Inflow Control Research Articles

Current Pattern of Use and Impact of Pringle Maneuver in Liver Resections in the United States

BackgroundPringle maneuver (PM) is used for inflow vascular control during hepatectomy, but its use remains controversial. We aimed to report its pattern of use and association with postoperative outcomes. MethodsWe identified hepatectomy patients using the liver-targeted National Surgical Quality Improvement Program database (2014-2016). Associations between PM and posthepatectomy liver failure (PHLF), receipt of blood transfusion, and total hospital length of stay (LOS) were evaluated. ResultsWe identified 7870 patients (74.9%) with no Pringle maneuver and 2632 (25.1%) with PM. PM patients were older (median age 61 versus 60 y, P = 0.002) and had higher ASA scores (76.1% versus 71.4% were ASA 3-4, P < 0.001). PM had more malignancy (83.0% versus 73.0%, P < 0.001), neoadjuvant therapy (37.7% versus 28.8%, P < 0.001), total lobectomy (30.6% versus 23.2%, P < 0.001), open resection (90.8% versus 74.9%, P < 0.001), and longer operations (246 min versus 212 min, P < 0.001). PM was associated with longer LOS (0.36 d, 95% confidence interval [CI] 0.11-0.60) and increased risk of PHLF (odds ratio [OR] 1.36, 95% CI 1.11-1.66), although not clinically significant grade B/C PHLF (OR 0.82, 95% CI 0.57-1.19), but was not associated with receipt of perioperative blood transfusions (OR 1.00, 95% CI 0.69-1.64). ConclusionsPM is associated with similar clinically significant PHLF and transfusion requirements but longer LOS compared with no Pringle maneuver.

Research and Field Application of Adaptive Inflow Control Technology

In view of conventional inflow control completion technique can not control water directly, the valid production period is relatively short, the control water effect become worse after bottom water breakthrough, easily lead to reservior second damage. Based on problem above, this paper presents an adaptive inflow control well completion technology, that uses adaptive inflow control device and precision sand filtering net control water screen, realizing to adjust the resistance of oil and water automaticlly, improving infow profile and oil well recovery, moreover, the adaptive inflow control well completion technology has the features of simple construction, high reliability and strong adaptability. Therefore, from the technological principle and characteristics, key implemental technology, the tool of adaptive inflow control device and screen, construction technology and other aspects of adaptive inflow control well completion technology, adaptive inflow control well completion technology were studied. The technology was applied in horizontal well completion in the B oilfield. After application, the oil production increased by 5 times, the oil production period of low water content was prolonged 400 days, a good effect of controlling water coning and increasing oil was acheved. The application suggests that adaptive infow control well completion technology can improve the effect of inflow control screen well completion that could be applied in the wells to increase the oil production.

Guest Editorial: Completion-System Reliability: Where Have We Been and Where Are We Going?

Guest editorial All completions systems should enable the safe and profitable extraction of reserves. Implicit in this statement is the presence of a stable, consistently performing completion system—in other words, a system with reliable hardware. This means that the completion system will enable production (or injection) with no system failures, over an expected span of time. This time span can range from 1 week for unconventional completions (fracturing plugs) to 30 years for deepwater completions. In all cases, reliable operations over some time t, or R(t), is the expectation. A goal for the completion system designer should be to maximize the useful life of the completion system (Fig. 1). In practice, this is achieved by minimizing what can be termed “infant mortality” and delaying the start of wear out. To maximize R(t), reliability of components, configurations, and processes must be maximized. Component Reliability Innovation leads to higher performance and optionality for most types of completion components. However, the development of new, innovative components also requires that their reliability be a design priority. Today, important drivers of component reliability are industry codes and standards (ICS). The American Petroleum Institute, the International Organization for Standardization, and NOR-SOK are ICS organizations with extensive portfolios of product standards. Each organization routinely updates its legacy standards and creates new ones. The Advanced Well Equipment Standards Group is a newer ICS organization that has recently completed a product standard for inflow control devices and is creating standards for encapsulated cable and degradable materials. Overall, the pace of standards creation is accelerating. A discussion of component reliability is incomplete without including the role of design for reliability (DFR) or design-assurance programs. These programs ensure that reliability receives due diligence in component development. The use of design failure mode effect analysis (DFMEA) is a cornerstone of an effective DFR program. These programs should be more prominent; this gap presents an opportunity for improvement. So, considering the question, “Where have we been?”, the answer is that the journey to date has been one of continuing improvements in the reliability of completion components. Configuration Reliability Is an Opportunity Of the technical paper abstracts I reviewed for the Completions feature in the April 2019 issue of JPT, 52% focus on completion configuration or optimization. Few abstracts focus on the ability of the completion configuration to perform reliably over long spans of time. Two critical aspects of configuration reliability are longevity and survivability.

