Laboratory Evaluation Experiment for Adaptability Analysis of Nitrogen Injection in Yanchang Oil Field

2021 ◽  
Author(s):  
Jiaxi Gao ◽  
Yuedong Yao ◽  
He Bao ◽  
Jinjiang Shen

Abstract: Yanchang Oilfield conducts systematic research on nitrogen injection to enhance oil recovery. Through the research of this project, the energy supplement method of horizontal wells suitable for the study area is determined, and its injection system and process parameters are optimized and determined. The optimal energy replenishment method selected by the mine field test achieves the following economic and technical indicators: Provide a nitrogen suitability evaluation plan; Complete the nitrogen flooding matching process design of the target well; Complete the design of the injection-production plan for the target well; Compare with other energy supplement methods. Through the analysis of two supplementary energy methods of water injection and gas injection in indoor and similar reservoirs, the following understandings have been obtained: (1) Nitrogen is insoluble in water, slightly soluble in oil, good swelling, large elastic energy, is an inert gas, exists widely in the atmosphere, inexhaustible, inexhaustible, has a wide range of sources. (2) the recovery rate of nitrogen flooding is significantly higher than that of water flooding. (3) The field test results of water injection and nitrogen test in similar reservoirs show that the supplementary formation energy of nitrogen injection is suitable for the later development of Chang 64 and Chang 71 in the Haobasi oil field. (4) Compared with deep ultra-low permeability reservoirs, it is more economical to use nitrogen to supplement formation energy and change oil. The rate is higher. From the above analysis, it can be seen that the supplementary energy of Chang 64 and Chang 71 reservoirs in the Haobasi oil area should be nitrogen injection as the main supplement, and water injection as a supplement. Gas/water alternate injection is used to adjust the gas injection profile to slow down the escape of injected nitrogen. . Although water injection supplements the formation energy with greater uncertainty, it can be used as a technical means of fluidity control in the gas injection process and is relatively economical.

2014 ◽  
Vol 13 (05n06) ◽  
pp. 1460007
Author(s):  
Hanshi Zhang ◽  
Pingya Luo ◽  
Lei Sun ◽  
Zhijun Fu

The fault roots of Liuzan north block in Jidong oilfield of China have been long-term explored by solution gas drive. Recently, oil production declined rapidly because of shortage of formation energy and needing high water injection pressure. Carbon dioxide injection pressure is found to be generally low, and CO 2 has good solubility in crude oil to supply formation energy and achieve high oil recovery efficiency. In this work, a pilot program of CO 2 EOR technology was carried out. The slim tube test results showed that the minimal miscible pressure of Liuzan north block was 28.28 MPa. The injection parameters were optimized by numerical simulation method: the injection method was continuous, the slug size was 0.2 HCPV and the EOR efficiency was 7.23%. After two months of gas injection field test, the formation pressure of two gas injectors just increased by 14.02 MPa and 2.98 MPa, respectively, indicating that carbon dioxide could supply the formation energy effectively. 16 months after gas injection, the CO 2 injection amount was 14640 t, and the oil increment was 16424 t. The present work demonstrates the potential applicability of CO 2 flooding technology from high water injection reservoirs.


2021 ◽  
Vol 73 (09) ◽  
pp. 58-59
Author(s):  
Chris Carpenter

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper OTC 30407, “Case Study of Nanopolysilicon Materials’ Depressurization and Injection-Increasing Technology in Offshore Bohai Bay Oil Field KL21-1,” by Qing Feng, Nan Xiao Li, and Jun Zi Huang, China Oilfield Services, et al., prepared for the 2020 Offshore Technology Conference Asia, originally scheduled to be held in Kuala Lumpur, 2–6 November. The paper has not been peer reviewed. Copyright 2020 Offshore Technology Conference. Reproduced by permission. Nanotechnology offers creative approaches to solve problems of oil and gas production that also provide potential for pressure-decreasing application in oil fields. However, at the time of writing, successful pressure-decreasing nanotechnology has rarely been reported. The complete paper reports nanopolysilicon as a new depressurization and injection-increasing agent. The stability of nanopolysilicon was studied in the presence of various ions, including sodium (Na+), calcium (Ca2+), and magnesium (Mg2+). The study found that the addition of nanomaterials can improve porosity and permeability of porous media. Introduction More than 600 water-injection wells exist in Bohai Bay, China. Offshore Field KL21-1, developed by water-flooding, is confronted with the following challenges: - Rapid increase and reduction of water-injection pressure - Weak water-injection capacity of reservoir - Decline of oil production - Poor reservoir properties - Serious hydration and expansion effects of clay minerals To overcome injection difficulties in offshore fields, conventional acidizing measures usually are taken. But, after multiple cycles of acidification, the amount of soluble substances in the rock gradually decreases and injection performance is shortened. Through injection-performance experiments, it can be determined that the biological nanopolysilicon colloid has positive effects on pressure reduction and injection increase. Fluid-seepage-resistance decreases, the injection rate increases by 40%, and injection pressure decreases by 10%. Features of Biological Nanopolysilicon Systems The biological nanopolysilicon-injection system was composed of a bioemulsifier (CDL32), a biological dispersant (DS2), and a nanopolysilicon hydrophobic system (NP12). The bacterial strain of CDL32 was used to obtain the culture colloid of biological emulsifier at 37°C for 5 days. DS2 was made from biological emulsifier CDL32 and some industrial raw materials described in Table 1 of the complete paper. Nanopolysilicon hydrophobic system NP12 was composed of silicon dioxide particles. The hydrophobic nanopolysilicons selected in this project featured particle sizes of less than 100 nm. In the original samples, a floc of nanopolysilicon was fluffy and uniform. But, when wet, nanopolysilicon will self-aggregate and its particle size increases greatly. At the same time, nanopolysilicon features significant agglomeration in water. Because of its high interface energy, nanopolysilicon is easily agglomerated, as shown in Fig. 1.


