Driving forces and their relative contributions to hydrocarbon expulsion from deep source rocks: A case of the Cambrian source rocks in the Tarim Basin

To thoroughly understand the dynamic mechanism of hydrocarbon expulsion from deep source rocks,in this study,five types of hydrocarbon expulsion dynamics(thermal expansion,hydrocarbon diffusion,compaction,product volume expansion,and capillary pressure difference(CPD))are studied.A model is proposed herein to evaluate the relative contribution of different dynamics for hydrocarbon expulsion using the principle of mass balance,and the model has been applied to the Cambrian source rocks in the Tarim Basin.The evaluation results show that during hydrocarbon expulsion from the source rocks,the relative contribution of CPD is the largest(>50%),followed by compaction(10%-40%),product volume expansion(5%-30%),and thermal expansion(2%-20%).The relative contribution of diffusion to hydrocarbon expulsion is minimal(<10%).These results demonstrate that CPD plays an important role in the hydrocarbon expulsion process of deep source rocks.The hydrocarbon expulsion process of source rocks can be categorized into three stages based on the contribution of different dynamics to the process:the first stage is dominated by compaction and diffusion to expel hydrocarbons,the second stage is dominated by product volume expansion and CPD,and the third stage is dominated by product volume expansion and CPD.This research offers new insights into hydrocarbon exploration in tight oil and gas reservoirs.

A novel triple responsive smart fluid for tight oil fracturing-oil expulsion integration

The traditional multi-process to enhance tight oil recovery based on fracturing and huff-n-puff has obvious deficiencies,such as low recovery efficiency,rapid production decline,high cost,and complexity,etc.Therefore,a new technology,the so-called fracturing-oil expulsion integration,which does not need flowback after fracturing while making full use of the fracturing energy and gel breaking fluids,are needed to enable efficient exploitation of tight oil.A novel triple-responsive smart fluid based on“pseudo-Gemini”zwitterionic viscoelastic surfactant(VES)consisting of N-erucylamidopropyl-N,N-dimethyl-3-ammonio-2-hydroxy-1-propane-sulfonate(EHSB),N,N,N′,N′-tetramethyl-1,3-propanediamine(TMEDA)and sodium p-toluenesulfonate(NaPts),is developed.Then,the rheology of smart fluid is systematically studied at varying conditions(CO_(2),temperature and pressure).Moreover,the mechanism of triple-response is discussed in detail.Finally,a series of fracturing and spontaneous imbibition performances are systematically investigated.The smart fluid shows excellent CO_(2)-,thermal-,and pressure-triple responsive behavior.It can meet the technical requirement of tight oil fracturing construction at 140°C in the presence of 3.5 MPa CO_(2).The gel breaking fluid shows excellent spontaneous imbibition oil expulsion(∼40%),salt resistance(1.2×104 mg/L Na+),temperature resistance(140°C)and aging stability(30 days).

Organic matter transformation ratio, hydrocarbon expulsion efficiency and shale oil enrichment type in Chang 7_(3) shale of Upper Triassic Yanchang Formation in Ordos Basin, NW China

The major enrichment type of shale oil in the Chang 7_(3) shale of Upper Triassic Yanchang Formation in the Ordos Basin is unknown.This paper analyzes the organic matter transformation ratio,hydrocarbon expulsion efficiency and roof/floor sealing conditions of the Chang 7_(3) shale,and evaluates the major enrichment type of shale oil in this interval.The average organic matter transformation ratio of the Chang 7_(3) shale is about 45%;in other words,more than 50%of the organic matters have not transformed to hydrocarbons,and the lower the maturity,the greater the proportion of untransformed organic matters.The cumulative hydrocarbon expulsion efficiency of the transformed hydrocarbon is 27.5% on average,and the total proportion of untransformed organic matters plus retained hydrocarbons is greater than 70%.The relative hydrocarbon expulsion efficiency of the Chang 7_(3) shale is 60%on average,that is,about 40% of hydrocarbons retain in the shale.The Chang 7_(3) shale corresponds to Chang 7_(1+2) and Chang 8 sandstones as the roof and floor,respectively,and is further overlaid by Chang 6 shale,where extensive low porosity and low permeability–tight oil reservoirs have formed in the parts with relatively good porosity and permeability.Moreover,the Chang 7_(3) shale is tested to be in a negative pressure system(the pressure coefficient of 0.80–0.85).Therefore,the roof/floor sealing conditions of the Chang 7_(3) shale are poor.The retained hydrocarbons appear mostly in absorbed status,with low mobility.It is concluded that the medium–high mature shale oil is not the major enrichment type of shale oil in the Chang 7_(3) shale,but there may be enrichment opportunity for shale oil with good mobility in the areas where the sealing conditions are good without faults and fractures and oil reservoirs are formed off Chang 7_(1+2),Chang 6 and Chang 8.Furthermore,low–medium mature shale oil is believed to have great potential and is the major enrichment type of shale oil in the Chang 7_(3) shale.It is recommended to prepare relevant in-situ conversion technologies by pilot test and figure out the resource availability and distribution.

