BackgroundTo curb coal mine gas accidents from sources, exploit low-carbon and clean coalbed methane (CBM) resources, and protect the atmospheric environment (achieved by methane emission reduction in coal mining areas), the authors’ team, by working with Shanxi Jincheng Anthracite Mining Group and cooperating closely with relevant research institutes, colleges, and universities, has progressively developed theories with clear concepts and scientific connotations, as well as relevant technical systems and industrial paradigms, for coal and CBM co-production through over two decades of original, integrated, and cross-industry innovations (spanning across fluid and solid mineral industries), along with theoretical exploration, technological research and development, and engineering practice. The mining theories, technical systems, and industrial paradigms of the coal and CBM co-production have undergone constant development. Influenced by national demands, economic conditions, industrial base, scientific and technological levels, professional talent, and cognitive level, among others, coal and CBM co-production has experienced several major development stages sequentially: (1) coal mining without gas extraction, (2) gas drainage followed by coal mining, and (3) integrated gas extraction and coal mining, with the former followed by the latter. This study provides a systematic summary of achievements obtained through over two decades of exploration and practices. Advances Primary innovations and advances are introduced as follows. The purpose of the coal and CBM co-production has been clarified. Specifically, through the full-time extraction of CBM across all vertical horizons throughout a coal mining area, the coal and CBM co-production is aimed at exploiting both coal (solid) and CBM (fluid)—two paragenetic or associated mineral resource types that are cogenetic, contemporaneous, and hosted by the same geological structure in a safe, efficient, and collaborative manner. This will help curb coal mine gas accidents from sources and practically gain multiple benefits including safety, resource utilization, and environmental protection. The concept of the coal and CBM co-production has been established as integrated gas extraction and coal mining, with the former followed by the latter. This means that the spatiotemporal cooperation between gas extraction, roadway tunneling, and coal mining should be planned and achieved based on the full lifecycle of the coal and CBM co-production. The core nodes of the collaborative co-production have been determined, referring to several key thresholds for safe production in coal mines, which consist of the maximum permissible gas content and gas pressure for safe tunneling and production. A technical logic and industrial paradigm of CBM extraction have been summarized, defined as surface-underground combined full-time gas extraction integrating four zones (i.e., planning, preparation, mining, and mining-affected or goaf zones) across all vertical horizons throughout a mining area. A technical system for CBM extraction has been innovatively developed, encompassing large-scale surface gas extraction in the planning zone of a coal mine (through commercial CBM development or advance surface pre-drainage of coal mine gas), surface-underground combined gas drainage in the preparation zone, large-scale and precise underground gas drainage in the mining zone, and surface or underground gas drainage in the mining-affected or goaf zone through pressure relief (CBM drainage in a mining-affected zone using an underground high-level borehole group is referred to as the technology of replacing roadways with boreholes). Significant theoretical innovations include the theory on two fluid seepage regimes in coal reservoirs (non-Darcy flow in coal matrix pores and Darcy flow in fractures and large and medium pores), the theory on multi-source gas gush in a mining-affected zone, and the disturbance effect of mining activities on the physical properties of CBM reservoirs (causing CBM reservoirs in different zones to occur in original, disturbed, and semi-open states). Prospects Based on the authors’ exploration and engineering practices in the in situ fluidized mining of coal and gas in recent years, this study proposes that in the future, the coal and CBM co-production should focus on the in situ fluidized mining of coal and CBM, involving physical, chemical, biological, and thermodynamic technical pathways. The authors have conducted innovative explorations and engineering tests on the theory and technology of the in situ fluidized mining of coal and CBM. The results indicate that in situ fluidized mining of coal and CBM represents a feasible technical pathway, signifying the coal and CBM co-production in the true sense.

