Tight oil reservoir production characteristics developed by CO2 huff ‘n’ puff under well pattern conditions

Abstract

Tight oil reservoirs have poor physical properties, and the problems including rapid oil rate decline and low oil recovery degree are quite common after volume fracturing. To obtain a general understanding of tight oil reservoir production improvement by CO2 huff ‘n’ puff, the high-pressure physical properties of typical tight oil samples are measured. Combining the typical reservoir parameters, the production characteristics of the tight oil reservoir developed by the CO2 huff ‘n’ puff are numerically studied on the basis of highly fitted experimental results. The results show that: (1) during the natural depletion stage, the oil production rate decreases rapidly and the oil recovery degree is low because of the decrease in oil displacement energy and the increase in fluid seepage resistance. (2) CO2 huff ‘n’ puff can improve the development effect of tight oil reservoirs by supplementing reservoir energy and improving oil mobility, but the development effect gradually worsens with increasing cycle number. (3) The earlier the CO2 injection timing is, the better the development effect of the tight reservoir is, but the less sufficient natural energy utilization is. When carrying out CO2 stimulation, full use should be made of the natural energy, and the appropriate injection timing should be determined by comprehensively considering the formation-saturation pressure difference and oil production rate. The research results are helpful for strengthening the understanding of the production characteristics of tight oil reservoirs developed by CO2 huff ‘n’ puff.

Characteristics of Tight Oil Reservoir Based on Nano-CT

“…Due to the inability to know the characteristics and formation mechanism of tight oil and gas reservoirs, Fan C used a series of analysis methods such as thin section, scanning electron microscope, and gas chromatography-mass spectrometry to study the tight reservoirs of the Xiagou Formation and the Zhonggou Formation [5]. In order to gain a general understanding of the enhancement of tight oil reservoir production by CO 2 hu and pu , Xia Z measured the high-pressure physical properties of typical tight oil samples [6]. Since it is difficult to classify the rock types and characterize the reservoirs in the marl interval, Cui J proposed a four-element classification method to determine the rock types by analyzing the mineral composition [7].…”

Characteristics of Crude Oil Production in Microscopic Pores of CO2 Huff and Puff in Shale Oil Reservoirs

“…Therefore, the shale oil recovery rate is low. In recent years, the technology of injecting CO 2 has been widely used in the exploitation of tight oil reservoirs. − The way of CO 2 injection is divided into CO 2 displacement and CO 2 huff and puff . Among them, the CO 2 displacement method is generally not suitable for shale reservoirs, mainly due to the existence of cracks formed after hydraulic fracturing of shale reservoirs, and the difference in viscosity in oil and gas is large.…”

Experimental Study on the Application of Cellulosic Biopolymer for Enhanced Oil Recovery in Carbonate Cores under Harsh Conditions

“…With growing calls to increase oil production, there is a need to develop novel techniques for recovering oil from depleted reservoirs [ 1 ]. Initial production from oil reservoirs is due to pressure depletion [ 2 ]. Thereafter, waterflooding is used to increase oil production [ 3 ].…”