The Experts below are selected from a list of 324 Experts worldwide ranked by ideXlab platform
Amanat U. Chaudhry - One of the best experts on this subject based on the ideXlab platform.
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Gas Well Testing Handbook - Chapter 16 – Application of Decline Curve Analysis Methods
Gas Well Testing Handbook, 2020Co-Authors: Amanat U. ChaudhryAbstract:This chapter deals with analysis of decline curves during the transient and pseudo-steady-state flow periods. It discusses the classifications of production decline curves and their practical uses are with field examples including methods to forecast performance of horizontal and vertical fracture gas reservoirs. The chapter also explains the use of the general infinite-acting solution and reservoir properties, to calculate Wellbore conditions during the transient production period of a gas Well. Based on this understanding, the development and the pertinent relationship for three types of production decline curves on coordinate, semilog and, log–log graph paper are derived. Decline curve analysis is a useful tool for reserves estimation and production forecasts, and also serve as diagnostic tools and indicates the need for stimulation or remedial work. Production decline curves are of three types—exponential decline, hyperbolic decline, and harmonic decline.
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Gas Well Testing Handbook - Chapter 6 – Fundamentals of Pressure Buildup Analysis Methods
Gas Well Testing Handbook, 2020Co-Authors: Amanat U. ChaudhryAbstract:This chapter discusses pressure buildup test. It is the simplest test that can be run on a gas Well. If the effects of Wellbore storage can be determined, much useful information can be obtained. This information includes permeability, “k”, apparent skin factor, s′, and average reservoir pressure, ¯P R . The test consists of flowing the Well at a constant rate, q sc for a period of time, t p , shutting the Well in (at Δt = 0), and measuring Wellbore pressure increase with shut-in time, Δt. Horner developed the test, and this method of analysis is generally considered the best. Other conventional methods of analysis include the Horner plot, the Miller-Dyes-Hutchinso plot, and the Muskat plot. Horne showed that a plot of the shut-in pressure, p ws versus log (t p + Δt)/Δt results in a straight line for an infinite-acting reservoir. In the buildup tests, “t” refers to the drawdown period prior to a buildup and Δt refers to the shut-in or buildup time. Matthews, Brons, and Hazebroek (MBH), extended the application of the Horner plot to finite reservoirs. A buildup test is always preceded by a drawdown, and the buildup data are directly affected by this drawdown. Usually, the drawdown starts from a stabilized reservoir condition represented by the stabilized reservoir pressure.
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Oil Well Testing Handbook - Chapter 5 – Pressure Buildup Analysis Techniques for Oil Wells
Oil Well Testing Handbook, 2020Co-Authors: Amanat U. ChaudhryAbstract:Pressure buildup Testing is the most familiar transient Well-Testing technique, which has been used extensively in the petroleum industry. Basically, the test is conducted by producing a Well at a constant rate for some time, shutting the Well in (usually at the surface), allowing the pressure to build up in the Wellbore, and recording the down-hole pressure in the Wellbore as a function of time. From these data, it is possible to estimate the formation permeability and current drainage area pressure, and to characterize damage or stimulation and reservoir heterogeneity or boundaries frequently. In this chapter, ideal, actual buildup tests, and buildup tests in infinite-acting reservoirs and in developed (finite) reservoirs are discussed. Multiphase buildup tests and the variable-flow-rate test analysis are also covered in detail. This chapter treats pressure buildup test analysis and presents methods for estimating formation characteristics such as the reservoir permeability, skin factor, Wellbore damage, and improvement evaluation, including average pressure for Well drainage areas and the entire reservoir. In addition, analysis methods for after flow-dominated pressure buildup data are presented to identify a linear flow, near-Wellbore permeability changes or boundaries using both accurate pressure and total after flow fluid rate.
