Multivariate Fracture Treatment Optimization for Enhanced Gas Production from Tight Reservoirs

Rahman, Motiur; Rahman, Sheik S.

doi:10.2118/75702-ms

Cited by 3 publications

(6 citation statements)

References 20 publications

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“…(1) Which is subjected to bound constraints represented as (2) and design constraints represented as (3) to ultimately minimize (4) where, denotes the vector of free design variables (the superscript 'T' for transpose); l i 's and u i 's are constants or functions of (in the latter case the bound constraints constitute moving boundaries) representing the ranges of The function f(x) is to be minimized, which can be regarded as a single objective or multiple objectives [3,5,10].…”

Section: Direct Search Based Algorithmmentioning

confidence: 99%

“…Of course, economics and environmental issues are highly important in the industry. The operational parameters are to be designed as an optimal ranges of values for treatment (design) parameters, such as fracturing fluid viscosity (power law parameters), injection rate & time, proppant concentration, etc, so that a desired fracture geometry can be created to achieve the objectives in a given deeper rock formation [1][2][3][4]. This becomes a complex problem which must be combined with formation in-situ properties, hydraulic fracture growth based on volume balance of injected fracturing fluid, reservoir fluid flow through fractures and economics.…”

Section: Introductionmentioning

confidence: 99%

“…Various methods are available in the literature to perform each of these tasks in the overall solution process. The solution method adopted over decades is not well established [1][2][3][4].…”

Section: Introductionmentioning

confidence: 99%

“…To systematically deal with such complexities/uncertainties at various levels, the authors presented this work as a hydraulic fracturing design process for unconventional gas resources. An globally appropriate method to perform a task is selected based on various aspects of the job, the degree of sophistication required in modeling the overall problem and uncertainties involved with all the alternative methods [1,2,4]. In selecting a method for a particular node, a bi-directional information exchange with compatible accuracy levels is emphasized between the decision node and its connecting nodes in a Unconventional Gas Production from Hydraulically Fractured Well-An Application of Direct Search Based Optimization Algorithm system analysis approach.…”

Section: Introductionmentioning

confidence: 99%

“…In selecting a method for a particular node, a bi-directional information exchange with compatible accuracy levels is emphasized between the decision node and its connecting nodes in a Unconventional Gas Production from Hydraulically Fractured Well-An Application of Direct Search Based Optimization Algorithm system analysis approach. The solution tool is seldom considered as an integral part of the overall hydraulic fracturing design process for exploiting unconventional gas resources [1][2][3][4]. This work selects a mathematical solution technique and then selects one for hydraulic fracture design task assessing its special features.…”

Section: Introductionmentioning

confidence: 99%

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Unconventional Gas Production from Hydraulically Fractured Well-An Application of Direct Search Based Optimization Algorithm

2019

IJRTE

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Unconventional gas reservoirs are now the targets for meeting the demand for gas. These reservoirs are at the depth of more than 10,000 ft (even over 15000 depth as well) and are difficult to be exploited by conventional methods. For the last decades hydraulic fracturing has become the tool to develop these resources. Mathematical models (2D and pseudo-3D) have been developed for fracture geometry, which should be realistically created at the depth by surface controllable treatment parameters. If the reservoir rock is sandstone, then proppant fracturing is suitable and if the rock is carbonates, then acid fracturing is applicable. In both cases, proper design of controllable treatment parameters within constraints is essential. This needs proper optimization model which gives real controllable parametric vales. The model needs the most important analyses from geomechanical study and linear elastic fracture mechanics of rock containing unconventional gas so that fracture geometry makes maximum contact with the reservoirs for maximum recovery. Currently available software may lack proper optimization scheme containing geomechanical stress model, fracture geometry, natural fracture interactions, real field constraints and proper reservoir engineering model of unconventional gas resources, that is, production model from hydraulically fractured well (vertical and horizontal). An optimization algorithm has been developed to integrate all the modules, as mentioned above, controllable parameters, field constraints and production model with an objective function of maximum production (with or without minimization of treatment cost). Optimization is basically developed based on Direct Search Genetic and Polytope algorithm, which can handle dual objective function, non-differentiable equations, discontinuity and non-linearity. A dual objective function will meet operator’s economic requirements and investigate conflict between two objectives. The integrated model can be applied to a vertical or horizontal well in tight gas or ultra-tight shale gas deeper than over 10,000 ft. A simulation (with industrial simulators) was conducted to investigate and analyse fracture propagation behavior, under varying parameters with respect to the fracture design process, for tight gas reservoirs. Results indicate that hydraulic fracture propagation behavior is not uninhibited in deep reservoirs as some may believe that minor variations of variables such as in-situ stress, fluid properties etc. are often detrimental to fracture propagation in some conditions. Application of this model to a hypothetical tight and ultra-tight unconventional gas formations indicates a significant gas production at lower treatment cost; whereas the resources do not flow without any stimulation (hydraulic fracturing).

