Injection-production System Research Articles

Faults Delicate Description Technology by Well-to-seismic Integration is applied to the Sabei Development Area of Daqing oil field

Due to the effect of faults, there are some problems such as the high oil wells ratios, and the partial incomplete injection-production relationship which effect the yield of the development in the west of Sabei Development Area that has a high content of oil. The effective method to improve the water-flooding control degree in densely faulted area is to further study the developmental morphology of fault area and improve the injection-production relationship. This passage combines the advantages of interpretation seismic data with high resolution and vertical plane strong data continuity, forming a technology of the description of well seismic combined with fault by breakpoint data logging boot, seismic trace, identify the properties of body, and carry out the verification of the interpretation results of well seismic combined with fault by dynamic analysis methods, implement the fault’s shape in the top surface of each reservoir group of the study area, and applied the guidance of research to guide the adjustment of injection-production system in the West of oil area, improve the injection-production relationship of complex fault zone, achieving a good effect of tapping the potential.

Synchronous injection-production energy replenishment for a horizontal well in an ultra-low permeability sandstone reservoir: A case study of Changqing oilfield in Ordos Basin, NW China

It is difficult to build an effective water flooding displacement pressure system in the middle section of a horizontal well in an ultra-low permeability sandstone reservoir. To solve this problem, this study proposes to use packers, sealing cannula and other tools in the same horizontal well to inject water in some fractures and produce oil from other fractures. This new energy supplement method forms a segmental synchronous injection-production system in a horizontal well. The method can reduce the distance between the injection end and the production end, and quickly establish an effective displacement system. Changing the displacement between wells to displacement between horizontal well sections, and point water flooding to linear uniform water flooding, the method can enhance water sweeping volume and shorten waterflooding response period. The research shows that: (1) In the synchronous injection and production of horizontal well in an ultra-low-permeability sandstone reservoir, the water injection section should select the section where the natural fractures and artificial fractures are in the same direction or the section with no natural fractures, and the space between two sections should be 60–80 m. (2) In addition to controlling injection pressure, periodic water injection can be taken to reduce the risk of re-opening and growth of natural fractures or formation fracture caused by the gradual increase of water injection pressure with water injection going on. (3) Field tests have verified that this method can effectively improve the output of single well and achieve good economic benefits, so it can be widely used in the development of ultra-low permeability sandstone reservoirs.

Study on Injection-Production System Adjustment of Fault Block Reservoir Based on Equilibrium Displacement

This paper proposed a method of injection-production system adjustment to solve the problem that the water flooding effect was restricted because of the horizontal and vertical contradictions during the development process of fault block reservoirs. Considering the heterogeneity of reservoir, the Buckley-Leverett water flooding theory was applied to establish the relationship between the recovery and cumulative water injection. In order to achieve the goal of vertically balanced recovery of each section, the calculation method of vertical sectional injection allocation was proposed. The planar triangular seepage unit was assumed and sweep coefficients of different oil-water distribution patterns were characterized using multi-flow tube method. In order to balance and maximize the plane sweep coefficient, the calculation method of plane production system optimization was obtained. Then the injection-production system stereoscopic adjustment method based on equilibrium displacement was proposed with vertical sectional injection allocation and plane production system optimization. This method was applied to injection and production adjustment of BZ oilfield in southern Bohai. The effect of water control and oil increase was obvious. This method can greatly improve the effect of water flooding of offshore fault block reservoirs with the adjustment of injection-production system.

Dynamic Model and Analysis of a Sucker-rod Pump Injection-production System

Dynamic Model and Analysis of a Sucker-rod Pump Injection-production System

Practice and Effect of Fine Development in High Water Cut Stage of An Oilfield

In order to improve the development effect of An oil field Oilfield in high water cut stage, the author has adopted the method of fine reservoir characteristics description, fine injection-production system adjustment, fine injection-production structure adjustment and further studied on the reservoir development characteristics and channel sand body sedimentary model, remaining oil type and potential, single sand body tapping potential. The results show that, based on the correct understanding of the characteristics of reservoir sedimentation, using the favorable timing of encryption and carrying out the adjustment of injection and production system to determine methods of improving relationship of injection-production in different types of sand bodies and improve the control degree of water flooding. By studying on injection-production adjustment of different area, Well patterns and sand bodies, the matching adjustment of the two well patterns is realized, and three kinds of planimetric connectivity and longitudinal “345” subdivision boundaries are determined. Using the technology of “five directions” tapping potential and fine development, the oil field decline has been effectively controlled and the development effect has been improved.