Investigation on the causes of abnormal increase of water inflow in underground water-sealed storage system

Water inflow is a crucial factor in underground water-sealed storage for both safety and operation costs. Water inflow control measurements have mainly focused on the grouting of the cavern regardless of considering the influence of the access tunnel (i.e. the water flows directly through the fissures connecting the access tunnel and tanks after the access tunnel impoundment). In this study, the water control measurement related to access tunnel was investigated in certain project. First, based on monitoring data before the operational condition (including water inflow, groundwater level, and operating water level), the water inflow variation laws were explored in different construction phases. Then, the cause for abnormal increase in the water inflow after the access tunnel impoundment was explored using cross-correlation analysis and linear regression. Finally, some novel recommendations were provided for avoiding the abnormal increase in water inflow after the access tunnel impoundment: (1) zones with great fracture density or zones of water leakage should be identified through a geological survey and grouted before the access tunnel impoundment; (2) the access tunnel should avoid intersecting the advantage trend of fissures at a large angle to the greatest extent possible, and the layout of the access tunnel could be changed from the “wrap-around” to “direct-type” configuration; (3) smaller cross-section sizes and shorter lengths should be adopted for the access tunnel to retain proper functioning of the access tunnel and reduce the possibility of hydraulic connections between the access tunnel and tanks.

Analytical, numerical and experimental study of gas coning on horizontal wells

Nowadays, new horizontal wells prone to experience gas cone problem usually have multiple production zones. These wells are equipped with inflow control devices (ICDs) or autonomous inflow control devices (AICDs) to mitigate the production of the undesired fluid. In the proposed study, we use analytical calculation, numerical simulations and experimental results to analyze different production strategies when using long horizontal wells in such reservoirs. By the end, we first identified numerical models to represent the dynamic behavior of a gas–oil interface. By validating them through an analytical solution, we used an active control strategy both to obtain and to analyze the associated flow rate for different positions of the interface in steady state from static equilibrium to the well neighborhood. The findings of this research reaffirm there is no strategy that overcomes the production with critical flow rate in steady state. However, the exact critical flow rate is a theoretical value, being hard to assess in the field. In this way, the main contribution of this study is to indicate for the case in consideration the usual production strategy of using multiple zones equipped with AICDs, since it has a cumulative production extremely close to the theoretical maximum and it represents a well-known technology for field applications.

Principles of rapid design of an inflow control device completion in homogeneous and heterogeneous reservoirs using type curves

This paper discusses the development and application of universal type-curves for the design of Advanced Well Completions (AWCs) equipped with passive (non-adjustable), flow control devices {a.k.a. Interval Control Devices (ICDs)}. This work provides an innovative, rapid approach to their design without the need for numerical simulators.AWCs equipped with ICDs aim to delay the early breakthrough of unwanted fluids in wells constructed close to a reservoir fluid contact. An uneven inflow profile due to reservoir permeability heterogeneity, multiple fluid contacts or an undulating well path needs to be managed. In addition, the Heel-to Toe effect (HTE) by frictional pressure loss due to fluid flow along the length of the completion interval also promotes a non-uniform inflow profile.The main AWC design challenge is to balance the trade-off between loss in well productivity from the added flow restrictions and the benefit of an improved inflow profile. This paper reviews the development of the analytical modelling of the inflow performance of horizontal wells with ICD completions, It presents new semi-analytical, mathematical models describing the ability of AWCs to mitigate production problems created by (reservoir) permeability heterogeneity and the (in-well) HTE. New dimensionless numbers allow the development of universal type-curves (TCs) for AWC design. The new workflow is illustrated for several case studies and the results validated by their good agreement with calculations made with the standard “well-reservoir” numerical simulator employed by engineers for this task.This novel approach for rapid analysis of the implications of well log data, such as that obtained shortly before the beginning the installation of the well completion, is the latest addition to the well completion engineering toolbox.