Fracturing and Episodic Fluid Expulsion in Pressure Compartments

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Hydrocarbon expulsion model and resource potential evaluation of high-maturity marine source rocks in deep basins:Example from the Ediacaran microbial dolomite in the Sichuan Basin,China

Hydrocarbon expulsion features and resource potential evaluation of source rocks are crucial for the petroleum exploration.High-maturity marine source rocks have not exhibited a hydrocarbon expulsion mode owing to the lack of low-maturity source rocks in deep petroliferous basins.We considered the Ediacaran microbial dolomite in the Sichuan Basin,the largest high-maturity marine gas layer in China,to exhibit a method that quantitatively characterizes the hydrocarbon expulsion of high-maturity marine source rocks.The experiment of fluid inclusion,rock pyrolysis,and vitrinite reflectance(Ro)of 119 microbial dolomite core samples obtained from the Dengying Formation were performed.A hydrocarbon expulsion model of high-maturity source rock was established,and its resource potential was evaluated.The results showed that the Ediacaran microbial dolomite in the Sichuan Basin is a good source rock showing vast resource potential.The hydrocarbon expulsion threshold is determined to be vitrinite reflectance at 0.92%.The hydrocarbon expulsion intensities in the geologic history is high with maximum of 1.6×10^(7)t/km^(2).The Ediacaran microbial dolomite expelled approximately 1.008×10^(12)t of hydrocarbons,and the recoverable resource was 1.5×10^(12)m^(3).The region can be categorized into areasⅠ,Ⅱ,Ⅲ,andⅣ,in decreasing order of hydrocarbon expulsion intensity.Areas with a higher hydrocarbon expulsion intensity have a lower drilling risk and should be prioritized for exploration in the orderⅠ>Ⅱ>Ⅲ>Ⅳ.Two areas,northern and central parts of Ediacaran in the Sichuan Basin,were selected as prospects which had the drilling priority in the future gas exploration.The production data of 55 drilled wells verified the high reliability of this method.This model in this study does not require low-maturity samples and can be used for evaluating high-maturity marine source rocks,which has broad applicability in deep basins worldwide.

Spontaneous expulsion of a duodenal lipoma after endoscopic biopsy: A case report

BACKGROUND Gastrointestinal(GI)lipomas are benign submucosal tumors of mature adipocytes that arise mainly in the colon and stomach,sometimes in the ileum and jejunum,and rarely in the duodenum.Patients with symptomatic lipomas require endoscopic or surgical treatment.Spontaneous expulsion of lipomas after biopsy is a rare condition that has limited case reports.CASE SUMMARY A 56-year-old man presented to our hospital with intermittent postprandial epigastric fullness.Esophagogastroduodenoscopy(EGD)revealed a 10-mm soft yellowish submucosal lesion with the“pillow sign,”located in the second portion of duodenum.Endoscopic ultrasonography(EUS)using a 12-MHz catheter probe showed a hyperechoic,homogenous,and round solid lesion(OLYMPUS EUS EUME2,UM-DP12-25R,12-MHz radial miniprobe,Olympus Corporation,Tokyo,Japan).Deep biopsy was performed using the bite-on-bite technique with forceps.Histological examination was compatible with submucosal lipoma.The lesion spontaneously expelled 12 d after the biopsy.Follow-up EUS performed after 2 mo confirmed this condition.CONCLUSION Deep biopsy could lead to spontaneous GI lipoma expulsion.This might be the first step in lipoma diagnosis and treatment.

Textiloma: A Case Report of Rectal Expulsion

Textiloma is a rare pathological entity which can possibly complicate any surgery. Its incidence, reported in literature, is estimated between 1/1000 and 1/15,000. Abdominal and gynecological surgeries are responsible for the vast of majority of intra abdominal textiloma. Very few cases of spontaneous rectal expulsion of textiloma have been reported. We report the case of rectal expulsion of textiloma in a 26-year-old female who had undergone a C section for dynamic dystocia a year prior to her admission.