Diseño experimental para la evaluación del daño de formación por contaminación microbiana en procesos de inundación de agua. Un caso de estudio colombiano

Microbial contamination is well known in the oil and gas industry and it occurs in most processes where water processing systems are involved. Microorganisms are spread everywhere, even in the subsurface, where operations of oil exploration and production are developed. For this reason, different genera of microorganisms can affect the Oil & Gas Industry. One of the major problems in oil mature fields undergoing secondary recovery is the contamination with sulfate reducing bacteria (SRB), caused generally by the injection water system (fresh and/or production) and/or of the reservoir (natural or by drilling fluids, completion, stimulation, etc.). This problem causes formation damage and microbiological induced corrosion (MIC) in the injection-production system. In many producing wells, formation damage by microbiological contamination is initially masked by a decline in reservoir pressure; however, initial production of H2S does provide a possible microbial contamination of water production, water injection and eventually petroleum reservoir. In some producing wells, H2S concentrations have exceeded the lethal limits of 250 ppm and there are cases of producing wells with levels above 1000 ppm. In this work, both a conceptual study and an experimental protocol were developed for the evaluation of formation damage by microbial contamination in water flooding processes. It is focused on finding the best stimulation treatment with biocides to H2S and corrosion control in Producer Wells of Oil Fields Undergoing Secondary Recovery as part of the comprehensive strategy to implement in the injection-reservoir-production system of the Chichimene field in Colombia. This study included the following stages:1. State of the art to define main bactericides, matrix stimulation treatments to H2S and corrosion control, removal of biomass (biofilm) and iron sulfide, etc. in producers wells. 2. Conceptual study of the formation damage by growth of sulfate-reducing bacteria.3. Experimental protocol for the evaluation of formation damage due to microbial contamination in water flood processes.4. Experimental evaluation of formation damage due to microbial contamination in cores of the Chichimene field, in Colombia. Finally, the main findings, conclusions and recommendations obtained in this study are shown.Keywords: microbial contamination, microorganisms, secondary recovery, stimulation, formation damage, sulfate-reducing bacteria, water production, waterflooding.

Rational Matching Injection and Production Pump for Rod Pump Injection-Production Systems

Single-well injection-production technology is an effective measure for stabilizing oil and water control of the high water cut oilfield. The rod pump injection-production system uses gravity to separate oil and water under the well; throught two sets of rod pumps, the water is injected back into the formation and the concentrate is lifted to the ground. Because of the particularity of pump structure and the complexity of its working environment, the calculation method of 1st pump efficiency is quite different from that of conventional pumps. Reasonable matching of the production pump and the infection pump is the key factor to reduce the water cut of the produced liquid. Based on the gas PVT theory and the principle of mass conservation, the gas volume equation of the down well was established in this paper, and the calculation method of pump efficiency of single well injection-production system was established, which was verified and corrected by 17 field test wells, with considering the influence of pump stroke loss and leakage. Combining the established mechanical model of the single-well injection-production system, aimed at the lowest water cut of the produced fluid, we use the enumeration method to design a reasonable matching of the production-injection pump and suction parameters, and formulated the selection template of production-injection pump type and the selection of the working system for the rod pump single-well injection-production system. It provides a basis for the process design of the single-well injection-production system and provides technical support for the field application of the fourth generation oil recovery technology.