Simulation of the water controlling ability of an adaptive inflow control device

Traditional adaptive inflow control device (AICD) has low water control efficiency. Based on adaptive inflow control device, numerical simulation method is used to analyze the internal flow of the device. Influence of relevant design parameters on its water control capacity is studied. Internal structure of AICD is optimized to change internal flow and the flow path of oil flow in the restrictor. Purpose of controlling the flow of oil by using different viscosities of two flow states is achieved. Results show that setting the baffle to distinguish the annular passage and control chamber can improve pressure drop of water flow. The direction and number of flow channels have significant influence on AICD water control ability. Optimizing the shape of flow channel can change entrance speed and entrance angle, improving the water control capacity of inflow controlling device. The AICD achieves the optimal control capacity when it adopts the one transitional flow channel with 45°A angle.

Research and application of gravel-packing flow-regulation water-control screen completion technique in horizontal wells

Horizontal well inflow control screen completion require packer to stage on the reservoir, however, the numbers of packer are limited to section of the reservoir, the reservoir sealing length is limited by packer rubber, effective sealing length is short, that restricts to the control precision of ICD in horizontal wells. In view of above, this paper presents a new horizontal well gravel packing inflow control screen completion technology, that uses gravel to replace the packer to seal the reservoir, resisting the transverse flow in the wellbore, making the inflow control screen can control water directly on formation in which the position is located, to realize the dynamic adjustment the flow profile in the whole horizontal well section. From the technological principle and characteristics, key implemental technology, gravel and supporting tools, construction technology and other aspects of horizontal well gravel filling, the gravel packing inflow control screen completion technology were studied. The technology was applied in adjustment horizontal well completion in the xinjiang A oilfield. After application, the oil production increased by 5.1 times, the water content decreased by 13.5%, and achieved a good effect of controlling water coning and increasing oil. The application results suggest that horizontal gravel inflow control screen pipe completion technology can improve the effect of inflow control screen completion, that could be applied in the new wells and old wells second completion.

Structural Parameter Optimization and Performance Analysis of Autonomous Inflow Control Device

The Autonomous Inflow Control Device (AICD) adjusts the inflow of the horizontal wellbore by adding additional resistance to the fluid, thereby prolonging the water seepage time and enhancing oil recovery. The performance of AICD mainly depends on structural parameters. The computational fluid dynamics software is used to analyze the influence of structural parameters on the performance of AICD. The results show that the diameter of the variable diameter section, the diameter of the restrictor and the diameter of the outlet are the main factors affecting the performance of the inflow control device. The fluid parameter sensitivity simulation results show that the oil phase viscosity and water content have a great influence on the performance of AICD, while the influence of oil phase density on the performance of the device is negligible; the pressure drop under the pure water condition of this type of AICD is more than twice that of pure oil condition, so it has better water control ability.

Prediction analysis model for groundwater potential based on set pair analysis of a confined aquifer overlying a mining area

One important prerequisite for mine water inrush prevention and water inflow control in a coal mine is groundwater potential mapping. In this study, a synthetical method was developed to evaluate the groundwater potential of a confined aquifer overlying a mining area using the improved set pair analysis (ISPA) theory. Considering the influence of the hydrogeological and geological conditions, the characteristics of rock stratum and geological tectonics were used as the two major aspects to evaluate groundwater potential. The degree of connection was determined by the relationship between the total number of element characteristics and the number of identical, contradictory, and discrepant terms. The weight of evaluation indices was calculated based on information entropy, and the grade of groundwater potential was determined by the improved evaluation criterion of set pair analysis. To validate the practicality of the method, a case study at Hongliu coal mine was carried out. An entropy-set pair analysis-cosine model was constructed and five evaluation indices were selected: sandstone thickness, flushing fluid consumption, core recovery, fault fractal dimension, and fold fractal dimension. The groundwater potential of the study area was classified into four levels. The quantitative results were validated with data from field observations and compared with the results of geographic information systems (GIS), which were found to be in very good agreement.

