Journal of Southwest Petroleum University(Science & Technology Edition)

The Mechanism of Alkali Sensitivity in Carboniferous Donghe Sandstone Reservoir of Donghetang Structure in Tarim Basin

Sheng Mingdao;Tang Hongming;Kang Yili;Xiong Youming

1998, 20(1): 1-5. DOI: 10.3863/j.issn.1000-2634.1998.01.001

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In drilling and production operations, formation damage may occur when the drilling fluid is incompatible with sensitive components in a reservoir. In this paper, the interaction between high pH fluids and the Carboniferous Donghe sandstone reservoir in the Tarim Basin is investigated. Combined with core-flood tests for sensitivity evaluation, petrographical analyses were made on more than 200 samples from the reservoir. The results indicate that the higher the PH of the fluids, the severe the formation damage is. High PH fluids not only cause dispersion/movement of the clay, but also result in partial dissolution/precipitation of certain minerals, leading to drastic decrease in permeability. In addition, the level of formation damage involving alkali sensitivity is also related to the salinity and velocity of the test fluid.

A Study of Fractures in Extreme-low Permeability Sandstone Reservoirs in Baka Oilfield, TurpanHami Basin

Zhao Zhigang Li Ming Zhao Xiaojun Lu Yushe Huang Qizhi

1998, 20(1): 6-10. DOI: 10.3863/j.issn.1000-2634.1998.01.002

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The producing mid-Jurassic sandstones in the Baka oilfield have an average matrix permeability of 0.3×10-3μm2.Within these sandstones four kinds of fractures have been recognized. With fractures providing the major passage for fluid flow, these sandstone reservoirs fall into the fractured-porous category. Field survey and statistical data from core measurements indicate that the distribution of fractures is principally controlled by lithology, bed thickness and stress conditions, the geometry of matrix blocks is a function
of fracture type and the combination of fracture types, and the size of matrix blocks is controlled by the frequency of fractures. The conceptual model of fracture distribution is proposed.

The Formation damage due to the Re-distribution of Stress Around a Hole

Duan Yuting

1998, 20(1): 11-15(2. DOI: 10.3863/j.issn.1000-2634.1998.01.003

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The stress around a hole will re-distribute after the hole has been drilled, due to the loss of original stress balance, There exists a plastic zone around hole for the poorly consolidated sand formation, The zone near well bore gas the lowest permeability because of the invasion of drilling fluid, solid particles. and the influence of plastic deformation, There exist three different ermeability zones around wellbore, damaged zone having plastic feature, plastic zone, and elastic zone. The plastic zone will extend for width when the fluid
flows into the well, and cause formation damage aggravation. The critical flow rate depends On the permeability of damaged zone,formation consolidation and the viscosity Of formation fluid.

On the Improvement to the Partition Method of Reservoir

Wei Yong Li Yun

1998, 20(1): 16-20. DOI: 10.3863/j.issn.1000-2634.1998.01.004

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This paper presents studies on the improvement to the partition method of reservoir. A new partition method of reservoir is achieved,which can overcome all the defects of the common methods. The partition system produced by the new method has nothing to do with the ordinal number of the points. and the partition system are completely controlled by the standardδ. Meanwhile the method is raised to tell if the standard of partition system is appropriate.

An Evaluation of the Factors Affecting Reservoir Property for Xinkai Area

Zhong Dakang Chen Jingshan Lin Weicheng

1998, 20(1): 21-24. DOI: 10.3863/j.issn.1000-2634.1998.01.005

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The petrophysical character of reservoir rocks of different facies, different areas and different depths in Xinhai Area, Liaohe Oilfield was investigated. Analyses were made on the relationship between petrophysical parameters and rock components and fabric, facies and burial depth. Examination was carried out on pore cast thin sections of selected reservoir samples. The results lead to the conclusion that factors affecting the quality of reservoir rocks in the studied area include depositional conditions, compaction, dissolution and post-solution cementation, among which, dissolution and post-solution cementation are most important, compaction is less and depositional condition least.

Design and Realization of Information System Integrated Project for Oil/Gas Exploration and Exploitation

Chen Mingqiang Li Yun Huang Chunguo Yan Yongsheng

1998, 20(1): 25-28. DOI: 10.3863/j.issn.1000-2634.1998.01.006

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Along with the advancement of science and technology, and its widely application in various scopes, information processing technique have bring up great benefit to factory, cooperation, and all other fields. According to the requirements of oil and gas industry and the characteristics of petroleum exploration and development information, we presented a petroleum exploration and development information system integrated project which runs in distributed Client/Server network model with distributing, isomers, exoteric, based on YHCSBroker integrated agent.

