The popularization and application of compound salt drilling fluid has become the new normal of drilling in Shengli Oilfield. In view of the problems existing in the exploration period, the construction plan and supporting measures are gradually improved to form a mature construction technology. Compared with the conventional polymer drilling fluid, the improved compound salt drilling fluid not only reduces the hole enlargement rate by 70.61%, improves the ROP by 30.59% and achieves 100% success rate of one-time logging, but also solves the reaming problem in the upper Ng Formation caused by sticking and wellbore stability problem in the lower Es Formation, which is worthy of popularization and application.
Aiming at the problem of drill pipe washout in the SHYB583 well in Saudi Arabia, the failure mechanism of drill rod is studied by analyzing the physical and chemical properties of thickened transition zone, stress analysis of transition zone under the combined action of tension, bending and torsion, flow field characteristics of inner channel, dynamic characteristics and fatigue analysis of drill string under the condition of actual well trajectory. The results show that the thickness of some parts of the coating of the failed drill pipe sample does not meet the requirements of SY/T 0544-2010 technical conditions for internal coating of petroleum drill pipe (seriously thin), and the drill pipe material contains high index nitride, which reduces the impact toughness of the drill pipe, thus reducing the fatigue life of the drill pipe. Under the combined load, the transition section of the drill pipe has a high stress level, and there is a significant eddy current near the transition zone, and the total pressure of the drill pipe caused by the internal flow field is large. The drill string does not produce more severe whirl, and the amplitude of axial vibration and transverse vibration is small, but the vibration frequency of bending stress is twice of the rotation frequency of the drill string. The large dogleg of the failed drill string increases the bending stress, which makes the drill string more prone to fatigue failure.
Microorganisms as the biotic factor are capable to participate in processes leaching of a rock of an oil layer directly, and also by secretion of various agents leaching -gases, acids, spirits, slime, etc. The basic mechanism leaching of a rock is formation of chelates by microbial agents with minerals of a rock. The order of carrying out of elements from minerals of rock of a class alumosilicates basically is defined by structure and property of the mineral. The elements making cristallic a lattice of a mineral will least intensively be mobilized; isomorphically replaced or exchange ions which are taking place on peripheral sites of mineral particles will most intensively be mobilized . Knowledge of physical and chemical features of a collector - the nature and a cementing mineral of a rock, his maintenance in a rock, type of cement (bazalic or pore type etc.) and other parameters, in the certain degree allow to predict probability of shaking of structure of a rock of a collector and speed of his destruction during technological influence. At selective leaching minerals of collector properties of rock can be modified both aside deterioration, and aside improvements of filtrational properties of pore spaces of a reservoir. Deterioration of collector properties can be shown, for example, in display sand recovery to wells-bottom (most likely in the first in sandy collectors with the small maintenance of a cementing material of montmorillonite type). In collectors with the high maintenance of a cementing material (bazalic or pore type of cement) leaching can promote substantial improvement of collector properties in connection with increase of permeability due to formation of secondary porosity.
Coalbed methane (CBM) is a kind of natural gas which is stored in the micropores and fractures of the “coal seam” and has not been transported out of the source rock. Conventional logging technology plays an important role in coalbed methane exploration and development. By analyzing the response characteristics of conventional logging of coalbed methane, coal bearing strata are accurately determined. Two methods of statistical model and volume model are established to analyze and calculate industrial components. Based on the study of adsorption isotherm and correlation between logging parameters and coal core gas content, the calculation method of coal seam gas content is determined In practices, the calculation accuracy of industrial components and gas content of coal seam has been significantly improved. Abstract: coalbed methane (CBM) is a kind of natural gas which is stored in the micropores and fractures of “coal seam” and has not been transported out of the source rock. Conventional logging technology plays an important role in coalbed methane exploration and development. By analyzing the response characteristics of conventional logging of coalbed methane, coal bearing strata are accurately determined. Two methods of statistical model and volume model are established to analyze and calculate industrial components. Based on the study of adsorption isotherm and correlation between logging parameters and coal core gas content, the calculation method of coal seam gas content is determined In practice, the calculation accuracy of industrial components and gas content of coal seam has been significantly improved.
Offshore Testing is a world-wide difficult problem with high danger and high risk. Many technical problems in the field of national offshore oil production are still pending. The safety of testing string is affected by multiple complex factors, and it is a complicated nonlinear problem with marked deformation and indeterminacy. The traditional risk assessment methods no longer meet the need for risk assessment of testing string. This paper adopts fuzzy comprehensive evaluation, which is based on the AHP (analytic hierarchy process) to assess the security of strings of deepwater gas well. First of all, it makes model, analyses the factors of the risk, divides the hierarchy and adopts AHP (analytic hierarchy process) to determine the weight of each factor. Secondly it seeks the experts’ reviews to establish the aggregation of comments, researches the effect of each assessment factors, makes fuzzy assessment of each factor, and makes fuzzy information of many describing different aspects of the object which has different dimensions quantification. Lastly, it makes fuzzy comprehensive evaluation in order to make sure the risk assessment level of testing string and achieve quantitative analysis of the risk factors that effect testing string and assess the safety of testing string scientifically.