Developing efficient surfactant-based fracturing fluids for deep coalbed methane (CBM) extraction has been a great challenge for coal industries due to the harsh environmental conditions of high temperature and salinity in reservoirs. In this work, a novel zwitterionic surfactant, p-tetradecyl oxybenzyl dimethyl betaine (P-ToB), was synthesized by introducing a rigid phenyl group into the carboxylbetaine structure, enabling the formation of wormlike micelle (WLM) networks without the aid of specialized hydrotropic additives. The resulting P-ToB fluid exhibited good sand-carrying and gel-breaking properties, along with the outstanding thermal stability (100 degrees C) and high salinity tolerance (up to 3.0 x 105 mg L-1). Moreover, its feasibility of preparing the fracturing fluid with on-site flowback water was evaluated, and the formulated fluid was shown to maintain a viscosity greater than 50 mPa center dot s at 100 degrees C and 170 s-1 . Adsorption experiments revealed that the attachment of surfactant molecules onto coal surfaces could effectively neutralize surface charges and promote surface wettability, thereby facilitating particle aggregation and sedimentation. Overall, the P-ToB system provides a promising solution to challenges in on-site fluid preparation, freshwater scarcity, and coal fines migration during CBM operations.

This article presents an effective method for improving the structure and performance of coal rock masses, thereby facilitating coalbed methane extraction—the grouting solidification technique. A systematic review is conducted on grouting solidification materials, process methods, evaluation techniques, and other related aspects. In conclusion, it is emphasized that the grouting solidification technique requires further refinement in its system, and its continued significance in the dynamically evolving energy and coal industry is underscored. This is crucial for ensuring the efficient development and sustainable utilization of coal and coalbed methane resources.

当前,世界各国的国家综合实力及世界格局正发生着前所未有的变化,全球能源格局正经历颠覆性重塑,能源安全已被推高到国家安全的战略高度.在油气供给危机全球和平发展的背景下,资源量巨大、分布面积较广的煤层气资源开发意义重大.煤层气开发利用,不仅是增加了不可多得的低碳清洁能源,更是现实的"碳中和"工业路径(大幅度减少采煤过程的甲烷排放,降低甲烷的温室气体效应).近二十年的煤层气开发实践表明,我国煤层气储层低压、低渗、低饱和特征突显,解吸-扩散-渗流经典理论表现出严重的"水土不服",不能合理解释我国煤层气单井产量和采收率低的原因,以固-气吸附解吸及扩散理论为主导的传统的煤层气藏工程方法、数值模拟技术、排采控制技术与提高采收率技术,其预测结果很难与生产实际吻合,因此煤层气开发面临传统解吸扩散理论是否合理、开采技术是否配套的重大科学问题.

针对油气田开发对压裂支撑剂的性能要求愈来愈高的产业重大需求,油田化学领域运用现代化学理论与技术,开展了一系列卓有成效的压裂支撑剂化学覆膜改性研究和产品研发,为油气工业的快速发展做出了突出贡献.本文从化学和工程两个视角,系统阐述了压裂支撑剂化学覆膜改性的研究方向.化学角度,主要研究方向包括:在支撑剂表面涂层构成化学覆膜、通过化学手段科学改变支撑剂表面特性、化学涂层与改性并举.工程角度,大致分为三个重要研究方向:一是通过在石英砂、陶粒等支撑剂表面涂敷覆膜来提升支撑剂强度;二是通过在石英砂、陶粒等支撑剂表面涂敷覆膜来降低整个支撑剂的相对密度(如自悬浮涂层技术等);三是石英砂、陶粒等支撑剂表面涂敷覆膜实现堵水疏油的功能.本文还简要阐述了树脂覆膜支撑剂、疏水支撑剂、憎水憎油支撑剂、自悬浮支撑剂、自聚型支撑剂、无机聚合物涂覆支撑剂以及功能性支撑剂等主要产品的特性.展望支撑剂未来的发展趋势,提出支撑剂应向多功能、高性能、小尺寸和智能化方向发展以及开发出更加适合无水压裂的支撑剂和原位生成型自支撑压裂体系.

页岩等非常规油气储层水平井分段压裂改造用液规模大,返排效率低,其诱发的孔弹性效应不可忽视,然而孔弹性效应对缝间应力干扰、多裂缝竞争扩展的影响机理尚未明晰.为了揭示压裂液滤失诱发的孔弹性效应对地应力场及多裂缝扩展的影响规律,基于平面三维多裂缝模型,在考虑液体滤失诱发的孔弹性效应的基础上,建立了水平井压裂裂缝扩展数学模型,并开展了水平井多簇压裂裂缝扩展数值模拟研究,针对孔弹性诱导应力导致多裂缝扩展不均匀提出了解决的工艺手段.研究结果表明:①孔弹性应力与裂缝诱导应力具有相似的效果,其大小约为裂缝诱导应力的 30%,影响范围约为裂缝诱导应力的 40%;②孔弹性效应会增大缝内压力、强化缝间应力干扰、加剧裂缝不均衡扩展,与不考虑孔弹性效应的模拟案例相比,考虑孔弹性效应后裂缝宽度降低约 8%,缝内压力升高约 0.5 MPa,井底压力升高 0.62 MPa,各簇瞬时进液差异系数升高 6.5%、整体进液差异系数升高 5%;③保持限流射孔摩阻为 3～6 MPa可在一定程度上克服孔弹性效应对各簇均衡进液的负面影响.结论认为,孔弹性效应研究可为水平井多簇压裂诱导应力及裂缝扩展分析提供重要的理论支撑和依据,该成果可为非常规油气储层现场压裂设计提供更加全面的参考依据.

