile strain, designated Pet-1T, was isolated from oil-contaminated soil collected from Daqing oil field in China. Optimal growth occurred at 37 °C, pH 5.5 and in 1 % (w/v) NaCl. Q-10 was the sole respiratory quinone. The most abundant fatty acid was C18 : 1ɷ7c/C18 : 1ɷ6c (67.4 %). The major polar lipids were phosphatidylglycerol, aminolipid, phosphatidylethanolaine, phosphatidycholine, two unidentified lipids and two unidentified phospholipids. The genomic DNA G+C content was 69.3 mol%. Phylogenetic analysis based on 16S rRNA gene sequences revealed that Pet-1T shared the highest similarity (95.1 %) to Rhodobacter vinaykumarii DSM 18714T, followed by Sinorhodobacter populi sk2b1T (95.0 %) and Haematobacter massiliensis CCUG 47968T (95.0 %). In the phylogenetic tree, strain Pet-1T formed a separate branch from the closely related genera Rhodobacter, Pararhodobacter, Defluviimonas and Rhodovulum within the family Rhodobacteraceae. Based on the data from the current polyphasic study, it is proposed that the isolate is a novel species of a novel genus within the family Rhodobacteraceae, with the name Solirhodobacter olei gen. nov., sp. nov. The type strain of the type species is Pet-1T (=KCTC 72074T =CCTCC AB 2018368T).

SYNTHESIS AND APPLICATION OF AN EFFICIENT DEGREASING AGENT FOR OILY DRILLING CUTTINGS

Oil-based drilling fluids are widely used in oil and gas exploration and development. Large amounts of oily drilling cuttings are produced in the drilling process, and improper treatment can cause serious secondary pollution. Chemical cleaning is commonly used to treat oily drilling cuttings. However, most degreasing agents are not environmentally friendly and can cause secondary pollution. Thus, the processing requirements of oily cuttings are difficult to meet. In this study, an environmentally friendly degreasing agent CYJ-1 that is biodegradable and can efficiently treat oily drilling cuttings was designed and prepared using optimized treatment agents and conditions, achieving an oil removal rate of 93.02%. In addition, a harmless degreasing formula utilizing this environmentally friendly degreasing agent was developed and had a remarkable oil removal effect on oily drilling cuttings. Transition state theory was applied to explain the degreasing effect of oily drilling cuttings for the first time, and the mechanism of action of the degreasing agent was analyzed in conjunction with the interfacial tension and potential energy. The formula was applied at two wells in the Xinjiang oilfield in China. It could achieve a high oil removal rate, which efficiently solved the pollution and resource recovery problems associated with oily drilling cuttings.

Research and Application of Air Source Heat Pump Technology at Rd. 60-10 Oil Delivery Site

The heating methods currently used at oil delivery sites and transfer stations on North China Oilfield include electric bar heating, fuel oil heating, gas heating, etc. The traditional heating methods have adverse effect on energy conservation and environmental protection. They have low energy efficiency of heating and produces great pollution to the environment. The air source heat pump technology uses the heat in the air as the low-temperature heat source and transforms it to the high-temperature hot water, which will later serve as a heat tracing for crude oil gathering and transportation. No combustion effluent is produced in operation and the energy-saving effect is outstanding with high social-benefit.