A Study on the Effect of Adsorption for Reserves in Place in Gas Condense in Place in Gas & Gas Condense Reservoirs

Guo Ping Sun Liangtian Sun Lei Li Shilun

1998, 20(1): 29-33(3. DOI: 10.3863/j.issn.1000-2634.1998.01.007

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This paper raises a theoretical model, which considers the effect of adsorption on reserves in place. The Movable Adsorption Model in chemical industry is adopted to calculate the adsorption of gas in gas reservoirs. At first, we simulate the single component adsorptive experiment data so as to gain some basic parameters and apply the experimental data of a two components system to exam the adsorptive model. Then we gain the fundamental parameters on the basis of simulating the real single component adsorptive experiment data or the spread theory of adsorption of single component in more actual porous media by Clark, a actual multi Component natural gas
system and a gas condense system are calculated respectively as examples. At the end, we give the tendency and extent of the effection reserves in place under different formation conditions such as systems, porous media and others.

A Study of the Gas-pool Forming Conditions in Daan-Xingzhao Region of Songliao Basin

Lou Qun

1998, 20(1): 34-37. DOI: 10.3863/j.issn.1000-2634.1998.01.008

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Natural gas distribution in Daan-Xingzhao Region is seemingly a function of structural control as indicated by the concentration of natural gases in the structural highs or along the axial positions of nose structures. However, the great variation of gas shows in exploratory wells located on different structural noses implies the complexity of pool-forming conditions in this region. It is proposed in this paper that the main factors controlling gas accumulation in the studied area are distribution of faults and sand bodies, while the level of“matching”of directions of nose plunging, fault stretching and sandbody wedging determines the easiness of gas-pool formation
and the size, type and distribution of gas pools. Furthermore, natural gas accumulating within the hanging wall of faults is an important expression of fault controls over pool formation in this region.

Characteristics of Terrestrial Organic Matter Evolution and Regularity ofHydrocarbon Distribution in Lower Jurassic in Sichuan Basin

Li Yaohua

1998, 20(1): 38-41. DOI: 10.3863/j.issn.1000-2634.1998.01.009

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On the basis of organic geochemical analyses, a study was made on the abundance, type, thermal evolution characteristics and hydrocarbon generation history of terrestrial organic matter in the Lower Jurassic of Sichuan basin . The relationship between hydrocarbon generation, migration, accumulation and pool formation was investigated. It is proposed in this paper that the paleo-anticlines in the southwest of the source depression to be the major targets of future exploration.

Terrigenous Sequences and Depositional System Configuration in Fault-depressed Biyang Lacustrine Basin

Hu Shouquan

1998, 20(1): 42-48. DOI: 10.3863/j.issn.1000-2634.1998.01.010

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Biyang fault-depression experienced three evolutional phases: pull-apart during Mesozoic, rift during Paleogene, and downwarping in Neogene. Accordingly, three basin-fill sequences and corresponding tectonic sequences have developed. These sequences are defined by regional unconformities, with their general sedimentary style being respectively assemblage of fluvial fan-flood-lake depositional systems, fluvial fan-fan delta-lacustrine-delta depositional systems, and fluvial plain-sand-mud flat-coastal-shallow lacustrine depositional systems. Tectonic sequence II ( Eogene) comprises the main sedimentary fill of the basin and can be divided into seven seismic sequences, each of which exhibits specific depositional system configuration. The Hetaoyuan Formation (Eh), a major target of petroleum exploration in the basin, can be further divided into twelve sequences, whose boundaries are mainly discontinuous or transformed facies interfaces, or in minor cases are subaerial erosion surfaces or depositional hiatus.

