Lithologic Reservoirs

Petroleum seismogeologywas developed in the early 1980’s and advanced with the development of geophysical technologies. Its goal is to find hydrocarbon reservoir and to improve the recovery ratio. Because of the lack of independent theory, it is nownot a real discipline but an integration of geophysical technologies for petroleum geology study and reservoir description. It has three characteristics, including multi-technology integration, well-seismic integration and refining study, as well as study frompetroleum exploration to development geology. There are three key points which influence the development of petroleum seismogeology. They are seismic resolution, geological meaning of seismic reflection data and geologic model in seismic interpretation. Although it made successful use in petroleum exploration and development, petroleumseismogeology study need improvement in four aspects in the future, including: ① The development of systematized theory; ② Integration of multi-discipline and multi-scale study; ③ Isochronic strata units and their seismic reflection characteristics;④Study fromreservoir description to hydrocarbon detection.

Seismic response characteristics and identification method of fracture-cavity reservoir

SA Liming， YAO Fengchang， DI Bangrang， YAO Yao

2011, Vol.23(1): 23–28 Abstract ( 577 ) PDF (1224 KB) ( 655 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2011.01.002

Aimed at the identification difficulties and present situation, the identification of carbonate fracture-cavity reservoir is discussed in the aspects of theory and actual application. The studies on fracture-cavity reservoir identification completed by the authors in recent years are summarized, including physical simulation and numerical simulation of fracture-cavity reservoir model, seismic wave field analysis and the identification method of fracture-cavity reservoir, as well as the case of successful identification of fracture-cavity reservoir fromwestern China.

Relation of matching type of gas accumulation and loss ability with gas reserves abundance in Xushen Gasfield

FU Guang, WANG Xin

2011, Vol.23(1): 29–33 Abstract ( 410 ) PDF (420 KB) ( 424 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2011.01.003

Based on the characteristics of displacement pressure caprocks and remaining pressures of reservoirs, the relation ofmatching type of gas accumulation and loss ability with reserves abundance is studied. The result shows that matching type of strong gas accumulation and poor loss ability is favorable for gas accumulation, followed by strong gas accumulation and mediumloss ability and better gas accumulation and poor loss ability. It is considered that there are 5 matching types of gas accumulation and loss ability of 19 gas reservoirs in Xushen Gasfield. The most is the matching type of strong gas accumulation and better loss ability, and the second is the matching type of strong gas accumulation and medium loss ability. Among the 19 gas reservoirs in Xushen Gasfield, those with medium gas reserves abundance are the most, while those with high and lowgas reserves abundance are relatively less. It is considered that the matching type of strong gas accumulation and medium loss ability and the matching type of better gas accumulation and medium loss ability are the best matching types for forming gas reservoirs with high gas reserves abundance in Xushen Gasfield.

Diagenesis of Triassic Zhongyou Formation and its influence on physical properties in AT1 area, Tahe Oilfield

LI Zijia，ZHANG Zhiqiang，FU Guomin

2011, Vol.23(1): 34–38 Abstract ( 509 ) PDF (614 KB) ( 392 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2011.01.004

Based on cast thin section, scanning electron microscope, electron microprobe and X- diffraction analysis, the diagenesis of Triassic Zhongyou Formation and its influence on physical properties in Tahe oilfield are studied. It is believed that Zhongyou Formation has lowcompositional maturity and textural maturity. The reservoir is mainly at late disgenesis stage A with complicated epidiagenesis. Compaction can reduce the porosity, while denudation is constructive to the increase of porosity.

Reservoir prediction constrained with high resolution sequence stratigraphy and exploration prospect of lithologic reservoirs in SZ36-1S area in Bohai Bay

WANG Bo， WANG Yuhuan， ZUO Yujie

2011, Vol.23(1): 39–41 Abstract ( 495 ) PDF (421 KB) ( 858 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2011.01.005

Based on seismic data, well logging and drilling data, under the guidance of high resolution sequence stratigraphy, the base level cycles in the SZ36- 1S area are divided into four mid-term cycles and 13 short-term cycles. Making the short-term cycle as the basic time stratigraphic unit, the high resolution sequence stratigraphic framework in SZ36- 1S area is established based on well tie sequence stratigraphy contrast. Combined the seismic attribute analysis and wave impedance inversion data, the distribution of sand bodies is predicted and the main controlling factors for sand bodies are analyzed, which designates the direction for the further oil and gas exploration .