The coalbed methane blocks are always structurally and topographically complex, and there are no models to accurately predict the coalbed methane content in the southern Sichuan Basin, China. This study proposes a feasible machine learning model to achieve a more accurate estimation of coalbed methane content with a small data set. A revised estimate of depth (Z) based on hydrogeological grounds was used as a feature of the prediction model, which can resolve the errors introduced by using the commonly used measured depth as a feature in areas with drastic topographical and structural changes. The revised estimate of depth (Z) and the measured depth were applied for data analysis along with three machine learning algorithms (support vector regression, gradient boosting decision tree, and CatBoost) to obtain the optimized model for coalbed methane content estimation. Modeling results show that the coefficient of determination (R2), mean absolute error, and mean square error of all algorithms were improved after replacing the measured depth with the revised estimate of depth (Z). The Catboost algorithm performed better than the other two algorithms in this study. The prediction results based on CatBoost using the revised estimate of depth (Z) showed the highest accuracy among all the comparison models. The analysis results show that the R2 between Z and coalbed methane content was 150% higher than that between measured depth and coalbed methane content. This vast difference between measured depth and revised estimate of depth (Z) outputs was caused by drastic changes in topography and structure.

Excess water production has become an important issue in the oil and gas extraction process.Preformed particle gels（PPGs）,show the capability to control the conformance and reduce excess water cut.However,conventional PPGs have poor mechanical properties and their swollen particles are easily damaged by shearing force when passing through the fractures in formations,meanwhile PPGs can be also degraded into various byproducts,leading to permanent damage to the reservoir permeability after temporary plugging.Herein,a novel type of dual cross-linked PPGs（d P PGs） was designed and synthesized using sodium alginate（SA） and acrylamide（AAm）,cross-linked with N,N’-methylenebisacrylamide（MBA） and Fe 3+ .Results show that d P PGs have excellent mechanical properties with a storage modulus up to 86,445 Pa,which is almost 20 times higher than other reported PPGs.Meanwhile,d P PGs can be completely degraded into liquid without any solid residues or byproducts and the viscosity of d P PGs degraded liquid was found to be lower than 5 mPa·s.A laboratory coreflooding test showed that the plugging efficiency of d P PGs was up to 99.83% on open fractures.The obtained results demonstrated that d P PGs could be used as economical and environment-friendly temporary plugging agent with high-strength,self-degradation,thermal stability,and salt stability,thus making it applicable to a wide range of conformance control to enhance oil recovery.

Efficient CO2/C2H2 separation at ambient conditions is an essential but challenging process owing to their similar molecular sizes and physical properties. In this work, a novel approach of charge/strain-regulated gas capture and separation was proposed, which offered the advantages of reversibility and controllable kinetics. Highly selective CO2 separation from CO2/C2H2 with porous g-C9N7 nanosheets were demonstrated with varying charge densities and strains using molecular dynamics (MD) simulations and first-principle density function theory (DFT) calculations. The remarkable CO2 permeance up to 5.85 x 10(7) GPU can be achieved by charge engineering. Under the condition of tensile strain, a controllable CO2 separation performance was exhibited, whose CO2 permeance increased with increasing the applied strain. The maximum permeance was 3.44 x 10(7) GPU with 9% strained g-C9N7 membrane. More interestingly, a promising approach combining the charge regulation with strain engineering was explored to investigate the synergistic effect. Under conditions of 2 e(-) charge and 3% tensile strain on g-C9N7 membrane, the CO2 permeance reached 4.24 x 107 GPU, which was 1.6 times of CO2 permeability when only 2 e(-) was added and 10 times of CO2 permeance when only 3% strain was added. Additionally, the energy barrier of CO2 decreased with the increasing degree of regulation (charge and strain engineering) on the g-C9N7 membrane, indicating that the g-C9N7 membrane can be served as an excellent candidate for CO2/C2H2 separation. These results provide useful guidance for developing advanced materials and applying new regulation techniques to realize highly tunable and selective CO2/C2H2 separation.

