Troll Horizontal Well Tests Demoristrate Large Production Potential From Thin Oil Zones

Seines, K.; Lien, S.C.; Haug, B.T.

doi:10.2118/22373-pa

Cited by 21 publications

(2 citation statements)

References 12 publications

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“…Horizontal wells have become a research interest among hydrogeologists, environmental scientists, and engineers in the past several decades, due to many technical advantages over vertical wells for thin aquifers [ Babu and Odeh , ; Hantush and Papadopulos , ; Muskat and Wyckoff , ]. For instance, horizontal wells are generally more productive than vertical wells because of the relatively long intervals or screens exposed to the aquifer in which they are installed [ Knut et al ., ; Maurer , ]. If installed in a coastal aquifer, a horizontal well could reduce salt water coning for a given production rate, which subsequently reduces the potential of seawater intrusion [ Sawyer and Lieuallen‐Dulama , ].…”

Section: Introductionmentioning

confidence: 99%

Intrawellbore kinematic and frictional losses in a horizontal well in a bounded confined aquifer

Wang

Zhan

2017

Water Resources Research

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Horizontal drilling has become an appealing technology for water resource exploration or aquifer remediation in recent decades, due to decreasing operational cost and many technical advantages over vertical wells. However, many previous studies on flow into horizontal wells were based on the Uniform Flux Boundary Condition (UFBC), which does not reflect the physical processes of flow inside the well accurately. In this study, we investigated transient flow into a horizontal well in an anisotropic confined aquifer laterally bounded by two constant-head boundaries. Three types of boundary conditions were employed to treat the horizontal well, including UFBC, Uniform-Head Boundary Condition (UHBC), and Mixed-Type Boundary Condition (MTBC). The MTBC model considered both kinematic and frictional effects inside the horizontal well, in which the kinematic effect referred to the accelerational and fluid-inflow effects. A new solution of UFBC was derived by superimposing the point sink/source solutions along the axis of a horizontal well with a uniform flux distribution. New solutions of UHBC and MTBC were obtained by a hybrid analytical-numerical method, and an iterative method was proposed to determine the well discretization required for achieving sufficiently accurate results. This study showed that the differences among the UFBC, UHBC, and MTBC solutions were obvious near the well screen, decreased with distance from the well, and became negligible near the constant-head boundary. The relationship between the flow rate and the drawdown was nonlinear for the MTBC solution, while it was linear for the UFBC and UHBC solutions.

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Section: Introductionmentioning

confidence: 99%

Intrawellbore kinematic and frictional losses in a horizontal well in a bounded confined aquifer

Wang

Zhan

2017

Water Resources Research

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“…To obtain the formation parameters, pressure transient analysis is often used. Many scholars had done study on interpretations of formation parameters using pressure data [22][23][24][25][26][27]. But for low permeability reservoirs, this work has not been done by considering threshold pressure gradient and stress sensitivity which cause the nonlinear flow.…”

Section: Introductionmentioning

confidence: 99%

Nonlinear Flow Characteristics and Horizontal Well Pressure Transient Analysis for Low-Permeability Offshore Reservoirs

Jiang

Teng

2015

Mathematical Problems in Engineering

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Threshold pressure gradient (TPG) and stress sensitivity which cause the nonlinear flow in low permeability reservoirs were carried out by experiments. Firstly, the investigation of existing conditions of TPG for oil flow in irreducible water saturation low-permeability reservoirs was conducted and discussed, using the cores from a real offshore oilfield in China. The existence of TPG was proven. The relationship between TPG and absolute permeability was obtained by laboratory tests. TPG increases with decreasing absolute permeability. Then, stress sensitivity experiment was carried out through depressurizing experiment and step-up pressure experiment. Permeability modulus which characterizes stress sensitivity increases with decreasing absolute permeability. Consequently, a horizontal well pressure transient analysis mathematical model considering threshold pressure gradient and stress sensitivity was established on the basis of mass and momentum conservation equations. The finite element method (FEM) was presented to solve the model. Influencing factors, such as TPG, permeability modulus, skin factor, wellbore storage, horizontal length, horizontal position, and boundary effect on pressure and pressure derivative curves, were also discussed. Results analysis demonstrates that the pressure transient curves are different from Darcy’s model when considering the nonlinear flow characteristics. Both TPG and permeability modulus lead to more energy consumption and the reservoir pressure decreases more than Darcy’s model.

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Horizontal simulation grids as alternative to structure-based grids for thin oil-zone problems: a comparison study on a Troll segment

Pettersen¹

2011

Comput Geosci

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The layering in reservoir simulation grids is often based on the geology, e.g., structure tops. In this paper we investigate the alternative of using horizontal layers, where the link to the geology model is by the representation of the petrophysics alone. The obvious drawback is the failure to honor the structure in the grid geometry. On the other hand, a horizontal grid will honor the initial fluid contacts perfectly, and horizontal wells can also be accurately represented. Both these issues are vital in thin oil-zone problems, where horizontal grids may hence be a viable alternative. To investigate this question, a number of equivalent simulation models were built for a segment of the Troll Field, both geology-based and horizontal, and various combinations of these. In the paper, it is demonstrated that the horizontal grid was able to capture the essentials of fluid flow with the same degree of accuracy as the geology-based grid, and near-well flow was considerably more accurate. For grids of comparable resolution, more reliable results were obtained by a horizontal grid than a geo-grid. A geo-grid with local grid refinement and a horizontal grid produced almost identical results, but the ratio of computing times was almost 20 in favor of the horizontal grid. In the one-phase regions of the reservoir, relatively coarse cells can be used without significant loss of accuracy.

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Troll Horizontal Well Tests Demoristrate Large Production Potential From Thin Oil Zones

Cited by 21 publications

References 12 publications

Intrawellbore kinematic and frictional losses in a horizontal well in a bounded confined aquifer

Intrawellbore kinematic and frictional losses in a horizontal well in a bounded confined aquifer

Nonlinear Flow Characteristics and Horizontal Well Pressure Transient Analysis for Low-Permeability Offshore Reservoirs

Horizontal simulation grids as alternative to structure-based grids for thin oil-zone problems: a comparison study on a Troll segment

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