Analysis of sequence stratigraphic framework and model of Badaowan Formation in Bohu Depression of Yanqi Basin

HUA Caixia， LI Xiaogang， ZANG Suhua

2011, Vol.23(1): 42–46 Abstract ( 414 ) PDF (591 KB) ( 656 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2011.01.006

The principle of sequence stratigraphy and line drawing method of seismic-reflection profile are applied to establish the sequence stratigraphic framework of Jurassic Badaowan Formation in Bohu Depression of Yanqi Basin. The Badaowan Formation is divided into three third-order sequences, including SQ1, SQ2 and SQ3 from base to top, of which the stratigraphic framework characteristics are analyzed respectively. The sequence stratigraphic model is established and the direction of oil and gas exploration is indicated. The research result shows that the LST is generally not developed widely in those three sequences within the Badaowan Formation, while the TST and HST are well developed; the depositional systems are mainly braided river delta, fan delta and lacustrine deposit and their distributions are mainly controlled by the morphology of the basin.

Fracture characteristics of Carboniferous volcanic reservoirs in Hongche fault belt of Junggar Basin

YUAN Yunfeng，CAI Ye，FAN Zuochun，JIANG Yiyang，QIN Qirong， JIANG Qingping

2011, Vol.23(1): 47–51 Abstract ( 527 ) PDF (816 KB) ( 681 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2011.01.007

Based on core observation, well drilling and image logging data, the fracture characteristics of Carboniferous volcanic reservoirs in Hongche fault belt of Junggar Basin are studied. The result shows that fractures in volcanic reservoirs are well developed. They are mainly structural fractures formed in the tectonic movement, and most of themare filled with some kinds of solid minerals, which affects the effectiveness of the fractures to petroleum accumulation and migration. The main fracture directions are NNE and NNW, consistent with outstanding tectonic direction. According to the fracture characteristics and origin, the fractures are divided comprehensively. The relation between fracture and tectonic movement is discussed, and it is recognized that the four stages of fracturing are corresponding with the tectonic movement. Fractures mainly distributed at the depth of 250 meters under the top of Carboniferous in the vertical, and concentrated in Hongche fault belt and around secondary fault in the plane.

Study on characteristics and distribution of Archaeozoic reservoir in Dongying Sag

LI Bo， TIAN Meirong， ZHANG Fan， XU Bing， WANG Xingzhi

2011, Vol.23(1): 52–56 Abstract ( 508 ) PDF (563 KB) ( 522 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2011.01.008

The rock type, reservoir space and physical property of Archaeozoic reservoir are studied by means of core observation, thin section and logging analysis. The result shows that Archaeozoic reservoir rocks are mainly composed of granitic rock, dioritoid and dike rock; the reservoir space of Archaeozoic burial hill is mainly fracture; emposieu pore and eluvial pore are valid for oil and gas accumulation; the Archaeozoic reservoir belongs to fractured reservoir with strong heterogeneity both in vertical and areal, and mainly developed in three intervals （the range from 0 to 30 m, from 30 to 60 mand from60 to 120 m） under the apex face of burial hill and distributed around burial hills presented in banded in the plane.

Sedimentary facies and lithofacies characteristics of modern Chaobai River

GUO Ling，JIANG Zaixing，XU Jie

2011, Vol.23(1): 57–61 Abstract ( 447 ) PDF (485 KB) ( 660 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2011.01.009

The lithofacies and sedimentary facies of modern Chaobai River in Baimiao（Tongzhou district in Beijing） are detailedly studied by digging deep trenches, pits and field profile. It is shown that Baimiao is a meandering river sedimentary body. Eight lithofacies are identified, and they are massive bedding fine conglomerate（clay gravel-based）, large-scale low-angle trough cross bedding fine sandstone，low-angle trough cross bedding fine-grained sand-stone, synsedi-mentary distortion bedding fine sandstone, parallel bedding fine sandstone, tabular and wavy cross bedding fine sandstone, thin massive bedding siltymudstone and fine sandstone and massive beddingmuddy siltstone. Two subfacies developed and they are river channel and flood plain sub-phase. Five kinds of microfacies named riverbed, point bar,levee, crevasse splay and floodplain developed in Chaobai River in Baimiao. Sedimentary body of Chaobai River developed three sedimentary cycles in vertical and they are controlled by sediment supply, climate and quality of river banks. The analysis of lithofacies and sedimentary facies is significant for finding lithologic reservoir and the development and utilization of Chaobai River.

