Lithologic Reservoirs

The volcanic lithofacies and reservoir characteristics in Wangshen 1 block in northern Songliao Basin are analyzed. The volcanic lithofacies of Yingcheng Formation in Wangshen 1 block can be divided into volcanic vent facies, eruptive facies, overflow facies and volcanic sedimentary facies. The main lithofacies are eruptive facies and overflow facies. Based on this division, the volcanic eruption model is established. There are six types of volcanic reservoir space in this area. The volcanic reservoir is mainly controlled by lithology, lithofacies and postdiagenesis. The favorable reservoir mainly distributed in the band of autoclastic lava in the upper subfacies of effusion and in the common volcanic breccia in eruption air fall subfacies. Condensation, effusion of residual liquid，dissolution and tectogenesis are the main advantageous diagenesis for the formation and conservation of pore and seam. The volcanic reservoir in this area is evaluated, and it can be mainly divided into typeⅡ and type Ⅲ reservoir.

Controlling effect of cap rock on gas accumulation and distribution in Xujiaweizi Depression

FU Guang， GUO Dujun

2009, Vol.21(3): 7–11 Abstract ( 393 ) PDF (381 KB) ( 351 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2009.03.002

Based on drilling and testing data, the distribution and seal ability of gas cap rock in Xujiaweizi Depression are studied. It is considered that there are mainly 4 kinds of gas cap rocks in Xujiaweizi Depression, including mudstones, volcanic rocks with high and low interval transit time and argillaceous conglomerates. Mudstones are regional cap rocks, which mainly distributed in K1d2 and strata above it. Volcanic rocks with high interval transit time are local cap rocks, which mainly distributed on the top of K1yc1. Volcanic rocks with lowinterval transit time mainly distributed in K1yc1 and K1 yc3, and argillaceous conglomerate cap rocks are mainly in K1 yc4. The seal abilities of mudstone, volcanic rocks with high interval transit time and argillaceous conglomerate cap rocks are strong, while the seal ability of volcanic rocks with low interval transit time is weak. Based on the study of the distribution relation between cap rocks and gas, the controlling effect of cap rocks on gas accumulation and distribution in Xujiaweizi Depression is concluded and mainly displayed in the following 3 aspects: ①Cap rocks in K1d2 and the top of K1 yc1 control the vertical distribution of gas;②The difference of distribution horizons of cap rocks leads to different reservoirseal assemblage and different enrichment degree of gas in the south and north of depression; ③The difference of volcanic cap rocks with high and lowinterval transit time causes that gas mainly distributed on the top of volcanic rock bodies.

Application of sequence stratigraphy in block D of Cambodia Sea in Gulf of Thailand

XU Zhaohui，LIU Zhen，WANG Lu，LIANG Quansheng，CHANG Mai

2009, Vol.21(3): 12–17 Abstract ( 550 ) PDF (1353 KB) ( 400 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2009.03.003

The block D of Cambodia Sea in Gulf of Thailand is a newarea with low exploration degree. The petroleum geology study on the nearing area is much deeper. However, there has no systematic sequence division in the block Dby now. The 2D seismic lines played a main part together with the assist of the nearingwell. The sequence divisions inwell and seismic sections are carried out individually. Combined with the two divisions, the comprehensive sequence division of the area is obtained. There are totally 6 sequences, and the first isochronal sequence framework is set up. In the unit of sequence, the section feature and plane feature of the seismic facies are analyzed. The method used here offers an effective way for the study of sequence stratigraphy on offshore low-degree exploration areas.

Lithofacies and reservoir characteristics of Late Carboniferous-Permian volcanic rocks in Niudong block, Santanghu Basin

NIE Bao-feng1，2， YU Bing-song1， LI Zheng-ke3，WEN Chuan-jiang3， LIU Yong-shun2， SONG Ben-biao4

2009, Vol.21(3): 18–22 Abstract ( 565 ) PDF (714 KB) ( 372 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2009.03.004

The rock types, lithofacies and reservoir characteristics of Late Carboniferous-Permian volcanic rocks in Niudong block of Santanghu Basin are analyzed. The main volcanic rocks are pyroclastic rocks and lavas. The volcanic pyroclastic rocks are composed of tuff, volcanic breccia and volcanic agglomerate, while the lavas are composed of basalt and basaltic andesite. Vesicular basalt and basaltic andesite mainly distributed in roof and floor of the flow unit. It is amygdaloidal basalt and basaltic andesite in the middle and upper part, and dense basalt in the middle and lower part. The primary pore in the roof and floor of amygdaloidal lava belt developed well, which is the favorable reservoir.

