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Abstract Wells that are already drilled and producing are the most viable sources of future earnings for all oilfield operating companies. Keeping these wells producing economically at optimal rates throughout their lifetimes is top priority. With time, some oilfield operating companies face with production related problems, such us water breakthrough. Production logging is well known technique for locating source of water breakthrough in oil and gas producers. In near-vertical, or slightly deviated wells, producing at high rates, traditional production logging tool string can deliver reliable results. On the other side, in deviated wells, producing at small rates, advanced production logging tool is required, due to presence of fluid segregation and recirculation within borehole. Our experience shows that wisely selected logging technique, depending on downhole logging environment, allows to locate source of water production with confidence for planning water shut-off remedial operations. In wells completed with standalone sand screens water shut-off operation might be complicated as often rig is required for pulling out of hole tubing with sand screens. Another method is to perform chemical water shut-off treatment that might be expensive in some cases. Alternative method is to confirm compact sand accumulation in the annulus and set through tubing bridge plug inside sand screens in wells that producing water from bottommost layers. Plug is deployed in wells without pulling out of hole tubing, as it can pass through restrictions, making this rigless intervention fifty times cheaper compared to intervention with rig. Field examples, presented in this paper, describe fit-for-purpose logging approach for locating source of water production accurately and executing unique rigless water shut-off operations in cased wells completed with standalone sand screens to increase hydrocarbons production in cost-effective way. After remedial operations we observed significant decline in water production and increase in oil rates in all wells that were intervened.
- Europe (0.46)
- Asia > Turkmenistan (0.30)
- Asia > Turkmenistan > Caspian Sea > Cheleken Contract Area > Block 2 > Lam Field > Zone 7 Formation (0.99)
- Asia > Turkmenistan > Caspian Sea > Cheleken Contract Area > Block 2 > Lam Field > Zone 6 Formation (0.99)
- Asia > Turkmenistan > Caspian Sea > Cheleken Contract Area > Block 2 > Lam Field > Zone 5 Formation (0.99)
- Asia > Turkmenistan > Caspian Sea > Cheleken Contract Area > Block 2 > Lam Field > Zone 4 Formation (0.99)
_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 208547, “Locating Source of Water Production and Performing Cost‑Effective Rigless Remedial Operations in Deviated Wells Completed With Standalone Sand Screens,” by Andrey Timonin, SPE, Schlumberger, and Eldar Mollaniyazov, Dragon Oil. The paper has not been peer reviewed. _ Field examples presented in the complete paper describe a fit-for-purpose logging approach for locating sources of water production accurately and executing rigless water-shutoff operations to increase cost-effective hydrocarbon production in cased wells completed with standalone sand screens. After remedial operations, the authors observed a significant decline in water production and an increase in oil rates in all remediated wells. Introduction The operator was granted a production license for exploration and development of oil and gas resources in the Cheleken Contract Area in the Caspian Sea. The area consists of two offshore oil and gas fields, Dzheitune (LAM) and Dzhygalybeg, in water depths between 8 and 42 m. The fields consist of two elongated anticlines at the eastern end of the prolific hydrocarbon Apsheron Ridge. The LAM field is a multilayer reservoir with pressure regimes producing at various gas/oil ratios with complex inflow profiles downhole. Most of the wells drilled in the LAM field were completed with 9.625-in. casing and 7-in. liner across the reservoir section. The A sand reservoir, at depths of 1500–1800 m, and the CH sand reservoir, below 2000 m, are produced separately by using dual-string tubing to avoid crossflow. Over time, depletion in reservoir pressure caused formation failure in the A sand reservoir. Wells producing from this formation began to produce sand. As a result, the operator had to change the completion strategy for newly drilled wells and recomplete some old wells by pulling dual-string completions out of hole and running in hole single tubing with sand screens across existing perforations. Some wells completed with standalone sand screens across the A sand reservoir experienced water breakthrough over time. Locating the source of water breakthrough and achieving timely intervention to shut off water inflow is paramount to keeping these wells producing at economically optimal oil rates. Overview of Rigless Wireline Logging and Intervention Techniques Rigless wireline logging and intervention techniques, the implementation and components of which are detailed in the complete paper, were used in several wells in the LAM field to shut off water production in a cost-effective way. The three field examples demonstrate rigless logging and intervention results in wells completed with standalone sand screens.