Study on system and method of ranking coalbed methane development perspectives

KANG Yuanyuan，SHAO Xianjie，SHI Lei，SHAN Yu，YU Hang

2011, Vol.23(1): 62–66 Abstract ( 481 ) PDF (394 KB) ( 715 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2011.01.010

Although the study on coalbed methane（CBM） has lasted for 20 years in China, the ranking systemof CBM perspectives has not been established, which restricts the large-scale industrial development of CBM. Based on a large number of basic information and former researches on CBM, the influences of geological factors in coal reservoir on the enrichment abundance and the development effect of CBMare analyzed detailedly, and the relevant assessment index system for CBMperspectives is built up. The weight value is determined by AHP and a group of processing functions have been designed for different types of indices. The weighted average model is used to comprehensively evaluate the perspectives. Finally, some CBMregions in China are comprehensively evaluated. The practical application has a good result, so it can be used to effectively guide the exploration and development of the coalbed methane.

Main controlling factors of hydrocarbon accumulation of Middle-Lower Triassic in western margin of western Sichuan Depression

SONG Xiaobo， LIU Shirong， WANG Qiongxian， DENG Daping

2011, Vol.23(1): 67–73 Abstract ( 480 ) PDF (924 KB) ( 508 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2011.01.011

The western Sichuan Depression has superior geologic condition of oil and gas，where has discovered many marine gas reservoir, so it is an area with gas prospecting potentia1. But in the recent twenty years, the exploration of marine carbonate reservoir did not get breakthrough, and the exploratory extent is low. The typical structural gas reservoirs in northern, middle and southern part of western margin of western Sichuan Depression are analyzed respectively. It is proposed that the development of high quality shoal facies reservoir is the basement for hydrocarbon accumulation, and the preservation condition is the key for hydrocarbon accumulation of Middle-Lower Triassic in western margin ofwestern Sichuan Depression.

Sedimentary environment of Paleogene in Xihu Sag：Microfossil as the main foundation

JIANG Haijun，HU Mingyi，HU Zhonggui，KE Ling，XU Yanxia，WU Lianqian

2011, Vol.23(1): 74–78 Abstract ( 595 ) PDF (509 KB) ( 709 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2011.01.012

The group of Paleogene in Xihu Sag in Donghai Basin contains Huagang Formation，Pinghu Formation and Baoshi Formation，which not only are the important layers but also the layers where hydrocarbon source rocks developed well. Predecessors made a great deal of studies on sedimentary environment in Xihu Sag， but different people have different view-point to Pinghu Formation. Through the study on themicrofossil data （spore and pollen，calcareous nannofossils， ostracods，oraminifera， pediastrum，marine dinoflagellates etc.） in BS- 1，CHX- 1，TWT- 1， DQ- 1，PH- 1 and NB2- 1- 1 well in Xihu Sag, it is believed that Huagang Formation should be terrestrial deposit, with marine deposit in middle and lower part and terrestrial deposit in the upper part, and Baoshi Formation should be terrestrial deposit. It is deduced that Paleogene should be the subtropical climate.

Analysis on petroleum preservation condition in the coupling area between Longmen Mountain and Sichuan Basin

ZHAO Jiancheng， LIU Shugen， SUN Wei， DAI Hansong， ZHANG Zhijing， DENG Bin

2011, Vol.23(1): 79–85 Abstract ( 398 ) PDF (871 KB) ( 497 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2011.01.013

The coupling area between Longmen Mountain and Sichuan Basin across western Sichuan Depression and Longmen Mountain mainly includes the front range and the front of Longmen Mountain, and the two parts are separated by the Guanxian- Jiangyou （Guankou） fault. Due to multiple phase of thrust nappe, there developed a large number of faults in the coupling area, and the strata suffered from erosion. Therefore, the petroleum preservation conditions are crucial for the petroleum exploration in this area. Based on the distribution of caprocks, fluid pressure and surface bitumen, combined with earthquake epicenters distribution, the petroleum preservation conditions in the coupling area are analyzed. And it is concluded that: it suffered from uplift-erosion in the hanging wall of Guanxian- Jiangyou fault, and large area of the Late Paleozoic strata outcropped, so the petroleum preservation condition here is destroyed; there exists gypsum mudstone in the footwall of Guanxian- Jiangyou fault, so the petroleum preservation condition of deep marine layers is well, therefore, it is favorable exploration area; the strata developed completely in the front of Longmen Mountain, so the petroleum preservation conditions is well.