Characteristics and controlling factors of volcanic reservoir of Carboniferous in Santanghu Basin

LIU Juntian，ZHU Youxin，LI Zaiguang，YAN Ligang，QIN Xinping，LIU Yuanping

2009, Vol.21(3): 23–28 Abstract ( 533 ) PDF (714 KB) ( 673 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2009.03.005

The reservoir characteristics of C2 h and C2 k of Carboniferous in Santanghu Basin are analyzed. It is considered that effective source rock, favorable facies zone and faulted zone, paleo tectonic near petroleum genetative depression and late reformation are the main controlling factors of reservoir accumulation of Carboniferous volcanic rocks in Santanghu Basin. The volcanic reservoir in Santanghu Basin is complex, and petroleum migrated mainly in vertical direction, with limited lateral migration. The effective source rock has a significant controlling effect on oil and gas distribution. Ancient uplift and paleo tectonic provide structural setting for hydrocarbon multi-stage migration and accumulation. Volcanic activity is controlled by deep fault, and fault is the main migration pathway. Oil and gas that generated fromthe deep fault migrated along fault and fracture to uplift and accumulated there. The upper subfacies of effusive facies is favorable zone for volcanic reservoir. Volcanic breccia has the best reservoir property and oiliness, followed by basalt and andesite. Micro-fracture that generated by tectonic movement and weathering and leaching effectively improved the reservoir space. Oil and gas mainly occurred in volcanic solution pore linked up by fracture. It is pointed out that Malang Sag, Tiaohu Sag, Tiaoshan Sag, Weibei uplift and the thrust belt in the southern margin of Santanghu Basin are the favorable exploration field.

Petroleum geological conditions and exploration direction in north piedmont zone of Tuha Basin

LI Zaiguang，CHEN Qilin，LV Ximin，YANG Zhanlong，HUANG Yunfeng，WU Qingpeng

2009, Vol.21(3): 29–34 Abstract ( 612 ) PDF (850 KB) ( 459 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2009.03.006

The north piedmont zone of Tuha Basin is adjacent to three large oil-gas generating depressions (Shengbei, Qiudong and Xiaocaohu), and developed several reservoir-cap assemblages. Experienced multiple tectonic movements such as Yanshanian tectonic movement and Himalayan tectonic movement, it developed thrust belt, anticlinal belt and slope nose-shaped uplift belt from north to south, and the reservoirs formed by multi-stage hydrocarbon migration and accumulation. At present, five oilfields have been found such as Shanle, Qialekan, Kekeya, Yuguo and Qiquanhu, and six layer series obtained commercial oil and gas flow. The reservoir forming and distribution are controlled by Yanshanian palaeostructure, the existing structural high, faults, reservoirs and caps. It is proposed that the prospecting for Shuixigou Group reservoir and the middle-eastern shallow reservoir should be strengthened while expanding the dominated reservoir of J2s.

Sedimentary facies characteristics of Triassic Chang 6 reservoir in Dalugou area, Ordos Basin

WU Chunying，HAN Huiping，JIANG Jihui，WANG Baoqing，JI Haikun，ZHAO Xiaohui，CHEN Juanping

2009, Vol.21(3): 35–39 Abstract ( 527 ) PDF (550 KB) ( 938 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2009.03.007

The sixth member of Upper Triassic Yanchang Formation is the major exploration target zone in Dalugou area, Ordos Basin. Based on the outcrop observation, core description and logging analysis, the sedimentary systems, sedimentarymicrofacies and evolution ofUpper Triassic Yanchang Formation in Dalugou area are analyzed. The result shows that Chang 6 reservoir in Dalugou area mainly developed delta deposit system which includes delta plain facies and delta front facies. Distributary channel and subaqueous distributary channel sandstones are the skeletal sand bodies. In Chang 6 period, the sedimentary microfacies experienced delta front, delta plain to high curvature river of blending load. The distribution of the sedimentary microfacies of each sublayer of Chang 6 reservoir is studied. It is concluded that the hydrocarbon accumulation is controlled by sedimentary microfacies. The subaqueous distributary channel of delta front and distributary channel of delta plain are the most favorable facies belts for reservoir distribution and development.