This article aims to provide technical support for the high-efficiency and high-quality horizontal drilling construction in Zhengan shale gas field. Based the analysis of the formation characteristics and drilling conditions in the Zhengan area, the technical issues of horizontal drilling improving in this area are explained, and based on speed-up and efficiency-increasing technologies such as the resigned high-efficiency PDC bit, high-torque&long-life motor, drilling parameter optimization, friction&torque monitoring, friction-reducing and torsion-reducing tools, near-bit geology steering technology, rotary steerable drilling technology and loss control and anti-collapse mud etc., solutions for the issues have been proposed. Through the application of related technologies, it is expected that improvements for the ROP of horizontal wells in the area and the drilling cycle will be made.
This paper summarizes the main characteristics of foreign accident investigation through the in-depth analysis of typical cases of foreign accident investigation. This paper contains the process and methods of accident investigation abroad and the suggestions given in the accident investigation report. Through analyzing the relationship between accident investigation and accident management, this paper is going to give some suggestions for industrial accident management in domestic from the aspect of investigation.
Staged premium screen technology has been widely used in Shengli Oilfield, and works as a reliable method for sectional inflow control completion in horizontal wells. The completion plan of staged premium screen were originally optimized by flow loop test, however, the test procedure is usually as long as 12 working days. Therefore, a fast calculation method with processing time of no more than 2 days is proposed. When the well bore segmentation scheme is available, screen number as well as base pipe hole density are selected as the key parameters, and are optimized from one interval to the next on the basis of inflow control characteristics formula of staged premium screen. During the optimization of each interval, the parameters which best fit the requirements of “reasonable inflow control pressure drop” and “maximum discharge area” are determined from many alternative values. G6-P15 well, designed under the guidance of fast calculation method, obtained more balanced fluid and oil production profile versus Reference Well G6-P12. So far, 15 wells have been designed by this fast method. On average, the annual decline rate of daily oil production, the annual increase rate of water cut as well as annual mean of water cut of application wells are observed to be 36.7%, 9.4% and 7.9% lower than those of reference wells, respectively, while the annual accumulation oil production of target wells is 12.2% higher than that of reference wells. These successful applications prove that the fast calculation method has provided reasonable design.
In order to describe the shale-fissure's structure and distribution accurately, this paper combines with complex features of shale rock mass' multilevel micro-scale fissure network, putting forward that utilizing the multi-fractal method to describe the distribution of fissures with different dimensions. By choosing some oil field's block shale samples, obtain the fissure distribution characteristics by CT scanning and calculate with the multi-fractal theory, the results show that the shale rock mass' fissure distribute in a multiple-fractal regularity. The study results lay a solid foundation of subsequent press shale fissure network's formation and description.
A good protection of coalbed methane reservoir can facilitate its exploitation and usage of, cover the shortage of oil and natural gas supply for China, help cut greenhouse gas emissions, phase down environmental pollution and prevent mine accidents from happening. Firstly, damage mechanisms of coalbed methane reservoir in Qinshui basin of Shanxi province were comprehensively analyzed by X-ray diffraction (XRD), Scanning Electron Microscope (SEM), liner swelling test and hot rolling dispersion experiments, thin-section analysis, mercury penetration analysis, wettability measurement and evaluation of sensitivity. Based on this work, pertinent protection counter- measure study were conducted, the surface wettability modifier SLJ-2 and water sensitivity inhibitor SLYZ-1 were selected out, and then drilling fluid for coalbed methane reservoir in Qinshui basin of Shanxi province composed of 0.4%SLJ-2 + 0.5%SLYZ-1 was developed, which has minimal damage to permeability of ingredient under hygrometric state.