Application of facies-controlled modeling to reservoir description in Honglian Oilfield

XIE Ruijie， ZHANG Yan-wen， QIN Gang， LUO Xuan

2011, Vol.23(1): 86–89 Abstract ( 517 ) PDF (393 KB) ( 555 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2011.01.014

Hongnan 9 block in Honglian Oilfield has complicated structure and oil-gas-water relation. TakingK1sⅡ- 6 individual layer in Hongnan 9 block as an example, based on structure interpretation, logging data processing and interpretation and sedimentary microfacies study, the structural model, sedimentary microfacies model and attribute model controlled bymicrofacies are established bymodeling technology, which provides geological model for numerical simulation and also provides geologic foundation for the development of remaining oil in Hongnan 9 block.

Study on azimuthal anisotropy of converted wave in fracture medium

LIU Kaiyuan

2011, Vol.23(1): 90–93 Abstract ( 447 ) PDF (472 KB) ( 576 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2011.01.015

Based on Thomsen fracture theory, the converted wave approximate reflection coefficient of in weak anisotropic HTI media is introduced. Through AVO forward modeling, the influences of the anisotropy coefficient on P- SV wave reflection coefficient and P- P wave approximate reflection coefficient are analyzed and compared. The result shows that combining P- P wave and P- SVwave data to carry out inversion can get more accurate fracture parameters.

Seismic response of 40m caves with different distances from limestone top bounday

SUN Dong， WANG Hongbin， YONG Xueshan， ZHANG Huquan， GAO Jianhu， DONG Ruixia

2011, Vol.23(1): 94–97 Abstract ( 534 ) PDF (883 KB) ( 593 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2011.01.016

The Upper Ordovician reservoirs mostly are close to the limestone top boundary where seismic reflection is strong, which causes influence on the seismic response of the reservoir. Forward modeling result shows that: the seismic reflection at the limestone top boundary is absent or decreased obviously with disorder inside reflection when the distance from fracture-cavity to the limestone top boundary ranges from 0 to 30 m; the seismic reflection at the limestone top boundary softens with strong inside reflection when the distance fromfracture-cavity to the limestone top boundary is 60m; the seismic reflection at the limestone top boundary has no change when the distance from fracture-cavity to the limestone top boundary is over 150 m, and the inside reflection presents moniliform. Based on the fine calibration of the actual drilling, the forward modeling result is verified.

Permeability prediction method based on improved BP neural network

YANG Jian，YANG Chengbo，ZHANG Yan，CUI Ligong，WANG Longfei

2011, Vol.23(1): 98–102 Abstract ( 514 ) PDF (548 KB) ( 775 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2011.01.017

The traditional BP algorithmhas slowconvergence rate, and is easy to fall into local minimum. It is improved based on Kozeny-Carman equation and the study of Yang Zhengming, and a three-layer feedforward BP neural network model for permeability prediction is established bymeans ofMATLAB neural network toolbox. The simulation training of the improved neural network model is carried out. The result shows that the improved model has faster convergence rate and higher accuracy. The values predicted by the model are consistent with the laboratory test values, and the relative error is less than 10%, so it can completelymeet the accuracy demand ofwell site.

Improved method of particle swarm impedance inversion and its application

WANG Li， WANG Shanshan， YANG Wei

2011, Vol.23(1): 103–106 Abstract ( 406 ) PDF (463 KB) ( 436 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2011.01.018

A new method of particle swarm optimization（PSO） impedance inversion is proposed because of the short comings of conventional PSO algorithm which has slow convergence rate and low inversion efficiency. The algorithm uses PSO algorithm to calculating the sample number and impedance for each layer of the model, and then uses the scanning method to obtain the optimal number of the layer. Compared with conventional PSO algorithm, the examples of synthetic data showthat the method significantly improves the inversion accuracy and convergence rate, and the actual data also proves the validity of this method.