Characteristics and controlling factors of subaqueous fan reservoir of Shuangyang Formation in Moliqing Fault Depression, Yitong Basin

LIU Guochao

2009, Vol.21(3): 40–44 Abstract ( 460 ) PDF (521 KB) ( 541 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2009.03.008

A great of subaqueous fan sand bodies developed in Shuangyang Formation in Moliqing Fault Depression, Yitong Basin. Based on core observation, thin section analysis and physical property statistics, it is indicated that the subaqueous fan reservoir belongs to low-porosity, ultra-low permeability and thin throat reservoir. The reservoir space types are mainly primary intergranular pore and secondary erosion pore. The rock types are mainly feldspathic litharenite and lithic arkose. The physical property of middle fan reservoir is better than outer fan. According to the reservoir evaluation result, it is shown that the favorable reservoir mainly distributed in the southwest of Kaoshan Sag and in the northeast of Jianshan bulge. The subaqueous fan sand bodies in these areas have good potentials for oil and gas exploration.

Characteristics of gravity flow deposit of the third member of Shahejie Formation in Banqiao-Beidagang area

WANG Chunlian，HOU Zhongjian，LIU Lihong

2009, Vol.21(3): 45–49 Abstract ( 415 ) PDF (402 KB) ( 429 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2009.03.009

Based on the research of the gravity flow deposit characteristics in Banqiao- Beidagang area in Huanghua Depression, the characteristics of gravity flow deposit in the aspects of petrology, texture, structure and biology are detailedly described. According to the study of single well sedimentary section, the general development rule of turbidite is analyzed. Two types of sediment gravity flows are identified, which are deep water turbidite fan and gravity flow channel sediment. The sedimentary mirofacies and sedimentary assemblage are also analyzed, and the turbidite sedimentary sequence model is established. The environment characteristics for sediment gravity flow forming are discussed.

Controlling factors of order degree of dolomite in carbonate rocks：A case study from Lower Paleozoic in Tahe Oilfield and Triassic in northeastern Sichuan Basin

ZHONG Qianqian，HUANG Sijing，ZOUMingliang，TONG Hongpeng，HUANG Keke， ZHANG Xuehua

2009, Vol.21(3): 50–55 Abstract ( 559 ) PDF (408 KB) ( 744 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2009.03.010

As an important mineralogical characteristic, the order degree of dolomite is widely used in the study of dolomite formation mechanism and carbonate reservoir research. Based on the X-ray diffraction analysis of Cambrian-Ordovician carbonatite samples in Tahe Oilfield and Triassic carbonatite samples in northeastern Sichuan Basin, the controlling factors of the order degree of dolomite are discussed. The conclusions obtained as follows: ①The order degree of dolomite is related to its crystallinity. For example, the order degree of the dolomite with ethereal and relatively large crystals is higher than that of micritic dolomite. ②The lower the molar percentage of CaCO3 in dolomite is, the higher the order degree of the dolomite is. ③ The order degree of dolomite undergone dolomitization completely is higher than that undergone incompletely dolomitization. ④In all controlling factors, including other mineralogical elements, crystalline temperature is the most important one. For instance, the order degree of dolomite which formed in high temperature is higher than that formed in lowtemperature. As a result, in regard to dolomitization mechanism, the order degree of dolomite associated with penecontemporaneous dolomitization (seepage reflux dolomitization, evaporationpump dolomitization and so on) is low, while the order degree of dolomite connected with burial dolomitization is high and the order degree of dolomite concerned with dorag dolomitization maybe among the above two.

Mesozoic sequence stratigraphy and sedimentary facies characteristics in northern Bonaparte Basin, Australia

ZHOU Chuan，WANG Yingmin，HUANG Zhichao，CHEN Lingling，WANG Yanqing，ZHUO Haiteng

2009, Vol.21(3): 56–59 Abstract ( 460 ) PDF (584 KB) ( 722 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2009.03.011

Based on the theory of sequence stratigraphy and sedimentology, the characteristics of sequence stratigraphy and sedimentary facies of Mesozoic in northern Bonaparte Basin are studied. The Mesozoic formation can be divided into four second-order sequences and nine third-order sequences, which is classified into two kinds of sequence combination. The lower and middle sequences are dominated by descending cycle, which belongs to typical regression series, while the upper sequence is dominated by rising cycle, which belongs to transgression series. The sedimentary environment changed frommarine facies to fluvial facies then transitional delta facies, eventually neritic facies, forming a whole set of regression and transgression cycle. Finally, it is pointed out that the shore in the eastern slope and the delta and the shore in the Sahul platform are the favorable exploration belts.