- Asia > Turkmenistan > Caspian Sea > Cheleken Contract Area > Block 2 > Lam Field > Zone 7 Formation (0.99)
- Asia > Turkmenistan > Caspian Sea > Cheleken Contract Area > Block 2 > Lam Field > Zone 6 Formation (0.99)
- Asia > Turkmenistan > Caspian Sea > Cheleken Contract Area > Block 2 > Lam Field > Zone 5 Formation (0.99)
- Asia > Turkmenistan > Caspian Sea > Cheleken Contract Area > Block 2 > Lam Field > Zone 4 Formation (0.99)
Enhancing Production Through Well Interventions Using End-to-End Evaluation Methodology
Oatey, Mark (Chrysaor) | Duff, Fay (Chrysaor) | Emslie, Neil (Chrysaor) | Christie, Steven (Chrysaor) | Rikabi, Rida (Chrysaor) | Henderson, Peter (Chrysaor) | Singh, Kamaljeet (Schlumberger) | Kumar, Apoorva (Schlumberger) | Agrawal, Gaurav (Schlumberger) | Dutta, Shaktim (Schlumberger) | Bajwa, Haroon (Schlumberger)
Abstract In this paper, an end-to-end evaluation service using well historical production, petrophysics and reservoir data combined with new logs to perform well intervention solution methodology is followed. Across four wells, production logging data is acquired and analysed to understand the current performance of different heterogeneous layers. Combining this with openhole data, additional perforations and reperforations are planned. Perforations are carried out using deep-penetration charges to create a larger and deeper flow path between the reservoir and the wellbore. Post-perforation production logs are carried out, and the data is analysed to understand the effectiveness of newly perforated layers. Detailed production enhancement of all four wells is discussed in the paper. The majority of the wells displayed a significant increase in production when compared with pre-intervention flow rates. Minor scale buildup in the production liner was observed during pre-perforation production log data which was observed to be cleared during post-perforation production log data. The deliverability of the wells had also gone up, with similar production rates at much higher bottomhole pressure compared with pressures before intervention. This also confirmed the effectiveness of deep-penetration charges during perforation in providing better conduit from reservoir to wellbore. Additional perforations carried out, based on the heterogeneity of the reservoir and combining the openhole data, proved to be highly effective, with high deliverability observed from these new layers. In conclusion, a successful production enhancement of these low-flow-rate gas condensate wells was achieved with an end-to-end solution. A highly heterogeneous reservoir with multiple thinly bedded layers presented challenges in understanding their productivity. The combination of pre-perforation production log and post-perforation production log enabled evaluation of the deliverability of the complex heterogeneous reservoir. Further, production enhancement from each reperforated interval was confirmed using a direct measurement, i.e., production log data instead of relying on surface flow rates to better understand the downhole dynamics.
- Europe > United Kingdom > North Sea > Central North Sea > Moray Firth > Moray Firth Basin > Witch Ground Graben > Block 16/27b > Britannia Field (0.99)
- Europe > United Kingdom > North Sea > Central North Sea > Moray Firth > Moray Firth Basin > Witch Ground Graben > Block 16/27a > Britannia Field (0.99)
- Europe > United Kingdom > North Sea > Central North Sea > Moray Firth > Moray Firth Basin > Witch Ground Graben > Block 16/26 > Britannia Field (0.99)
- (2 more...)
