Papers by Keyword: Low Permeability

Abstract: In an oilfield factory, the blocking and jam in Chang 2 reservoir is very serious. In recentyears, according to analysizing different plugging mechanism and optimizing acidizing formula, theoptimal plugging removal technology was formed suitable for the solution for the Chang 2 reservoirof oilfield factory. This plugging removal formula increases the efficiency radius, and increases thedosage of additives to protect the pipe, rod and pump from the precipitation such as Ca2+and Mg2+,which causes new pollution. Reasonable multiple technologies were designed, and low displacementmethod was used in the injection process, aiming at the characteristics of Chang 2 reservoir. Thismethod extends the time of plugging removal fluid staying around the well bore, which can eliminateplugging near well bore area effectively, and improve the permeability. DQ-1 composite pluggingremoval and other kinds of plugging removal methods have been used more than 50 times, and theeffect is remarkable, which made a positive contribution to stable production of the oilfield.

Abstract: The Xishanyao reservoir in Niuquanhu area is a typical low permeability reservoir Diagenesis is very important for the physical property of reservoir. Through analyzed data of cast thin sections and scanning electron microscopy (SEM) data, analyzed the impact of main diagenesis on reservoir properties in Niuquanhu area. First, quantitative analyzed the various types of diagenesis on reservoir porosity contribution rate. Second, through restoring the original porosity, quantitative analyzed the pore evolution of reservoir caused by various types of diagenesis. Realized the quantitative analysis of porosity of each diagenesis stage. The quantitative calculation results agree well with the experimental analysis results, the error is 1.09%~1.51%, which showed the rationality of research method and the research results have certain reliability. The study of diagenesis has important significance for fine evaluation and favorable area prediction of Niuquanhu area reservoir.

Abstract: In order to study the development characteristics of low permeability gas reservoirs, long cores sampled from natural outcrop are selected to carry out depletion development experiments by using two development modes, namely constant production and constant pressure development modes. The results show: when the average flow rate is equal to bottomhole pressure,constant production development mode is adopted, reservoir pressure drops evenly and gas produces stably. Therefore, its requirements for gas production equipment are relatively low, although its recovery percent is 2% lower than that when constant pressure development mode is adopted. Moreover, when constant production development mode is adopted, the higher the flow rate, the shorter the stable production period and lower the recovery percent. The fitted experimental data shows that the gas well may get reasonable production which is stability and high efficiency when produced in 20%~30% of AFO.

Abstract: Horizontal well hydraulic fracture construction technology has already become the main development means of low permeability reservoir, and the crack initiation pressure is a key factor in fracture construction. Taking ABAQUS as the platform, combined with rock mechanics, elastic mechanics, fracture mechanics, damage mechanics and fluid-solid coupling theory, to establish horizontal well mechanical model, crack initiation law of horizontal well under different conditions were obtained by using finite element method. According to the horizontal well fracture tested data in Daqing peripheral oil fields, the crack initiation pressure and numerical simulation results are in good agreement, it shows that the numerical simulation method is reasonable, then analyze influence factor of crack initiation pressure on the basis.

Abstract: The fine grain, poor sorting and high cement content in low permeability reservoirs lead to poor reservoir property, low porosity and permeability and have strong damage to the reservoir .The conventional way of low permeability oil mining is mainly fracture and chemical flooding, which cost is relatively high and will cause serious irreparable damage to formation. People are in favor of physical oil production technology because it is no harm and pollution to the reservoir, more flexible to operate and it has wide range of application and low cost. By using high frequency pulse pressure servo system and ZC-type I, this paper examines the low-frequency vibration oil recovery indoor simulation test device hydraulic pulse oil displacement effect of low permeability cores. The experiment selecting the artificial core (permeability are less than 50), examines the effects of different hydraulic pulse parameters (frequency, static pressure and dynamic pressure) on low permeability core permeability and recovery factor. The results showed that only when the three parameter ,hydraulic pulse frequency, static pressure and dynamic pressure, suitably combined will greatly increase the reservoir recovery efficiency and reduce residual oil saturation.