Oil and gas distribution and controlling factors of Mesozoic in Mahuangshan area

FENG Yibo，DING Xiaoqi，XIE Shiwen，ZHANG Fawang

2009, Vol.21(3): 60–64 Abstract ( 521 ) PDF (596 KB) ( 426 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2009.03.012

The Mesozoic in Mahuangshan area has a fine hydrocarbon exploration potential in the western margin of Ordos Basin. Based on the analysis of regional structure, core observation and logging, the hydrocarbon distribution, pool forming process and the main controlling factors in different tectonic zones are discussed. It is suspected that lithologic and lithologic-structural reservoirs mainly developed in the structurally stable zones, while fault block and fault-nose reservoirs mainly developed in faulted zones. Oil and gas distribution has a large vertical span with oil on the top and water at the bottom. Oil and gas in the plane mainly distributed in the high structural area or in the axial region of fault anticline, and are mainly controlled by sedimentary facies, diagenesis and tectonic control. The sand of weak cementation and strong dissolution is hydrocarbon-rich site in vertical direction, and so is the sand in distributary channel with strong hydrodynamic in high structural area in the plane.

Oiliness of Chang 6² reservoir in Zhenyuan and Jingchuan area in southern Ordos Basin

GE Pengli，ZHANG Shaonan，DING Xiaoqi，YUE Jinbo

2009, Vol.21(3): 65–69 Abstract ( 500 ) PDF (579 KB) ( 546 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2009.03.013

Yanchang Formation is an important hydrocarbon-exploring layer in Zhenyuan and Jingchuan area in southwestern Ordos Basin. Based on core observation, well log analysis, thin section analysis and conclusion of oil testing, the oiliness of Chang 62 reservoir is discussed. The result indicates that Chang 62 is a delta-lacustrine depositional system, and the principal producing pay is in subaqueous distributary channel where deposit fine sandstones and have good physical properties. The areas in the center of subaqueous distributary channel get high oilproduce while the flanks get lower oil-produce relatively. The distribution of oil layer is mainly controlled by lithology, and Chang 62 is lithologic reservoir developed in the monocline setting which cline to the northwest. Reservoir exploitation presently focuses on the upside ofChang 6 2- 2, and the transition zone carrying remaining oil can be prospected and exploited in the next step.

Sedimentary facies of Upper Triassic Xujiahe Formation in Maliuchang-Datachang area, southern Sichuan Basin

LIU Juan,TIAN Jingchun， ZHANG Xiang,WANG Wenzhi

2009, Vol.21(3): 70–75 Abstract ( 524 ) PDF (834 KB) ( 496 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2009.03.014

Based on detailed field outcrop profiles and the core drilling observation, combining with the rock color, sedimentary structures, profile structures and log facies, the sedimentary facies of Xujiahe Formation in Maliuchang-Datachang area of southern Sichuan Basin is analyzed. There are two kinds of sedimentary facies which are braided delta and lacustrine facies. Furthermore, the braided delta is divided into braided delta plain and braided delta front sub-facies, and the lacustrine facies is divided into coastal lake and shallow lake sub-facies. The characteristics of sedimentarymicrofacies are studied. The study results are useful to detailedly understand the depositional environment during the period ofXujiahe Formation, and provide basic geologic data for oil and gas exploration in southern Sichuan Basin.

Application of logging technology to reservoir description in X gasfield

WANG Hongliang，WANG Jun，YANG Yingbo，LUO XingpingWAN Bingqian，WANG Wei

2009, Vol.21(3): 76–81 Abstract ( 472 ) PDF (666 KB) ( 376 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2009.03.015

The Carboniferous gas reservoir in X gasfield consists of four well blocks: well block X17, X14, X18 and X10. On the basis of lithology research, seven different reservoir matrix parametric charts are established. According to reservoir lithology and differences of the lithofacies characteristics, four types of litho-electrical parameters charts of basalt, rhyolite, irruptive rock, glutinite are set up. Based on the studies of reservoir parameters, a variety ofmethods are used to determine the lower limits of the effective thickness of different lithological division in order to provide accurate reserve parameters on reservoir description. Through coring wells gas saturation analysis and porosity test results, the calculated porosity and gas saturation results meet the error requirements of reserve calculation, which plays an important role in proved reserves calculation of Carboniferous in X gasfield.