Abstract In complex situations production optimisation often differs from plan to reality. Ideally a set of known factors are used to determine the optimal course of action for a production well. However, in reality many factors remain unknown and of those that are, many are only known within a range of uncertainty. Uncertainty is persistent; whether in the form of failed instrumentation, erroneous metering or production reconciliation to multiple reservoirs in commingled completions. Further, well optimisation is always governed by economics and operational constraints. Such constraints limit well surveillance activities and compound uncertainty. These challenges united when a large bore deviated depletion drive gas well on a small unmanned offshore platform in the Otway Basin began to exhibit unexpected production decline. The large bore gas well with commingled reservoir completions was diagnosed as exhibiting liquid loading behavior. The intervention objective was to isolate the probable formation water source and restore water free gas production. A production log was required to confirm water was present and identify the source from three groups of completed intervals, each separated from one another using packers and mechanical sliding side doors. After risk assessments conducted during the intervention an active decision was taken to abort the work and not isolate the water source in favour of continuing cycled production to maximise gas recovery. Introducing an unknown, production logging identified that one of the three completed reservoir intervals was isolated by a closed sliding side door, previously believed to be open, presenting an incremental production opportunity. A follow-up intervention retained an objective of isolating the water source, with the additional objective of accessing the isolated reservoir interval. Detailed planning and uncertainty analysis was conducted ahead of the campaign with a key risk being the range of pressure possibly present within this target interval and the resultant wellbore cross-flow immediately after accessing it. Whilst the second intervention experienced mechanical failure, the ensuing pragmatic decisions that were taken "on the fly" ultimately resulted in a successful production outcome. The water source was isolated and incremental rate and reserves were achieved through perforation of blast joints opposite the target interval. This paper presents the workflows, tools & interventions used to diagnose production decline and optimise production from this challenging well. It is a case study in production surveillance utilising limited data, decision tree analysis and contingency planning for interventions performed with significant operational limitations. It includes the use of slickline production logging, tubing plugs, and electric wireline perforating in a strong cross-flow wellbore environment. This paper will be of interest to operators of unmanned platforms in hostile environments, commingled completions or wells with compromised production data. By integrating the learnings presented, engineers will get a head start when tackling similar uncertainties with their own challenging production optimisation activities.
- Well Completion > Completion Installation and Operations > Perforating (1.00)
- Reservoir Description and Dynamics > Formation Evaluation & Management > Well performance, inflow performance (1.00)
- Reservoir Description and Dynamics > Formation Evaluation & Management > Open hole/cased hole log analysis (1.00)
- (4 more...)
Production Optimization in Plio-Pleistocene Sequences by Through Tubing Perforations and Sand Consolidation in Rigless Activities: Italian Case Histories
Marotta, M. (Eni-Upstream, DICS Italy ) | Morsetti, C. (Eni-Upstream, DICS Italy ) | Mazzoni, S. (Eni-Upstream, DICS Italy ) | Diaf, R. (Eni-Upstream, DICS Italy ) | Cherri, R. (Eni-Upstream, DICS Italy )
ABSTRACT Complex case histories of rigless activities for Production Optimization, in Eni offshore wells, are presented as pattern of methodology, with low economic impact, to increment production in difficult geological and technical situation. Several offshore gas fields are present in Adriatic Sea (Italy) producing since the 60s, biogenic gas from multilayer metric and submetric sand reservoirs. The production decline in these mature fields is commonly offset by drilling new infilling wells which require time and high associated cost, meanwhile rigless intervention could achieve in very short time important results in production optimization. The identification of rigless intervention needs a good understanding of the field. Detailed field production analysis, well pressure trends, stratigraphic correlations and log analysis and well completion architecture are the main keys to identify target layers never or poorly produced. Furthermore it's fundamental to define if layers target of T.T. perforations are isolated by other productive zones or it is necessary their isolation. Formation Evaluation Cased Hole log, on Pulsed Neutron base, is planned to confirm the residual potential in target layers. The presented case histories show two different applications in Plio-Pleistocene Sequence, in complex well situations. Both wells completed with 2"3/8 dual completion. By geological analysis the interesting layers resulted in intra-packer intervals where a previous productive layer was present. First step in both presented cases was to isolate the existing watered out layers by a water shut-off polymer. Once isolated, the new intervals identified were opened using the through tubing perforation technique using 1"11/16 gun. Afterwards when production history of the wells showed a sand production issue, a chemical sand consolidation job has been performed on the both cases with successful results. These experiences tested the combination of different technologies; it enabled to put in production secondary layers at limited costs.
- Europe (0.89)
- North America > United States > Texas (0.28)
- Phanerozoic > Cenozoic > Quaternary > Pleistocene (1.00)
- Phanerozoic > Cenozoic > Neogene > Pliocene (1.00)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Sandstone (0.67)
- Geology > Structural Geology > Tectonics > Compressional Tectonics > Fold and Thrust Belt (0.46)
- Energy > Oil & Gas > Upstream (1.00)
- Materials > Chemicals > Commodity Chemicals > Petrochemicals (0.68)
- Well Completion > Completion Installation and Operations > Perforating (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Exploration, development, structural geology (1.00)
- Reservoir Description and Dynamics > Formation Evaluation & Management > Open hole/cased hole log analysis (1.00)
- Production and Well Operations > Well Operations and Optimization (1.00)