A Novel Chemical Sand and Fines Control Using Zeta Potential Altering Chemistry and Placement Techniques
Authors: Singh Pratyush , van Petegem Ron 
Published: March 2015

Sand and fines production is one of the oldest problems in the petroleum industry and one of the toughest to solve. Today, many technologies and methods exist; in some cases some sand and fines production is manageable, while for others it cannot be tolerated at all. Also, many wells do not produce sand or fines from the onset and may not require an active sand control solution until later in their lives. Sand influx into the wellbore may lead to various down-hole and surface problems. Chemical sand control solutions have been around for many years and have always been attractive due to their ability to be installed without any restrictions to the well bore geometry. However due to the difficulties with placement, and in many cases their association with formation damage, there have been reservations regarding the use of chemical methods as a standard sand control method. This paper presents a unique and novel chemistry that increases the maximum sand/fines free rate without a significant reduction in permeability and discusses the placement techniques essential for a successful application. It includes a review of laboratory tests, treatment design considerations and study of some wells that have been treated with zeta potential altering chemistry.

Introduction

Approximately 70% of the world's oil and gas reserves are found in poorly/weakly consolidated reservoirs. Sand production has been a major concern to the industry for decades, and has become more critical today as higher drawdowns and deeper depletion schedules are implemented. Sand influx may lead to various problems such as erosion of valves and pipelines, plugging of production casing/liner, sand deposits in the separators and direct economic loss due to production limitations. Besides overburden and reservoir depletion another major mechanism that directly causes or enhances sand production is water breakthrough. Water breakthrough may cause the loss of natural cementation of the rock and alteration of the capillary pressure.

Mechanical methods are considered highly reliable and depending on the applications and economic drivers for the field or well; there are various options in the industry that range from highly sophisticated (Frac Packs, Expandable screens, etc.) to simpler systems (slotted liners, standalone screens, etc.). When sand production is predicted to become an issue during the life of the well, operators have to choose to install a mechanical sand-control system during the completion, perform an intervention during the life of the well or rely on reducing the sand production by choking back the well.

A major concern when a well is completed without any form of sand control or if the mechanical method has failed is that passive methods, such as reducing the drawdown will inhibit the commercial viability of the well or even the field. Hence the use of chemical methods becomes more attractive.

The introduction of an advanced chemical method that alters the zeta potential of sandstone formations, present a new remedial sand and fines control solution with little to zero reduction in the permeability.