Estimation of costs for monitoring urban water and wastewater networks

Abstract In many water distribution systems, water losses are a major problem and an integrated management strategy is required for both the efficient use of water resources and the minimisation of non-revenue water. For foul sewer systems, the inflow of stormwater and infiltration of groundwater affects the management of both sewer systems and wastewater treatment plants. Monitoring of flows represents a critical task within approaches for control of either water losses in distribution systems and infiltration and rain-induced inflows in foul systems. Implementation of monitoring typically involves the following steps: (i) system information updating and digital mapping; (ii) system zoning; and (iii) system flow monitoring. Costs for monitoring are essential for utilities to estimate more accurately the costs of control of water losses, infiltration and inflow and to support more robust decision-making. Costs and infrastructure data were collected from 20 Portuguese water and wastewater utilities. Multiple linear regression analysis is used to obtain cost functions for meter chambers as a function of the volume and for purchase and installation of flow meters as a function of nominal diameter in water supply systems. For the steps of system information updating, digital mapping and system zoning single unit costs are estimated.

Theory of Relativity for Posterosuperior Segments of the Liver.

The accessibility to posterosuperior segments of the liver has traditionally constituted a restrain to adopt the laparoscopic approach in this setting. To overcome this challenge, multiple approaches have been reported in literature. Total transabdominal approach has been previously described for this purpose, even though the rationale to standardly adopt it and a technical depiction of how to achieve an optimal mobilization has never been specifically addressed. Total transabdominal purely laparoscopic approach to posterosuperior segments of the liver is presented, with detailed emphasis to the rotational motions targeted in laparoscopy. A literature review is presented to summarize all other possible accesses to posterosuperior area of the liver. The institutional series for the laparoscopic approach to Sg 7, Sg 6+7, and Sg8 is retrospectively described. Three rotational motions of the liver are specifically addressed in a video presentation and described for the laparoscopic total-transabdominal approach; the local institutional series using this approach is presented. Other miscellaneous approaches identified from literature encompassing variations in operative position, transabdominal, transthoracic, and combined approaches are described. Complete mobilization of the ligaments of the liver leads to a rotation of the transection line in front of the operator's view, allowing to achieve a safe total trans-abdominal laparoscopic approach to the posterosuperior ligaments of the liver, without compromising the vascular inflow control, the possibility to convert to open approach, nor requiring potentially harmful decubitus.

Developments and perspectives of laparoscopic liver resection in the treatment of hepatocellular carcinoma.

Laparoscopic liver resection (LLR) was introduced in the early 1990s, initially for partial resection of the anterolateral segments, from where it has expanded in a stepwise fashion. Movement restriction makes bleeding control demanding. Managing pneumoperitoneum pressure with inflow control can inhibit venous bleeding and create a dry surgical field for easier hemostasis. Since the lack of overview leads to disorientation, simulation and navigation with imaging studies have become important. Improved direct access to the liver inside the rib cage can be obtained in LLR, reducing destruction of the associated structures and decreasing the risk of refractory ascites and liver failure, especially in patients with a cirrhotic liver. Although LLR can be performed as bridging therapy to transplantation for severe cirrhosis, its impact on expanding the indications of liver resection (LR) and the consequent survival benefits must be evaluated. For repeat LR, LLR is advantageous by producing fewer adhesions and reducing the need for adhesiolysis. The laparoscopic approach facilitates better access in a small operative field between adhesions. Further evaluations are needed for repeat anatomical resection, since alterations of the anatomy and surrounding scars and adhesions of major vessels have a larger impact.

Learning curve of laparoscopic living donor right hepatectomy to mimic open procedure: review of single surgeon’s 103 laparoscopic cases compared to open cases

Introduction: To evaluate the feasibility of laparoscopic living donor right hepatectomy and analyze how many cases are required for overcoming the learning curve Method: Data of living donors who underwent right hepatectomy by a single surgeon at Samsung Medical Center were reviewed. Comparisons regarding the anatomy, operation, and recovery were performed between open and laparoscopy group. Surgical videos were reviewed for each procedure. Linear regression was used for analyzing operational procedures showed linear decrease in time. Result: During the period, 96 and 103 donors underwent open and laparoscopic living donor right hepatectomy, respectively. Median estimated blood loss was smaller (300 vs. 200mL, P<0.001) and mean operation time (301.3±63.3 vs. 252.2±42.8 minutes, P<0.001) and median hospital stay was shorter in the laparoscopy group. (10 vs. 8 days, P<0.001). There was no difference in complication rate. (24.0% open vs. 14.6% laparoscopy, P=0.092) Although overall bile duct openings were more than expected in the laparoscopy group, (P=0.022) it showed improvement with the increase in case numbers and there was no difference in the outcome in the later half of cases (P=0.207) Total operation time of laparoscopy showed linear decrease along with increase in laparoscopic cases. (R2=0.407, β=-0.914, P=0.001) and it significantly decreased after nearly 50 cases (2nd to 3rd and 3rd to 4th, P=0.001 and P=0.023, respectively). Inflow control and ischemic line marking (R2=0.238, β=-4.4), parenchymal transection time (R2=0.290, β=-22.4) and graft placement in laparoscopic plastic bag (R2=0.204, β=-1.7) showed the most significant decrease in time. (P<0.001 for each) Conclusion: Although bile duct division is challenging in laparoscopic living donor right hepatectomy, it showed comparable feasibility to open surgery along with the learning curve.