Reviewing of some Niger Delta oil field reservoirs indicate that most of them are brown fields, thereby vulnerable to challenges such as; coning due to reduced size of the oil column, low oil production and lack of access to the residual oil trapped between existing wells of the brown field. Due to coning occurrences in the Niger-Delta brown oil field, most wells have been shut-in and a lot of recompletions are being made in order to combat this problem. To proffer solutions to these technical challenges of these brown oil fields, this study seeks to review the potentials of re-entry horizontal well technology and its viable application to optimizing oil production from brown oil field. Re-entry horizontal well Technology involves a method of converting an existing vertical well into an horizontal well to save cost as oppose to drilling a fresh horizontal well from the surface. The object of the re-entry well is to reduced cost, especially in areas where drilling costs are very high. The re-entry horizontal in this research was represented by a virtual horizontal well to study the potentials of producing brown fields. The simulation paradigm studied was Black oil with light oil type variation of 32 O API. This article is therefore aimed at suggesting the conversion of existing vertical wells in the Niger-Delta into re-entry horizontal wells as a measure to optimize oil productionof these brown oil fields.
Using fresh water with small amount of air bubbles of size as small as a pencil dot, the existing flow meter in the flow system (hydraulics) was proved using the Sierra Ultrasonic meter (Innova-SonicTM Model 210i) with measurement medium taken at ambient temperature of 30oC. The procedures for installation of the ultrasonic meter were followed and measurement taken with transducers mounted using V-method and N-method respectively, on a pipe size of 20mm. The V-method and N-method gave average flow rates of 0.02918cf/sec and 0.04402cf/sec respectively. The V-method resulted in a meter factor of 1.9610, while the N-method resulted in a meter factor of 3.2511. The V-method and N-method gave relative percentage error values of 49% and 69.2% respectively. The V-method proved to be suitable for the pipe size of 20mm used in the experiment, with standard deviation of 5.3339x10-4 and variance of 2.84505x10-7 compared to standard deviation of 6.8x10-3 and variance of 4.624x10-5 obtained from N-method. It is recommended that a meter factor of 1.9610 obtained from V-method be applied on the existing meter. The liquid flow rates at measurement medium temperatures of 50oC and 70oC were determined by the use of poly-vinyl chloride and steel pipes respectively. It was observed that fluid flow rate increased with increase in temperature, and flow rate determined with ultrasonic flowmeter depends on material type as flow through poly-vinyl chloride pipe was generally higher compared with steel pipe at the temperatures values considered.
In view of the serious membrane pollution and short stable operation period of the existing heavy oil wastewater treatment process in a combined station of an oil field, the organic pollution is determined to be the main cause of the membrane pollution on the basis of the analysis of the wastewater quality and membrane pollutants. In view of the characteristic pollutants in heavy oil wastewater, the efficient degrading bacteria were screened by restrictive culture technology, and the strains were identified as Pseudomonas and Bacillus. The effects of environmental conditions on the growth of bacteria and the degradation of heavy oil by bacteria were investigated. In the existing process, biological treatment unit was added, simulation process was established, and long-term operation experiment was carried out. The results show that after biological treatment, the oil content of wastewater is less than 1 mg/L, COD is less than 100 mg/L, suspended matter is less than 1 mg/L, and the median particle size is 0.92 um, which is better than the first kind of water injection index (SY/T 5329-2012). Biological treatment effectively degraded organic pollutants in heavy oil wastewater and delayed membrane fouling. The loss rate of membrane flux was less than 15%. The microscopic morphology of membrane surface also showed that membrane fouling was effectively suppressed.
Block 2 is located at the northeastern end of the Sanzhao sag in the Liao Basin.The main oil layer is Fuyang oil layer.There is a problem that the sand body develops rapidly and the reservoir distribution is not clear. In order to solve the problem of modification, this paper uses the seismic attribute technique to analyze the lateral distribution characteristics of the reservoir in the Shang 2 block of the Sanzhao Sag in the study area. On the basis of establishing the forward modeling by ray tracing method, the influence analysis of mudstone interlayer thickness and sand-ground ratio forward analysis are carried out. The analysis results show that the sedimentary environment of the Fuyang oil layer is mainly the sub-facies of the delta diversion plain, which develops the diversion channel, the diversion bay and the mat-like sand microfacies, and the channel is mainly distributed in the eastward direction.
For improvement of contactless power transformer which is used in rotary steering system, this paper uses simulation method to study on the influence of the shape of the ferrite, the number os turns and installation position on the efficiency and power of the contactless power transformer. As well as, the author take several test to study the influence of environment, fixed position, etc. on this equipment and the regularity of power and efficiency. The research shows that the contactless power transformer is competent for rotary steering system, and the axial installation error impact the transmission efficiency and power which has the most power and efficiency at -3mm axial fixed position and ±3mm fixed position error can meet the rotary steering system requirements.
with the increasing time of water drive development in the Sazhong development zone, the oilfield has gradually entered the stage of high water cut stage or ultra-high water cut stage, and now it has entered the development stage of the high water cut period of the coexistence of the two drive. In order to extend the production life of the oilfield and plan the scale of production, based on the application of reservoir engineering method to calculate the natural decline rate and by grouping the Sa Pu oil layer and the Gaotaizi oil reservoir in the Sazhong oilfield, reducing the yield base of each year and re prediction of water drive production decline rule in Sazhong development area, which is concluded that the average decline rate is 7.46%. At the same time, the characteristics of tertiary oil recovery are analyzed, and the production replacement equation is established through the production demand under different production decline conditions. Based on the law of decreasing water drive and the change rule of chemical flooding production, the average chemical drive reserves in 12th Five-Year and the annual largest chemical drive reserves as tertiary oil recovery reserves, and the output forecast index of the sash development zone can be obtained.
