Advanced Materials Research Vols. 616-618

Abstract: In order to optimize space of tertiary infill wells and tertiary recovery wells, this paper applies numerical simulation method to study Xingqi Area in Daqing oil field. According to serious lateral and vertical heterogeneity and different control degree of water flooding in different parts of reservoir, 3 development schemes are designed. Numerical simulation results show that Scheme 2 is the best, whose well pattern consists of tertiary infill wells and tertiary recovery wells. When water cut is 98%, the ultimate recovery reaches 58.66%, which is 10.74% higher than the ultimate recovery of old well pattern. The result possesses great theoretical guidance for the same kinds of reservoirs.

Abstract: According to material balance principle, gas/water bearing height in gas reservoir with bottom water could be deduced. Additionally, sweep efficiency could be approximately determined, then based on the equivalent flowing resistance method and critical vertical velocity of bottom water drive, computational model of Critical Producing Pressure Drop during the development of gas reservoir with bottom water could be derived. Therefore, the variance principle of Critical Producing Pressure Drop of horizontal well can be expressed quantitatively, and this paper also analyzes that it is influenced by the ratio of vertical permeability to horizontal permeability, the difference between water and gas density, the ratio of water viscosity to gas viscosity and height for bottom water coning. The results could provide guidelines for the determination of reasonable producing pressure drop and producing rate of horizontal well in gas reservoir with bottom water.

Abstract: The high water content of heavy oil emulsions are O / W or W / O unstable estate, to solve the problem of heavy oil wells in the viscosity, after a large number of laboratory tests, a water-soluble drag reduction agent(DRA) with excellent drag reducing effect for high water heavy oil well is developed. The water-soluble DRA does not have combustible nature and solves also the problem of the security risk commonly used lower flash point viscosity reducing agent in paraffin oil well. The formulations and preparation method of the water-soluble drag reduction agent are introduced and the field applications are evaluated in this paper. The applications of more than 110 oil wells in Fifth Oil Production Plant in North China Oilfield have shown that the heavy oil viscosity reduction and drag reduction effects of water-soluble DRA are remarkable, and the hot wash cycle of oil well is prolonged.

Abstract: With the use of casing running tool (CRT), casing can be rotated and reciprocated at the same time with circulation of drilling fluid. Thus the flow in well bore was eccentric annular helical. Pressure exerted on casing was important for casing buckling analysis. A numerical model of eccentric annular helical flow of power law fluid was built in this paper. The relationship between average pressure gradient on pipe and some influence factors (pipe axial velocity, rotating angular velocity, drilling fluid circulation velocity, and axial coordination) was analyzed. Results showed that average pressure gradient caused by shear stress was only affected by average annular flow velocity, and it didn’t change along pipe length. Effect of rotating angular velocity on average pressure gradient on pipe was very small and could be negligible. A fitting function between average pressure gradient and average annular flow velocity was obtained in this end.

Abstract: In Sabei Development Area, with the developments of oilfield infill wells, the production targets of each set of well nets went bad and had interleaved distributions with old well patterns. At the same time, polymer flooding well patterns made the conflict of cohesion and dynamic regulation outstanding. Especially, Beierdong, which was the earliest block using infill drilling modification, got the good development effect at beginning, however, with the progress of oilfield development, there were some troubles in the development period with extra high water, such as long section of perforation, obvious inconsistencies between formations and high water of layers, which brought difficulties to dynamically adjusting. To fully exploit the remaining oil potential, this paper selected 1.30 km2 west blocks in Beierdong, made tests about sediment group restructuring to improve water flooding development effect, redistribute the series of strata and redistribute the flooding network according to the characteristics of development between the layers, combined comprehensive consideration with follow-up adjustment such as primary network, injection production system and type II reservoir the tertiary oil production, optimized the layers combination and well patterns arrangement, finally formed technical ideas of high water cut layers adjustment and well nets evolution.

Abstract: For an oil well, when its water cut rises to a certain high point, the economical input gets equal to the economical output, at this time, this oil well produces nothing economically. If the water cut exceeds this point, then this oil well produces a deficit. This point is the so-called economical terminal water cut. Based on the theory of break even analysis, this paper determined the components of the cost of an oil well, analyzed the factors affecting the economical terminal water cut of oil well and developed a mathematical model to predict the value of economical terminal water cut.

Abstract: Because the hard strata and big angle of bedding, deep wells in Daqing Xujiaweizi area well deviate easily. Low efficiency and long drilling cycle are big problems of drilling engineering since small bit weight is used to avoid well deviation. To improve efficiency, Smooth drill collars with high bit weight WOB technology is used in the deep wells in Daqing Xujiaweizi area. Facts prove that penetration rate can be increased more than 20% , bit life can be extended more than 30% and well deviation can be corrected in Daqing Xujiaweizi deep drilling. This paper through analyzes the mechanism of smooth drill collars BHA ,then build kinematic model and dynamic mode,so bit side force's Solution formula is worked out,Get the principles and applicability of smooth drill collars with high bit weight WOB technology.

Abstract: The south of Daqing placanticline is mainly front facies reservoir which is chiefly the smooth, direct, narrow and small river. The size of the river is small and the reservoir thickness is mainly 1.0m-1.2m.The prediction accuracy of the interwell sandbody is only up to 60~70% under the condition of existing well network and well spacing, causing the relatively worse development effect. In order to raise the prediction accuracy of the interwell sandbody, it proposes the thinking of identifying the boundary and orientation of the inner front facies by means of the combination of wells and seismos of 3D seismic data. After the comparative analysis of the wells and the seismos, it determines the seismic attributes which can reflect the sandstone and identify mudstone preferablely, and proposes the method of reservoir description by means of the combination of wells and seismos which makes the prediction accuracy of the interwell sandbody reach to 80.77%.

Abstract: Research feasibility of steamflooding after polymerflooding to thin oil reservoir to improve recovery, experiments are carried out. Materials are natural core cylindrical. First, waterflooding and polymerflooding are studied at 45°C and steamflooding the environment temperature and injection steam temperature is studied. The results showed range of steamflooding recovery increased to 28.3%. When fixed pressure, steamflooding recovery is increasing with the number PV. Ultimately they are stable value. Efficient the number of PV is 1.4.Steamflooding recovery range is increasing then reducing. Optimum displacement temperature is exceeding saturation vapor 10-15°C.Steamflooding efficiency is concerned with pressure and steam injection rate. Excessive steam rate is insignificant and in this experiment 0.2ml/min is appropriate.Permeability increasing contributes to recovery increasing. But in higher steam injection temperature, extortionate permeability , 1μm2 ,can increase steam fingering. Increasing steam injection temperature can boost obviously steam recovery to medium permeability cores .

Abstract: Hydrocarbon detection while drilling (HDWD) is important for obtain proper drilling performance. In this report, Raman spectra for hydrocarbon in returned water based drilling fluid have been acquired using He-Ne laser (633nm) excitation. The relative intensities of several Raman bands are found to depend on the concentration of hydrocarbon in returned drilling fluid. Spectra are interpreted as indicating that Raman spectra could be used as potential method for HDWD.