中国新疆阜康白杨河矿区42号煤层倾角大,浅部煤系地层露出,为研究煤层气从该区域溢出问题,防止煤层气资源浪费,基于大倾角煤层中气-水分异现象,修正了大倾角煤层三维气-水两相渗流模型,结合阜康白杨河矿区42号煤层实际地质资料与历史拟合储层再描述,展开了大倾角煤层浅部露出区煤层气溢出问题数值模拟仿真研究.研究结果表明:大倾角煤层浅部露出区煤层气溢出问题的存在;埋深300、500和700 m直井生产15 a累计溢出量分别为1.02×105、1.08×107以及1.33×107 m3,和产量比值分别是5.06ü、668.02ü以及335.77ü,直井生产时会造成大量的煤层气资源浪费;溢出现象并非伴随整个生产周期,溢出量先增后降直到溢出现象结束,使用顺层井生产时可以完整观测这一过程,溢出现象持续了1918 d,日溢出量上升和下降过程近似对称,累计溢出量为7.18×105 m3,和累计产气量比值为1.54ü.补充400 m和600 m埋深直井模拟方案后,发现煤层气最大溢出量和累计溢出量与直井埋深呈正相关线性关系,而溢出现象开始时间随着埋深增加逐渐提前,500 m以深溢出现象开始时间保持不变.综合分析煤层气溢出现象是造成该区直井产能较差的原因之一,使用顺层井排采能有效提高经济效益和降低煤层气溢出现象.

The initial formation pressure of coalbed methane（CBM） reservoir is a key parameter used for the evaluation of CBM reserves and productivity, which plays a guiding role in CBM production. Therefore, it is of great significance to accurately calculate the initial reservoir pressure of CBM reservoir. Based on the pressure potential superposition principle of the seepage mechanics theory, the pressure potential model in the process of fracturing and shut in after fracturing is established, and a method for determining the initial reservoir pressure of CBM reservoir is proposed by using the wellhead pressure drop data in the shut-in stage of hydraulically fractured gas well under two conditions: ignoring or considering the fracture network permeability change in the process of fracturing and shut in after fracturing. And then, a field application is carried out. From the fitting results of the case study, it can be seen that the linear relationships for both methods are obvious, indicating that the established methods are effective. From the perspective of interpretation accuracy, the method of considering the fracture network permeability change after fracturing involves more data points in fitting, and the fracture network permeability change during fracturing and after fracturing is an indisputable fact, so the interpretation result by using the method considering the fracture network permeability change is more reliable. If the change process of fracture network permeability of coal formation during shut in after fracturing is ignored, the interpreted stable permeability of fracture network and initial reservoir pressure will be high. Since this method can not only be used to determine the initial reservoir pressure, but also to determine the stable permeability of fracture network after fracturing and evaluate the change trend of fracture network permeability, it provides a basis for the classification of CBM reservoir types, CBM reserve calculation, fracturing effect evaluation, and optimization design of drainage and production system.

As the main unconventional natural gas reservoirs, shale gas reservoirs and coalbed methane (CBM) reservoirs belong to adsorptive gas reservoirs, i.e., gas reservoirs containing adsorbed gas. Shale gas and CBM reservoirs usually have the characteristics of rich adsorbed gas and obvious dynamic changes of porosity and permeability. A generalized material balance equation and the corresponding reserve evaluation method considering all the mechanisms for both shale gas reservoirs and CBM reservoirs are necessary. In this work, a generalized material balance equation (GMBE) considering the effects of critical desorption pressure, stress sensitivity, matrix shrinkage, water production, water influx, and solubility of natural gas in water is established. Then, by converting the GMBE to a linear relationship between two parameter groups related with known formation/fluid properties and dynamic performance data, the straight-line reserve evaluation method is proposed. By using the slope and the y-intercept of this straight line, the original adsorbed gas in place (OAGIP), original free gas in place (OFGIP), original dissolved gas in place (ODGIP), and the original gas in place (OGIP) can be quickly calculated. Third, two validation cases for shale gas reservoir and CBM reservoir are conducted using commercial reservoir simulator and the coalbed methane dynamic performance analysis software, respectively. Finally, two field studies in the Fuling shale gas field and the Baode CBM field are presented. Results show that the GMBE and the corresponding straight-line reserve evaluation method are rational, accurate, and effective for both shale gas reservoirs and CBM reservoirs. More detailed information about reserves of shale gas and CBM reservoirs can be clarified, and only the straight-line fitting approach is used to determine all kinds of reserves without iteration, proving that the proposed method has great advantages compared with other current methods.