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Section: Direct Search Based Algorithmmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Unconventional Gas Production from Hydraulically Fractured Well-An Application of Direct Search Based Optimization Algorithm

2019

IJRTE

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Challenges and Solutions in Hydraulic Fracture Jobs in Land Fields in Alagoas, Brazil

Payao

Gomes

2007

Latin American &Amp; Caribbean Petroleum Engineering Conference

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In this paper, we will describe techniques used to overcome the problems faced on the hydraulic fracturing jobs during the oil-to-gas conversion campaign in the Pilar field, Brazil. The increasing demand for clean-burning natural gas in the Northeast of Brazil is fueled by the region's industrial growth over the recent years, and represents the main drive for the oil-to-gas conversion campaign witnessed in the wells previously producing at marginal oil rates from the Coqueiro Seco formation in the Pilar field. These old wells are now producing gas from the 3000 meters deep Penedo sandstone formations. One of the main steps to meet the goals for natural gas output in the Pilar field was the hydraulic fracturing campaign in the deep Penedo formation. The treatment design and execution process to create these fractures was quite distinct from the normal jobs aiming at increasing the oil productivity in wells producing from the shallow Coqueiro Seco formation. The Barra de Itiúba gas-bearing formation in the Furado, São Miguel dos Campos and Cidade de São Miguel dos Campos fields was also included, to a lesser extent, in the stimulation campaign aiming at the increase in natural gas production. This paper describes the completion strategy for the old wells converted from oil to gas producers, highlighting the problems faced and overcome during the hydraulic fracturing campaign. In deviated wells crossing the deep Penedo reservoir, the risk of multiple fractures and influence of tortuosity have been diminished through corrective techniques, unique for each one of the existing wells. In the early hydraulic fracture treatments performed in the Pilar field, premature screen-outs were commonplace, disencouraging the use of the technique. The need to produce gas brought new ideas to the battlefield, and their implementation led to results beyond expectations. Introduction The intense investiment to increase production of natural gas in the Alagoas, and its export through an expansion of the domestic natural gas transport network in the Northeast of Brazil, has the objective to keep up with the rapid growth in the regional gas consumption, due to an increase in the natural gas fired electricity generating capacity. Natural gas demand in Brazil, 1600 million scf/day in 2006, is expected to reach 4300 million scf/day by 2010, the direct result of investments in the sector estimated in US$ 22 billion. The natural gas processing plant in Pilar was built to develop the compressed natural gas market for automotive, residential and commercial use in Alagoas, and to export gas through the Pilar-Cabo pipeline. Before its construction, all natural gas produced in Pilar and its neighboring fields was exported for processing and pumped back in the form of liquified petroleum gas. Seventy million scf/day of natural gas are processed in the Pilar plant, producing liquified petroleum gas, industrial gas and gasoline. Given the increased demand for natural gas in the region, the gas-bearing formations in the Pilar area became attractive targets. Hydraulic fracturing played a major role in converting old oil wells producing at marginal rates from the shallow Coqueiro Seco reservoirs into good gas producers. The Pilar Field The Pilar, São Miguel dos Campos, Cidade de São Miguel dos Campos and Furado onshore gas and oil fields are located in the state of Alagoas, in the Sergipe-Alagoas Basin, in the Northeast of Brazil (Figure 1). The Pilar field, discovered in 1981, is located near the city of Pilar (Figure 2). The Pilar field is characterized by intense compartmentalization produced by deltaic sedimentation that resulted in a stacked package of more than one hundred pay intervals, and by the extensional tectonics that produced a large number of fault blocks (Figure 3). The deposition occurred during the rift phase of the geologic evolution of the Sergipe-Alagoas Basin, in the Lower Cretaceous. Intercalations of deltaic sandstones and shales compose the Coqueiro Seco formation, found at depths ranging from 500 to 2500 meters. These oil-producing sandstones have porosity of 20% and permeability of 100 mD.

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Stress Anisotropy, Long-Term Reservoir Flow Regimes and Production Performance in Tight Gas Reservoirs

Bahrami

Rezaee

Asadi

2010

SPE Eastern Regional Meeting

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Tight gas reservoirs normally have production problems due to very low matrix permeability and different damage mechanisms during drilling, completion and stimulation. Tight reservoirs need advanced drilling and completion techniques to efficiently connect wellbore to the formation open natural fractures and produce gas at commercial rates. Stress regimes have significant influence on tight gas reservoirs production performance. The stress regimes cause wellbore instability issues while drilling, which can result in large wellbore breakouts. The stress regimes can also control the well long-term production performance, since they affect permeability anisotropy. The preferred horizontal flow direction is expected to be parallel to the maximum in situ horizontal stress. The production and welltest data in non-fractured as well as hydraulically fractured wells in tight reservoirs have indicated the presence of a long-term linear flow regime due to the well and reservoir geometry and also as a result of the permeability anisotropy. The stress anisotropy leads to different permeabilities in different directions, and the natural fractures that are aligned with maximum horizontal stress; they might have larger aperture and greater permeability. Due to the more severe stress anisotropy in tight formations, permeability in maximum stress direction might significantly be larger than permeability in the direction of minimum stress. This study represents evaluation of parameters that might control well productivity and long-term well production performance in tight gas reservoirs. Geomechanical modeling is performed in order to understand the effect of stress anisotropy on aperture evolution of natural fractures in different directions. Furthermore, single well reservoir simulation study is performed in order to generate pressure build-up data for a typical tight gas reservoir, in order to evaluate effect of reservoir geometry and permeability anisotropy on late time linear flow regime, and also assess the well production performance for different well and reservoir conditions.

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Multivariate Fracture Treatment Optimization for Enhanced Gas Production from Tight Reservoirs

Cited by 3 publications

References 20 publications

Unconventional Gas Production from Hydraulically Fractured Well-An Application of Direct Search Based Optimization Algorithm

Unconventional Gas Production from Hydraulically Fractured Well-An Application of Direct Search Based Optimization Algorithm

Challenges and Solutions in Hydraulic Fracture Jobs in Land Fields in Alagoas, Brazil

Stress Anisotropy, Long-Term Reservoir Flow Regimes and Production Performance in Tight Gas Reservoirs

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