Showing papers on "Steam injection published in 2016"

Pore-Scale Experiment on Blocking Characteristics and EOR Mechanisms of Nitrogen Foam for Heavy Oil: A 2D Visualized Study

Abstract: How to enhance heavy oil recovery to meet the oil consumption is a popular issue around the world, and it has attracted widespread attention. A two-dimensional visualized model was adopted to study the pore-scale mechanisms and development effects of foam for enhancing oil recovery in steam injection processes for heavy oil. Experimental images visually presented that small bubbles gather together to form bigger foams, thus blocking the small pores and throats and leading to fluid diversion in porous media. As a result, the sweep efficiency was improved from 46.18% to 77.93% after foam injection. Foams could effectively improve the mobility ratio between oil and water and decreased water cut after foam injection, which was significant for decaying the decline of oil production. As for the pore-scale level, after foams were injected into the visualized model, the residual oil caused by steam flooding entered into the main streamline under the disturbance of foams and was carried out by the following displa...

Steam Regeneration of Polyethylenimine-Impregnated Silica Sorbent for Postcombustion CO2 Capture: A Multicyclic Study

Abstract: Steam regeneration of polyethylenimine (PEI)-impregnated commercial grade silica was investigated in a packed bed reactor. Adsorption was performed at 75 °C under 10% CO2/N2, and desorption was carried out under steam at 110 °C for 20 consecutive cycles. CO2 adsorption capacity was found to decrease by 9 mol % over the period of 20 cycles. No evident signs of sorbent degradation due to PEI leaching or changes in surface morphology and amine functionalities were observed upon characterization of the sorbent after the cyclic study. Most of the loss in adsorption capacity was associated with thermal degradation of the sorbent during drying under N2 after steam stripping at 110 °C. The desorption kinetics during steam stripping was found to be much faster than during N2 stripping. Over 80% of the total CO2 was released within the first 3 min of steam injection into the reactor. A separate packed bed study was conducted to investigate the influence of moisture content (5.3–14.7 vol %) in flue gas on the CO2 ad...

Chemical Flooding in Heavy-Oil Reservoirs: From Technical Investigation to Optimization Using Response Surface Methodology

Abstract: Heavy-oil resources represent a large percentage of global oil and gas reserves, however, owing to the high viscosity, enhanced oil recovery (EOR) techniques are critical issues for extracting this type of crude oil from the reservoir. According to the survey data in Oil & Gas Journal, thermal methods are the most widely utilized in EOR projects in heavy oil fields in the US and Canada, and there are not many successful chemical flooding projects for heavy oil reported elsewhere in the world. However, thermal methods such as steam injection might be restricted in cases of thin formations, overlying permafrost, or reservoir depths over 4500 ft, for which chemical flooding becomes a better option for recovering crude oil. Moreover, owing to the considerable fluctuations in the oil price, chemical injection plans should be employed consistently in terms of either technical or economic viewpoints. The numerical studies in this work aim to clarify the predominant chemical injection schemes among the various combinations of chemical agents involving alkali (A), surfactant (S) and polymer (P) for specific heavy-oil reservoir conditions. The feasibilities of all potential injection sequences are evaluated in the pre-evaluation stage in order to select the most efficient injection scheme according to the variation in the oil price which is based on practical market values. Finally, optimization procedures in the post-evaluation stage are carried out for the most economic injection plan by an effective mathematic tool with the purpose of gaining highest Net Present Value (NPV) of the project. In technical terms, the numerical studies confirm the predominant performances of sequences in which alkali-surfactant-polymer (ASP) solution is injected after the first preflushing water whereby the recovery factor can be higher than 47%. In particular, the oil production performances are improved by injecting a buffering viscous fluid right after the first chemical slug rather than using a water slug in between. The results of the pre-evaluation show that two sequences of the ASP group have the highest NPV corresponding to the dissimilar applied oil prices. In the post-evaluation, the successful use of response surface methodology (RSM) in the estimation and optimization procedures with coefficients of determination R2 greater than 0.97 shows that the project can possibly gain 4.47 $MM at a mean oil price of 46.5 $/bbl with the field scale of a quarter five-spot pattern. Further, with the novel assumption of normal distribution for the oil price variation, the chemical flooding sequence of concurrent alkali-surfactant-polymer injection with a buffering polymer solution is evaluated as the most feasible scheme owing to the achievement of the highest NPV at the highly possible oil price of 40–55 $/bbl compared to the other scheme.

Mechanism of High Stability of Water-in-Oil Emulsions at High Temperature

Abstract: Thermal flooding by steam injection was a traditional method for exploiting heavy oil. The produced liquid was a highly stable water-in-oil or oil-in-water emulsion in several oilfields. In this work, we focused on studying the effect of high temperature on the stability of an emulsion system involving two typical crude oils (heavy crude oil and light crude oil) and brine. It was impossible to directly measure the interfacial viscoelastic modulus because of the high viscosity of the heavy oil. In order to solve this problem and analyze the contribution of those fractions to the formation of stable emulsions, the heavy crude oil was divided into three cuts: remaining fraction, resin, and asphaltene. The model oils were prepared from the mixture of several heavy crude oil fractions with kerosene:xylene (1:1 v/v) to investigate the high-temperature behaviors of their emulsions. The stability was evaluated through a high-temperature–high-pressure (HTHP) visual pressure–volume–temperature cell, and a temperatu...