Identification and evaluation of shale oil micromigration and its petroleum geological significance

Taking the Lower Permian Fengcheng Formation shale in Mahu Sag of Junggar Basin,NW China,as an example,core observation,test analysis,geological analysis and numerical simulation were applied to identify the shale oil micro-migration phenomenon.The hydrocarbon micro-migration in shale oil was quantitatively evaluated and verified by a self-created hydrocarbon expulsion potential method,and the petroleum geological significance of shale oil micro-migration evaluation was determined.Results show that significant micro-migration can be recognized between the organic-rich lamina and organic-poor lamina.The organic-rich lamina has strong hydrocarbon generation ability.The heavy components of hydrocarbon preferentially retained by kerogen swelling or adsorption,while the light components of hydrocarbon were migrated and accumulated to the interbedded felsic or carbonate organic-poor laminae as free oil.About 69% of the Fengcheng Formation shale samples in Well MY1 exhibit hydrocarbon charging phenomenon,while 31% of those exhibit hydrocarbon expulsion phenomenon.The reliability of the micro-migration evaluation results was verified by combining the group components based on the geochromatography effect,two-dimension nuclear magnetic resonance analysis,and the geochemical behavior of inorganic manganese elements in the process of hydrocarbon migration.Micro-migration is a bridge connecting the hydrocarbon accumulation elements in shale formations,which reflects the whole process of shale oil generation,expulsion and accumulation,and controls the content and composition of shale oil.The identification and evaluation of shale oil micro-migration will provide new perspectives for dynamically differential enrichment mechanism of shale oil and establishing a“multi-peak model in oil generation”of shale.

Expulsion of geopressured hydrothermal system along active faults and its relation to the occurrence of earthquakes in the Shinanogawa seismic belt, Japan

The 1995 Northern Niigata Earthquake (M 6.0) occurred at a shallow depth in the Niigata seismic gap. The anomaly areas in temperature, electrical conductivity and Cl- concentration of groundwater trend northeast as linear distribution in the epicentral area and are approximately coincident with the area of the seismic intensity 6 (JMA scale). The distributions of seismic intensity 6 and groundwater anomalies convincingly imaged the presence of a buried active fault beneath the epicentral area. The occurrence of this earthquake and the anomalies of groundwater were related to the expulsion of geopressured hydrothermal system (GHS). All epicenters of the destructive earthquakes along the Shinanogawa seismic belt are actually located in the buried active fault zones characterized by the areas of temperature and geochemical anomalies of groundwater. These earthquakes might have been triggered by the activity of GHS. The expulsion of GHS along an active fault in combination with the thermal softening of fault zone attributed to high rock temperature may reduce fracture strength of the rock, and trigger earthquake occurrence. The dimension of the anomaly area of groundwater temperature at the epicentral area reflected the scale of the earthquake fault. The linear anomaly areas of groundwater resulting from the expulsion of GHS and having no historical destructive earthquake are of the predicated areas of future destructive earthquakes. Monitoring of groundwater conditions in these areas may provide useful information regarding the future occurrence of earthquakes.

Characteristics of hydrocarbon generation and expulsion in matrix and stylolite of carbonate rocks

Characteristics of organic matter content, hydrocarbon generation and expulsion of carbonate rocks are discussed by analysis of organic carbon and pyrolysis. There is a strong inhomogeneity in distribution of organic matter in carbonate rocks. The organic matter abundance is higher in stylolites, carbonate varves or marls, while it is the lowest in matrixes (purer carbonate rocks around stylolites). Because of stable thickness and broad area, marls and carbonate varves may become good source rocks. At the same depth, stylolites, carbonate varves and matrixes generate and expel hydrocarbons almost at the same time. Expulsion efficiency of carbonate varve is the highest; that of matrixes is the lowest and that of stylolites is between marl’s or carbonate varve’s and matrix’ s.

Expulsion and primary migration of the oil derived from coal

The characteristics of coal pores and the interaction relationship between hydrocarbons and pores in coal are analysed based on the typical example of oil from coal in Tuha Basin, pointing out that the interaction between hydrocarbon molecules and coal pore surface particles is a major controlling factor of expulsion of oil from coal. Distribution characteristics of coal pores and the ability of hydrocarbon generation are inner factors of the expulsion of the oil from coal; tectonic compressive shear stress is an external force of the expulsion of oil from coal; expulsion of the oil from coal has greater geochromatographic effect than that from mudstone, the low mature stage (or vitrinite reflectance R\-o is less than 0.9%) is advantageous to the coal-formed oil expulsion and migration; hydrocarbons in the hydrocarbon network are linked with carrier beds (such as fault), through the pore network and fissure which are connected with each other, which constitutes the main pathway of expulsion and migration.