The boreholes of the horizontal side-drilled wells with casing windows in Changqing Oilfield are all Φ118mm. Difficulties in the construction of small-hole drilling include high landing risk in the horizontal section, difficulty in slope prediction and trajectory control, and limited extension capacity of small wellbore. By optimizing the trajectory of the borehole, designing the trajectory adjustment section before the horizontal landing well, and introducing the equilibrium trend angle method to predict the slope of the directional tool, we improved the trajectory control ability; by calculating the stability of the drill string and the loss of cyclic pressure and analyzing the displacement extension ability, we optimized drill string selection and formed a precise trajectory control method based on sidetrack horizontal well trajectory optimization. Based on the analysis of displacement and extension ability, a non-standard drill pipe with a large diameter of 88.9mm and a small hydrophthalmia was selected. It is considered that the technical countermeasures and suggestions in this paper are of good reference and guiding significance for the development of sidetracked horizontal wells drilling in Changqing Oilfield.
When infill wells were drilled and massively upscaled within cluster well groups in the artifi-cial island B of the Bohai Sea,it was difficult with low efficiency in the design of anti-collision and obstacle-bypassing systems.According to the analysis of the overall anti-collision situation and characteristics of the infill wells,the data of previously drilled wells were accurately calibrated;the principles for cluster well group platform optimization and anti-collision design which were specified in the industrial standard were used to formulate the specific workflow for anti-collision trajectory design in order to massively upscale the infill wells,and thus form an overall optimal design method and optimized the drilling sequence,slot matc-hing relations,as well as anti-collision trajectory design parameters.Through multiple rounds of slots ad-justment and trajectory optimization,trajectory design and anti-collision analysis were conducted in 45 in-filling wells in a limited well platform space.The lowest separation coefficient values of all wells met the minimum limit of 1.5 specified by the industrial standard,and 70% of such values concentrated at more than 1.7,reducing the risk of borehole collision on the whole.The research results showed that the anti-collision optimization design technology can effectively solve the anti-collision design problem in large-scale infilling adjustment of well cluster groups,and improve the design quality and efficiency.
The leak of pipelines causes product loss which result to environmental damages. This can be minimized through careful pipeline supervision, early detection and location followed by quick responses to the incidence. The Niger delta region ushers an avenue where pipelines are regularly vandalized. These have led to severe environmental degradation as well as huge financial loss for the country. In this work, a mathematical model was developed for leak detection in pipelines. The result of the mathematical model showed good potential for leak detection in pipelines especially when used with alarm generator for better output. The developed model was validated with pipeline data from the Niger Delta region. The research study will be useful in identifying leaks in pipelines as well as reduction in pipeline vandalism.
With the current growing demand for oil, oil price and the concerns about future oil supplies increases the pressure in securing oil resources. Enhanced oil recovery processes are applied to recover oil not produced by natural and secondary energy drive of the reservoir. In this study, Simulation has been carried out on a hypothetical model using (ECLIPSE 100) as the simulator. Three cases natural depletion, waterflooding, and injection of low saline polymer were considered.5-spot pattern of four vertical producers wells and one vertical injector well was used as a hypothetical well model. Economics analysis were carried out in this three scenario to determine their net present value, profit per dollar invested, payout and Discounted flow-rate of return. The results shows that low salinity polymer flooding has the highest recovery of 62% and profit with NPV @ 10 ($412.9MM), payout 0.9 years, profit per dollar invested $25.9 and dcf-ror 82%. However, waterflooding gave recovery of 42%. NPV @10 ($ 317.3MM), payout 1.2 years, profit per dollar invested $20.8, dcf-ror 78%. Natural depletion gave recovery of 16.5 %, profit with NPV @10 (230.0MM), payout 1.0 years, profit per dollar invested $9.3, dcf-ror 78%. Decision rule was applied using NPV, DCF-ROR, NCR and payout which states that project with higher NPV, DCF-ROR, NCR and less Payout are more economically viable. The result of the three cases considered shows that low salinity polymer injection is more profitable followed by waterflooding and natural depletion.