Transfer Potential and Scheme Optimization of the Central Encryption Well Area of Block A-1

After the encryption adjustment in the central encryption well area of block A-1, the production in the well area is improved, but at the same time, the production decline of old wells in the well area is accelerated, and water injection is not effective in some oil wells. In order to improve the wells development effect, the adjustment of injection-production system in this well area is analysed in detail, three transfer schemes are designed, the feasibility of different schemes is compared and analysed, it is preferred to select scattered transfer as the best transfer scheme.

Research on optimization of development technology policy for low-permeability and low-pressure reservoir in Yangbaishan Block

There are poor physical properties and insufficient natural energy in the low-permeability and low-pressure reservoir of the Yangbaishan Block. Early this reservoir was mined by natural energy with a serious producing energy deficit. Subsequently, it was developed with mild water injection. During the water injection development, water quickly slid into the oil well along the crack, oil production decreased sharply and water content increased rapidly in the oil well, the water flooded well and the ineffective well gradually increased. Therefore, based on the reservoir geological characteristics, principle of injection and production balance is used to optimize reasonably for the development technology policy. Research indicates that the square inverted nine spot flooding pattern is recommended with a reasonable injection well direction of NE 72°and technical well spacing of 150 m. Reasonable injection-production ratio should be 2.16, reasonable technical well pattern density is 23 wells per square kilometer, and the average daily water injection rate of single well should be 11 m3. When injection-production system and injection proration are improved, water drive controlled degree is expected to increase by 16 %. This research can provide reference for the efficient development and safety management of other similar reservoirs.

The Development Effect of Oilfield Can Be Improved by Using Injection-Production System Adjustment

Oilfield development has entered into high water cut stage, the development difficulty is increasing, in order to raise recovery ratio and improve the development effect of the block, the injection and production system has been adjusted. The ratio of oil and water wells is reduced by changing the water injection well network; oil and water wells are complemented accordingly, the injection and production relationship of single sand body in this layer is improved; complementation of well network are carried out, and the injection and production relationship of other layers are improved; complementary utilization of well pattern and treatment of inefficient wells are adopted in fault area and so on, good development result is achieved, and it provides reference for development of water-drive remaining oil in future.

An independent fracturing water-flooding development method for shallow low-permeability thin oil layers in multi-layer sandstone reservoirs

Lots of multi-layer heterogeneous sandstone reservoirs have reached extreme high water content and high recovery after long-time water-flooding development, and their low-permeability thin oil layers (LPTOLs) have gradually been the main potential reserves. Therefore, taking the geology of LPTOLs into account, an independent water-flooding development (IWD) method with stratified hydraulic fracturing (SHF) for LPTOLs is put forward. The method combines undeveloped LPTOLs as an individual strata series in one injection-production system, and the HPTOLs even with low water content are abandoned in order to reduce the reservoir vertical heterogeneity. To realize economic benefits, mature stratified hydraulic fracturing is necessary to increase production. The key of IWD is selecting and combining appropriate LPTOLs in an individual strata series.Two development modes, OW-OL and WW-OL, are designed by different wells' perforations and the oil layers' distribution. The difference between these two modes mainly depends on whether the oil-wells perforate the HPTOLs connected with the LPTOLs. Upon an embedded fracture model for simulating hydraulic fractures, the oil production and water content of one LPTOL are calculated with different physical factors of reservoir and fractures. According to the cumulative oil production under different factors, their impact degrees are evaluated by gray relative analysis method. Permeability, oil layer thickness and oil viscosity are three main factors influencing the development of LPTOLs, and flow coefficient is a comprehensive index composed of these three factors. Therefore, the flow coefficient variation degree is a core indicator to evaluate the vertical heterogeneity of an individual strata series, and IWD will get better water-flooding effect with lower flow coefficient variation degree. In order to analyze the effect of IWD, 30 cases are designed with different flow coefficient variation degree, different thickness of HPTOL and different IWD modes. Oil production and water content variation of two development modes are studied by simulation. OW-OL mode is superior to the WW-OL mode on water-flooding recovery. That is because the oil is mainly produced from layered-LPTOLs with less water content, the vertical water-flooding efficiency is higher at the production side, and the whole displacement is more balanced in the whole OW-OL strata series. IWD of LPTOLs is not only suitable for Chinese sandstone oilfields, but also has a general significance for other multi-layer sandstone reservoirs owing high-potential LPTOLs.

