Lost Circulation Materials
Wellbore instability caused by depleted zones or weak formations in maturing fields has led to considerable expenses due to lost circulation. Mitigating these expenses should not be complex; it only requires a change in approach from reactive to preventative. Innospec Oilfield Services (OFS) is an industry leader in lost circulation solutions — offering a wide range of LCM systems, depending upon your situation.
In situations where fluid loss is isolated, remedial treatments such as hesitation squeezes use high-concentration lost circulation material (LCM) pills to seal fractures or micro fractures. The purpose is to create a temporary bridging agent while drilling continues. However, in these remedial applications, the seals are not always strong enough to withstand the significant pressures coming from both sides of the wellbore.
For these reasons, OFS developed the RediSeal high fluid loss squeeze pill application to produce a viable, cost-effective method to form a tighter seal in order to produce a significant decrease in leak-off. RediSeal improves the compressive strength of the filter cake, thereby increasing leadoff hesitation. On average, compressive strength on these filter cakes is about 150-400 psi.
One of the most reliable LCM products available is Innospec’s Vanguard. Vanguard is a multi-purpose blend of large PSD of inert granular particulates sized for easy passage through downhole drilling tools in order to prevent seepage, heal up to major losses, prevent losses while cementing, help get cement to surface/casing point, and prevent cement fall-back. Vanguard easily mixes with all drilling fluids and is recommended for use to seal severe to total loss situations.
OFS offers efficient approach to prevent or stop lost circulation. One of the options is the fast-acting, single sack lost circulation solution named FRAC-ATTACK. FRAC-ATTACK has a proprietary diatomaceous earth blend specifically designed to provide a complete seal which improves formation integrity. FRAC-ATTACK allows heavier mud weights to be pumped as well as withstand formation pressures. It has also been proven effective in controlling underground cross flows and blowouts.
Case History: FRAC-ATTACK Improves WTX Operator’s ROL with Single Treatment
In Texas, a Culberson County operator started to experience total mud losses when they had drilled a section to 8,888’. Drilling was halted and, in an attempt to regain circulation, several conventional LCM sweeps were performed. They proved to be unsuccessful. The remaining treatment options available to operator were to cement and redrill the well or try an alternative lost circulation treatment.
OFS Technical experts recommended a program of a single FRAC-ATTACK pill. Frac-Attack is a proprietary diatomaceous earth blend specifically designed to provide a complete seal. After placing the FRAC-ATTACK pill, the well was shut in to let the pill heal. After eight hours, the well was re-opened and the backside monitored. After observing that the backside fluid level had slowly fallen and then stabilized, it was refilled and monitored for 30 minutes. Afterwards, circulating began with 90% returns achieved in the first 20 bbls. This was followed by a bottom-up circulation that yielded 98% returns. They operator then pulled out of the hole, picked up the directional drilling tools, and ran back in the hole. Able to get to bottom and circulate without further losses, drilling was resumed with no negative issues experienced.
StrataFlex is a unique blend of inert, resilient, and malleable particles designed to form an elastomeric sealant that forms an optimum seal in the fractures of depleted and weak formations. The product is available in fine and medium grades to cover a wide range of fracture sizes. It has been proven to prevent differential sticking. Compatible with all drilling fluids, StrataFlex can withstand high differential pressures while isolating and sealing fractures from further propagation.
- Contains a unique elastomeric sealant
- Inert, resilient particles