Interference Test Analysis In Limited Reservoirs Using The Pressure Derivative Approach Field Example

Pressure communication between adjacent wells is frequently encountered in multi-stage hydraulic fractured shale gas reservoirs. An interference test is one of the most popular methods for testing the connectivity of a reservoir. Currently, there is no practical analysis model of an interference test for wells connected by large fractures. A one-dimensional equation of flow in porous media is established, and an analytical solution under the constant production rate is obtained using a similarity transformation. Based on this solution, the extremum equation of the interference test for wells connected by a large fracture is derived. The type-curve of pressure and the pressure derivative of an interference test of wells connected by a large fracture are plotted, and verified against interference test data. The extremum equation of wells connected by a large fracture differs from that for homogeneous reservoirs by a factor 2. Considering the difference of the flowing distance, it can be concluded that the pressure conductivity coefficient computed by the extremum equation of homogeneous reservoirs is accurate in the order of magnitude. On the double logarithmic type-curve, as time increases, the curves of pressure and the pressure derivative tend to be parallel straight lines with a slope of 0.5. When the crossflow of the reservoir matrix to the large fracture cannot be ignored, the slope of the parallel straight lines is 0.25. They are different from the type-curves of homogeneous and double porosity reservoirs. Therefore, the pressure derivative curve is proposed to diagnose the connection form of wells.

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Application of Pressure Derivative in Oil Well Test Analysis

Oil Well Testing Handbook ◽

10.1016/b978-075067706-6/50101-6 ◽

2004 ◽

pp. 359-371

Author(s):

Amanat U. Chaudhry

Keyword(s):

Oil Well ◽

Well Test ◽

Well Test Analysis ◽

Pressure Derivative ◽

Test Analysis

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Pressure-Derivative Approach to Transient Test Analysis: A High-Permeability North Sea Reservoir Example (includes associated papers 15270 and 15320 )

Journal of Petroleum Technology ◽

10.2118/12959-pa ◽

1985 ◽

Vol 37 (11) ◽

pp. 2023-2039 ◽

Cited By ~ 14

Author(s):

D.G. Clark ◽

T.D. Van Golf-Racht

Keyword(s):

North Sea ◽

High Permeability ◽

Pressure Derivative ◽

Test Analysis

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Type Curves for a Reservoir Subject to Active Bottom Water Drive

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.824.373 ◽

2013 ◽

Vol 824 ◽

pp. 373-378

Author(s):

I. Eiroboyi ◽

E. Steve Adewole

Keyword(s):

Steady State ◽

Bottom Water ◽

Early Time ◽

Dimensionless Time ◽

Pressure Derivative ◽

Test Analysis ◽

Type Curves ◽

Well Completion ◽

Dimensionless Pressure ◽

Large Pressure

The use of dimensionless pressure and dimensionless pressure derivative type curves has fully overcome the challenges experienced in the use of straight line methods and has brought about major successes in well tests analyses. Flow periods and reservoir boundary types are easily delineated and identified with the use of these curves. Furthermore, near wellbore characterization results are now more reliable. In this study, type curves for a reservoir subject to bottom water energy and a vertical well completion are developed to reveal specific signatures that can be used to achieve efficient pressure test analysis. Both early and late flow periods were considered for a wellbore of negligible skin and wellbore storage influences. Results obtained show that dimensionless pressures depart from infinite-acting behavior and attain steady state at dimensionless time of order proportional to the square of dimensionless reservoir thickness. Wellbore dimensionless radius affects dimensionless time of attainment of steady state inversely, which is rather accelerated by large fluid withdrawal rates (large pressure drawdown). On the other hand, dimensionless pressure derivatives show gradual collapse to zero after expiration of infinite flow. The rate of collapse is strongly affected by wellbore properties and pressure drawdown. Radial flow is generally characterized by a constant slope of 1.151 during which period the dimensionless pressure derivative gave a value of 0.5. Following assumption of negligible wellbore skin and storage, no early time hump is observed on dimensionless derivative curves.

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