Application of grey relational analysis to confirm influencing factors for gas reservoir recovery

YANG Qianqian， LI Xiangfang， WU Qiong

2011, Vol.23(1): 107–110 Abstract ( 439 ) PDF (290 KB) ( 385 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2011.01.019

The stage gas reservoir recovery is closely related to its ultimate recovery. In order to analyze the effects of production wells, formation pressure drop, gas production rate and annual output on the stage recovery, the gray relational analysis method is introduced and applied to confirm the influence of all selected factors. The factor affecting gas reservoir recovery is mainly development technique, and the grey relational analysis theory is a suitable method for it. The grey slope correlation degree method is chosen to compute the correlation degree, make them in sequence, and then determine the primary and secondary influencing factors. Case analysis result shows that the grey relational analysis method can be applied to quantitatively analyze the influencing factors for stage gas reservoir recovery. The method is simple in principle and calculation, and has no special requirements for the types of data distribution and the types of variables. The analysis result provides a certain basis for further optimizing gas reservoir development technologies and realizing advisable and efficient development of the gas reservoir.

Calculation methods of rational infill well number in water drive field

YU Chenglong， LI Huimin， ZHAO Min， LUO Chihui

2011, Vol.23(1): 111–113 Abstract ( 523 ) PDF (213 KB) ( 876 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2011.01.020

Well pattern infill can improve the effect of oilfield development and enhance oil recovery. The denser the well spacing density is, the better the effect of oilfield development will be. There are manymethods for calculatingwell spacing density at present, but only a few methods are suitable for calculating the reasonable well numbers of well pattern infill and economic limit well number in water drive field. Based on В. Н. шелкачев formula, the net present value formula is applied to deduced the theoretical calculation formula for reasonable well numbers ofwell pattern infill and economic limit well number in water drive field. The application result shows that the calculation result is reasonable, and this method can provide theoretical support for well pattern infill in oilfield.

Using grey correlation analysis method to optimize fractured well in Daniudi Gasfield

LI Guofeng1， LI Guofeng， WANG Dean， CHENG Yong， SU Rong， LI Yueli， WANG Wenqing

2011, Vol.23(1): 114–117 Abstract ( 422 ) PDF (278 KB) ( 432 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2011.01.021

Daniudi Gasfield is characterized by multi-layers in vertical, large interval between layers, tight reservoir and low deliverability of single layer, even no natural deliverability without fracturing. The grey correlation analysis method is used to optimize the factors which affect the well selection in fracturing. The level analysis principle of system engineering which takes the complexity and malconformation of each factor into consideration is applied to ascertain the weight of each factor. The application result proves the scientificity and applicability of this grey correlation analysis method.

Application of multilateral well technology to development of heavy oil fields in the Bohai Sea

ZHANG Yingchun， ZHAO Chunming， LIU Xin， LI Yunpeng， TONG Kaijun

2011, Vol.23(1): 118–122 Abstract ( 484 ) PDF (604 KB) ( 538 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2011.01.022

The heavy oil fields in the Bohai Sea are characterized by low productivity. The heavy oil area of SZ36- 1 Oilfield is chosen for a pilot area which aims at improving both well productivity and ultimate recovery efficiency. Based on the existing inverted nine-spot pattern, five multilateral wells are located in the stably distributed sands with relatively thicker pay zones where put into production along with those existing directional well. It has been proven to be successful with the productivity of a multilateral well as high as 90 to 150 m3/d, which is 3 to 4 times than that of a directional well. Reservoir numerical simulation result shows that the increment of the ultimate recovery efficiency in pilot area could reach as much as 4%. The successful drilling and developing ofmultilateral wells breaks a new path to efficiently develop heavy oil fields.

A method for improving calculation accuracy of static pressure at bottom hole of gas well

GUO Jing， HUANG Zhaoting， LU Hongjiang， YUAN Qingyun， JIANG Xue， ZHANG Junjie

2011, Vol.23(1): 123–126 Abstract ( 489 ) PDF (279 KB) ( 557 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2011.01.023

The methods for calculating static pressure at bottom hole in the past do not take the varying temperature, pressure and gas components into consideration. According to the variation range of temperature and pressure, different computation models of gas deviation factor are applied to calibrate the critical parameter of acidic gas with high content of hydrogen sulfide, so as to improve the calculation accuracy of gas deviation factor. And based on the above-mentioned method, the static pressure at bottomhole is calculated. The actual data shows that a relative high accuracy is obtained.