Distribution prediction and gas reservoir evaluation of Xing 9 conglomerate body

LIANG Xingru，LUO Yongsheng，DU Xinjiang，XIONG Dongfang

2009, Vol.21(3): 82–85 Abstract ( 467 ) PDF (729 KB) ( 425 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2009.03.016

Based on EPS inversion, AIW wave impedance inversion, multi-attribute analysis and geological statistics, the distribution characteristics, thickness variation, dynamic data and oiliness features of Xing 9 conglomerate body are analyzed. Forecasting techniques and effective evaluation method suitable for Xing 9 conglomerate body are proposed. The good result has proved the validity of this method.

Application of stochastic simulation in Oued Mya Basin, Algeria

GAO Jinyu，MA Mingfu，SHA Xuemei4，ZHANG Jing

2009, Vol.21(3): 86–89 Abstract ( 615 ) PDF (496 KB) ( 577 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2009.03.017

Stochastic simulation method is an effective reservoir prediction technique based on geological statistics. Based on seismic, geology and logging, and combined with geological model, it is applied to carry out the simulation of reservoir distribution. According to the analysis of log response and physical properties, we select reasonable inversion parameters to carry out stochastic inversion and lithology modeling, and then predict the distribution of favorable reservoir. Study and practical application showthat stochastic simulation method can improve the inversion resolution. This method is used in the prediction of reservoir distribution and physical properties ofDevonian in OuedMya Basin in Algeria, and good result has been proved.

Four properties characteristics of JZ25-1S buried hill metamorphic reservoir in Liaodong Bay

HAN Xuefang，ZHU Xiaomin，DONG Yanlei

2009, Vol.21(3): 90–93 Abstract ( 563 ) PDF (399 KB) ( 432 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2009.03.018

According to the analysis of core, conventional log and formation micro-resistivity scan, the four properties (lithologic characteristic, physical property, oiliness and electrical property) characteristics and the relationships among them of JZ25-1S buried hill metamorphic reservoir in Liaodong Bay are studied based on the theory and method of lithology, reservoir geology and well-logging geology. The lithology of JZ25-1S ribbons with dominated gneiss and cataclasite and partlymetamorphosed granite. Cataclasite and metamorphosed granite have good oil-bearing probability, while gneiss is poor. The laboratory test reveals that reservoir properties of JZ25-1S buried hill are relatively good, but still very heterogeneous. The favorable reservoirs are characterized by obvious positive separation in dual lateral log, high in acoustic log and neutron log and low in density log. The thickness of the favorable metamorphic reservoirs in JZ25-1S buried hill is thin in the west and thick in the east. This comprehensively study of the four properties characteristics of JZ25-1S buried hill metamorphic reservoir is favorable for exploration activity in this area.

Application of crossplot technique to identify lithology of igneous rocks in Santanghu Basin

CHEN Rong，GAO Chuqiao，JIN Yunzhi

2009, Vol.21(3): 94–97 Abstract ( 525 ) PDF (375 KB) ( 614 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2009.03.019

Santanghu Basin is located in Xinjiang, northwest China, where developed huge area and various system of igneous rock formations. The conventional log data and ECS (Elemental Capture Spectroscopy) data are analyzed. Combined with the rock section analysis and sample log data, the log response characteristics of basalt, andesite, tuff, diabase, sandstone and mudstone in the study area are summed up. The physical quantities and parameters sensitive to igneous rock lithology are selected tomake crossplot for lithology identification. A set of lithologic chart suitable for this area is set up and the log parameters for different lithologies are determined.

Using Walsh transform to improve signal-to-noise ratio of seismic data

XU Yunxia，WANG Shanshan，YANG Shuai

2009, Vol.21(3): 98–100 Abstract ( 373 ) PDF (477 KB) ( 596 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2009.03.020

The filter technique based on Walsh transform is used to suppress seismic noise in order to improve the signal-to-noise ratio of seismic data. This method uses the spectrum analysis of seismic signal to realize the noise suppression. Through estimation of theoretical model and application in the real seismic data, this method has a nice effect in elimination the noise of seismic data. This method is very simple to realize and very fast to calculate. It has a good practicability in suppressing noise and increasing the signal-to-noise ratio of the seismic data.