A Tailored Strategy for Recipient Hepatectomy: Left Portal Flow Preserving High Hilar Dissection

Summary: High hilar dissection (HHD) technique was reported as a novel technique for recipient hepatectomy. It allowed performing multiple tension-free duct to duct biliary anastomoses, hence reducing biliary complications. However, longer anhepatic phase is its main drawback. We describe a new modification of HHD technique, called left portal vein flow preserving HHD (LFP-HHD). It involves high intrahepatic division of hilar structures while maintaining the portal venous drainage through the left portal vein. Control of right hemi-liver inflow allows for division of the right hepatic vein, and further dissection of the retro-hepatic inferior vena cava easily and safely. Dissection of the anterior hilar structures can be accomplished. According to the co-ordination with the donor and bench surgery, the liver could be easily explanted. LFP-HHD technique is a novel simple technique for recipient hepatectomy that can be tailored for certain clinical conditions. It overcomes limitations of original HHD technique without compromising its merits.

Laparoscopic Non Anatomical Hepatectomy

Introduction: Despite advances in field of energy devices and surgical techniques, Performing Hepatectomy is still considered a difficult task. Anatomical Hepatectomy is further difficult compared to Non-Anatomical Hepatectomy. Apart from Inflow Outflow Control & Parenchymal Transection, which are challenges even in Conventional Open Hepatectomy, Laparoscopic Hepatectomy has additional challenges of 1)Risk of massive air embolism during vascular dissection 2)Difficult ergonomics & 3)Accessibility issues. So Anatomical Laparoscopic Hepatectomy is considered a pinnacle . Due to these reasons laparoscopic hepatectomy is facing stiff resistance in making progress by leaps & bounds on par with rest of the laparoscopic procedures. Anatomical Laparoscopic Hepatectomy, though challenging, can be performed in a few select cases. But, in certain benign indications such as hydatid cysts, cystic neoplasms & some hemangiomas, Laparoscopic Non-Anatomical Hepatectomy can avoid large incisions like right subcostal(Kocher’s), bilateral subcostal (Roof-top), Makuchi, Seagull, etc., thereby reducing morbidity due to pain & lung complications with early return to work. Also, Non-Anatomical Hepatectomy is technically easier to perform than Anatomical Hepatectomy, as we can avoid critical steps such as inflow & outflow control. Method: We present a series of 5 cases, which include 2 Right & 3 Left Non-Anatomical Hepatectomies which were done for 3 patients with Hydatid Cysts (2 in left lobe & 1 in right lobe) & 2 Benign cystic neoplasm (1 in left lobe & 1 in right lobe). We present a video of laparoscopic left and right hepatectomy. Result: All patients were discharged with Mean length of hospital stay 2.5 days, Intra-operative blood loss less than 500 ml, Nil port site compilations, Mean pain score 2.8, Nil required drain placement, Nil required re-exploration/resurgery. Conclusion: Hence, small, benign, peripheral located, less vascular lesions can be managed with Laparoscopic Non-Anatomical Hepatectomy,with small incision, good cosmesis, less risks, and less morbidity.