2021 ◽  
Author(s):  
Kok Liang Tan ◽  
Sulaiman Sidek ◽  
Syakirin M. Nazri ◽  
Haziqah Hamzah

Abstract Immiscible Water Alternating Gas (iWAG) scheme was adopted in Echo field, offshore Sarawak Malaysia, to increase recovery factor of the matured oil reservoir after more than two (2) decades of peripheral water injection. It was implemented through four (4) horizontal wells located at reservoir’s eastern and western flanks. Since the commencement of iWAG injection, multiple challenges occured interrupting the stable injection that halting the success of this integrated mega scale project. It started with prolonged iWAG performance test run due to surface constraint, measurement and well issues on executing switching test, followed with low injectivity during switching operation. Subsequently, injectivity issues occured in the gas phase after several injection cycles. In addition to that, injector wells facing high downtime due to surface facilities and well integrity issues, causing low injection rates and unavailability to meet cycle volume within the stipulated duration. Reactivation of iWAG benefiter wells also prove to be challenging due to wells have been idle for a long time and multiple interventions required to revive the well. Injection data for both gas and water phase were analysed to improve iWAG operating procedure and understand the wells performance. INJ-J2 was installed with temporary pressure gauge during the water to gas switching, while the other two (2) wells are equipped with Permanent Downhole Gauge (PDG) to monitor the well injectivity. Application of non-intrusive flowmeter was also proven useful in calibrating the Flow Transmitter (FT) for both water and gas injectors, ensuring the accuracy and precision in the water and gas injection measurement. Besides that, fluid temperature trending was referred to validate on the meter measurement. Low injection rate compared to original plan were reviewed with the Reservoir Management Plan (RMP). Several approaches are implemented in order to achieve the iWAG RMP target and idle well reactivation. Analysis of injection data showed that gas injectivity issue occurred after the water to gas switching cycle. Injectivity improves slightly after long duration of continuous gas injection and applying higher Tubing Head Pressure (THP), unfortunately some wells remain with low injectivity because of insufficient discharge pressure to push the water from the near-wellbore deep into the reservoir to improve injection. Low injection rate issue is mitigated by extending injection cycle duration in order to meet the RMP cycle volume. Besides that, wells are normally injected with higher injection rate to cater for the high downtime. Both gas and water injection are balanced to ensure that the wells reached their cycle volume at similar duration. With limited new field discovery by the Operator, tertiary recovery on the mature field is inevitable. However, there is less implementation of iWAG in offshore field. Through this paper, authors wish to provide insights and lesson learnt for others when planning for iWAG tertiary recovery, taking account of various challenges faced.


2012 ◽  
Vol 524-527 ◽  
pp. 1217-1222 ◽  
Author(s):  
Zhi Qiang Huang ◽  
Zhen Chen ◽  
Gang Zheng ◽  
Jian Qiang Xue ◽  
Xue Yuan Li

With the characteristics of low permeability, pressure and abundance, it's extremely hard to exploit the super low permeability reservoirs in ChangQing oil field. For this reason, the water injection recovery technique has been widely used. Analysis showed that a serious problem of high energy consumption exist in the water injection system, the power consumption of which accounts for about 44%. And the energy cost of pump units reach up to 43%, it's the highest energy consumption link in the system. In this paper the load rate classification method (LRCM) is firstly adopted to statistical analyze water injection stations, which are divided into the owing and over load rate stations. As a result, the owing load rate stations accounts for 83.8%, with a serious phenomenon of the Big Horse Pull A Small Carriage, causing the large-scale backflow in the station, and the efficiency is low, the energy consumption is on the high side. Aimed at water injection stations with different load rate, the methods of reasonable shutting down the pumps, pump replacement, optimizing the transmission ratio and piston size, as well as the speed control technology have been used to make the outlet flow and actual demand reasonable matching. The test result shows that the energy saving technology is well targeted, simple, practical and low cost. The pump units’ efficiency improves obviously, the consumption reduces by 10%, which greatly improve the oilfield economic benefits.


Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Xiang Li ◽  
Yuan Cheng ◽  
Wulong Tao ◽  
Shalake Sarulicaoketi ◽  
Xuhui Ji ◽  
...  

The production of a low permeability reservoir decreases rapidly by depletion development, and it needs to supplement formation energy to obtain stable production. Common energy supplement methods include water injection and gas injection. Nitrogen injection is an economic and effective development method for specific reservoir types. In order to study the feasibility and reasonable injection parameters of nitrogen injection development of fractured reservoir, this paper uses long cores to carry out displacement experiment. Firstly, the effects of water injection and nitrogen injection development of a fractured reservoir are compared through experiments to demonstrate the feasibility of nitrogen injection development of the fractured reservoir. Secondly, the effects of gas-water alternate displacement after water drive and gas-water alternate displacement after gas drive are compared through experiments to study the situation of water injection or gas injection development. Finally, the reasonable parameters of nitrogen gas-water alternate injection are optimized by orthogonal experimental design. Results show that nitrogen injection can effectively enhance oil production of the reservoir with natural fractures in early periods, but gas channeling easily occurs in continuous nitrogen flooding. After water flooding, gas-water alternate flooding can effectively reduce the injection pressure and improve the reservoir recovery, but the time of gas-water alternate injection cannot be too late. It is revealed that the factors influencing the nitrogen-water alternative effect are sorted from large to small as follows: cycle injected volume, nitrogen and water slug ratio, and injection rate. The optimal cycle injected volume is around 1 PV, the nitrogen and water slug ratio is between 1 and 2, and the injection rate is between 0.1 and 0.2 mL/min.


2005 ◽  
Vol 8 (06) ◽  
pp. 548-560 ◽  
Author(s):  
Gene M. Narahara ◽  
John J. Spokes ◽  
David D. Brennan ◽  
Gregor Maxwell ◽  
Michael S. Bast

Summary This paper describes a methodology for incorporating uncertainties in the optimization of well count for the deepwater Agbami field development. The lack of substantial reservoir-description data is common in many deepwater discoveries. Therefore, the development plan must be optimized and proven to berobust for a wide range of uncertainties. In the Agbami project, the design of experiments, or experimental design (ED) technique, was incorporated to optimize the well count across a wide range of subsurface uncertainties. The lack of substantial reservoir-description data is common for many deepwater discoveries. In the Agbami project, the uncertainty in oil in place was significant (greater than a factor of 2). This uncertainty was captured in a range of earth (geologic) models. Additional uncertainty variables, including permeability, fault seals, and injection conformance, were studied concurrently. Multiple well-count development plans (high, mid, and low) were developed and used as a variable in ED. The ED technique allowed multiple well counts to be tested quickly against multiple geologic models. With the net present value (NPV) calculated for each case, not only was the well count for the overall highest NPV determined, but discrete testing of each geologic model determined the optimum well count for each model. The process allowed for testing the robustness of any well count vs. any uncertainty (or set of uncertainties). A method was demonstrated quantifying the difference between perfect and imperfect knowledge of the reservoir description (geologic model) as it pertains to well locations. Introduction The Agbami structure is a northwest/southeast-trending four-way closure anticline and is located on the Niger delta front approximately 65 miles offshore Nigeria in the Gulf of Guinea (see the map in Fig. 1). The structure spans an area of 45,000 acres at spill point and is located in 4,800 ft of water. The Agbami No. 1 discovery well was drilled in late 1998. The appraisal program was completed in 2001 and included five wells and one sidetrack drilled on the structure, with each encountering oil pay. These five wells and a sidetrack penetrated an average of approximately 350 ft of oil. In this phase (Phase 3) of the development process, the key objectives are to construct a field-development plan and to obtain sanctioning. With drilling depths of up to 10,000 ft below mudline in 4,800 ft of water, well costs at Agbami will be at the high end of typical deepwater costs. Therefore, an important optimization parameter in the field development is the total well count. Agbami is typical of many deepwater developments in that the seismic is less than perfect and the appraisal well data are sparse relative to the area coverage. Therefore, subsurface uncertainty is high. In fact, the 5% probable oil in place is more than two times the oil in place at the 95% probability. As a result, the development process is challenged with determining the optimum well count for the field development across the wide range of subsurface uncertainty. Several key development decisions were determined in the previous phase(Phase 2) of the development process. These decisions were taken as givens in this study and are listed as follows:• The recommended pressure-maintenance scheme and gas-disposition strategy for the 17 million-year (MY) units is a combination of crestal gas injection with peripheral water injection.• The recommended pressure-maintenance scheme and gas-disposition strategy for the 14MY/16MY units is crestal gas injection only.• The facility design capacity recommendations are:- 250,000 stock-tank bbl per day (STB/D) oil.- 450,000 thousand cubic ft per day (Mcf/D) gas production.- 250,000 STB/D water production.- 450,000 STB/D liquid production.- 450,000 STB/D water injection.