Grey comprehensive evaluation method in the optimization of fracturing well

OUYANG Chuanxiang，TU Zhiyong，FU Rong

2009, Vol.21(3): 101–104 Abstract ( 369 ) PDF (265 KB) ( 634 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2009.03.021

The mathematical model of grey comprehensive evaluation is introduced. Grey correlation analysis method is used to confirm the importance degree of all the selected projects and the optimal decision is then obtained. The selecting of appropriate well for fracturing is the basic condition to obtain nice commercial efficiency. At present, it depends on the expert experience in oilfield to select fracturing well, which has certain blindness. The factors affecting the fracturing effect are mainly geologic factor, construction factor and other human factor, of which the relations are complex and nonlinear. The geologic factor is mainly considered and the analytical hierarchy process is applied to determine the weight of the factors. Grey correlation analysis method is used to analyze the correlation between the selected well and optimum well, and then optimize the appropriate wells for fracturing. This method is applied in Huangchang block in Jianghan Oilfield, and the result proves the effectiveness.

Oil production decline law of Wa 20 block in Dawa Oilfield

HE Dezhi

2009, Vol.21(3): 105–107 Abstract ( 478 ) PDF (206 KB) ( 781 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2009.03.022

The three production decline formulas proposed by J. J. Arps and the extended two production decline formulas are applied to carry out the production decline regression in Wa 20 block in Dawa Oilfield. The correlation coefficients of several regression equations are all greater than 0.8, and the results are close to the actual production. Typical hyperbolic decline is selected to forecast the future production decline situation. Aimed at the status quo of the oilfield development, the counter measure is put forward to slow the production decline.

Application of Logistic model based on grey system modeling in oil-gas field development

WEN Hua，SUN Na，TIAN Huafeng

2009, Vol.21(3): 108–110 Abstract ( 416 ) PDF (251 KB) ( 443 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2009.03.023

The accurate forecasting of oil-gas field output is very important to the oil-gas field development. But the oil gas field development is an extremely complex non-linearity successional process. Based on the growth rule of the natural biology, the Logistic forecast model for forecasting oil-gas field output is established, and the Logistic model parameters are estimated by grey systemmodeling. The application practice indicates that the Logistic model based on grey systemmodeling has higher forecast precision than regression parameter estimation method, and has better forecast effect.

Influencing factors of productivity in gas well and gas condensate well

LI Hua，LIU Shuangqi，ZHU Shaopeng

2009, Vol.21(3): 111–113 Abstract ( 433 ) PDF (211 KB) ( 549 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2009.03.024

In the development of gas reservoir and condensate gas reservoir, absolute open flow and reasonable deliverability of single well are very important parameters, which directly affects the feasibility of the development of gas well and condensate gas well and the development scale of the whole gas field. There are many parameters that affect the deliverability in gas well and condensate gas well, and some parameters are uncertain. Howto evaluate these parameters is very important for confirming the absolute open flow of gas well and condensate gas well. An analytic method of deliverability parameter based on orthogonal test is introduced, and some important factors that are uncertain are studied and selected. This study provides a newmethod and technical support for deliverability evaluation of gas well and condensate gas well.

Well test analysis of unconsolidated sandstone gas reservoir in consideration of stress sensitivity

SHI Ying，YAN Fei，LI Xiaobo，GAO Zeli，ZHONG Jie，XIE Shishu

2009, Vol.21(3): 114–117 Abstract ( 500 ) PDF (382 KB) ( 561 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2009.03.025

Due to the rock skeleton structural deformation and body deformation in the exploitation of unconsolidated sandstone gas reservoir, permeability and porosity become lower and make strong stress sensitivity，which results in that the well test data can not be accurately explained by the conventional well test model. A mathematical model of homogeneous circular gas reservoir with closed border in consideration of stress sensitivity is presented, and the typical curves are analyzed. The research shows that the stress sensitivity appears in the latter part of the pseudo-steady stage, and the index change in relations between permeability and pressure has a clear impact on the dynamic test results only when B>0.1MPa- 1. The upwarping feature of pseudo-pressure is similar to the well test model of sandstone gas reservoir which does not have stress sensitivity and impermeable boundary. The well test model which considers the stress sensitivity can be used to analyze the well test data in unconsolidated sandstone gas reservoirs and provides some guidance for these reservoirs exploitation.

