Integrated Approach To Managing Formation Damage in Waterflooding

Carpenter, Chris (JPT Technology Editor)

OnePetro 

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 174174, “Integrated Approach To Managing Formation Damage in Waterflooding,” by Sergey Aristov, Paul van den Hoek, and Eddie Pun, Shell, prepared for the 2015 SPE European Formation Damage Conference, Budapest, Hungary, 3–5 June. The paper has not been peer reviewed.

Understanding of formation damage is a key theme in a waterflood project. An integrated multidisciplinary approach is required to determine an optimal design and strategy. An operator has developed a suite of tools to tackle these issues and help in adequate design and optimization of waterfloods.

Introduction

Many waterfloods in the operating phase do not perform as expected. Often this is because of well-injectivity issues where the required water quality for the injected water is either not properly defined (i.e., by the subsurface disciplines) or not properly managed (i.e., at the surface facilities). A rapid decline in well injectivity can result when injecting under matrix conditions, and a loss in reservoir containment caused by out-of-zone injection (OOZI) or a short-circuiting injector and producer can occur when injecting under fractured conditions, all negatively affecting reservoir sweep.

Subsurface and Subsurface-Modeling Work Flows

To determine an optimal waterflooding concept, it is important for the integrated work flow that the outcome of the sub-surface assessment be a range of technically feasible scenarios. These scenarios should incorporate the ranges in subsurface uncertainties combined with sub-surface concept options. The objective for the subsurface work flow is to define for each of these scenarios the production profile for the field, injection volume, quality of injected water, number of injection wells, subsurface targets, risk, and mitigations.

The subsurface work flow is illustrated in Fig. 1 of the compete paper. The following main steps are identified:

  1. Identification of potential water sources. All available water sources need to be identified, and a screening should be performed by assessing the compatibility of the injected water with the clays in the reservoir (i.e., risk of clay swelling).
  2. Injection targets for field development. On the basis of the expected reservoir performance for waterflooding in a field development, the targets for the total water-injection volume for the (full) field should be defined.