A new approach of proration-injection allocation for water-flooding mature oilfields

Abstract This paper presents a new method of injection-production allocation estimation for water-flooding mature oilfields. The suggested approach is based on logistic growth rate functions and several type-curve matching methods. Using the relationship between these equations, oil production and water injection rate as well as injection-production ratio can be easily forecasted. The calculation procedure developed and outlined in this paper requires very few production data and is easily implemented. Furthermore, an oilfield case has been analyzed. The synthetic and field cases validate the calculation procedure, so it can be accurately used in forecasting production data, and it is important to optimize the whole injection-production system.

Practical Adjustment of Stratum Series for S Oilfield

In S Development Area, the production targets of each well net went bad and had interleaved distributions with old well patterns. Meanwhile, polymer flooding well patterns made the conflict of cohesion and dynamic regulation outstanding. Especially, Bei block, first using infill drilling modification, however, had troubles in extra high water period, such as long section of perforation, obvious inconsistencies between formations and high water of layers, which brought difficulties to dynamically adjusting. We selected 1.30 km2 west blocks in Bei block, made tests about sediment group restructuring to improve water flooding development effect, redistributed the series of strata and redistributed the flooding network according to the characteristics of development between the layers, combined comprehensive consideration with follow-up adjustment, such as primary network, injection production system and typed II reservoir the tertiary oil production, optimized the layers combination and well patterns arrangement, finally formed technical ideas of high water cut layers adjustment and well nets evolution.

The Study on well Pattern Adaptability of Single Sand-Body

According to sand-body genetic types, single sand-body is divided into five types include the polytectonic river-channel superimposed type, branching-river channel type, single river-channel type, sheet sand type and lentoid sand type. The use of multi-factor analysis to determine the index weight of control-degree of water flooding, recovery percent, water content, injection-production ratio and pressure distribution in different types of single sand-body, calculate different types of comprehensive Index of single sand-body adaptability. And analyze injection-production system to the well pattern adaptability in different types of single sand-body.

Research on Reservoir Flow Unit Classification at Block D404 of Xinzhan Oilfield in Songliao Basin

Remaining oil is enrichment relative, and the reservoir heterogeneity is serious at D404 block of Xinzhan oilfield, Songliao Basin. It is necessary of classification research to guide the infilling and the injection-production system adjustment. Through consolidation analysis of Core sample, porosity, permeability, shale content and flow zone index are selected as classification parameters of the division of flow unit. Using flow zone indicator method , the reservoir was divided into four types including I,II, III,IV types. The Classification results show that I type is the best reservoir and the strongest percolation capacity, and II,III types are the second, however IV type reservoir is the worst, the weakest seepage ability. the flow unit classification has solved some problem that the heterogeneity of reservoir has an influence on logging response, laying the foundation for the watered-out mechanism research and for the establishment of the identification standard.

Practice and Theory of Restructuring Water Flooding Series in Sabei Oilfield

In Sabei Development Area, with the developments of oilfield infill wells, the production targets of each set of well nets went bad and had interleaved distributions with old well patterns. At the same time, polymer flooding well patterns made the conflict of cohesion and dynamic regulation outstanding. Especially, Beierdong, which was the earliest block using infill drilling modification, got the good development effect at beginning, however, with the progress of oilfield development, there were some troubles in the development period with extra high water, such as long section of perforation, obvious inconsistencies between formations and high water of layers, which brought difficulties to dynamically adjusting. To fully exploit the remaining oil potential, this paper selected 1.30 km2 west blocks in Beierdong, made tests about sediment group restructuring to improve water flooding development effect, redistribute the series of strata and redistribute the flooding network according to the characteristics of development between the layers, combined comprehensive consideration with follow-up adjustment such as primary network, injection production system and type II reservoir the tertiary oil production, optimized the layers combination and well patterns arrangement, finally formed technical ideas of high water cut layers adjustment and well nets evolution.