原始煤储层压力是煤层气储量和产能评价中一个非常重要的参数,对煤层气开采具有指导作用,准确计算原始煤储层压力具有重大意义.因此,基于渗流力学理论压力势叠加原理,建立了压裂过程中和压裂后关井过程中压力势模型,并分忽略与考虑煤储层压裂过程中和压裂后裂缝网络渗透率变化两种情况,提出了利用水力压裂煤层气井关井阶段井口压力降落数据反演原始煤储层压力的方法,并进行了实例应用.从实例井拟合结果可以看出,忽略与考虑煤储层裂缝网络渗透率变化的原始地层压力方法线性关系都很明显,说明建立的方法有效.从解释精度的角度来看,考虑煤储层压裂后裂缝网络渗透率变化的方法参与拟合的数据点更多,且压裂过程和压裂后煤储层裂缝网络渗透率变化是不争的事实,解释结果更加可靠.如果忽略压后关井期间煤层裂缝网络渗透率的变化过程,评价的裂缝网络稳定的渗透率及原始煤储层压力会偏高.该方法在确定原始煤储层压力的同时,还可以确定煤储层压裂后裂缝网络稳定的渗透率并评价裂缝网络渗透率变化趋势,为煤层气藏类型划分、煤层气储量计算、压裂效果评价和排采制度优化设计提供依据.

In order to accurately predict the production performance of coalbed methane (CBM) wells and to formulate a reasonable production system, this paper established a coal reservoir permeability model considering the influence of pulverized coal blockage. Then, on the basis of this model, the flow velocity sensitivity (FVS) experimental data of 15 groups of coal samples taken from the Baode Block, Qinshui Basin, Liulin Block, Hancheng Block, and the Huanglong Coalfield were fitted to determine the permeability models for different coal samples. On this basis, this newly established permeability model was incorporated into a previously developed CBM well performance analysis software, and production history matching was carried out on two CBM wells. Finally, the effects of the parameters of pulverized coal blockage on the permeability of coal reservoirs and the production performance of CBM wells were studied by taking the fitting parameters of CBM Well W1 as the reference. And the following research results are obtained. First, this new model considering the influence of pulverized coal blockage can quantitatively describe the variation of coal reservoir permeability with fluid velocity. In addition, this model can be incorporated into a CBM numerical simulation software or a CBM well performance analysis software to apply it in a wide range. Second, the coal reservoir permeability is less affected by pulverized coal blockage in the Baode Block, but this effect shall not be ignored in the Qinshui Basin and the Huanglong Coalfield. Third, the greater the theoretical maximum permeability damage degree (Dmax) and the permeability damage degree index (n) are, the lower the relative flow velocity (v0.5) corresponding to the critical flow velocity of pulverized coal blockage is and the more obvious the effect of pulverized coal blockage on coal reservoir permeability is. Fourth, in order to reduce the adverse effect of pulverized coal blockage on coal reservoir permeability, it is suggested to reduce the production pressure difference appropriately in the process of production, especially in the initial stage of gas production, so as to avoid severe damage to coal reservoir permeability.

针对鄂尔多斯盆地东缘临兴-神府区块3种典型的煤系储层岩性组合赋存模式,利用数值模拟方法,分析射孔位置与射孔打开程度对裂缝在层间、层内扩展延伸能力的影响,以裂缝穿层扩展能力和裂缝延伸长度为评价指标,研究了砂岩-煤层接触、砂岩-煤层-泥岩互层和煤层-砂岩-煤层多煤层3种模式下的多储层合层压裂射孔方案,提高煤系储层油气资源综合利用效率.结果表明:层间界面对能量的传播产生明显的负效应;煤层-砂岩-煤层多煤层与砂岩-煤层-泥岩互层式储层的射孔比例以50％～80％为宜;砂岩-煤层接触模式储层适宜采用间接压裂工艺,射孔方案为砂岩的70％～75％+煤层的25％～50％.该研究可为煤系多储层合层压裂射孔优化提供参考.