Main factors influencing the expulsion of oil derived from coal

THE expulsion of hydrocarbons from coal is controlled by two main factors. The first is theproperties inherited from coal itself and contains two implications. One is original potential ofhydrocarbon generation from coal, which determines the degree of oil-bearing saturability;

Shale oil enrichment evaluation and production law in Gulong Sag,Songliao Basin,NE China

Based on the results of drilling,tests and simulation experiments,the shales of the Cretaceous Qingshankou Formation in the Gulong Sag of the Songliao Basin are discussed with respect to hydrocarbon generation evolution,shale oil occurrence,and pore/fracture evolution mechanism.In conjunction with a substantial amount of oil testing and production data,the Gulong shale oil enrichment layers are evaluated and the production behaviors and decline law are analyzed.The results are drawn in four aspects.First,the Gulong shales are in the stage of extensive hydrocarbon expulsion when R_(0) is 1.0%-1.2%,with the peak hydrocarbon expulsion efficiency of 49.5%approximately.In the low-medium maturity stage,shale oil migrates from kerogen to rocks and organic pores/fractures.In the medium-high maturity stage,shale oil transforms from adsorbed state to free state.Second,the clay mineral intergranular pores/fractures,dissolution pores,and organic pores make up the majority of the pore structure.During the transformation,clay minerals undergo significant intergranular pore/fracture development between the minerals such as illite and illite/smectite mixed layer.A network of pores/fractures is formed by organic matter cracking.Third,free hydrocarbon content,effective porosity,total porosity,and brittle mineral content are the core indicators for the evaluation of shale oil enrichment layers.Class-I layers are defined as free hydrocarbon content equal or greater than 6.0 mg/g,effective porosity equal or greater than 3.5%,total porosity equal or greater than 8.0%,and brittle mineral content equal or greater than 50%.It is believed that the favourable oil layers are Q2-Q3 and Q8-Q9.Fourth,the horizontal wells in the core area of the light oil zone exhibit a high cumulative production in the first year,and present a hyperbolic production decline pattern,with the decline index of 0.85-0.95,the first-year decline rate of 14.5%-26.5%,and the single-well estimated ultimate recovery(EUR)greater than 2.0×10^(4)t.In practical exploration and production,more efforts will be devoted to the clarification of hydrocarbon generation and expulsion mechanisms,accurate testing of porosity and hydrocarbon content/phase of shale under formation conditions,precise delineation of the boundary of enrichment area,relationship between mechanical properties and stimulated reservoir volume,and enhanced oil recovery,in order to improve the EUR and achieve a large-scale,efficient development of shale oil.

Exploration progress of the Paleogene in Jiyang Depression,Bohai Bay Basin

With increased exploration in the faulted basins of eastern China,petroleum exploration in this region has been challenged by unclear remaining petroleum resources distribution,complex reservoir and hydrocarbon enrichment patterns,and lacking of suitable exploration techniques.Aiming at resolving these problems,studies on source rocks,reservoirs,hydrocarbon accumulation and geophysical prospection were carried out by laboratory analysis,reservoir anatomy,and seismic analysis.A highlyefficient hydrocarbon generation/expulsion model of source rocks in saline environment was established,which aided in the discovery of a new set of source rocks in the Jiyang Depression.This study also reveals the formation process of high-quality reservoir by alternating acid and alkaline fluids during deposition and diagenesis,and pattern of secondary pores development in deep clastic rocks.Through the fine anatomy of the oil reservoirs,an orderly distribution pattern of the oil reservoirs is established,and the potential exploration targets in the undrilled area are identified.In addition,single-point highdensity seismic acquisition and high-resolution imaging technologies are developed,enabling fine and efficient exploration in areas with high exploration maturity.The research result plays a leading and demonstrative role in the fine and efficient exploration of faulted basins in eastern China.

Polygonal faults in the Sanzhao sag of the Songliao basin:their significance in hydrocarbon accumulation

Polygonal faults,generally distributed in fine-grained sediments,are layer-bound faults and are important in hydrocarbon accumulation.Using 3D seismic data,we analyzed the plane and profile features of faults developed in the Qingshankou formation of the Sanzhao sag.We identified these faults as having typical features of polygonal faults:1) layer-bound;2) normal faults;3) slight fault displacements and steep in dip angles;4) multi-directional in strike and 5) a single fault has a short horizontal extension.In addition,these faults intersect each other and form polygons.These polygonal faults are the result from the combined action of compaction,volume contraction and episodic hydraulic fracturing,conditions favorable for oil/gas accumulation.They are the dominant channels for migration of fluids in the Qingshankou mudstone,forming a large number of fault-lithologic oil traps.Polygonal faults improve reservoirs.

