Innovative Approach to Stimulate Horizontal Gas Well Using DTS Technology Combined with Coiled Tubing in Saudi Arabia

Day 2 Mon, December 07, 2015

Burgos

Delgado

et al. 2015

An innovative methodology using a new bottomhole flow measurement tool and distributed temperature surveying was used to treat two openhole carbonate water injectors using coiled tubing (CT) equipped with fiber optics. The system capabilities were leveraged to control, in real time, the dual injection process and ensure that the treatment covered the entire horizontal section. The new level of efficiency of this approach was proven in the outstanding results of this stimulation campaign.The method takes advantage of the fiber optics present in a CT string to acquire, in real time, both downhole flow measurements and distributed temperature surveys to identify areas of higher and lower injectivity along the wellbore. It also enables clear and rapid evaluation of the depth to the level that bullheaded fluid would normally reach downhole. The real-time flow measurement is further used to optimize the stages of the treatment that aim at placing fluid across the interval initially poorly covered, as it gives direct feedback of the efficiency of the pumping through the annulus and CT.Matrix stimulation in water injector wells is often handled in a straightforward way by simply bullheading the treatment from surface. Used within the context of horizontal or highly deviated openhole wells, this frequently leads to an overstimulation at the casing shoe or along the first part of the zone of interest, and a significant section of wellbore is poorly covered or even remains untreated. The new approach not only enables visualizing where the treatment fluid goes, it also gives a new level of control of downhole injection, in real time. This new capability was taken advantage of within the context of long horizontal openhole water injectors, whose previous stimulation treatments left untouched a significant portion of the reservoir, even when complementing bullheading by the placement of treatment fluid with CT. The methodology enabled clear identification of which pumping method was beneficial to which interval. It also proved very efficient, leading to an increase in the injectivity index of the wells of nearly threefold, beyond the expectations based on previous stimulation interventions.The new downhole flow measurement tool and its use within this innovative workflow address many limitations usually encountered during the stimulation of horizontal or highly deviated openhole water injectors. In particular, the approach enables taking full advantage of the dual injection process, which often proves difficult to control and optimize in real time. The end result is an unprecedented level of efficiency of the process.

Section: Introductionmentioning

confidence: 99%

An Innovative Methodology for Real-Time Control and Optimization of Dual Injection Increases Efficiency of Carbonate Stimulation in Horizontal Openhole Water Injectors

Day 2 Mon, December 07, 2015

Burgos

Delgado

et al. 2015

“…For instance, such methods may not necessarily be adapted to long horizontal wells, or even to interventions during which the rates are so high that temperature fronts cannot be recorded with enough accuracy by DTS. The interpretation based on identification of warm-back or cool-down events during shut-in periods immediately following fluid injection can be used in most settings, but presents the disadvantage of being mostly qualitative, based on the comparison of temperature profiles acquired during the shut-in periods with a geothermal trace obtained at the beginning of the job (Cantaloube et al 2010;Garzon et al 2010). The last category of DTS interpretation techniques corresponds to a quantitative methodology that relies on the comparison and matching of simulated temperature profiles to the ones acquired with DTS.…”

Section: Introductionmentioning

confidence: 99%

Using Fiber-Optic-Enabled Coiled Tubing to Quantify Fluid Placement and Optimize Stimulation Effectiveness During Matrix Stimulation Treatments in Carbonate Reservoirs

Baez

2013

All Days

When performing matrix stimulation treatments, coiled tubing (CT) is a preferred placement technique due to the ability to spot fluid in front of the target zone(s). This method becomes a key solution when formation heterogeneities require a very selective fluid placement strategy.In today's industry, the most common approach is to design a treatment with volumes of stimulation and diverter fluids that are determined largely based on local practices. Often, it amounts to targeting a uniform stimulation, thus requiring a predefined amount of treatment fluid per length of total pay zone. That approach, although widely used and accepted, may not necessarily yield an optimum stimulation.We present an alternative technique that relies on the accurate quantification of fluid placement along the formation in order to define the respective volumes of stimulation and diverter fluids to be pumped. This method relies on the analysis of the distributed temperature sensing (DTS) data recorded by a fiber-optic line enclosed inside the CT and data processing through a fast interpretation algorithm to yield a zonal coverage profile. During a job, DTS data corresponding to the preflush can be used to estimate the initial placement distribution across the pay zone. This allows stimulation engineers to determine the best strategy for the subsequent well stimulation treatment, including fluid volumes and placement sequence. After every major pumping stage, a new DTS analysis assesses how the formation reacted to the treatment, improving placement strategy.This method has been used in multiple matrix stimulation treatments of injector and producer wells. The described innovative approach allows engineers to make more informed decisions between stages, optimizing fluid resources, fluid placement and, ultimately, stimulation effectiveness. It also leads to noteworthy advantages when designing new acidizing treatments, as companies can build on previous experience from similar wells and fields.

“…The analysis of DTS logs acquired during a post-injection shut-in has been performed previously to estimate acid placement (Garzon et al 2010) and also successfully in real time (Cantaloube 2010), but always on a qualitative basis. This technique is suitable for relatively moderate to low injection rates during bullheading, where temperature front movements may be seen with sufficient accuracy by the DTS.…”

Section: Introductionmentioning

confidence: 99%

Inversion of Distributed-Temperature-Sensing Logs To Measure Zonal Coverage During and After Wellbore Treatments With Coiled Tubing

Tardy

SPE Production &Amp; Operations

Weng

et al. 2012

Distributed temperature sensing (DTS) is a fiber-optic technology that provides continuous temperature profiles along the length of a well. When placing the fiber inside a coiled tubing (CT), one can monitor the temperature evolution while pumping as well as during a shut-in period. This evolution, in turn, yields some indications about the fluid-placement performance or zonal coverage. So far, interpretation of such DTS traces has been mostly qualitative. The work presented here demonstrates how DTS data can be used, coupled with an inversion algorithm and a forward model of fluid injection into a reservoir, to quantify the intake profile of treatment fluid along the wellbore. Recent field cases of matrix acidizing treatments in carbonate reservoirs are analyzed to illustrate the workflow and how it may yield valuable information. from Universidad de los Andes, Colombia.Kaveh Yekta-Ganjeh, P. Eng., SPE, is a senior technical engineer in coiled-tubing services at Schlumberger in Calgary. He has 10 years of experience in oilfield industry, all in coiled-tubing services. Yekta-Ganjeh joined Schlumberger in 2001 and has held different positions in field operation and technical support. He has worked in Iran, UAE, Libya, and Canada in land and offshore operations. Yekta-Ganjeh holds a BS degree in mechanical engineering from Sharif University of Technology, Iran.