**Application of Control Theory to Optimize Horizontal Well Location Producing from a Thin Oil Zone

Abstract At inception of a production rate regime, a horizontal well is expected to sweep oil within its drainage radius until the flow transients are interrupted by an external boundary or an impermeable heterogeneity. If the interruption is an impermeable heterogeneity or sealing fault, then the architecture of the heterogeneity must be deciphered in order to be able to design and implement an effective work-over or well re-entry to boost oil production from the reservoir. In this paper, therefore, the behavior of a horizontal well located within a pair of sealing faults inclined at 90 degrees is investigated using flow pressures and their derivatives. It is assumed that the well flow pressure is undergoing infinite activity, and each fault acts as a plane mirror. The total pressure drop in the object well is calculated by superposition principle. Damage and mechanical skin and wellbore storage are not considered. The main objective of our investigation is to establish identifiable signatures on pressure-time plots that represent infinite flow in the presence of adjacent no flow faults inclined at 90degrees. Results obtained show that the flowing wellbore pressure is influenced strongly by object well design, object well distance from each fault, and distance of each image from the object well. Irrespective of object well distance from the fault, there are three (3) images formed. Central object well location yields a square polygon, with two image wells nearer to the object well at equidistance from the object well, and the farthest image well to be 2d2. From the object well For off-centered object well location within the faults, a rectangular polygon is formed, with each image at a different distance from one well to another. Dimensionless pressure and dimensionless pressure derivative gradients during infinite-acting flow are (4.6052/LD) and 2/LD, respectively for all well locations within the faults.

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Stream depletion rate with horizontal or slanted wells in confined aquifers near a stream

Hydrology and Earth System Sciences ◽

10.5194/hess-14-1477-2010 ◽

2010 ◽

Vol 14 (8) ◽

pp. 1477-1485 ◽

Cited By ~ 13

Author(s):

P.-R. Tsou ◽

Z.-Y. Feng ◽

H.-D. Yeh ◽

C.-S. Huang

Keyword(s):

Point Source ◽

Horizontal Well ◽

Late Time ◽

Principle Of Superposition ◽

Stream Depletion ◽

Well Location ◽

Depletion Rate ◽

Drawdown Constraint ◽

Steady Solutions ◽

Time Required

Abstract. Pumping in a vertical well may produce a large drawdown cone near the well. In this paper, the solution is first developed for describing the groundwater flow associated with a point source in a confined aquifer near a stream. Based on the principle of superposition, analytical solutions for horizontal and slanted wells are then developed by integrating the point source solution along the well axis. The solutions can be simplified to quasi-steady solutions by neglecting the exponential terms to describe the late-time drawdown, which can provide useful information in designing horizontal well location and length. The direction of the well axis can be determined from the best SDR subject to the drawdown constraint. It is found that hydraulic conductivity in the direction perpendicular to the stream plays a crucial role in influencing the time required for reaching quasi-steady SDR. In addition, the effects of the well length as well as the distance between the well and stream on the SDR are also examined.

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Semi-analytical model of multiple fractured horizontal well across a discontinuity in a linear composite reservoir

Journal of Geophysics and Engineering ◽

10.1093/jge/gxab055 ◽

2021 ◽

Vol 18 (6) ◽

pp. 845-861

Author(s):

Junjie Ren ◽

Xiaoxue Liu ◽

Qingxing Wu ◽

Shuai Wu

Keyword(s):

Analytical Model ◽

Horizontal Well ◽

Superposition Principle ◽

Hydraulic Fractures ◽

Inversion Algorithm ◽

Type Curves ◽

Pressure Behavior ◽

Linear Composite ◽

Well Location ◽

Production Wells

Abstract Many geologic settings can be treated as linear composite (LC) reservoirs, where linear discontinuities divide the formation into multiple zones with different properties. Although there have been many studies on pressure behavior of production wells in an LC reservoir, most of the studies focus on vertical wells. The modeling of multiple fractured horizontal (MFH) wells in an LC reservoir remains limited. The goal of the present work is to propose a general semi-analytical model of an MFH well situated anywhere in a two-zone LC reservoir. This model can take into account the situation where the horizontal well intersects with the discontinuity and hydraulic fractures are distributed in both the two zones. According to the point-source function method, the semi-analytical solution for an MFH well in LC reservoirs is derived by using superposition principle, fracture discrete scheme and numerical inversion algorithm of Laplace transformation. Type curves of MFH wells far away from a discontinuity and across a discontinuity in an LC reservoir are drawn and analysed, respectively. Furthermore, the effects of some parameters on pressure behavior and rate response of an MFH well across a discontinuity are studied. This research finds that the pressure behavior and rate response of an MFH well across a discontinuity are significantly affected by the well location, properties of hydraulic fractures and formation properties.

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