Numerical simulation study of three-dimensional two-phase black oil model in fractured low permeability reservoirs

YANG Kai，GUO Xiao

2009, Vol.21(3): 118–121 Abstract ( 623 ) PDF (358 KB) ( 996 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2009.03.026

Alarge number of experimental and field data showthat starting pressure gradient exists in low permeability reservoirs and fracture is more sensitive than the matrix for stress. Based on dual porosity/dual permeability Darcy seepage flow mathematical model, pressure gradient and stress sensitivity are introduced. A seepage flow model in fractured low permeability reservoir is established, and a full-implicit simultaneous solving and examples calculation are carried out.

Query about petroleum downward migration

ZHANG Jinglian

2009, Vol.21(3): 122–128 Abstract ( 461 ) PDF (465 KB) ( 588 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2009.03.027

Petroleum migration is an important issue in petroleum geology, and petroleum downward migration is a controversary figure. Taking the Weiyuan Gasfield in Sichun Basin, Xifeng Oilfield and Jinybian Gasfield in Ordos Basin and Fuyang reservoir in Songliao Basin as examples, the probability of deep source oil and gas which could migrate upward and accumulate in some traps is analyzed. The concept of petroleum downward migration violates the fundamental lawof physics by which the oil and gas always migrate upward from belowdue to the buoyancy action. If the viewpoint of petroleum deep source is recognized, the petroleum exploration targets could be expanded, which provides theoretical foundation for the exploration of basement reservoirs.

Hydrocarbon accumulation mechanism of lithologic reservoir of Chang 8 member in Jiyuan area, Ordos Basin

SHI Jiannan，ZHENG Rongcai，HAN Yonglin，WANG Haihong，WANG Chengyu，NIU Xiaobing，LIANG Xiaowei，XIN Honggang

2009, Vol.21(3): 129–133 Abstract ( 518 ) PDF (560 KB) ( 862 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2009.03.028

The accumulation mechanismof lithologic reservoir in tight sandstone gradually becomes the main difficulties and frontier areas for exploration arrangement in Yanchang Formation ofOrdos Basin. Based on the analysis of potential source rock and oil-to-source correlation, combined with pressure field evolution, fluid dynamics and fluid kinematics, the accumulation mechanism of lithologic reservoir of Chang 8 member is discussed by using petrology and advanced techniques used in geochemistry and basin numerical simulation. The results show that the hydrocarbon of Chang 8 member mainly originated fromthe generating organic matter in Chang 7 and Chang 8 member ofYanchang Formation. Reservoirs of Chang 8 member take on two-stage charging processes, and the main charging time is in late Early Cretaceous (105～95 Ma). Since 210 Ma, the pressure field evaluation experienced three processes: early increase, middle quick increase and late reduce. Moreover, the broad hydrocarbon generation in Early Cretaceous and the tectonic compression inMiddle-Late Yanshanian are the main formation mechanismfor overpressure. The accumulation model of lithologic reservoir in Chang 8 member presents near-source charging, latent conduit and rapid accumulation.

Calculation of rock compressibility and the impact on gas reservoir numerical simulation

LEI Fangfei， HE Chengcai

2009, Vol.21(3): 134–137 Abstract ( 512 ) PDF (279 KB) ( 567 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2009.03.029

Rock compressibility is an important parameter in gas reservoir engineering. It affects the results of gas reservoir numerical simulation. At present, there are many calculation methods of rock compressibility. In the mine field, the most commonly used method of calculation is Hall Plate empirical formula. But there is a wide gap between its results and the actual. The Hall Plate empirical formula and the elastic modulus method are comparatively analyzed, and the impacts of different calculation methods on gas reservoir numerical simulation results are studied. If rock compressibility is calculated by the elastic modulus method, its results are relatively reasonable. But if it is calculated by the Hall Plate empirical formula, the value of rock compressibility is too large. That’s to say, it overvalues the elastic energy of formation rocks. And the velocity of pressure drawdown of the gas reservoir numerical simulation is caused to be too slow.