جستجوی مقالات مرتبط با کلیدواژه « نرخ نفوذ » در نشریات گروه « مهندسی شیمی، نفت و پلیمر »

Today, pilot wells are used for sampling the layers of the earth during deviation drilling. In order to reduce costs and facilitate operations in situations where it is not possible to use a pilot well for coring, coring studies are carried out in a deviant manner. Investigating the effect of drilling parameters on penetration rate in core drilling of deviated wells is important to optimize operations. In this regard, the rate of penetration is studied and simulated by preparing concrete samples for coring in a deviant way with laboratory devices, so that it reaches the most optimal state with the least amount of time, along with the necessary safety. In this research, cubic concrete samples with uniaxial compressive strength of 30 MPa and porosity of 31% have been used, and the effect of these parameters on the rate of penetration has been investigated by applying various weight on bit and angles of deviation. According to the experiments, the direct effect of the weight on bit on the penetration rate until reaching the turning point and the optimal value was observed. Also, by increasing the extra weight on bit, it causes a change in the mechanism of the bit's performance in drilling and loses its tangential state and causes the small particles of the sample to be torn off, which reduces the life of the drill bit.

Time and cost are of great important issues in each project. Therefore, in the drilling industry as well, which is one of the most costly industries, there should be taken appropriate measures to save time and cost. In drilling, the operation can be carried out at a lower cost and time, by choosing the appropriate tool, as well as predicting accurate and timely parameters and probable problems. In this regard, one of the most effective strategies is to investigate field data and subsequently development and improvement of tools for the achieved results. In the drilling industry, in order to identify the problem and improve the drilling performance, generally, either laboratory tests or empirical models are used in accordance with previous experience. In this research, we tried to use novel methods and intelligent modeling to predict the penetration rate in drilling operations. For this purpose, artificial neural network (ANN) approach was used. In this paper, using an artificial neural network and data from Shadegan oil field drilling data (400 data), a model was developed to predict the rate of penetration, and then the results were compared with the results of modeling with multivariate regression. To evaluate the main characteristics of the model, its accuracy was measured using adjacent wells data. The results of the research showed that the correlation coefficient for the neural network is 0.97, and determination coefficient is 0.94 and the error histogram rate is proportional to the zero error 0.005, while the corresponding value in the statistical analysis the correlation coefficient is 0.94 and the determination coefficient is equal to 0.89, which indicates a higher accuracy of neural network modeling.

Drillability of rock is defined in terms of a large number of parameters. However, in most drilling rate models uniaxial compressive strength (UCS) was used as rock drillability. There is a paucity of researches to combine rock drillability with the penetration rate model. Thus, in this study, rock drillability will be calculated based on the penetration rate. BYM was chosen as drilling rate mathematical model to normalize the penetration rate into operational parameters. After eliminating effects of drilling parameters, regression method will be used to evaluate relationships of rock paramters (such as Confined Compressive Strength (CCS), UCS, porosity, clay content, density, Poisson’s ratio, and internal friction angle) with drilling rate. Then, the best parameters of rock based on determination of coefficient will be selected to compute rock drillability. To define coefficients of this model, multiple non-linear regression will be used. The comparison between the modified version of BYM with rock dirllability index and the prior BYM will be done to validate the proposed method. For this research data were gathered from one vertical well in Karanj oilfield. Results indicated that rock parameters significantly affect the penetration rate. Evaluating relationships of understudied rock parameters with drilling rate revealed that UCS, CCS, porosity and shale content have high determination coefficients. The comparison between modified BYM and original BYM showed that applying computed rock drillability using three rock parameters (i.e. CCS, friction angle, density and Poisson’s ratio clay content) in BYM improves accuracy of prediction.

Summary Due to the importance of the rate of penetration and hole cleaning in directional wells to reduce the costs, after detection of critical inclination, the relationship between the effective parameters has been studied in an experimental flow loop. The cuttings, used in the tests, have had a specific size distribution in three types of sand, silica and limestone. The results illustrate that the hole cleaning index (HCI) of powder types in comparison to non-powder types is higher. The effects of bit and pipe rotation on the HCI have been studied in this research work. In this regard, there is an optimum point of the HCI for each of these effects. The end point and the length of the cutting bed have the same behavior. The larger density and lower size cuttings, compared to the lower density and larger size cuttings have higher HCI. In addition, the effect of the shape and size distribution of cuttings on the HCI seems to be remarkable.  Introduction Reparability, durability, cost, drill ability and many other parameters are important in using the bits. Based on these parameters and the softness or hardness of the formation, a bit is selected. The cuttings that are generated in directional drilling, based on the bit type and formation type, have different sizes, shapes, densities and volumes. In this paper, the hydraulic effect after releasing the wait on bit is discussed. Hole cleaning is a key parameter in extended reach drilling, especially in critical inclination periods, where the probability of the different sticking types is increased. The critical inclination is the angle that has the worst hole cleaning. In this research, by applying discrete angles in laboratory tests, one specific angle is determined as the critical point, and in this regard, the effect of size, shape, density and volume of cuttings are studied.

Unlike traditional drilling methods which often reduce the permeability of the rocks drastically, drilling method using laser technology increases the permeability of the rock and ultimately increases well oil production. Rock drilling using laser technology, is a process for removal of stones in which the thermal stress is used to break the stone into smaller pieces and removing debris and small stones left are carried out by the standard evacuation procedures. The rock laser drilling operation depends on wave laser parameters, beam characteristics and associated gas cleaning. The main objective of this article is studying pullsednd:yag laser technology strategy, in order to increase the penetration rate and rock drilling parameters that affect the use of lasers; also at the end of this article, the use of laser technology to reduce drilling costs, is presented.