Can we use sea water in scale clean out job?

[nong]

We used filtered fresh water with NH4CL for circulate in Coil tubing job, however it's very expensive and consume time much. So we would like to use SEA WATER instead with any chemial additive, ex NH4CL to prevent clay swell(ion exchange), Bioside to kill bacteria, filtered to prevent fine particle, but wht about ion in sea water? can we treat it?
And other tough ques is "Is SEA WATER really harmful to the formation??"

Appreciate for any opinions

 

[ArtLift]

It's common to use seawater for workovers on marginal wells. But it has oxygen, small particles and many different ions. Because it has calcium, you should avoid using it with mud acid. Even with hydrochloric, it would probably be a good idea to use a spacer of NH4Cl. I would think you'd also want a biocide additive and deoxygenator.

 

[nong]

Yes, I think I can manage the clay swell issue, bacteria issue, but my concern is scaling or ion exchange from Ca+, Mg+ in seawater. Do you have any idea?

 

[rguill5]

It's not good to use seawater for workover operations b/c the barium in the seawater will mix with the sulfate in the formation water to form scale. This happend to us on a well a few months ago. We spent all kind of money on this new chemical BJ has to dissolve the scale.

 

[Jepster]

rguill5,
I believe that you've got the barium and sulphate mixed up as to where they derive. I have extensive North Sea experince with formation water barium (up to 5000 ppm) and seawater injection for pressure support, which is why we lost early wells that were produced and why the company that I work for developed the sulphate removal technology with nanofiltration (you couldn't remove all the ions due to breaking down of the clays and causing fines migration).

Jep Bracey
Flow Assurance Specialist
jtbracey@marathonoil.com

 

[TJWATKINSPG]

I would have to agree with Jep, there are many formations and down hole conditions that will accept the use of seawater as a workover fluid. Yet there could also be a undesireable chemical reaction with some of the ions in the formation water. Scale can be formed through a variety of paths and seawater carries with it almost every ion that is water soluble. A quick chemical analysis of your formation water would answer most of these concerns The truth will set you free. Best of luck. Geodude