Experimental Investigation on CO2 Injection in Block M

Peng Chen,Linlin Wang,Song Lu,Junqiang Fan,Sidun Zhang

doi:10.1155/2018/8623020

Abstract

The purpose of this report was to perform an experimental evaluation of enhanced oil recovery (EOR) using CO2 injection. A slim tube test and PVT experiment are used to determine the minimum miscibility pressure as well as a few related physical properties. Combined with a long core displacement experiment and nuclear magnetic resonance, CO2 flooding and CO2-water alternate flooding are simulated, and the displacement efficiency of different types of pores is evaluated. The results indicate that the minimum miscibility pressure is 32.6 MPa, and the CO2 flooding is at near-miscible conditions at the current formation pressure. The CO2 solubility of crude oil is large, and the crude oil has a strong expansion ability after the CO2 injection, which is beneficial for improving the recovery of CO2. The EOR of CO2-water alternate flooding is 3.97% higher than that of continuous CO2 flooding, and the EOR in the small and middle pores in the CO2-water alternate flooding is clearly higher. These results will be relevant for the future development of Block M.

Highlights

Located in the abdomen of the Junggar Basin, Block M has a reservoir depth of approximately 3900 m, porosity of 13.52%, and permeability of 15.27 mD, and it can be categorized as a low porosity and low permeability reservoir. e formation experiences a long period of sedimentary cycles with strong planar and longitudinal heterogeneity, which occur initially for the delta front sediments and later for the former delta sediments [1, 2]. e oil reservoir is developed using water injection; the effects of water flooding are poor, and there are significant problems in the development process
When the rate of water content is increased to 98%, the injection of water in sample no. 1 is terminated. e recovery factor is 50.17%, and the sample is scanned using nuclear magnetic resonance. en, CO2 ooding is performed, and the displacement is terminated without apparent oil recovery, resulting in a recovery rate of 58.91%, en, the core is rescanned, and the recovery rate of the CO2 ooding
Based on the slim tube test, PVT experiment, and flooding experiment of the long core, the miscible pressure of Block M is determined, the feasibility of CO2 injection to enhance oil recovery is evaluated, and nuclear magnetic resonance is combined to analyze the recovery of oil in different sizes of pore throats

Summary

Introduction

Located in the abdomen of the Junggar Basin, Block M has a reservoir depth of approximately 3900 m, porosity of 13.52%, and permeability of 15.27 mD, and it can be categorized as a low porosity and low permeability reservoir. e formation experiences a long period of sedimentary cycles with strong planar and longitudinal heterogeneity, which occur initially for the delta front sediments and later for the former delta sediments [1, 2]. e oil reservoir is developed using water injection; the effects of water flooding are poor, and there are significant problems in the development process. E oil reservoir is developed using water injection; the effects of water flooding are poor, and there are significant problems in the development process. The overall development effects are poor, the current recovery rate is only 15.6%, and the remaining reserves of the reservoir are large. Based on the production date of the CO2 EOR project in the Jilin oilfield, reservoir pressure and wellhead injection pressure are the primary factors used to control the performance of wells, whereas gravity extraction and light/medium distillation extraction are the key mechanisms for enhancing oil recovery in tight reservoirs [9]. Yu et al analyzed the EOR mechanism in tight oil reservoirs using a CO2 huff and puff technology and verified its feasibility to increase the recovery in volume fracturing horizontal wells in the Bakken oilfield [10]

Methods

Results

Conclusion