The Application of Correlation Technique in Seismic While Drilling

Han Jiyong

1998, 20(1): 49-52. DOI: 10.3863/j.issn.1000-2634.1998.01.011

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Technique of seismic while drilling uses the vibrations produced by a drill bit while drilling as a downhole seismic energy source. The continuous signals generated by the drill bit are recorded by a pilot sensor attached to the top of the drillstring and by receivers located around the borehole. Signals from the reference sensor are used as a pilot signal for cross-correlation with signals from the surface geophones. The cross-correlation method accomplishes two important objectives. First, the cross-correlation function is a measure of the
travel time of drill-bit generated energy up through the strata to the surface geophones minus the travel time from the drill bit up the drill string to the reference sensor. Even though the drill bit vibrations are continuous, in the cross-correlation function they are compressed into pulse-like events. Second, the cross-correlation process also enhances low-level, drill-bit generated signals from weak reflectors. The pilot signal is cross-correlated with the receiver signals to compute travel times of the arrivals and to attenuate incoherent noise.

Studies on the Rheological Behavior of ASP system

Chen Tielong Dong Fan Yon Dongqing Chen Yanliang

1998, 20(1): 53-55. DOI: 10.3863/j.issn.1000-2634.1998.01.012

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The theological behavior of the ASP (Alkaline-Polymer-Surfactant) system with different formulations was measured by rheomters (HAAKE RV-100 and TR-1). The results indicated that the Carrean is the beat model to describe the rheology of the ASP system. 1st Newtonian zone at low shear rate, sheaf thenning zone within medium shear rate, and 2nd Newtonian zone at high shear rate. The zero shearing viscosity decreased and shear thinning exponent increased with the increase of the concentrations of the con-
centrations of alkaline and surfactant.

The Study on Productivity of Horizontal Well 9-spot Patterns

Li Chunlan Chen Lingsong Zhang Lihua Lang Zhaoxin

1998, 20(1): 56-58. DOI: 10.3863/j.issn.1000-2634.1998.01.013

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By basic theory (conformal transformation, imaging, superposition principle etc.) author derived the calculating formulas for horizontal well productivity in three kinds of horizontal well 9-spot patterns, and correlated to experiment results. Correlated results indicated: the derived by author analytical formulas gave fairly accuracy, and can completely meet the need of reservoir engineering

Analysis for Longitudinal Vibration of the Coiled Tubing

Cai yaxi Shi Taihe Wang Youjing

1998, 20(1): 59-60. DOI: 10.3863/j.issn.1000-2634.1998.01.014

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This paper studies the affection that the flowing force of fluid inside coiled tubing is correlated to longitudinal vibration of coiled tubing. After building a differential equation for longitudinal vibration of coiled tubing considering fluid hydrodynamic force, the frequency equation on longitudinal vibration of coiled tubing is obtained. It is an attempt to explore the affection of fluid inside coiled tubing on law of longitudinal vibration of coiled tubing.

Probing into Radial Deformation of Packer Rubber in Test Well

Deng Xiong Liang Zheng

1998, 20(1): 61-63. DOI: 10.3863/j.issn.1000-2634.1998.01.015

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At the base of rejecting normal suppose of impressibility of rubber volume, the packer rubber radial displacement formula were derived from Lame formula and elastic mechanics resolution of spatial axial symmetric problem. The example showed that results we calculated was greater than actual value. According to experiment testing, it was found that the elasticity modulus of packer rubber was ten times as much as value given in the literatures. However, the value we calculated was greater than actual value in the deep well. So it was considered that Lame formula which was widely used in packer design and calculation was only used in shallow well. A kind of method used spatial axial symmetric theory to analyze packer rubber that was constrained in the both ends was referred in shallow well, at the same time, the nonlinear problem should be considered in the deep well, at the base of it, more accurate resolution can be obtained expectively.

Thermal Calculation of Oil Pipeline

Liang Guangchuan

1998, 20(1): 75-77(8. DOI: 10.3863/j.issn.1000-2634.1998.01.019

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The calculation of the unstable temperature of the soil around pipeline is the first step to evaluate the hot oil pipeline. This paper deals with the ordinary form of pipeline, using two-dimensional unstable heat transmission equations to describe the heat transfer process and build the temperature calculation mode. The effects of the parameters, such as ground surface temperature and pipe diameter etc,are concerned in boundary conditions. The finite difference approach is used to resolve the equations and the thermal parameters of hot
oil pipeline can be got from it. The calculation of a practical examples indicates that the method and codes in this paper meet the needs of actual uses.