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Oil Well Testing Handbook - Chapter 10 – Application of Pressure Derivative in Oil Well Test Analysis
Oil Well Testing Handbook, 2020Co-Authors: Amanat U. ChaudhryAbstract:The pressure derivative application in oil Well test analysis involves the combined use of existing type curves in both the conventional dimensionless pressure form and the new dimensionless pressure derivative grouping. This new approach has combined the most powerful aspects of the two previously distinct methods into a single-stage interpretive plot. Use of the pressure derivative with pressure behavior type curves reduces the uniqueness problem in type curve matching and gives greater confidence in the results. Features that are hardly visible on the Horner plot or that are hard to distinguish because of similarities between a reservoir system and another are easier to recognize on the pressure derivative plot. A new technique presented in this chapter analyzes data in the bilinear flow period. New type curves are now available for pressure analysis of fractured oil Wells, and the problem in the analysis is reduced considerably with the use of these type curves. Prefracture information about the reservoir is necessary to estimate fracture parameters.
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Gas Well Testing Handbook - Chapter 7 – Predicting Future Deliverability Using Empirical Relationships
Gas Well Testing Handbook, 2020Co-Authors: Amanat U. ChaudhryAbstract:This chapter provides an overview of deliverability Testing, which is a commonly used technique for predicting short term and long-term behavior of gas Wells. Typically, a Well is flowed at different rates, and the pressure–rate–time response is recorded. From analysis of these data, information is obtained regarding the deliverability of the Well, and its ability to produce against a given backpressure at a given stage of reservoir depletion. Such forecasting is often required input for designing production facilities, planning field development, estimating payout time, and setting allowable rates. Deliverability Testing is done using multipoint flow tests. The chapter explains empirical equations to predict current and future gas Well deliverability. It also discusses deliverability calculations for both unfractured and fractured gas Wells. Finally, the chapter presents simplified procedures for gas deliverability calculations using dimensionless IPR curves and includes a discussion of a new method or deliverability calculations of fractured and unfractured gas Wells, which eliminates the need for conventional multipoint tests.
Hafeza Abu Bakar - One of the best experts on this subject based on the ideXlab platform.
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transient pressure analysis of geothermal Wells fractured during Well Testing
Geothermics, 2018Co-Authors: Hafeza Abu Bakar, Sadiq J ZarroukAbstract:Abstract Fracturing during injectivity Testing can take place in geothermal Wells when the reservoir has low permeability or when the Well has significant skin damage. The transient behavior (pressure falloff) of these Wells cannot be matched using existing Well test analysis methods. At the same time, modelling fracturing in geothermal reservoirs using rock mechanics and commercial finite element software is complicated due to several field uncertainties (e.g. formation height, reservoir permeability and porosity). In addition, rock mechanics data (rock stress, strain and Young’s modulus) are normally unknown in geothermal fields. This makes it difficult to develop an appropriate fracture model that matches the field test data. This study attempts to develop a fracture model without integrating rock mechanics. The model is setup with a simple grid using the TOUGH2 geothermal reservoir simulator and validated using the advanced pressure derivative transient analysis. Multiple subsets of fracture geometries were developed to represent the different stages of fracture closure during pressure falloff. The PyTOUGH code was used to simplify the running of the different fracture stages. The results are very promising and provide a clear justification and explanation for the commonly encountered fractured Well behavior. This model should be of use in matching data from geothermal Wells with similar pressure response.
Sadiq J Zarrouk - One of the best experts on this subject based on the ideXlab platform.
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transient pressure analysis of geothermal Wells fractured during Well Testing
Geothermics, 2018Co-Authors: Hafeza Abu Bakar, Sadiq J ZarroukAbstract:Abstract Fracturing during injectivity Testing can take place in geothermal Wells when the reservoir has low permeability or when the Well has significant skin damage. The transient behavior (pressure falloff) of these Wells cannot be matched using existing Well test analysis methods. At the same time, modelling fracturing in geothermal reservoirs using rock mechanics and commercial finite element software is complicated due to several field uncertainties (e.g. formation height, reservoir permeability and porosity). In addition, rock mechanics data (rock stress, strain and Young’s modulus) are normally unknown in geothermal fields. This makes it difficult to develop an appropriate fracture model that matches the field test data. This study attempts to develop a fracture model without integrating rock mechanics. The model is setup with a simple grid using the TOUGH2 geothermal reservoir simulator and validated using the advanced pressure derivative transient analysis. Multiple subsets of fracture geometries were developed to represent the different stages of fracture closure during pressure falloff. The PyTOUGH code was used to simplify the running of the different fracture stages. The results are very promising and provide a clear justification and explanation for the commonly encountered fractured Well behavior. This model should be of use in matching data from geothermal Wells with similar pressure response.