A New Method for Quantitative Simulating Hydrocarbo

We should understand that the content of chlo-roform bitumen“A”from source rocks at any depth(or period)is not the content of residuary oil,but it is the oil content of source rocks in a condition of dynamic equilibrium of generation and expulsion in an 1nstant.Sc can be measured by laboratory experiment and determined from the curve of S-A"versus depth for the same source rock.(Fig.l)

Evaluation of Hydrocarbon Generated and Expelled from the Jurassic to Early Cretaceous Source Rocks in the Lynedoch Field, Northern Bonaparte Basin, Australia

The Lynedoch field is located on the west flank of the Calder Graben in the north-eastern Bonaparte Basin, Australia. The data from the wells Lynedoch 1 and Lynedoch 2 and Seismic Line N11809 were used to reconstruct the burial and thermal histories and evaluate the hydrocarbon generated and expelled from the Jurassic to Early Cretaceous source rocks of the study area. Basin Mod 1-D and 2-D softwares were used for modeling. The Upper Jurassic Cleia (Lower Frigate) and Lower Cretaceous Echuca Shoals formations source rocks in the well Lynedoch 1 were a fair-to-good source richness with poor hydrocarbon generating potential, showing kerogen type III and gas prone. The Middle Jurassic Plover Formation source rock in the well Lynedoch 2 was a good organic matter richness with poor hydrocarbon generative potential, the late Middle Jurassic (Callovian) Elang Formation source rock in the same well was a fair source rock with poor hydrocarbon generation potential, and the Lower Cretaceous Echuca Shoals Formation source rock in the same well was a fair-to-very good organic richness with poor-to-fair hydrocarbon generating potential, gas prone with kerogen type III, and reaching wet gas window at present day. These previous formations of the both wells generated oil at the Late Cretaceous and gas at the Early Neogene. But, only Echuca Shoals Formation source rock in the well Lynedoch 2 was able to expelled hydrocarbon at the Middle Paleogene and continued up to present day. This Formation represents fair to slightly good potential source rock in the Lynedoch field.

Modeling of the whole hydrocarbon-generating process of sapropelic source rock

Based on experimental data from hydrocarbon generation with a semi-open system, hydrocarbon generation kinetics modeling in gold tube of closed system, high temperature pyrolysis chromatography mass spectrometry experiment with open system and geological data, the characteristics of whole hydrocarbon-generating process, hydrocarbon expulsion efficiency and retained hydrocarbon quantity, origins of natural gas generated in high-over mature stage and cracking temperature of methane homologs were investigated in this study. The sapropelic source rock has a hydrocarbon expulsion efficiency of 30%-60% and 60%-80% in the major oil generation window(with Ro of 0.8%-1.3%) and high maturity stage(with Ro of 1.3%-2.0%) respectively; and the contribution ratio of kerogen degradation gas to oil cracking gas in total generated gas in high maturity stage is about 1:4. The degradation gas of kerogen accounts for 20%, the retained liquid hydrocarbon cracking gas accounts for 13.5%, and the amount of out-reservoir oil cracking gas(including aggregation type and dispersed oil cracking gas) accounts for 66.5%. The lower limit of gas cracking is determined preliminarily. Based on the new understandings, a model of the whole hydrocarbon-generating process of source rock is built.

新式剖宫产术娩出胎头困难60例临床分析

目的：探讨新式剖宫产术娩出胎头困难的原因及处理。方法：均在持续硬膜外麻醉下进行处理。结果：麻醉不满意，25例，占41．7％；胎头高浮，20例，占33．3％；巨大儿，腹壁子宫切口相对小，10例，占16.7％；胎头深定，10例，占16．7％;医源性，5例，占8.3%。结论：术前仔细检查是关键。

米拉贝隆治疗输尿管远端结石的疗效评价

目的观察米拉贝隆治疗输尿管远端结石的疗效。方法随机分为两组,研究组采用米拉贝隆+间苯三酚,对照组单用间苯三酚。比较年龄、性别、肾积水严重程度、结石情况。评价药物排石率(SER)、排石时间及每日肾绞痛发作频次及程度。结果研究组1例因加服中药排石制剂而排除,此外研究组1例、对照组1例未参加随访被排除在研究之外。米拉贝隆组排石率为71.6%,对照组48.1%,差异有统计学意义(P=0.021),结石排出时间方面差异无统计学意义(P=0.876)。对照组每日发作肾绞痛的频次高于米拉贝隆组,VAS评分米拉贝隆组低于对照组。结论初步临床观察米拉贝隆是一种治疗输尿管远端结石有效、安全、不良反应低的药物。