水平井分段压裂技术已在低渗透油气藏及煤层气开发过程中得到了较为广泛的应用,并取得了良好的经济效果.但是,由于分段压裂会使直井段的套管承受交变应力作用,进而造成其在软硬交错地层处发生严重变形,从而影响压裂安全作业,甚至引发所有剩余压裂段报废.为探索其破坏机理,开发一个类似弹簧单元的用户子程序来模拟循环荷载作用下套管-水泥环界面的受力情况,并将该单元植入到套管-水泥环-岩层系统的ABAQUS轴对称有限元模型中,模拟水平井分段压裂过程中套管的力学行为.结果表明,在软硬交错地层中,采用水平井分段压裂时,注入压力与地应力之间的交变应力差会造成套管的大变形.此外,基于ABAQUS的数值模拟结果,采用FE-safe评估套管疲劳寿命,发现处于软硬交错地层处套管的疲劳寿命最短.基于上述研究,建议在具有软硬交错地层的低渗透油藏及煤层气储层中进行分段压裂时,应设法提高非压裂阶段压力,以减轻交变应力对软硬交错地层处的套管损伤.

Efficient CO2 capture and separation, such as from natural gas, biogas, and landfill gas, is highly desirable to maximize the use of energy and alleviate carbon emission and greenhouse effect. A novel approach of charge/strain-regulated gas capture and separation has been proposed to offer the advantages of reversibility and controllable kinetics. We demonstrated the highly controllable CO2 capture and separation from CO2/CH4 on porous g-C9N7 nanosheets with varying charge densities and strains using molecular dynamics (MD) simulations and first-principle density function theory (DFT) calculations. The remarkable CO2 permeance up to 5.94 x 10(7) GPU can be achieved by charge engineering, such as through the strategies of electrochemical methods. A tunable CO2 separation performance was exhibited under the condition of tensile strain. The permeance of CO2 was found to increase with increasing the applied tensile strain, and the maximum permeance was 3.61 x 10(7) GPU with 7.5% strained g-C9N7 membrane. More interestingly, a promising approach for combining a charged state with the strain engineering was explored to investigate the synergistic effect. Under conditions of 1 e(-)-negative charge and 3% tensile strain on g-C9N7 membrane, the CO2 permeance reached 3.18 x 10(7) GPU, which was 9 times higher than only with adding 1 e(-), and 8 times higher than only applying 3% strain. Additionally, the temperature effect indicated that the g-C9N7 membrane can be served as an excellent candidate for CO2/CH4 separation at ambient conditions. These results provide useful guidance for developing advanced materials with highly controllable CO2 capture and separation properties.

To explore the influence of the capillary force in the coal matrix on the productivity, based on the dynamic capillary force of the gas and water phase, the high-pressure Hg injection method, the porous plate method, and the centrifuge method were used to analyze the No.3 coal seam of the Zhengzhuang block in the southern Qinshui Basin. Through the experimental analysis of 97 samples, 3 different capillary force models are proposed. Through data mining, it is found that when the displacement pressure is 1.247 MPa, the average residual water saturation of the sample is 89.21%; when the displacement pressure is 4.0 MPa, the residual saturation of 82.5% of the samples exceeds 80%. This means that the desorption process of adsorbed coalbed methane is subject to greater capillary force. If the capillary force cannot be overcome, the gas production of coalbed methane wells will be at a low level.

The production control of coalbed methane wells has long been viewed as the most challenging step in its development process. For human engineers, they rely too much on previous experience. For artificial intelligence, there is no complete frame to use. Here we proposed a system with reinforcement learning algorithm to CBM production control optimization that used a proxy model to simulate the gas and water seepage in coal seam, and a ‘value networks’ to evaluate gas and water production capability and three control policy mode: bottomhole pressure (BHP) regression model, BHP reduction rate mode, BHP table to select moves. The system achieved a 20.99% and 38.14% increment in cumulative gas and water production, respectively.