Abstract

A simple approach for determining the E.S.P. workover priority has been developed to maximize revenue where more than one E.S.P. has failed at the same time, especially as the number of pumping wells envisaged is increased throughout the oil field. Consequently, this approach may significantly improve the revenue.

The objective of this paper is to develop a simple model which will provide the solution to workover priority on several wells. A mathematical inequality has been generated for the above purpose. The criteria of the mathematical inequality are simplicity and the provision of a basis for quick decision making. Examples for illustrating the procedures and application in determining the workover priority are included.

Introduction

When an economic decision is desired to maximize the revenue in the event of more than one E.S.P. failing at the same time, the derived inequality will give you the optimal solution.

The generated mathematical inequality model involves some parameters such as, daily production, cost per barrel, distance between the rig site of each well as measured in days of rig travel time, etc.The derived inequality provides the optimal route in the event of two wells requiring workover and the rig being at a different site. For several wells (more than two wells) each two wells should be tested together, then we will obtain the sequence of the wells (the optimal route).

Studies examples to illustrate the procedures and applications in determining the workover priority are included.

Theoretical Discussion

To clarify the theoretical derivation of the inequality, the following is an application of the inequality in a general case.

Consider that we have the case of Fig. 1 described with the following information.

B and C - Two wells needing workover jobs.

Ql and Q2 - Daily production of B & C respectively,

Wt - Average workover performance time, in days.

X- Distance between rig site & well B, in days.

Y - Distance between well B and well C, in days.

Z - Distance between rig site and well C, in days.

tφ (Time zero) - Time starting from the rig site up to finishing the desired jobs, in days.

t1 - Time starting from after finishing the workover of the first well up to finishing the required workover jobs, in days.

P - Oil price - &BBL.

S1 & S2 - Cost per barrel of well B and well C, respectively - &/BBL.

Kl & K2 - Estimation of any other deductible payments and costs, (&), of well E and well C, respectively, e.g. tax, workover cost royalty, etc.

1. FIRSTLY

• If we choose the clockwise direction, "CWD", then well C will be starting to produce prior to well B by (Y + Wt) days, therefore,

PRODUCTION AT WELL C = Q2 (Y + Wt)

NET REVENUE AT WELL C = [P (Q2 (Y+Wt))] − [S2 (Q2 (Y+Wt)) + K2] Eqn (1)

• If we choose the counter-clockwise direction, "CCWD", then well B will start producing prior to well C by (Y + Wt) days, therefore,

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