Methods, apparatus, and systems for steam flow profiling

Abstract: Provided herein are systems, methods, and computer-readable medium for profiling steam injected into a formation. In one embodiment, the method includes receiving a dataset of temperature surveillance data, acoustic surveillance data, surface injection data, downhole pressure measurement device data, downhole temperature measurement device data, or any combination thereof. The method further include determining annular temperature profiles, tubing temperature profiles, behind liner temperature profiles, or any combination thereof from the dataset based on configuration of the fiber optic surveillance system in the well and design of the well. The method further includes using flow diagnostic results based on the dataset, the annular temperature profiles, the tubing temperature profiles, etc. to select which computational algorithm(s) can be used to determine a steam injection flow profile and associating each selected algorithm with a weight, executing each selected algorithm, and using results and the associated weight to determine the steam injection flow profile.

Heavy oil sands measurement and rock-physics modeling

Abstract: Heavy oil reservoirs are important alternative energy resources to conventional oil and gas reservoirs. However, due to the high viscosity of heavy oil, much production of heavy oil reservoirs involves injecting steam, and determining the temperature distribution is significant for production. To do this, time-lapse inversion is commonly used to derive the change of the oil sand properties during steam injection, and rock-physics models are used to link the properties and temperature. Many people have done research on simulating variations of the oil sand properties with temperature; however, the previous models fail to adequately represent our experimental data, and they overestimate their values. The errors between previous models’ predictions and measurements are quite large, especially at low temperatures. To study the oil sand properties, we first measured eight oil sand samples including five presteam samples and three poststeam samples, and we experimentally quantified the pressure sensitiv...

A New High-Temperature Gel for Profile Control in Heavy Oil Reservoirs

Abstract: Controlling the phenomenon of steam channeling is a major challenge in enhancing oil recovery of heavy oil reservoirs developed by steam injection, and the profile control with gel is an effective method to solve this problem. The use of conventional gel in water flooding reservoirs also has poor heat stability, so this paper proposes a new high-temperature gel (HTG) plugging agent on the basis of a laboratory experimental investigation. The HTG is prepared with nonionic filler and unsaturated amide monomer (AM) by graft polymerization and crosslinking, and the optimal gel formula, which has strong gelling strength and controllable gelation time, is obtained by the optimization of the concentration of main agent, AM/FT ratio, crosslinker, and initiator. To test the adaptability of the new HTG to heavy oil reservoirs and the performance of plugging steam channeling path and enhancing oil recovery, performance evaluation experiments and three-dimensional steam flooding and gel profile control experiments are conducted. The performance evaluation experiments indicate that the HTG has strong salt resistance and heat stability and still maintains strong gelling strength after 72 hrs at 200 °C. The singular sand-pack flooding experiments suggest that the HTG has good injectability, which can ensure the on-site construction safety. Moreover, the HTG has a high plugging pressure and washing out resistance to the high-temperature steam after gel forming and keeps the plugging ratio above 99.8% when the following steam injected volume reaches 10 PV after gel breakthrough. The three-dimensional steam flooding and gel profile control experiments results show that the HTG has good plugging performance in the steam channeling path and effectively controls its expanding. This forces the following steam, which is the steam injected after the gelling of HTG in the model, to flow through the steam unswept area, which improves the steam injection profile. During the gel profile control period, the cumulative oil production increases by 294.4 ml and the oil recovery is enhanced by 8.4%. Thus, this new HTG has a good effect in improving the steam injection profile and enhancing oil recovery and can be used to control the steam channeling in heavy oil reservoirs.

Study of the Parameters of Steam Assisted Gravity Drainage (SAGD) Method for Enhanced Oil Recovery in a Heavy Oil Fractured Carbonate Reservoir

Abstract: By increasing in the use of nonrenewable energy and decreasing in discovering hydrocarbonic reservoirs, in near future the world will encounter with a new challenge in the field of energy, so increase in recovery factor of the existing oil reservoirs is necessary after the primary production. In one hand the existence of untouched heavy oil reservoirs in Iran and lack of producing from them and maturity of light oil reservoirs to 2nd and 3rd stage of their production age in other hand make the development and production of these heavy oil reservoirs necessary in Iran. The goal of this study is to survey common methods of producing oil reservoirs and appliance in heavy oil reservoirs of Iran especially in Kuh-e-Mond. For choosing the best EOR method we should consider factors such as the reservoir fluid and rock characteristics, availability of injection material, available equipments and other items. One way to choose an optimized method is the comparison of reservoirs’ parameters in successful EOR projects with the considered reservoir. However, it should be consider that each reservoir has its especial characteristics and we can not give certain idea about it. Thermal methods have the most useage in the recovery of the world’s heavy oil and between these methods; steam injection with the most amount of oil production has terrific importance. The gained results show that the best way for recovery heavy oil of Sarvak reservoir of Kuh-e-Mond is thermal way and especially steam injection Steam modeling by activating gravity drainage drive process by using steam injection (SAGD) which is designed in a reservoir model in Sarvak reservoir of Kuh-e-Mond has been successful.