A Special Sealant Process For Subsurface Water Production
Authors: Smith C.W. , Mody B. 
Published: December 2007

Each year production is lost due to water influx from naturally occurring or induced channels or fractures. A special sealant process has been developed to help control subsurface water movement.

The special sealant process consists of two individual stages separated by a water spacer. Multiple treatments may be applied to control more severe down-hole conditions.

The first stage consists of about 200 gal/ft of a solids-free, non-Newtonian fluid with a viscosity of approximately 200 cp for matrix penetration. As much as 10 lb of solids per penetration. As much as 10 lb of solids per gallon may be added to this fluid for channels or fractures. This stage forms a very stiff gel when it contacts synthetic or formation brine. In fresh-water zones, where little salt is present, a preflush of concentrated brine is injected ahead of preflush of concentrated brine is injected ahead of the first stage.

The second stage consists of 10 to 30 sacks per foot of low water loss, accelerated cement per foot of low water loss, accelerated cement slurry. This cement slurry is used to complete the special sealant process by forming a permanent, high-strength plug. To fit specific well conditions, solids may be added to the cement slurry.

Successful sealant treatments have been performed in West Texas and New Mexico to correct performed in West Texas and New Mexico to correct subsurface water movement in producing wells. Most applications have been in naturally occurring or induced channels or fractures creating undesirable water flow. Sealant treatments up to 8,000 gal of first-stage fluid followed with 600 sacks of cement have been used.

Introduction

A special sealant process has been-developed and field tested to control underground water movement in subsurface formations and/or bottom water and to seal lost circulation zones in limestone, dolomite, and sandstone formations. In this study underground water movement problems were more prevalent in older producing wells than in newly prevalent in older producing wells than in newly drilled producers. Fewer, but very severe, problems with underground water flow or lost circulation were encountered during drilling.

Underground Water Movement Behind Casing

Underground moving water may be fresh, briney, or corrosive water located above the pay zone. This water may damage tubular goods, channel down behind the casing curtailing production, or channel up to the surface producing undesirable water. Conventional materials and procedures to control such water movement have had limited success. The special sealant process has had improved success in controlling underground water movement in recent applications.

Bottom-Water Production

Bottom water usually is produced with oil. It may or may not originate from the pay zone. In either case, the production of water may effect the rate and total volume of crude produced. Water production usually increases during the life of the production usually increases during the life of the well causing problems such as possible corrosion or requirement for larger lifting equipment. Source of this increase in water production is not well defined usually. Water may be produced through fractures (natural or induced) or fissures in the formation or through flow channels (formed during primary production) near the wellbore. Water-producing primary production) near the wellbore. Water-producing oil wells that are not properly treated, soon "water out" (WOR increases until the well is uneconomical to produce).

A variety of very good conventional water control materials and procedures such as organic and inorganic gels has been used to achieve deep penetration into zone to control matrix water production. The special sealant process described production. The special sealant process described in this paper is applicable for water production from both formation matrix and flowing water from fractures or channels.