Lateral hand-assistance port for Laparoscopic posterior sectionectomy

Background: The laparoscopic approach for lesion in posterosuperior location of liver is still challenging due to difficulty in traction and deep parenchymal dissection. Here we present a Case of 66-year-old female presented with abdominal pain and weight loss. CT Scan revealed a 4.4-cm lobulated cyst in liver segment6/7. Laparoscopic posterior sectionectomy with hand-assistance port at right lateral side was done. Methods: Trocars were placed. Pneumoperitoneum was made. The right hemiliver was fully mobilized. Intrahepatic posterior pedicle was controlled with the temporary inflow control of the glissonian pedicle (TICGL) technique.(1) Parenchymal dissection was proceed with ultrasonic dissector, CUSA and bipolar dissector. The hand-assistance port was made laterally. Surgeon’s left hand assisted in traction of the liver and in exposing the deeper parenchyma. The posterior pedicle was stapled. The right hepatic vein was resected. Specimen was put into a plastic bag. A Fortune drain was placed in subhepatic space and through the left lateral port. Results: The operative time was 8 hours 30 minutes. The estimated blood loss was 500 mL. No immediate postoperative complication. The drain was removed at postoperative day 5. The patient was discharged at postoperative day7. Histopathological report was lymphangioma with focal reactive change and calcification. Conclusion: Hand-assistance port can effectively assist in laparoscopic approach of posterosuperior location of liver, reducing operative time, less learning curve, while is still maintaining the benefit of laparoscopic surgery. Reference: Lee N, Cho CW, Kim JM, Choi GS, Kwon CHD, Joh JW. Application of temporary inflow control of the Glissonean pedicle method provides a safe and easy technique for totally laparoscopic hemihepatectomy by Glissonean approach. Ann Surg Treat Res. 2017;92(5):383-6.

Tips for junior HBP surgeon to perform laparoscopic anatomic S3 hepatectomy in a regional hospital

Summary: Purpose: Laparoscopic anatomic hepatectomy is an advanced procedure for HBP surgeons, and most junior HBP surgeons would perform laparoscopic left lateral segmentectomy or wedge resection as their initial experience for laparoscopic hepatectomy. Miaoli General Hospital is a regional hospital in alliance with Far-Eastern Memorial Hospital, and it provides surgical service majorly laparoscopic appendectomy, cholecystectomy or colectomy. Laparoscopic anatomic hepatectomy had never been performed in this hospital before, and some special devices for laparoscopic hepatectomy, such as laparoscopic ultrasound transducer or CUSA, are not available. This video would present a junior HBP surgeon to perform laparoscopic anatomic hepatectomy for hepatocellular carcinoma (HCC) at S3. Materials and Methods: A 78-year-old man, an HBV carrier, was diagnosed with a new hepatic nodule at lateral segment of liver under routine sonographic survey. Further abdominal CT and MR scan showed a solitary 1.9cm HCC at S3. As ICG test was not available in this hospital, laparoscopic anatomic S3 hepatectomy was indicated for this elderly patient with Child A cirrhosis, attempt to preserve normal liver parenchyma as much as possible. Results: Total operation time was 186 minutes, and blood loss was about 70ml. The intracorporeal Pringle maneuver was prepared with Fr. 16 foley catheter (Huang’s loop) but never applied during hepatectomy. Harmonic scalpel and monopolar coagulation were the major energy devices during hepatectomy. The patient had uneventful postoperative course and was discharged 7 days after operation. The final pathology report showed well differentiated HCC, pT1b, without margin, perineural or lymphovascular invasion. Conclusion: Laparoscopic anatomic hepatectomy is possible for junior HBP surgeons to do in a resource-limited hospital with basic energy devices and easy inflow control method. However, the operators should prepare to gain experience in hepatectomy during residency, observe plenty live laparoscopic hepatectomies and participate in hand-on laparoscopic skill workshop.

Predicting Performance of High Deliverability Horizontal Gas Wells and Control of Water Cresting in Tertiary Sands East Africa