Ronglei Zhang - One of the best experts on this subject based on the ideXlab platform.
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a simulation method for modified isochronal Well Testing to determine shale gas Well productivity
Journal of Natural Gas Science and Engineering, 2015Co-Authors: Xiaoliang Zhao, Xinwei Liao, Ronglei ZhangAbstract:Abstract A simulation method to determine shale gas Well productivity is developed based on modified isochronal Well Testing. The method is reliable and accurate and reduces the Well Testing time. First, the physical properties and Wellbore parameters of the reservoir are obtained using the production data analysis method or Well Testing method. Then the production sequence and time sequence are determined. The production sequence is estimated by the production data analysis method, which can calculate gas Well production under different pressures. The Testing time interval and duration are determined by using the time value of the inflection points on the curve of the productivity coefficient and the time sequence. A modified isochronal Well Testing simulation model is developed based on the dynamic change patterns of the reservoir and Well tubing, the production sequence, and time sequence. Finally, the simulation model is solved by the conventional production Well test regression method, and the Well productivity and open flow potential are calculated. Using a shale gas Well in the Changqing oilfield, China, as a case study, field test results and simulation result are analyzed and compared. The results confirm the reliability of the new method in a shale gas reservoir; the precision of the shale gas productivity evaluation improved and the cost and duration of the test were reduced. This method can be expanded to other unconventional tight gas reservoirs.
Xianglong Li - One of the best experts on this subject based on the ideXlab platform.
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Well Testing model for multi fractured horizontal Well for shale gas reservoirs with consideration of dual diffusion in matrix
Journal of Natural Gas Science and Engineering, 2014Co-Authors: Leng Tian, Cong Xiao, Daihong Gu, Guangyu Song, Xianglong LiAbstract:Abstract Shale gas reservoir is typical unconventional reservoir, it's necessary to take advantage of multi-stage fractured horizontal Well so as to develop those kinds of reservoirs, which can form high conductivity hydraulic fractures and activate natural fractures. Due to the existence of concentration gap between matrix and fractures, desorption gas can simultaneously diffuse into the natural fractures and hydraulic fractures. This process can be called dual diffusion. Based on the triple-porosity cubic model, this paper establishes a new Well Testing model of multi-stage fractured horizontal Well in shale gas reservoir with consideration of the unique mechanisms of desorption and dual diffusion in matrix. Laplace transformation is employed to solve this new model. The pseudo pressure transient responses are inverted into real time space with stehfest numerical inversion algorithm. Type curves are plotted, and different flow regimes in shale gas reservoirs are identified and the effects of relevant parameters are analyzed as Well. Considering the mechanism of dual diffusion in matrix, the flow can be divided into five regimes: early linear flow; pseudo-steady state inter-porosity flow; the diffusion from matrix into micro-fractures; the diffusion from matrix into hydraulic fractures and boundary-dominated flow. There are large distinctions of pressure response between pseudo steady state diffusion and unsteady state diffusion under different value of pore volume ratio. It's similar to the feature of pseudo-steady state inter-porosity flow, diffusion coefficient and Langmuir parameters reflect the characters of pseudo-steady state diffusion. The numbers of stage of hydraulic fractures have certain impact on the shape factor of matrix and the inter-porosity coefficient. This new model is validated compared with some existing models. Finally, coupled with an application, this mew model can be approximately reliable and make some more precise productivity prediction.