Improving the Recovery of Propane and Butane by Partially Refluxing natural Gasoline

Zhu Lin Ying Pin Deng Lan

1998, 20(1): 78-79(8. DOI: 10.3863/j.issn.1000-2634.1998.01.020

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In natural gas liquids (NGL) plants, the recovery of propane and butane usually declines with the variation in composition and flow
rate of the raw gas. The method of partially refluxing natural gasoline, which uses a pipe to connect the evaporator with the exit at
the bottom of the debutanizer in order to let a part of steady gasoline return to the evaporator, is one of the ways to improve the recov-
ery. Taking into consideration of influences of composition, temperature and pressure on phase equilibrium of hydrocarbon mixtures,
the SRK real gas state equation is used to study the relationship between sophistication ratio and recovery of propane and butane. The
result shows that under steady temperature and pressure conditions, improved recovery can be obtained with gasoline cycling and with
the increase in sophistication ratio. The most appropriate sophistication ratio can be determined through economic analysis.

Application of Gray Prediction to Multiobjective Programming in An Oil Field

Lian Zhanggui Dai Anli Li Hongwei

1998, 20(1): 80-83. DOI: 10.3863/j.issn.1000-2634.1998.01.021

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Optimal programming is performed to an oilfield on its exploration, development, refinery and chemical engineering, mechanical engi-
neering, public engineering, and poly-economy. Based on the analysis of available data, the critical factors, decisive variables and
objectives are defined and multi-objective planning models established. By means of correlation analysis, gray prediction and regres-
sion analysis, the constraining equations for the models are obtained. With the computing software provided, predictions of the yearly
cost and profit for the individual executive departments as well as the oilfield as a whole can be quickly and conveniently made.

An Analytical Method of Determining the Economic Life of Oil Field

Zhang Bin Zhang Mingquan Yong Qidong

1998, 20(1): 84-87. DOI: 10.3863/j.issn.1000-2634.1998.01.022

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Based on analyses of factors affecting the economic life of oil fields, a method of calculating the economic life is proposed in this paper.Firstly the definition of economic life of an oilfield is presented. Then the principles of system ntegration modeling and simulation are used to establish technological and economic criteria prediction models, economic-life computation models, integrated production-refinery black-box models, cost control models and performance optimization models. Finally, strategies of lengthening the economic life and maximizing the economic profits of oil fields are put forward.

A Study of the Methods of Business Management in the Information Age

Liu Xianfeng

1998, 20(1): 88-92. DOI: 10.3863/j.issn.1000-2634.1998.01.023

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The trend of information globalization brings enterprises not only opportunities but also challenges. Based on analyses of the effects of information technology and information globalization on the organization pattern of business management, the authors of this paper propose the integration of such concepts and methods as“Business Process Reengineering”,“Total Cost Management”and“Game Theory”in business management, so that the enterprise can make full use of the newest information technology and compete successfully in the market.

Finite Groups with Every Non-maximal Proper P^d-subgroup Being 2-closed and P-nilpotent

Tu Daoxing

1998, 20(1): 93-95. DOI: 10.3863/j.issn.1000-2634.1998.01.024

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In this paper, the author presents a complete classification of the finite groups whose every non-maximal proper p^d-subgroup is 2-closed and p-nilpotent, where p is the smallest odd prime divisor of the order of the group.

Neural Network Structure Design Based on Genetic Algorithms

Chen Wei Duan Yonggang Jang Hong

1998, 20(1): 96-98. DOI: 10.3863/j.issn.1000-2634.1998.01.025

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Artificial neural network (ANN) can be widely used in engimeering domain, but some difficulties are existed in practical application.So far there is no theory about how to optimize network stucture. In this paper a hybrid learning procedure that combines genetic algorithm (GA) and back-propagation errors algorithms is taken to research network structure designing. Applications show that optimizing the network structure by GA can improve efficiently the performance of ANN.

The Variational Principles in Contact Mechanics

Zhang Yan Kong Xiang an Chen Ping Shi Taihe

1998, 20(1): 99-104. DOI: 10.3863/j.issn.1000-2634.1998.01.026

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Contact problem is one of the most important problems frequently ncountered in engineering structures and processing technology.Collar rotary shouldered connection, contact between drillstring and hole, and between bit and rock as in petroleum engineering, and the quasi-static contact between bridge and concrete base and rolling contact between train wheel and track as in rail engineering are some special examples of contact problems. The most difficult and crucial issue in solving such problems is to establish contact varia-
tional function and solution method. In this paper, the current literature related to the theories and methods of variational principles of contact mechanics is reviewed, analyzed and compared, which sets a foundation for the establishment of variational principles specific to the rotary shouldered connection problem.

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