2013 ◽  
Vol 60 (4) ◽  
pp. 185-193 ◽  
Author(s):  
Dong Liu ◽  
Huiqing Liu ◽  
Li Li ◽  
Meng Yu ◽  
Jun Gong ◽  
...  

2018 ◽  
Vol 140 (11) ◽  
Author(s):  
Kobra Pourabdollah

The gradual decline in the oil production rate of water flooded reservoirs leads to decrease in the profit of water flooding system. Although cyclic water injection (CWI) was introduced to reduce the descending trend of oil production in water flooded reservoirs, it must be optimized based upon the process parameters. The objective of this study is to develop all process design criteria based upon the real-time monitoring of CWI process in a naturally fractured reservoir having five producing wells and five injector wells completed in an Arab carbonated formation containing light crude oil (API = 42 deg). For this aim, a small pilot oil field was selected with water injection facilities and naturally producing oil wells and all data were collected from the field tests. During a five years' field test, the primary observations at the onset of shutdown periods of the water injection system revealed a repeatable significant enhancement in oil production rate by a factor of plus 5% leading us to assess the application of CWI. This paper represents the significant parameters of pressure and productivity affected during CWI in naturally fractured carbonate reservoirs based upon a dual porosity generalized compositional model. The results hopefully introduce other oil producer companies to the potential of using CWI to increase oil production in conventional water injection systems. The results also outline situations where such applications would be desirable.


1983 ◽  
Vol 23 (02) ◽  
pp. 339-348 ◽  
Author(s):  
T. Ahmed ◽  
D. Menzie ◽  
H. Crichlow

Summary Miscible-displacement processes have generally been recognized by the petroleum industry as an important enhanced oil recovery (EOR) method. Nitrogen flooding has become an attractive method for economical EOR. Since no previous studies have been undertaken to observe miscibility conditions directly during their development in an oil reservoir, a research program was initiated to investigate experimentally the mechanism by which miscibility could be achieved in a reservoir model undergoing high-pressure nitrogen injection. Several experiments were conducted in a low-permeability, consolidated sandpacked stainless-steel tube 125 ft long and 0.435 in. in diameter. The apparatus was designed to allow sampling at selected locations along the core tube enabling researchers to investigate fluid behavior during the process. A more-detailed representation of the nitrogen displacement process is formulated and the graphical chromatographic results are presented to illustrate the nitrogen miscibility in consolidated cores. Introduction Previous researchers have investigated, experimentally and theoretically, the problem of predicting the effects of dry-gas injection into a reservoir. Most earlier experimental studies were concerned primarily with the effects of changing pressure, temperature, and gas solubility on oil recovery during gas injection. Vogel and Yarborough conducted a number of laboratory tests on several different reservoir fluids to determine the effect of nitrogen contact by varying the amounts of nitrogen. They reported that the solution-gas gravity, oil density, and oil viscosity increased with continued contact by nitrogen. No previous studies have been conducted to observe miscibility conditions directly during their development in an oil reservoir. This experimental work was initiated to investigatecompositional changes taking place during displacing of crude oil by continuous high-pressure nitrogen injection,change in properties of the liquid and vapor phases during the nitrogen injection,miscible pressures for nitrogen displacement, anddistance from the injection point at which miscibility would be achieved. Experimental Apparatus and Materials Apparatus The experiment was designed to studyvaporization of oil by high-pressure nitrogen injection,mechanisms of nitrogen multiple contact miscibility displacement, andcompositional changes that take place between nitrogen and in-situ oil during the test. Fig. 1 shows a schematic of the equipment used to perform the experimental study. For the purpose of description, the laboratory apparatus may be divided into three parts: a laboratory oil reservoir model, an injection system, and a production and analytical system. SPEJ P. 339^


2019 ◽  
Author(s):  
Jiabo Liang ◽  
Liping Jin ◽  
Wenyong Li ◽  
Qiang Li ◽  
Hussein Kadhim Laaby ◽  
...  

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