The Establishment and Evaluation of an Effective Driving Pressure System in a Rectangular Five-Spot Pattern

For rapid production decline in low-permeability reservoirs, and for pressure transmission discipline between injection and production wells, effective driving pressure system is proposed. An effective driving pressure system can supplement enough energy to layer on time to curb production decline. The calculation of pressure drop at a point in infinite rectangular five-spot pattern is simplified into pressure drop overlay of two bounded rectangular reservoirs by mirror image and inverse mirror image theory. Layer pressure caused by a well with uniform flux fracture in the center of a bounded rectangular reservoir is gained by integrating instantaneous source function. Bottomhole pressure (BHP) of a well with infinite-conductivity fracture in infinite five-spot pattern is gained by pressure overlay while injection and production wells work at the same time. The method of establishing and the model of evaluating effective driving pressure system are gained by demanding for time limits on BHP of the fractured well. Results show that the efficiency of an injection-production pressure system is in directly proportionate to reservoir thickness and permeability, producing pressure drop; is inversely proportionate to production rate and oil viscosity; and is also related to length of fractured crack, well spacing, and well draining. The bigger the production rate, the smaller the terminal well draining while other factors are given; The bigger the permeability, the bigger the production rate while other factors are given; optimizing relationship between permeability, production rate, well spacing, and well draining makes pressure system between injection and production wells stable, and an effective driving pressure system be established.

A Study on Development Adjustment Technique in the Block Bei301

In view of the broken fault, rapid sediment, high heterogeneity，high structural dip and rapid reservoir change in Block Bei301, fine reservoir description research was implemented including small fault identification, fan delta sedimentary microfacies subdivision and facies-constrained modeling, and the problems existing in production were analyzed zone by zone and interval by interval. Moreover, other unique adjustment strategies were implemented including reservoir engineering and numerical simulation researches, well pattern thickening, injection-production system adjustment, separated layer system adjustment, as well as horizontal well technology. Finally, oilfield development effect was improved and a series of unique adjustment technologies for complex fault block reservoir were preliminarily formed, which provides reference for the development adjustment in similar oilfields

Research on Injection-Production System’s Effectiveness of Completely Fractured Well Arrangement

For rapid production decline, difficult production stability ability in low permeability reservoirs, establishment of effective injection-production system between injection and production wells is proposed to curb production decline. The effectiveness of an injection-production system should contain two aspects, supplementing enough energy to layer on time and overcoming starting pressure gradient. Completely fractured injection-production well arrangement is simplified into an injection-production one-way flow model, and layer pressure calculation formula is derived by separating variables while single-phase flow. Formulas of determining terminal parameters and driving pressure gradient of an effective injection-production system are gained by demanding for time limits on layer pressure and letting production well’s B.H.P (bottom hole pressure) equal or a bit bigger than a minimum pressure. Results show that the efficiency of a completely fractured well arrangement is related to permeability, oil viscosity, reservoir thickness, well spacing, well draining, production rate, and maximum producing pressure drop. The bigger the production rate, the smaller well draining should adopt, and the driving pressure gradient will also become bigger. For a certain reservoir, several sets of effective injection-production systems are possible, and which effective injection-production system is the best should determine by the principle of cost-effective development.

Development Characteristics and Development Adjustment Countermeasures of Wangji Oilfield

Wangji oilfield is a complicated fault-block oilfield, with many oil-bearing systems and severe heterogeneity. More and more problems and conflicts are exposed during the production and it is hard to produce the remaining oil, when entering into the medium-late water cut stage. In this paper, current development characteristics and main existing problems of Wangji oilfield are analyzed, including low development degrees of reserve, low recovery percent, low oil recovery rate, low perfecting degree of well pattern and so on. The combined research means of reservoir performance analysis and numerical simulation are used to analyze the distribution characteristics and rich region of remaining oil, then, the technology policies of vector well pattern[1] adjustment which is suitable for later development was put forward. Based on these, the injection-production system was adjusted, the injection - production corresponding relation was improved and the economic benefit was increased, which possesses reference meaning in the development of the similar oilfield in future.