The field-A1 is an offshore gas field located about 56 km from the coast of East Africa with the water depth of 1153 m. The permeability distribution varies across different layers with an overall permeability of 680 m and porosity distribution for the reservoir field-A1 varies 0.21-023. The reservoir thickness also varies up to 50 m thick. This research work identifies parameters that will contribute to the impact of water coning. Simulation sensitivities are run to observe the effect of water coning/cresting in horizontal gas wells and predicting the performance of these wells using Petrel simulator. Results have shown that put horizontal well in East-west will have early water breakthrough and not recommended due to the impact of edge aquifer due to less recovery compared to north-south and original wells orientation (northwest-southeast). The varying height of perforation and standoff as identified is at the standoff between 30-40 m in the field-A2 will delay water coning high recovery with more extended plateau length period. The gas recovery may happen to be low, due to the distribution of permeability layer for the horizontal wells and low productivity index that is the performance of the well. Rate-dependent skin and mechanical skin evolution in time show that increasing non-Darcy /turbulence factor reduces the performance of the well and decreases gas recovery the high drawdown tendency is observed before water breakthrough time however there is early water breakthrough, thus use of deep penetration. Horizontal gas wells have a constant horizontal length for all cases of 300 m increasing tubing head pressure from 40-100 bars result to decrease plateau length period of the gas production, low water production rate, and low gas recovery. Varying the kv/kh ratio from 0.1, 0.6 to 1 shows early water breakthrough by 6 months earlier from the base case with 0.1 hence will not delay water coning. The gas recovery is reduced by 5%. Gas recovery is increased with an increase in gas rates constrain, and early water breakthrough is observed when producing at high rates. Producing at low rates may delay water coning. However, it is not economical since there is less gas recovery and may take a more extended period for production to reach to its total maximum gas production of which is less compared when producing at high gas rates. There is a stronger of the aquifer from the west side, which is predictable to cause water coning than on the east side. This aquifer impacts the gas recovery reduction by 19%, with water coning radial extension of 1.7 km and peak water production rate for 16 years. The aquifer influx rate is seen to be increased by 69% when the aquifer volume is double. Therefore, from the results producing at a high rate that has high recovery before the impact of aquifer or water has occurred to the wells, known as outrunning of the aquifer. To avoid water coning, using advance completion technique such as inflow control devices (ICD), installing a down hole gauge. Also, it is essential not to perforate if well is near to gas water contact the horizontal wells should be located at maximum distance from gas water contact to maximize gas recovery. Not only that but also use of fully open choke allows much water production rate increase, which leads to water coning.

Predicting Performance Of High Deliverability Horizontal Gas Wells And Control Of Water Cresting In Tertiary Sands East Africa

The field-A1 is an offshore gas field located about 56 km from the coast of East Africa with the water depth of 1153 m. The permeability distribution varies across different layers with an overall permeability of 680 m and porosity distribution for the reservoir field-A1 varies 0.21-023. The reservoir thickness also varies up to 50 m thick. This research work identifies parameters that will contribute to the impact of water coning. Simulation sensitivities are run to observe the effect of water coning/cresting in horizontal gas wells and predicting the performance of these wells using Petrel simulator. Results have shown that put horizontal well in East-west will have early water breakthrough and not recommended due to the impact of edge aquifer due to less recovery compared to north-south and original wells orientation (northwest-southeast). The varying height of perforation and standoff as identified is at the standoff between 30-40 m in the field-A2 will delay water coning high recovery with more extended plateau length period. The gas recovery may happen to be low, due to the distribution of permeability layer for the horizontal wells and low productivity index that is the performance of the well. Rate-dependent skin and mechanical skin evolution in time show that increasing non-Darcy /turbulence factor reduces the performance of the well and decreases gas recovery the high drawdown tendency is observed before water breakthrough time however there is early water breakthrough, thus use of deep penetration. Horizontal gas wells have a constant horizontal length for all cases of 300 m increasing tubing head pressure from 40-100 bars result to decrease plateau length period of the gas production, low water production rate, and low gas recovery. Varying the kv/kh ratio from 0.1, 0.6 to 1 shows early water breakthrough by 6 months earlier from the base case with 0.1 hence will not delay water coning. The gas recovery is reduced by 5%. Gas recovery is increased with an increase in gas rates constrain, and early water breakthrough is observed when producing at high rates. Producing at low rates may delay water coning. However, it is not economical since there is less gas recovery and may take a more extended period for production to reach to its total maximum gas production of which is less compared when producing at high gas rates. There is a stronger of the aquifer from the west side, which is predictable to cause water coning than on the east side. This aquifer impacts the gas recovery reduction by 19%, with water coning radial extension of 1.7 km and peak water production rate for 16 years. The aquifer influx rate is seen to be increased by 69% when the aquifer volume is double. Therefore, from the results producing at a high rate that has high recovery before the impact of aquifer or water has occurred to the wells, known as outrunning of the aquifer. To avoid water coning, using advance completion technique such as inflow control devices (ICD), installing a down hole gauge. Also, it is essential not to perforate if well is near to gas water contact the horizontal wells should be located at maximum distance from gas water contact to maximize gas recovery. Not only that but also use of fully open choke allows much water production rate increase, which leads to water coning.