Water production is a serious challenge when stimulating wells in mature reservoirs. Production results after acidizing sometimes reveal a higher water cut; in some cases this change is significant enough that the well is no longer able to flow unassisted. A typical acid stimulation in the field follows a predetermined pumping schedule, where diverter is squeezed into the high water cut interval prior to injecting acid into oil zones. The diverter volume is based on a rule of thumb and the acid is pumped after assuming that the diverter is efficiently sealing the high water cut zone. Several coiled tubing (CT) matrix stimulation jobs have yielded production results of 100% water cut.Prior to stimulation (a period of months or years), diagnostic logs were conducted to identify water producing intervals. Although, in some cases, the post-stimulation water cut may be as high as or higher than the water cut prior to the stimulation, suggesting that the diverter volume was not enough to seal the water zone. An innovative method is needed to confirm the isolation of high water cut zones before pumping acid, which would lead to increased oil production and reduce the risk of unintentionally stimulating water producing zones.

Te oil producer wells, in the southern are of Saudi Arabia, are mostly completed as horizontal open hole (OH). Some of these wells are dead or on itermittent production due to high water cut, which is caused mainly by water influx through carbonate fissures or fractures. Multiple water shut off (WSO) jobs using inflatable packers, were performed between 2005 and 2010 but failed during execution because of the packers setting failure in OH. The WSO candidate selection process starts with reservoir and production data evaluation, then requires a coiled tubing logging run to identify the water source and adjust the required isolating fluids formulation and volume. For the execution, there is a need to control the placement, inflation, injection and disconnect of the inflatable packers in order to ensure successful WSO treatment. This paper describes how the fiber optic enabled coiled tubing (FOECT) system, enabling realtime downhole data measurement, can optimize the WSO treatments design, execution and evaluation, and increase their success rate. For the job design, production logging tools were run with FOECT string to detect the water source, measure the BHT required for the formulation of WSO fluids, obtain a GR log, and get an X-Y OH caliper critical to decide the best setting depth for the inflatable packer and to confirm the required WSO fluids volume. For the job execution, the depth correlation for the packer setting was performed with the fiber optic bottom hole assembly FOBHA-GR. The inflation of the packer and the injection through it were monitored and adjusted realtime with the FOBHA-PTC measurement inside and outside the FOCT string. The confirmation of the packer setting and the release from it were confirmed with the world's first applications of FOBHA-Tension/Compression sub. Recent production results showed previously dead well flowed at significant oil rate with 10% water cut after performing a WSO with FOECT innovative solution. The integrated FOECT solution, eliminating engineering assumptions during the full cycle of design-execution-evaluation, is a proven WSO technique in OH, which can bring many wells back to economical production.

Измерение забойных параметров в режиме реального времени для повышения эффективности кислотных обработок на месторождении каспийского региона Мансур Аглямов, Данияр Агрынов, Артем Савин, Николай Кулинич, Антон Буров, Общество инженеровнефтяников, Константин Бурдин, Общество инженеров-нефтяников, Шлюмберже Авторское право 2014 г., Общество инженеров нефтегазовой промышленности Этот доклад был подготовлен для презентации на Ежегодной Каспийской технической конференции и выставке SPE, 12 -14 ноября, 2014, Астана, Казахстан.Данный доклад был выбран для проведения презентации Программным комитетом SPE по результатам экспертизы информации, содержащейся в представленном авторами реферате. Экспертиза содержания доклада Обществом инженеров нефтегазовой промышленности не выполнялась, и внесение исправлений и изменений является обязанностью авторов. Материал в том виде, в котором он представлен, не обязательно отражает точку зрения SPE, его должностных лиц или участников. Электронное копирование, распространение или хранение любой части данного доклада без предварительного письменного согласия SPE запрещается. Разрешение на воспроизведение в печатном виде распространяется только на реферат объемом не более 300 слов; при этом копировать иллюстрации не разрешается. Реферат должен содержать явно выраженную ссылку на авторское право SPE.

In many fields, high water production can cause adverse effects on the reservoir performance, which can result in production losses. To mitigate this situation, it is crucial to utilize water management to reduce water production, optimize oil production, increase the well life and revive dead wells. One of the options is utilizing a workover rig to isolate the water entry zone by running swellable or inflatable packers. This option is costly and time consuming, taking into consideration the time required to prepare the location for the rig, stripping out and returning back flowline and cleaning wells prior returning to production. To overcome this challenge, it was essential to look for an alternative solution that requires less time and cost. One of those solutions is isolating the water producing zone by rigless water shut-off (WSO), using mechanical isolation. This kind of operation is more challenging for extended reach horizontal wells. This paper highlights the mechanical rigless WSO method used to mechanically isolate a water contribution zone by utilizing fiber optic enabled coiled tubing (FOECT) telemetry and setting an inflatable packer combined with a capped with cement. This successful WSO treatment positively impacted the overall performance of a dead horizontal oil producer with 4,000 ft of reservoir contact. The WSO resulted in decreasing the water cut from 68% to 0%, and revived the dead well with 10 thousand barrels per day (MBOD) oil gain. Real-time downhole temperature, pressure (inside and outside the coil tubing) and casing collar locator (CCL) measurements, obtained by FOECT was utilized to get accurate packer setting depth, confirm packer setting and ensure the suitability of cement recipe slurry design. The whole cycle of candidate selection, job design, execution challenges, post job evaluation, lessons learned and the experience gained to optimize the similar future jobs are covered in this paper.

Drilling of multilateral wells has increased significantly over the past few years as one of the reservoir development strategies to maximize well productivity through maximizing reservoir contact (MRC). These complex wells impose big challenges with respect to well accessibility for rigless well intervention. Means to access those wells were developed to perform conventional coiled tubing (CT) operations, such as reservoir stimulation. One of the existing challenges is to perform production logging in these complex wells to quantify oil and water contribution of each open hole lateral and pinpoint fluids entry, mainly deep water inside these laterals. This challenge was encountered in a multilateral oil evaluation producer, which was drilled in a carbonate oil reservoir but died shortly after being put on production due to high water production from an unknown source. This necessitates the logging of each of the well's laterals to identify the water contribution intervals to allow for the proper remedial action on this well, as well as to determine the optimal well completion for this type of reservoir, including inputting to geological modeling. At present, there is no single production logging tool (PLT) that can be utilized to log each lateral selectively. Therefore, a combination of a multilateral tool along with a reservoir saturation tool was utilized to locate and access laterals selectively and to record a pulsed neutron log to determine the produced water velocity across each of the laterals. The pulsed neutron log was combined with three phase hold-up logs allowing the generation of production profiles of each lateral as well as the detection of water entries across these laterals. This paper discusses the planning, execution and results evaluation of the logging job on an openhole multilateral oil producer along with all the techniques, which were employed to overcome challenges encountered along the way to acquire the best possible data on each lateral.